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Gehre F, Lagu HI, Achol E, Omari N, Ochido G, Shand K, Alvarado AM, Ruge G, Kezakarayagwa E, Kabatesi F, Ihorimbere T, Nkeshimana A, Roba A, Ndia MN, Githii SM, Kiiru JN, Samson DD, Nykwec GA, Moun IGC, Deng LL, Kelly ME, Mkama PBM, Msigwa FL, Magesa A, Pimundu G, Muyigi T, Nabadda SN, Nzeyimana E, May J, Affara M. The East African Community mobile laboratory network prepares for monkeypox outbreaks. J Public Health Afr 2023; 14:2309. [PMID: 37680705 PMCID: PMC10481785 DOI: 10.4081/jphia.2023.2309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 10/14/2022] [Indexed: 09/09/2023] Open
Abstract
In response to the largest recorded monkeypox virus outbreak outside of endemic Central and Western Africa, the East African Community (EAC), in cooperation with the Bernhard-Nocht- Institute for Tropical Medicine, coordinated an emergency monkeypox diagnostic training for the East African Region. As of June 2022, the Democratic Republic of Congo reported a steady increase of suspected monkeypox cases, increasing the risk of spill-over into the remaining six EAC Partner States. Within the existing EAC Mobile Laboratories project, laboratory experts of the National Public Health Laboratories of the remaining six EAC Partner States (Burundi, Rwanda, Tanzania, Kenya, Uganda, and South Sudan) participated in the workshop and were trained in the reception of suspect samples, DNA extraction and diagnosis using real-time polymerase chain reaction (RT-PCR). The EAC region is now equipped with the tools to prepare and rapidly respond to any emerging monkeypox outbreak.
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Affiliation(s)
- Forian Gehre
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
- East African Community (EAC), Arusha, Tanzania
| | | | | | - Neema Omari
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
- East African Community (EAC), Arusha, Tanzania
| | - Grace Ochido
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
- East African Community (EAC), Arusha, Tanzania
| | - Kerstin Shand
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Andrea Molina Alvarado
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Gerd Ruge
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Eric Kezakarayagwa
- National Institute of Public Health, Ministry of Health and Fight Against AIDS, Bujumbura, Burundi
| | - Francine Kabatesi
- National Institute of Public Health, Ministry of Health and Fight Against AIDS, Bujumbura, Burundi
| | - Théogene Ihorimbere
- National Institute of Public Health, Ministry of Health and Fight Against AIDS, Bujumbura, Burundi
| | - Anatole Nkeshimana
- National Institute of Public Health, Ministry of Health and Fight Against AIDS, Bujumbura, Burundi
| | - Abdi Roba
- National Public Health Laboratories, Ministry of Health, Nairobi, Kenya
| | | | - Susan Mahuro Githii
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - John Ndemi Kiiru
- National Public Health Laboratories, Ministry of Health, Nairobi, Kenya
| | - Donald Duku Samson
- Public Health Laboratory and National Blood Transfusion Centre, Ministry of Health, Juba, South Sudan
| | - Gwokpan Awin Nykwec
- Public Health Laboratory and National Blood Transfusion Centre, Ministry of Health, Juba, South Sudan
| | - Isaac Gatkuoth Chot Moun
- Public Health Laboratory and National Blood Transfusion Centre, Ministry of Health, Juba, South Sudan
| | - Lul Lojok Deng
- Public Health Laboratory and National Blood Transfusion Centre, Ministry of Health, Juba, South Sudan
| | - Maria Ezekiely Kelly
- Ministry of Health, Community Development, Gender, Elderly and Children, Dodoma, Tanzania
- National Health Laboratory, Quality Assurance and Training Centre, Dar es Salaam, Tanzania
| | - Peter Bernard Mtesigwa Mkama
- Ministry of Health, Community Development, Gender, Elderly and Children, Dodoma, Tanzania
- National Health Laboratory, Quality Assurance and Training Centre, Dar es Salaam, Tanzania
| | - Felician L Msigwa
- Ministry of Health, Community Development, Gender, Elderly and Children, Dodoma, Tanzania
| | - Alex Magesa
- Ministry of Health, Community Development, Gender, Elderly and Children, Dodoma, Tanzania
| | - Godfrey Pimundu
- National Health Laboratory and Diagnostic Services (NHLDS), Ministry of Health, Kampala, Uganda
| | - Tonny Muyigi
- National Health Laboratory and Diagnostic Services (NHLDS), Ministry of Health, Kampala, Uganda
| | - Susan Ndidde Nabadda
- National Health Laboratory and Diagnostic Services (NHLDS), Ministry of Health, Kampala, Uganda
| | | | - Juergen May
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
- Tropical Medicine II, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Muna Affara
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
- East African Community (EAC), Arusha, Tanzania
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Affara M, Lagu HI, Achol E, Omari N, Ochido G, Kezakarayagwa E, Kabatesi F, Nduwimana C, Nkeshimana A, Duku Samson D, Awin Nykwec G, Daniel Wani Lako J, Lasuba M, Lojok Deng L, Ezekiely Kelly M, Bernard Mtesigwa Mkama P, Magesa A, Said Ali S, Amour Rashid S, Pimundu G, Muyigi T, Ndidde Nabadda S, Rutayisire R, Kabanda A, Kabalisa E, May J, Nzeyimana E, Katende M, Gehre F. Regional Evaluation of Two SARS-CoV-2 Antigen Rapid Diagnostic Tests in East Africa. Microbiol Spectr 2023; 11:e0489522. [PMID: 37010436 PMCID: PMC10269495 DOI: 10.1128/spectrum.04895-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/24/2023] [Indexed: 04/04/2023] Open
Abstract
The clinical performance of two rapid antigen tests for the diagnosis of Severe Acute Respiratory Coronavirus (SARS-CoV-2) were regionally evaluated in East African populations. Swabs were collected from 1,432 individuals from five Partner States of the East African Community (Tanzania, Uganda, Burundi, Rwanda and South Sudan). The two rapid antigen tests (Bionote NowCheck COVID-19 Ag and SD Biosensor STANDARD Q COVID-19 Ag) were evaluated against the detection of SARS-CoV-2 RNA by the Reverse Transcription PCR (RT-PCR) gold standard. Of the concordant results with both RT-PCR and rapid antigen test data (862 for Bionote and 852 for SD Biosensor), overall clinical sensitivity was 60% and 50% for the Bionote NowCheck and the SD Biosensor STANDARD Q, respectively. Stratification by viral load, including samples with RT-PCR cycle thresholds (Ct) of <25, improved sensitivity to 90% for both rapid diagnostic tests (RDTs). Overall specificity was good at 99% for both antigen tests. Taken together, the clinical performance of both Ag-RDTs in real world settings within the East African target population was lower than has been reported elsewhere and below the acceptable levels for sensitivity of >80%, as defined by the WHO. Therefore, the rapid antigen test alone should not be used for diagnosis but could be used as part of an algorithm to identify potentially infectious individuals with high viral load. IMPORTANCE Accurate diagnostic tests are essential to both support the management and containment of outbreaks, as well as inform appropriate patient care. In the case of the SARS-CoV-2 pandemic, antigen Rapid Diagnostic Tests (Ag-RDTs) played a major role in this function, enabling widespread testing by untrained individuals, both at home and within health facilities. In East Africa, a number of SARS-CoV-2 Ag-RDTs are available; however, there remains little information on their true test performance within the region, in the hands of the health workers routinely carrying out SARS-CoV-2 diagnostics. This study contributes test performance data for two commonly used SARS-CoV-2 Ag-RDTs in East Africa, which will help inform the use of these RDTs within the region.
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Affiliation(s)
- Muna Affara
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
- East African Community (EAC), Arusha, Tanzania
| | | | | | - Neema Omari
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
- East African Community (EAC), Arusha, Tanzania
| | - Grace Ochido
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
- East African Community (EAC), Arusha, Tanzania
| | - Eric Kezakarayagwa
- National Institute of Public Health, Ministry of Health and Fight Against AIDS, Bujumbura, Burundi
| | - Francine Kabatesi
- National Institute of Public Health, Ministry of Health and Fight Against AIDS, Bujumbura, Burundi
| | - Cassien Nduwimana
- National Institute of Public Health, Ministry of Health and Fight Against AIDS, Bujumbura, Burundi
| | - Anatole Nkeshimana
- National Institute of Public Health, Ministry of Health and Fight Against AIDS, Bujumbura, Burundi
| | - Donald Duku Samson
- Public Health Laboratory and National Blood Transfusion Centre, Ministry of Health, Juba, South Sudan
| | - Gwokpan Awin Nykwec
- Public Health Laboratory and National Blood Transfusion Centre, Ministry of Health, Juba, South Sudan
| | - Joseph Daniel Wani Lako
- Public Health Laboratory and National Blood Transfusion Centre, Ministry of Health, Juba, South Sudan
| | - Michael Lasuba
- Public Health Laboratory and National Blood Transfusion Centre, Ministry of Health, Juba, South Sudan
| | - Lul Lojok Deng
- Public Health Laboratory and National Blood Transfusion Centre, Ministry of Health, Juba, South Sudan
| | - Maria Ezekiely Kelly
- Ministry of Health, Dodoma, Tanzania
- National Public Health Laboratory, Dar es Salaam, Tanzania
| | | | - Alex Magesa
- Ministry of Health, Dodoma, Tanzania
- National Public Health Laboratory, Dar es Salaam, Tanzania
| | - Salum Said Ali
- Zanzibar National Public Health Laboratory, Stonetown, Zanzibar
| | | | - Godfrey Pimundu
- National Health Laboratory and Diagnostic Services (NHLDS), Ministry of Health, Kampala, Uganda
| | - Tonny Muyigi
- National Health Laboratory and Diagnostic Services (NHLDS), Ministry of Health, Kampala, Uganda
| | - Susan Ndidde Nabadda
- National Health Laboratory and Diagnostic Services (NHLDS), Ministry of Health, Kampala, Uganda
| | | | | | | | - Jürgen May
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
- Tropical Medicine II, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | | | | | - Florian Gehre
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
- East African Community (EAC), Arusha, Tanzania
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Kelly ME, Msafiri F, Affara M, Gehre F, Moremi N, Mghamba J, Misinzo G, Thye T, Gatei W, Whistler T, Joachim A, Lema N, Santiago GA. Molecular Characterization and Phylogenetic Analysis of Dengue Fever Viruses in Three Outbreaks in Tanzania Between 2017 and 2019. PLoS Negl Trop Dis 2023; 17:e0011289. [PMID: 37099594 PMCID: PMC10166554 DOI: 10.1371/journal.pntd.0011289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 05/08/2023] [Accepted: 04/05/2023] [Indexed: 04/27/2023] Open
Abstract
BACKGROUND Dengue is a disease of public health interest, and Tanzania experienced major outbreaks in 2014 and 2019. Here, we report our findings on the molecular characterization of dengue viruses (DENV) that circulated during two smaller outbreaks (2017 and 2018) and one major epidemic (2019) in Tanzania. METHODOLOGY/PRINCIPAL FINDINGS We tested archived serum samples from 1,381 suspected dengue fever patients, with a median age of 29 (IQR:22-40) years, referred to the National Public Health Laboratory for confirmation of DENV infection. DENV serotypes were identified by reverse transcription polymerase chain reaction (RT-PCR), and specific genotypes were identified by sequencing the envelope glycoprotein gene and phylogenetic inference methods. DENV was confirmed in 823 (59.6%) cases. More than half (54.7%) of patients with dengue fever infection were males, and nearly three-quarters (73%) of the infected individuals were living in Kinondoni district, Dar es Salaam. DENV-3 Genotype III caused the two smaller outbreaks in 2017 and 2018, while DENV-1 Genotype V caused the 2019 epidemic. DENV-1 Genotype I was also detected in one patient in 2019. CONCLUSION/SIGNIFICANCE This study has demonstrated the molecular diversity of dengue viruses circulating in Tanzania. We found that contemporary circulating serotypes did not cause the major epidemic of 2019 but rather due to a serotype shift from DENV-3 (2017/2018) to DENV-1 in 2019. Such a change increases the risk for patients previously infected with a particular serotype to develop severe symptoms upon potential re-infection with a heterologous serotype due to antibody-dependent enhancement of infection. Therefore, the circulation of serotypes emphasizes the need to strengthen the country's dengue surveillance system for better management of patients, early detection of outbreaks, and vaccine development.
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Affiliation(s)
| | - Frank Msafiri
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Muna Affara
- Bernhard Nocht Institute for Tropical Medicine, Infectious Disease Epidemiology Department, Hamburg, Germany
- East African Community Secretariat, Health Department, Arusha, Tanzania
| | - Florian Gehre
- Bernhard Nocht Institute for Tropical Medicine, Infectious Disease Epidemiology Department, Hamburg, Germany
- East African Community Secretariat, Health Department, Arusha, Tanzania
| | - Nyambura Moremi
- National Public Health Laboratory, Ministry of Health, Dar es Salaam, Tanzania
| | - Janeth Mghamba
- Department of Epidemiology, Ministry of Health, Dodoma, Tanzania
| | - Gerald Misinzo
- SACIDS Foundation for One Health, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Thorsten Thye
- Bernhard Nocht Institute for Tropical Medicine, Infectious Disease Epidemiology Department, Hamburg, Germany
| | - Wangeci Gatei
- Centers for Disease Control and Prevention, Division of Global Health Protection, Atlanta, Georgia, United States of America
| | - Toni Whistler
- Centers for Disease Control and Prevention, Division of Global Health Protection, Atlanta, Georgia, United States of America
| | - Agricola Joachim
- Department of Microbiology and Immunology, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
| | - Nsiande Lema
- Tanzania Field Epidemiology and Laboratory Training Program, Dar es Salaam, Tanzania
| | - Gilberto A Santiago
- Centers for Disease Control and Prevention, Division of Vector-Borne Diseases, Dengue Branch, San Juan, Puerto Rico, United States of America
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Ahmad A, Mohammed NI, Joof F, Affara M, Jawara M, Abubakar I, Okebe J, Ceesay S, Hamid-Adiamoh M, Bradley J, Amambua-Ngwa A, Nwakanma D, D'Alessandro U. Asymptomatic Plasmodium falciparum carriage and clinical disease: a 5-year community-based longitudinal study in The Gambia. Malar J 2023; 22:82. [PMID: 36882754 PMCID: PMC9993664 DOI: 10.1186/s12936-023-04519-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 02/28/2023] [Indexed: 03/09/2023] Open
Abstract
BACKGROUND Carriers of persistent asymptomatic Plasmodium falciparum infections constitute an infectious reservoir that maintains malaria transmission. Understanding the extent of carriage and characteristics of carriers specific to endemic areas could guide use of interventions to reduce infectious reservoir. METHODS In eastern Gambia, an all-age cohort from four villages was followed up from 2012 to 2016. Each year, cross-sectional surveys were conducted at the end of the malaria transmission season (January) and just before the start of the next one (June) to determine asymptomatic P. falciparum carriage. Passive case detection was conducted during each transmission season (August to January) to determine incidence of clinical malaria. Association between carriage at the end of the season and at start of the next one and the risk factors for this were assessed. Effect of carriage before start of the season on risk of clinical malaria during the season was also examined. RESULTS A total of 1403 individuals-1154 from a semi-urban village and 249 from three rural villages were enrolled; median age was 12 years (interquartile range [IQR] 6, 30) and 12 years (IQR 7, 27) respectively. In adjusted analysis, asymptomatic P. falciparum carriage at the end of a transmission season and carriage just before start of the next one were strongly associated (adjusted odds ratio [aOR] = 19.99; 95% CI 12.57-31.77, p < 0.001). The odds of persistent carriage (i.e. infected both in January and in June) were higher in rural villages (aOR = 13.0; 95% CI 6.33-26.88, p < 0.001) and in children aged 5-15 years (aOR = 5.03; 95% CI 2.47-10.23, p = < 0.001). In the rural villages, carriage before start of the season was associated with a lower risk of clinical malaria during the season (incidence risk ratio [IRR] 0.48, 95% CI 0.27-0.81, p = 0.007). CONCLUSIONS Asymptomatic P. falciparum carriage at the end of a transmission season strongly predicted carriage just before start of the next one. Interventions that clear persistent asymptomatic infections when targeted at the subpopulation with high risk of carriage may reduce the infectious reservoir responsible for launching seasonal transmission.
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Affiliation(s)
- Abdullahi Ahmad
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia.
- Global Health Institute, University of Antwerp, Gouverneur Kinsbergencentrum, Campus Drie Eiken, Doornstraat 331, 2610, Wilrijk, Belgium.
| | - Nuredin Ibrahim Mohammed
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Fatou Joof
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Muna Affara
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Musa Jawara
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Ismaela Abubakar
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Joseph Okebe
- International Public Health Department, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Serign Ceesay
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Majidah Hamid-Adiamoh
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Alfred Amambua-Ngwa
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
| | - Davis Nwakanma
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia.
| | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O Box 273, Banjul, The Gambia
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Gehre F, Lagu H, Achol E, Omari N, Ochido G, Duraffour S, Hinzmann J, Kezakarayagwa E, Kabatesi F, Nkeshimana A, Nyandwi J, Samson DD, Nykwec GA, Lokore ML, Deng LL, Kelly ME, Mkama PBM, Magesa A, Beyanga M, Roba A, Ndia M, Lokamar P, Kiiru J, Kabanda A, Mukagatare I, Kabalisa E, Rutayisire R, Sewanyana I, Nambozo EJ, Muyigi T, Pimundu G, May J, Katende M, Nabadda S, Nzeyimana E, Affara M. The East African Community’s mobile laboratory network’s rapid response during the first 2 weeks of the Ebola Sudan virus disease (SVD) outbreak in Uganda and pandemic preparedness activities in South Sudan, Rwanda, Tanzania, Burundi, Kenya. BMJ Glob Health 2022; 7:bmjgh-2022-011073. [DOI: 10.1136/bmjgh-2022-011073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 11/19/2022] [Indexed: 12/15/2022] Open
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6
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Affara M, Lagu HI, Achol E, Karamagi R, Omari N, Ochido G, Kezakarayagwa E, Kabatesi F, Nkeshimana A, Roba A, Ndia MN, Abudo MU, Kabanda A, Mpabuka E, Mwikarago EI, Kutjok PE, Samson DD, Deng LL, Moremi N, Kelly ME, Mkama PBM, Magesa A, Balinandi SK, Pimundu G, Nabadda SN, Puradiredja DI, Hinzmann J, Duraffour S, Gabriel M, Ruge G, Loag W, Ayiko R, Sonoiya SS, May J, Katende MJ, Gehre F. The East African Community (EAC) mobile laboratory networks in Kenya, Burundi, Tanzania, Rwanda, Uganda, and South Sudan-from project implementation to outbreak response against Dengue, Ebola, COVID-19, and epidemic-prone diseases. BMC Med 2021; 19:160. [PMID: 34238298 PMCID: PMC8266482 DOI: 10.1186/s12916-021-02028-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 06/09/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND East Africa is home to 170 million people and prone to frequent outbreaks of viral haemorrhagic fevers and various bacterial diseases. A major challenge is that epidemics mostly happen in remote areas, where infrastructure for Biosecurity Level (BSL) 3/4 laboratory capacity is not available. As samples have to be transported from the outbreak area to the National Public Health Laboratories (NPHL) in the capitals or even flown to international reference centres, diagnosis is significantly delayed and epidemics emerge. MAIN TEXT The East African Community (EAC), an intergovernmental body of Burundi, Rwanda, Tanzania, Kenya, Uganda, and South Sudan, received 10 million € funding from the German Development Bank (KfW) to establish BSL3/4 capacity in the region. Between 2017 and 2020, the EAC in collaboration with the Bernhard-Nocht-Institute for Tropical Medicine (Germany) and the Partner Countries' Ministries of Health and their respective NPHLs, established a regional network of nine mobile BSL3/4 laboratories. These rapidly deployable laboratories allowed the region to reduce sample turn-around-time (from days to an average of 8h) at the centre of the outbreak and rapidly respond to epidemics. In the present article, the approach for implementing such a regional project is outlined and five major aspects (including recommendations) are described: (i) the overall project coordination activities through the EAC Secretariat and the Partner States, (ii) procurement of equipment, (iii) the established laboratory setup and diagnostic panels, (iv) regional training activities and capacity building of various stakeholders and (v) completed and ongoing field missions. The latter includes an EAC/WHO field simulation exercise that was conducted on the border between Tanzania and Kenya in June 2019, the support in molecular diagnosis during the Tanzanian Dengue outbreak in 2019, the participation in the Ugandan National Ebola response activities in Kisoro district along the Uganda/DRC border in Oct/Nov 2019 and the deployments of the laboratories to assist in SARS-CoV-2 diagnostics throughout the region since early 2020. CONCLUSIONS The established EAC mobile laboratory network allows accurate and timely diagnosis of BSL3/4 pathogens in all East African countries, important for individual patient management and to effectively contain the spread of epidemic-prone diseases.
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Affiliation(s)
- Muna Affara
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany.,East African Community (EAC), Arusha, Tanzania
| | | | | | | | - Neema Omari
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany.,East African Community (EAC), Arusha, Tanzania
| | - Grace Ochido
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany.,East African Community (EAC), Arusha, Tanzania
| | - Eric Kezakarayagwa
- National Institute of Public Health, Ministry of Health and Fight Against AIDS, Bujumbura, Burundi
| | - Francine Kabatesi
- National Institute of Public Health, Ministry of Health and Fight Against AIDS, Bujumbura, Burundi
| | - Anatole Nkeshimana
- National Institute of Public Health, Ministry of Health and Fight Against AIDS, Bujumbura, Burundi
| | - Abdi Roba
- National Public Health Laboratories, Ministry of Health, Nairobi, Kenya
| | | | - Mamo U Abudo
- National Public Health Laboratories, Ministry of Health, Nairobi, Kenya
| | - Alice Kabanda
- National Reference Laboratory Division, Rwanda Biomedical Centre, Ministry of Health, Kigali, Rwanda
| | - Etienne Mpabuka
- National Reference Laboratory Division, Rwanda Biomedical Centre, Ministry of Health, Kigali, Rwanda
| | - Emil Ivan Mwikarago
- National Reference Laboratory Division, Rwanda Biomedical Centre, Ministry of Health, Kigali, Rwanda
| | - Philip Ezekiel Kutjok
- Public Health Laboratory and National Blood Transfusion Centre, Ministry of Health, Juba, South Sudan
| | - Donald Duku Samson
- Public Health Laboratory and National Blood Transfusion Centre, Ministry of Health, Juba, South Sudan
| | - Lul Lojok Deng
- Public Health Laboratory and National Blood Transfusion Centre, Ministry of Health, Juba, South Sudan
| | - Nyambura Moremi
- Ministry of Health, Community Development, Gender, Elderly and Children, Dodoma, Tanzania.,National Health Laboratory, Quality Assurance and Training Centre, Dar es Salaam, Tanzania
| | - Maria Ezekiely Kelly
- Ministry of Health, Community Development, Gender, Elderly and Children, Dodoma, Tanzania.,National Health Laboratory, Quality Assurance and Training Centre, Dar es Salaam, Tanzania
| | - Peter Bernard Mtesigwa Mkama
- Ministry of Health, Community Development, Gender, Elderly and Children, Dodoma, Tanzania.,National Health Laboratory, Quality Assurance and Training Centre, Dar es Salaam, Tanzania
| | - Alex Magesa
- Ministry of Health, Community Development, Gender, Elderly and Children, Dodoma, Tanzania.,National Health Laboratory, Quality Assurance and Training Centre, Dar es Salaam, Tanzania
| | | | - Godfrey Pimundu
- National Health Laboratory and Diagnostic Services (NHLDS), Ministry of Health, Kampala, Uganda
| | - Susan Ndidde Nabadda
- National Health Laboratory and Diagnostic Services (NHLDS), Ministry of Health, Kampala, Uganda
| | - Dewi Ismajani Puradiredja
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Julia Hinzmann
- Virology Department, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany.,German Center for Infection Research (DZIF), partner site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Sophie Duraffour
- Virology Department, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany.,German Center for Infection Research (DZIF), partner site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Martin Gabriel
- Virology Department, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany.,German Center for Infection Research (DZIF), partner site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany
| | - Gerd Ruge
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Wibke Loag
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | | | | | - Juergen May
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany.,German Center for Infection Research (DZIF), partner site Hamburg-Lübeck-Borstel-Riems, Hamburg, Germany.,Tropical Medicine II, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | | | - Florian Gehre
- Department for Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany. .,East African Community (EAC), Arusha, Tanzania.
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Njenge H, Copper F, Bell A, Charles D, Mullen L, de Vázquez CC, Wesonga T, Wakhungu JN, Katende M, Komba EA, Kituyi PNN, Mmbaga V, Nguvila T, Makata MA, Chinyuka H, de La Rocque S, Sreedharan R, Stephen M, Mayigane LN, Saguti GEB, Ganda N, Gachohi J, Nyaberi JM, Kabanda D, Marwa F, Mwatondo A, Mukora GG, Muinde JM, Komora S, Msangi C, Malinda BL, Uiso V, Mwaipopo C, Dulu TD, Gehre F, Affara M, Mutabazi F, Balikowa D, Kiarie SW, Kivuva J, Wambua C, Were W, Nyakundi PM, Makayotto L, Njoroge M, Kebaki GM, Swai ES, Mwakyusa EK, Kauki G, Fasina FO, Byoona K, Woldetsadik SF, Allan M, Wekesa J, Nanyunja M, Mutoka FB, Knaggs D, Nsenga N, Yahaya AA, Talisuna A, Omaar A, Ho ZJM, Kandel N, Chungong S. Lessons Learned From a Large Cross-Border Field Simulation Exercise to Strengthen Emergency Preparedness in East Africa, 2019. Health Secur 2021; 19:413-423. [PMID: 34339258 DOI: 10.1089/hs.2020.0162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Field simulation exercises (FSXs) require substantial time, resources, and organizational experience to plan and implement and are less commonly undertaken than drills or tabletop exercises. Despite this, FSXs provide an opportunity to test the full scope of operational capacities, including coordination across sectors. From June 11 to 14, 2019, the East African Community Secretariat conducted a cross-border FSX at the Namanga One Stop Border Post between the Republic of Kenya and the United Republic of Tanzania. The World Health Organization Department of Health Security Preparedness was the technical lead responsible for developing and coordinating the exercise. The purpose of the FSX was to assess and further enhance multisectoral outbreak preparedness and response in the East Africa Region, using a One Health approach. Participants included staff from the transport, police and customs, public health, animal health, and food inspection sectors. This was the first FSX of this scale, magnitude, and complexity to be conducted in East Africa for the purpose of strengthening emergency preparedness capacities. The FSX provided an opportunity for individual learning and national capacity strengthening in emergency management and response coordination. In this article, we describe lessons learned and propose recommendations relevant to FSX design, management, and organization to inform future field exercises.
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Gehre F, Lagu H, Achol E, Katende M, May J, Affara M. Commentary: mobile laboratories for SARS-CoV-2 diagnostics: what Europe could learn from the East African Community to assure trade in times of border closures. Global Health 2021; 17:49. [PMID: 33892773 PMCID: PMC8063167 DOI: 10.1186/s12992-021-00700-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 04/12/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The emergence of SARS-CoV-2 mutants might lead to European border closures, which impact on trade and result in serious economic losses. In April 2020, similar border closures were observed during the first SARS-CoV-2 wave in East Africa. MAIN BODY Since 2017 the East African Community EAC together with the Bernhard-Nocht-Institute for Tropical Medicine BNITM established a mobile laboratory network integrated into the National Public Health Laboratories of the six Partner States for molecular diagnosis of viral haemorrhagic fevers and SARS-CoV-2. Since May 2020, the National Public Health Laboratories of Kenya, Rwanda, Burundi, Uganda and South Sudan deployed these mobile laboratories to their respective borders, issuing a newly developed "Electronic EAC COVID-19 Digital Certificate" to SARS-CoV-2 PCR-negative truck drivers, thus assuring regional trade. CONCLUSION Considering the large financial damages of border closures, such a mobile laboratory network as demonstrated in East Africa is cost-effective, easy to implement and feasible. The East African Community mobile laboratory network could serve as a blueprint for Europe and other countries around the globe.
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Affiliation(s)
- Florian Gehre
- Department of Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany.
- East African Community Secretariat, Health Department, Arusha, Tanzania.
| | - Hakim Lagu
- East African Community Secretariat, Health Department, Arusha, Tanzania
| | - Emmanuel Achol
- East African Community Secretariat, Health Department, Arusha, Tanzania
| | - Michael Katende
- East African Community Secretariat, Health Department, Arusha, Tanzania
| | - Jürgen May
- Department of Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
- Tropical Medicine II, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
- German Center for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany
| | - Muna Affara
- Department of Infectious Disease Epidemiology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
- East African Community Secretariat, Health Department, Arusha, Tanzania
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Sepúlveda N, Grignard L, Curry J, Mahey L, Bastiaens GJH, Tiono AB, Okebe J, Coulibaly SA, Gonçalves BP, Affara M, Ouédraogo A, Bougouma EC, Sanou GS, Nébié I, Lanke K, Sirima SB, Dicko A, d’Alessandro U, Clark TG, Campino S, Chen I, Eziefula AC, Gosling R, Bousema T, Drakeley C. G6PD Polymorphisms and Hemolysis After Antimalarial Treatment With Low Single-Dose Primaquine: A Pooled Analysis of Six African Clinical Trials. Front Genet 2021; 12:645688. [PMID: 33897764 PMCID: PMC8062977 DOI: 10.3389/fgene.2021.645688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 02/23/2021] [Indexed: 11/13/2022] Open
Abstract
Primaquine (PQ) is an antimalarial drug with the potential to reduce malaria transmission due to its capacity to clear mature Plasmodium falciparum gametocytes in the human host. However, the large-scale roll-out of PQ has to be counterbalanced by the additional risk of drug-induced hemolysis in individuals suffering from Glucose-6-phospate dehydrogenase (G6PD) deficiency, a genetic condition determined by polymorphisms on the X-linked G6PD gene. Most studies on G6PD deficiency and PQ-associated hemolysis focused on the G6PD A- variant, a combination of the two single nucleotide changes G202A (rs1050828) and A376G (rs1050829), although other polymorphisms may play a role. In this study, we tested the association of 20 G6PD single nucleotide polymorphisms (SNPs) with hemolysis measured seven days after low single dose of PQ given at the dose of 0.1 mg/kg to 0.75 mg/kg in 957 individuals from 6 previously published clinical trials investigating the safety and efficacy of this drug spanning five African countries. After adjusting for inter-study effects, age, gender, baseline hemoglobin level, PQ dose, and parasitemia at screening, our analysis showed putative association signals from the common G6PD mutation, A376G [-log10(p-value) = 2.44] and two less-known SNPs, rs2230037 [-log10(p-value] = 2.60), and rs28470352 [-log10(p-value) = 2.15]; A376G and rs2230037 were in very strong linkage disequilibrium with each other (R 2 = 0.978). However, when the effects of these SNPs were included in the same regression model, the subsequent associations were in the borderline of statistical significance. In conclusion, whilst a role for the A- variant is well established, we did not observe an important additional role for other G6PD polymorphisms in determining post-treatment hemolysis in individuals treated with low single-dose PQ.
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Affiliation(s)
- Nuno Sepúlveda
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- CEAUL – Centro de Estatística e Aplicações da Universidade de Lisboa, Lisbon, Portugal
| | - Lynn Grignard
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | | | - Guido J. H. Bastiaens
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Alfred B. Tiono
- Department of Public Health, Centre National de Recherche et de Formation sur le Paludisme & Institut National de Santé Publique, Ouagadougou, Burkina Faso
| | - Joseph Okebe
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Sam A. Coulibaly
- Department of Public Health, Centre National de Recherche et de Formation sur le Paludisme & Institut National de Santé Publique, Ouagadougou, Burkina Faso
| | - Bronner P. Gonçalves
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Muna Affara
- MRC Unit The Gambia at the London School of Hygiene & Tropical Medicine, Fajara, Gambia
| | - Alphonse Ouédraogo
- Department of Public Health, Centre National de Recherche et de Formation sur le Paludisme & Institut National de Santé Publique, Ouagadougou, Burkina Faso
| | - Edith C. Bougouma
- Department of Public Health, Centre National de Recherche et de Formation sur le Paludisme & Institut National de Santé Publique, Ouagadougou, Burkina Faso
| | - Guillaume S. Sanou
- Department of Public Health, Centre National de Recherche et de Formation sur le Paludisme & Institut National de Santé Publique, Ouagadougou, Burkina Faso
| | - Issa Nébié
- Department of Public Health, Centre National de Recherche et de Formation sur le Paludisme & Institut National de Santé Publique, Ouagadougou, Burkina Faso
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Sodiomon B. Sirima
- Department of Public Health, Centre National de Recherche et de Formation sur le Paludisme & Institut National de Santé Publique, Ouagadougou, Burkina Faso
| | - Alassane Dicko
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Sciences, Techniques and Technology of Bamako, Bamako, Mali
| | - Umberto d’Alessandro
- MRC Unit The Gambia at the London School of Hygiene & Tropical Medicine, Fajara, Gambia
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Taane G. Clark
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Susana Campino
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Ingrid Chen
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, United States
| | - Alice C. Eziefula
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Global Health and Infection, Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom
| | - Roly Gosling
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, United States
| | - Teun Bousema
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Chris Drakeley
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Pinder M, Bradley J, Jawara M, Affara M, Conteh L, Correa S, Jeffries D, Jones C, Kandeh B, Knudsen J, Olatunji Y, Sicuri E, D'Alessandro U, Lindsay SW. Improved housing versus usual practice for additional protection against clinical malaria in The Gambia (RooPfs): a household-randomised controlled trial. Lancet Planet Health 2021; 5:e220-e229. [PMID: 33838737 PMCID: PMC8051018 DOI: 10.1016/s2542-5196(21)00002-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 12/21/2020] [Accepted: 12/21/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND In malaria-endemic areas, residents of modern houses have less malaria than those living in traditional houses. We aimed to assess whether children in The Gambia received an incremental benefit from improved housing, where current best practice of insecticide-treated nets, indoor residual spraying, seasonal malaria chemoprevention in children younger than 5 years, and prompt treatment against clinical malaria was in place. METHODS In this randomised controlled study, 800 households with traditional thatched-roofed houses were randomly selected from 91 villages in the Upper River Region of The Gambia. Within each village, equal numbers of houses were randomly allocated to the control and intervention groups using a sampling frame. Houses in the intervention group were modified with metal roofs and screened doors and windows, whereas houses in the control group received no modifications. In each group, clinical malaria in children aged 6 months to 13 years was monitored by active case detection over 2 years (2016-17). We did monthly collections from indoor light traps to estimate vector densities. Primary endpoints were the incidence of clinical malaria in study children with more than 50% of observations each year and household vector density. The trial is registered at ISRCTN02622179. FINDINGS In June, 2016, 785 houses had one child each recruited into the study (398 in unmodified houses and 402 in modified houses). 26 children in unmodified houses and 28 children in modified houses did not have at least 50% of visits in a year and so were excluded from analysis. 38 children in unmodified houses were recruited after study commencement, as were 21 children in modified houses, meaning 410 children in unmodified houses and 395 in modified houses were included in the parasitological analyses. At the end of the study, 659 (94%) of 702 children were reported to have slept under an insecticide-treated net; 662 (88%) of 755 children lived in houses that received indoor residual spraying; and 151 (90%) of 168 children younger than 5 years had seasonal malaria chemoprevention. Incidence of clinical malaria was 0·12 episodes per child-year in children in the unmodified houses and 0·20 episodes per child-year in the modified houses (unadjusted incidence rate ratio [RR] 1·68 [95% CI 1·11-2·55], p=0·014). Household vector density was 3·30 Anopheles gambiae per house per night in the unmodified houses compared with 3·60 in modified houses (unadjusted RR 1·28 [0·87-1·89], p=0·21). INTERPRETATION Improved housing did not provide protection against clinical malaria in this area of low seasonal transmission with high coverage of insecticide-treated nets, indoor residual spraying, and seasonal malaria chemoprevention. FUNDING Global Health Trials funded by Medical Research Council, UK Department for International Development, and Wellcome Trust.
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Affiliation(s)
- Margaret Pinder
- Department of Biosciences, Durham University, Durham, UK; Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - John Bradley
- MRC Tropical Epidemiology Group, London School of Hygiene & Tropical Medicine, London, UK
| | - Musa Jawara
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - Muna Affara
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia; Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Lesong Conteh
- London School of Economics and Political Science, London, UK
| | - Simon Correa
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - David Jeffries
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - Caroline Jones
- KEMRI-Wellcome Trust Programme, Kilifi, Kenya and Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Balla Kandeh
- National Malaria Control Programme, Banjul, The Gambia
| | - Jakob Knudsen
- Royal Danish Academy - Architecture, Design, Conservation, Copenhagen, Denmark
| | - Yekini Olatunji
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia
| | - Elisa Sicuri
- School of Public Health, Imperial College London, London, UK; ISGlobal, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
| | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, The Gambia; Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Steve W Lindsay
- Department of Biosciences, Durham University, Durham, UK; Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK.
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Wu L, Mwesigwa J, Affara M, Bah M, Correa S, Hall T, Singh SK, Beeson JG, Tetteh KKA, Kleinschmidt I, D’Alessandro U, Drakeley C. Sero-epidemiological evaluation of malaria transmission in The Gambia before and after mass drug administration. BMC Med 2020; 18:331. [PMID: 33183292 PMCID: PMC7664049 DOI: 10.1186/s12916-020-01785-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 09/16/2020] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND As The Gambia aims to achieve malaria elimination by 2030, serological assays are a useful surveillance tool to monitor trends in malaria incidence and evaluate community-based interventions. METHODS Within a mass drug administration (MDA) study in The Gambia, where reduced malaria infection and clinical disease were observed after the intervention, a serological sub-study was conducted in four study villages. Spatio-temporal variation in transmission was measured with a panel of recombinant Pf antigens on a multiplexed bead-based assay. Village-level antibody levels were quantified as under-15 sero-prevalence, sero-conversion rates, and age-adjusted antibody acquisition rates. Antibody levels prior to MDA were assessed for association with persistent malaria infection after community chemoprophylaxis. RESULTS Seasonal changes in antibodies to Etramp5.Ag1 were observed in children under 15 years in two transmission settings-the West Coast and Upper River Regions (4.32% and 31.30% Pf prevalence, respectively). At the end of the malaria season, short-lived antibody responses to Etramp5.Ag1, GEXP18, HSP40.Ag1, EBA175 RIII-V, and Rh2.2030 were lower amongst 1-15 year olds in the West Coast compared to the Upper River, reflecting known differences in transmission. Prior to MDA, individuals in the top 50th percentile of antibody levels had two-fold higher odds of clinical malaria during the transmission season, consistent with previous findings from the Malaria Transmission Dynamics Study, where individuals infected before the implementation of MDA had two-fold higher odds of re-infection post-MDA. CONCLUSIONS Serological markers can serve dual functions as indicators of malaria exposure and incidence. By monitoring age-specific sero-prevalence, the magnitude of age-stratified antibody levels, or identifying groups of individuals with above-average antibody responses, these antigens have the potential to complement conventional malaria surveillance tools. Further studies, particularly cluster randomised trials, can help establish standardised serological protocols to reliably measure transmission across endemic settings.
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Affiliation(s)
- Lindsey Wu
- Faculty of Infectious Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT UK
| | - Julia Mwesigwa
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Muna Affara
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Arusha, Tanzania
| | - Mamadou Bah
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Simon Correa
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Tom Hall
- St. George’s University of London (SGUL), London, SW17 0RE UK
| | - Susheel K. Singh
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
- Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - James G. Beeson
- Burnet Institute, Melbourne, Victoria 3004 Australia
- Central Clinical School, Monash University, Melbourne, Victoria Australia
- Department of Medicine, University of Melbourne, Melbourne, Victoria Australia
| | - Kevin K. A. Tetteh
- Faculty of Infectious Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT UK
| | - Immo Kleinschmidt
- Faculty of Epidemiology and Population Health, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT UK
- School of Pathology, Wits Institute for Malaria Research, Faculty of Health Science, University of Witwatersrand, Johannesburg, South Africa
| | - Umberto D’Alessandro
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Chris Drakeley
- Faculty of Infectious Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT UK
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12
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Wu L, Mwesigwa J, Affara M, Bah M, Correa S, Hall T, Singh SK, Beeson JG, Tetteh KKA, Kleinschmidt I, D'Alessandro U, Drakeley C. Antibody responses to a suite of novel serological markers for malaria surveillance demonstrate strong correlation with clinical and parasitological infection across seasons and transmission settings in The Gambia. BMC Med 2020; 18:304. [PMID: 32972398 PMCID: PMC7517687 DOI: 10.1186/s12916-020-01724-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/30/2020] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND As malaria transmission declines, sensitive diagnostics are needed to evaluate interventions and monitor transmission. Serological assays measuring malaria antibody responses offer a cost-effective detection method to supplement existing surveillance tools. METHODS A prospective cohort study was conducted from 2013 to 2015 in 12 villages across five administrative regions in The Gambia. Serological analysis included samples from the West Coast Region at the start and end of the season (July and December 2013) and from the Upper River Region in July and December 2013 and April and December 2014. Antigen-specific antibody responses to eight Plasmodium falciparum (P. falciparum) antigens-Etramp5.Ag1, GEXP18, HSP40.Ag1, Rh2.2030, EBA175 RIII-V, PfMSP119, PfAMA1, and PfGLURP.R2-were quantified using a multiplexed bead-based assay. The association between antibody responses and clinical and parasitological endpoints was estimated at the individual, household, and population level. RESULTS Strong associations were observed between clinical malaria and concurrent sero-positivity to Etramp5.Ag1 (aOR 4.60 95% CI 2.98-7.12), PfMSP119 (aOR 4.09 95% CI 2.60-6.44), PfAMA1 (aOR 2.32 95% CI 1.40-3.85), and PfGLURP.R2 (aOR 3.12, 95% CI 2.92-4.95), while asymptomatic infection was associated with sero-positivity to all antigens. Village-level sero-prevalence amongst children 2-10 years against Etramp5.Ag1, HSP40.Ag1, and PfMSP119 showed the highest correlations with clinical and P. falciparum infection incidence rates. For all antigens, there were increased odds of asymptomatic P. falciparum infection in subjects residing in a compound with greater than 50% sero-prevalence, with a 2- to 3-fold increase in odds of infection associated with Etramp5.Ag1, GEXP18, Rh2.2030, PfMSP119, and PfAMA1. For individuals residing in sero-positive compounds, the odds of clinical malaria were reduced, suggesting a protective effect. CONCLUSIONS At low transmission, long-lived antibody responses could indicate foci of malaria transmission that have been ongoing for several seasons or years. In settings where sub-patent infections are prevalent and fluctuate below the detection limit of polymerase chain reaction (PCR), the presence of short-lived antibodies may indicate recent infectivity, particularly in the dry season when clinical cases are rare. Serological responses may reflect a persistent reservoir of infection, warranting community-targeted interventions if individuals are not clinically apparent but have the potential to transmit. Therefore, serological surveillance at the individual and household level may be used to target interventions where there are foci of asymptomatically infected individuals, such as by measuring the magnitude of age-stratified antibody levels or identifying areas with clustering of above-average antibody responses across a diverse range of serological markers.
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Affiliation(s)
- Lindsey Wu
- Faculty of Infectious Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT, UK.
| | - Julia Mwesigwa
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Muna Affara
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Arusha, Tanzania
| | - Mamadou Bah
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Simon Correa
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Tom Hall
- St. George's University of London (SGUL), London, UK
| | - Susheel K Singh
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark.,Centre for Medical Parasitology at Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - James G Beeson
- Burnet Institute, Melbourne, Australia.,Central Clinical School, Monash University, Melbourne, Victoria, Australia.,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
| | - Kevin K A Tetteh
- Faculty of Infectious Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT, UK
| | - Immo Kleinschmidt
- Faculty of Epidemiology and Population Health, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT, UK.,School of Pathology, Wits Institute for Malaria Research, Faculty of Health Science, University of Witwatersrand, Johannesburg, South Africa
| | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Chris Drakeley
- Faculty of Infectious Tropical Diseases, Department of Infection Biology, London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT, UK
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Mwesigwa J, Achan J, Affara M, Wathuo M, Worwui A, Mohammed NI, Kanuteh F, Prom A, Dierickx S, di Tanna GL, Nwakanma D, Bousema T, Drakeley C, Van Geertruyden JP, D'Alessandro U. Mass Drug Administration With Dihydroartemisinin-piperaquine and Malaria Transmission Dynamics in The Gambia: A Prospective Cohort Study. Clin Infect Dis 2020; 69:278-286. [PMID: 30304511 PMCID: PMC6603267 DOI: 10.1093/cid/ciy870] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 10/05/2018] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Mass drug administration (MDA) may further reduce malaria transmission in low-transmission areas. The impact of MDA on the dynamics of malaria transmission was determined in a prospective cohort study. METHODS Annual rounds of MDA with dihydroartemisinin-piperaquine (DP) were implemented were implemented in 2014 and 2015 in six village pairs before the malaria transmission season. Blood samples were collected from residents between July and December for microscopy and nested PCR. Incidence and prevalence of infection, clinical disease, and risk of malaria reinfection post-MDA were determined. RESULTS Coverage of three DP doses was 68.2% (2014) and 65.6% (2015), compliance was greater than 80%. Incidence of infection was significantly lower in 2014 (incidence rate [IR] = 0.2 per person year [PPY]) than in 2013 (IR = 1.1 PPY; P < .01); monthly infection prevalence declined in the first three months post-MDA. Clinical malaria incidence was lower in 2014 (IR = 0.1 PPY) and 2015 (IR = 0.2 PPY) than in 2013 (IR = 0.4 PPY; P < .01), but remained higher in eastern Gambia. Individuals infected before MDA had a 2-fold higher odds of reinfection post-MDA (adjusted odds ratio = 2.5, 95% confidence interval 1.5-4.3; P < .01). CONCLUSIONS MDA reduced malaria infection and clinical disease during the first months. The reduction was maintained in low-transmission areas, but not in eastern Gambia. Annual MDA could be followed by focal MDA targeting individuals infected during the dry season. Repeated MDA rounds, some during the dry season over larger geographical areas, may result in a more marked and sustained decrease of malaria transmission.
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Affiliation(s)
- Julia Mwesigwa
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul.,Department of Global Health, Faculty of Medicine and Health Sciences, University of Antwerp
| | - Jane Achan
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Muna Affara
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Miriam Wathuo
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Archibald Worwui
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Nuredin Ibrahim Mohammed
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Fatoumatta Kanuteh
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Aurelia Prom
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Susan Dierickx
- Centre of Expertise on Gender, Diversity and Intersectionality, Brussels University, Belgium
| | - Gian Luca di Tanna
- Risk Centre, Institut de Recerca en Economia Aplicada, Department of Econometrics, Statistics and Applied Economics, Universitat de Barcelona, Spain
| | - Davis Nwakanma
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Chris Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
| | | | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Banjul.,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, United Kingdom
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14
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Guest C, Pinder M, Doggett M, Squires C, Affara M, Kandeh B, Dewhirst S, Morant SV, D'Alessandro U, Logan JG, Lindsay SW. Trained dogs identify people with malaria parasites by their odour. Lancet Infect Dis 2020; 19:578-580. [PMID: 31122774 DOI: 10.1016/s1473-3099(19)30220-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 04/17/2019] [Indexed: 01/18/2023]
Affiliation(s)
| | | | | | - Chelci Squires
- ARCTEC, Chariot Innovations, London School of Hygiene and Tropical Medicine, London, UK
| | - Muna Affara
- Medical Research Councils Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Balla Kandeh
- National Malaria Control Programme, Banjul, The Gambia
| | - Sarah Dewhirst
- ARCTEC, Chariot Innovations, London School of Hygiene and Tropical Medicine, London, UK
| | - Steven V Morant
- Medicines Monitoring Unit, Medical Research Institute, University of Dundee, Dundee, UK
| | - Umberto D'Alessandro
- Medical Research Councils Unit The Gambia at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - James G Logan
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
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15
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Wu L, Hall T, Ssewanyana I, Oulton T, Patterson C, Vasileva H, Singh S, Affara M, Mwesigwa J, Correa S, Bah M, D'Alessandro U, Sepúlveda N, Drakeley C, Tetteh KKA. Optimisation and standardisation of a multiplex immunoassay of diverse Plasmodium falciparum antigens to assess changes in malaria transmission using sero-epidemiology. Wellcome Open Res 2020; 4:26. [PMID: 32518839 PMCID: PMC7255915 DOI: 10.12688/wellcomeopenres.14950.1] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2020] [Indexed: 09/12/2023] Open
Abstract
Background: Antibody responses have been used to characterise transmission and exposure history in malaria-endemic settings for over a decade. Such studies have typically been conducted on well-standardised enzyme-linked immunosorbent assays (ELISAs). However, recently developed quantitative suspension array technologies (qSAT) are now capable of high-throughput and multiplexed screening of up to hundreds of analytes at a time. This study presents a customised protocol for the Luminex MAGPIX © qSAT using a diverse set of malaria antigens. The aim is to develop a standardised assay for routine serological surveillance that is implementable across laboratories and epidemiological settings. Methods: A panel of eight Plasmodium falciparum recombinant antigens, associated with long- and short-lived antibody responses, was designed for the Luminex MAGPIX © platform. The assay was optimised for key steps in the protocol: antigen-bead coupling concentration, buffer composition, serum sample dilution, and bead storage conditions. Quality control procedures and data normalisation methods were developed to address high-throughput assay processing. Antigen-specific limits of quantification (LOQs) were also estimated using both in-house and WHO reference serum as positive controls. Results: Antigen-specific bead coupling was optimised across five serum dilutions and two positive controls, resulting in concentrations operational within stable analytical ranges. Coupled beads were stable after storage at room temperature (22⁰C) for up to eight weeks. High sensitivity and specificity for distinguishing positive and negative controls at serum sample dilutions of 1:500 (AUC 0.94 95%CI 0.91-0.96) and 1:1000 (AUC 0.96 95%CI 0.94-0.98) were observed. LOQs were also successfully estimated for all analytes but varied by antigen and positive control. Conclusions: This study demonstrates that developing a standardised malaria-specific qSAT protocol for a diverse set of antigens is achievable, though further optimisations may be required. Quality control and data standardisation methods may also be useful for future analysis of large sero-epidemiological surveys.
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Affiliation(s)
- Lindsey Wu
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Tom Hall
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Isaac Ssewanyana
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
- Infectious Diseases Research Collaboration (IDRC), Kampala, P O. Box 7475, Uganda
| | - Tate Oulton
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Catriona Patterson
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Hristina Vasileva
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Susheel Singh
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
- Centre for Medical Parasitology at Department of International Health, University of Copenhagen, Copenhagen, Denmark
| | - Muna Affara
- Infectious Disease Epidemiology Department, Bernhard Nocht Institute for Tropical Medicine, Hamburg, 20359, Germany
| | - Julia Mwesigwa
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Simon Correa
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Mamadou Bah
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Umberto D'Alessandro
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Nuno Sepúlveda
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Kevin K A Tetteh
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
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16
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Wu L, Hall T, Ssewanyana I, Oulton T, Patterson C, Vasileva H, Singh S, Affara M, Mwesigwa J, Correa S, Bah M, D'Alessandro U, Sepúlveda N, Drakeley C, Tetteh KKA. Optimisation and standardisation of a multiplex immunoassay of diverse Plasmodium falciparum antigens to assess changes in malaria transmission using sero-epidemiology. Wellcome Open Res 2020; 4:26. [PMID: 32518839 PMCID: PMC7255915 DOI: 10.12688/wellcomeopenres.14950.2] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2020] [Indexed: 11/30/2022] Open
Abstract
Background: Antibody responses have been used to characterise transmission and exposure history in malaria-endemic settings for over a decade. Such studies have typically been conducted on well-standardised enzyme-linked immunosorbent assays (ELISAs). However, recently developed quantitative suspension array technologies (qSAT) are now capable of high-throughput and multiplexed screening of up to hundreds of analytes at a time. This study presents a customised protocol for the Luminex MAGPIX
© qSAT using a diverse set of malaria antigens. The aim is to develop a standardised assay for routine serological surveillance that is implementable across laboratories and epidemiological settings. Methods: A panel of eight
Plasmodium falciparum recombinant antigens, associated with long- and short-lived antibody responses, was designed for the Luminex MAGPIX
© platform. The assay was optimised for key steps in the protocol: antigen-bead coupling concentration, buffer composition, serum sample dilution, and bead storage conditions. Quality control procedures and data normalisation methods were developed to address high-throughput assay processing. Antigen-specific limits of quantification (LOQs) were also estimated using both in-house and WHO reference serum as positive controls. Results: Antigen-specific bead coupling was optimised across five serum dilutions and two positive controls, resulting in concentrations operational within stable analytical ranges. Coupled beads were stable after storage at room temperature (22⁰C) for up to eight weeks. High sensitivity and specificity for distinguishing positive and negative controls at serum sample dilutions of 1:500 (AUC 0.94 95%CI 0.91-0.96) and 1:1000 (AUC 0.96 95%CI 0.94-0.98) were observed. LOQs were also successfully estimated for all analytes but varied by antigen and positive control. Conclusions: This study demonstrates that developing a standardised malaria-specific qSAT protocol for a diverse set of antigens is achievable, though further optimisations may be required. Quality control and data standardisation methods may also be useful for future analysis of large sero-epidemiological surveys.
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Affiliation(s)
- Lindsey Wu
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Tom Hall
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Isaac Ssewanyana
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK.,Infectious Diseases Research Collaboration (IDRC), Kampala, P O. Box 7475, Uganda
| | - Tate Oulton
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Catriona Patterson
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Hristina Vasileva
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Susheel Singh
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark.,Centre for Medical Parasitology at Department of International Health, University of Copenhagen, Copenhagen, Denmark
| | - Muna Affara
- Infectious Disease Epidemiology Department, Bernhard Nocht Institute for Tropical Medicine, Hamburg, 20359, Germany
| | - Julia Mwesigwa
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Simon Correa
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Mamadou Bah
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Umberto D'Alessandro
- MRC Unit at the London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Nuno Sepúlveda
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Kevin K A Tetteh
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
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17
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Ant T, Foley E, Tytheridge S, Johnston C, Goncalves A, Ceesay S, Ndiath MO, Affara M, Martinez J, Pretorius E, Grundy C, Rodrigues A, Djata P, d'Alessandro U, Bailey R, Mabey D, Last A, Logan JG. A survey of Anopheles species composition and insecticide resistance on the island of Bubaque, Bijagos Archipelago, Guinea-Bissau. Malar J 2020; 19:27. [PMID: 31941507 PMCID: PMC6964033 DOI: 10.1186/s12936-020-3115-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 01/10/2020] [Indexed: 11/10/2022] Open
Abstract
Background Bubaque is the most populous island of the Bijagos archipelago, a group of malaria-endemic islands situated off the coast of Guinea-Bissau, West Africa. Malaria vector control on Bubaque relies almost exclusively on the use of long-lasting insecticidal nets (LLINs). However, there is little information on local vector bionomics and insecticide resistance. Methods A survey of mosquito species composition was performed at the onset of the wet season (June/July) and the beginning of the dry season (November/December). Sampling was performed using indoor adult light-traps and larval dipping. Anopheles mosquitoes were identified to species level and assessed for kdr allele frequency by TaqMan PCR. Females were analysed for sporozoite positivity by CSP-ELISA. Resistance to permethrin and α-cypermethrin was measured using the CDC-bottle bioassay incorporating the synergist piperonyl-butoxide. Results Several Anopheles species were found on the island, all belonging to the Anopheles gambiae sensu lato (s.l.) complex, including An. gambiae sensu stricto, Anopheles coluzzii, Anopheles melas, and An. gambiae/An. coluzzii hybrids. Endophagic Anopheles species composition and abundance showed strong seasonal variation, with a majority of An. gambiae (50% of adults collected) caught in June/July, while An. melas was dominant in November/December (83.9% of adults collected). Anopheles gambiae had the highest sporozoite rate in both seasons, with infection rates of 13.9% and 20% in June/July and November/December, respectively. Moderate frequencies of the West African kdr allele were found in An. gambiae (36%), An. coluzzii (35%), An. gambiae/An. coluzzii hybrids (42%). Bioassays suggest moderate resistance to α-cypermethrin, but full susceptibility to permethrin. Conclusions The island of Bubaque maintained an An. gambiae s.l. population in both June/July and November/December. Anopheles gambiae was the primary vector at the onset of the wet season, while An. melas is likely to be responsible for most dry season transmission. There was moderate kdr allele frequency and synergist assays suggest likely metabolic resistance, which could reduce the efficacy of LLINs. Future control of malaria on the islands should consider the seasonal shift in mosquito species, and should employ continuous monitoring for insecticide resistance.
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Affiliation(s)
- Thomas Ant
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Erin Foley
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Scott Tytheridge
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Colin Johnston
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Adriana Goncalves
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Sainey Ceesay
- Disease Control & Elimination Theme, Medical Research Council Unit, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Mamadou Ousmane Ndiath
- Disease Control & Elimination Theme, Medical Research Council Unit, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Muna Affara
- Disease Control & Elimination Theme, Medical Research Council Unit, London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Julien Martinez
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Elizabeth Pretorius
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Chris Grundy
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | | | - Paulo Djata
- Ministério da saude chez Ministério da saude de Guinea-Bissau, Bissau, Guinea-Bissau
| | - Umberto d'Alessandro
- MRC The Gambia at the London School of Hygiene & Tropical Medicine, Fajara, Gambia
| | - Robin Bailey
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - David Mabey
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Anna Last
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - James G Logan
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK. .,ARCTEC, Chariot Innovations Ltd, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
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18
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Grignard L, Mair C, Curry J, Mahey L, Bastiaens GJH, Tiono AB, Okebe J, Coulibaly SA, Gonçalves BP, Affara M, Ouédraogo A, Bougouma EC, Sanou GS, Nébié I, Lanke KHW, Sirima SB, d'Alessandro U, Clark TG, Campino S, Bousema T, Drakeley C. Bead-based assays to simultaneously detect multiple human inherited blood disorders associated with malaria. Malar J 2019; 18:14. [PMID: 30665411 PMCID: PMC6341711 DOI: 10.1186/s12936-019-2648-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 01/12/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Glucose-6-phosphate dehydrogenase deficiency (G6PDd), haemoglobin C (HbC) and S (HbS) are inherited blood disorders (IBD) common in populations in malaria endemic areas. All are associated to some degree with protection against clinical malaria whilst additionally G6PDd is associated with haemolysis following treatment with 8-aminoquinolines. Measuring the prevalence of these inherited blood disorders in affected populations can improve understanding of disease epidemiology. Current methodologies in epidemiological studies commonly rely on individual target amplification and visualization; here a method is presented to simultaneously detect the polymorphisms and that can be expanded to include other single nucleotide polymorphisms (SNPs) of interest. METHODS Human DNA from whole blood samples was amplified in a novel, multiplex PCR reaction and extended with SNP-specific probes in an allele specific primer extension (ASPE) to simultaneously detect four epidemiologically important human markers including G6PD SNPs (G202A and A376G) and common haemoglobin mutations (HbS and HbC). The products were hybridized to magnetic beads and the median fluorescence intensity (MFI) was read on MAGPIX® (Luminex corp.). Genotyping data was compared to phenotypical data generated by flow cytometry and to established genotyping methods. RESULTS Seventy-five samples from Burkina Faso (n = 75/78, 96.2%) and 58 samples from The Gambia (n = 58/61, 95.1%) had a G6PD and a HBB genotype successfully assigned by the bead-based assay. Flow cytometry data available for n = 61 samples further supported the concordance between % G6PD normal/deficient cells and genotype. CONCLUSIONS The bead based assay compares well to alternative measures of genotyping and phenotyping for G6PD. The screening is high throughput, adaptable to inclusion of multiple targets of interest and easily standardized.
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Affiliation(s)
- Lynn Grignard
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK.
| | - Catherine Mair
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
| | | | | | - Guide J H Bastiaens
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Alfred B Tiono
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Joseph Okebe
- Disease Control & Elimination Theme, Medical Research Council Unit at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Sam A Coulibaly
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Bronner P Gonçalves
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
| | - Muna Affara
- Disease Control & Elimination Theme, Medical Research Council Unit at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Alphonse Ouédraogo
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Edith C Bougouma
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Guillaume S Sanou
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Issa Nébié
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Kjerstin H W Lanke
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Sodiomon B Sirima
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Umberto d'Alessandro
- Disease Control & Elimination Theme, Medical Research Council Unit at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Taane G Clark
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, UK
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - Susana Campino
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Teun Bousema
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
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19
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Shaffer JG, Doumbia SO, Ndiaye D, Diarra A, Gomis JF, Nwakanma D, Abubakar I, Ahmad A, Affara M, Lukowski M, Valim C, Welty JC, Mather FJ, Keating J, Krogstad DJ. Development of a data collection and management system in West Africa: challenges and sustainability. Infect Dis Poverty 2018; 7:125. [PMID: 30541626 PMCID: PMC6292095 DOI: 10.1186/s40249-018-0494-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 10/17/2018] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Developing and sustaining a data collection and management system (DCMS) is difficult in malaria-endemic countries because of limitations in internet bandwidth, computer resources and numbers of trained personnel. The premise of this paper is that development of a DCMS in West Africa was a critically important outcome of the West African International Centers of Excellence for Malaria Research. The purposes of this paper are to make that information available to other investigators and to encourage the linkage of DCMSs to international research and Ministry of Health data systems and repositories. METHODS We designed and implemented a DCMS to link study sites in Mali, Senegal and The Gambia. This system was based on case report forms for epidemiologic, entomologic, clinical and laboratory aspects of plasmodial infection and malarial disease for a longitudinal cohort study and included on-site training for Principal Investigators and Data Managers. Based on this experience, we propose guidelines for the design and sustainability of DCMSs in environments with limited resources and personnel. RESULTS From 2012 to 2017, we performed biannual thick smear surveys for plasmodial infection, mosquito collections for anopheline biting rates and sporozoite rates and year-round passive case detection for malarial disease in four longitudinal cohorts with 7708 individuals and 918 households in Senegal, The Gambia and Mali. Major challenges included the development of uniform definitions and reporting, assessment of data entry error rates, unstable and limited internet access and software and technology maintenance. Strengths included entomologic collections linked to longitudinal cohort studies, on-site data centres and a cloud-based data repository. CONCLUSIONS At a time when research on diseases of poverty in low and middle-income countries is a global priority, the resources available to ensure accurate data collection and the electronic availability of those data remain severely limited. Based on our experience, we suggest the development of a regional DCMS. This approach is more economical than separate data centres and has the potential to improve data quality by encouraging shared case definitions, data validation strategies and analytic approaches including the molecular analysis of treatment successes and failures.
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Affiliation(s)
- Jeffrey G. Shaffer
- Departments of Biostatistics (1440 Canal St., Suite 1610) and Tropical Medicine, (#8317 1430 Tulane Avenue, J.B. Johnston Building, Room 510), New Orleans, LA 70112-2699 USA
| | - Seydou O. Doumbia
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | | | - Ayouba Diarra
- University of the Sciences, Techniques and Technologies of Bamako, Bamako, Mali
| | | | | | | | | | - Muna Affara
- Medical Research Council Unit, Fajara, The Gambia
| | | | - Clarissa Valim
- Harvard T.H. Chan School of Public Health, Boston, MA USA
| | - James C. Welty
- Departments of Biostatistics (1440 Canal St., Suite 1610) and Tropical Medicine, (#8317 1430 Tulane Avenue, J.B. Johnston Building, Room 510), New Orleans, LA 70112-2699 USA
| | - Frances J. Mather
- Departments of Biostatistics (1440 Canal St., Suite 1610) and Tropical Medicine, (#8317 1430 Tulane Avenue, J.B. Johnston Building, Room 510), New Orleans, LA 70112-2699 USA
| | - Joseph Keating
- Departments of Biostatistics (1440 Canal St., Suite 1610) and Tropical Medicine, (#8317 1430 Tulane Avenue, J.B. Johnston Building, Room 510), New Orleans, LA 70112-2699 USA
| | - Donald J. Krogstad
- Departments of Biostatistics (1440 Canal St., Suite 1610) and Tropical Medicine, (#8317 1430 Tulane Avenue, J.B. Johnston Building, Room 510), New Orleans, LA 70112-2699 USA
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20
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Taylor WR, Naw HK, Maitland K, Williams TN, Kapulu M, D'Alessandro U, Berkley JA, Bejon P, Okebe J, Achan J, Amambua AN, Affara M, Nwakanma D, van Geertruyden JP, Mavoko M, Lutumba P, Matangila J, Brasseur P, Piola P, Randremanana R, Lasry E, Fanello C, Onyamboko M, Schramm B, Yah Z, Jones J, Fairhurst RM, Diakite M, Malenga G, Molyneux M, Rwagacondo C, Obonyo C, Gadisa E, Aseffa A, Loolpapit M, Henry MC, Dorsey G, John C, Sirima SB, Barnes KI, Kremsner P, Day NP, White NJ, Mukaka M. Single low-dose primaquine for blocking transmission of Plasmodium falciparum malaria - a proposed model-derived age-based regimen for sub-Saharan Africa. BMC Med 2018; 16:11. [PMID: 29347975 PMCID: PMC5774032 DOI: 10.1186/s12916-017-0990-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 12/12/2017] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND In 2012, the World Health Organization recommended blocking the transmission of Plasmodium falciparum with single low-dose primaquine (SLDPQ, target dose 0.25 mg base/kg body weight), without testing for glucose-6-phosphate dehydrogenase deficiency (G6PDd), when treating patients with uncomplicated falciparum malaria. We sought to develop an age-based SLDPQ regimen that would be suitable for sub-Saharan Africa. METHODS Using data on the anti-infectivity efficacy and tolerability of primaquine (PQ), the epidemiology of anaemia, and the risks of PQ-induced acute haemolytic anaemia (AHA) and clinically significant anaemia (CSA), we prospectively defined therapeutic-dose ranges of 0.15-0.4 mg PQ base/kg for children aged 1-5 years and 0.15-0.5 mg PQ base/kg for individuals aged ≥6 years (therapeutic indices 2.7 and 3.3, respectively). We chose 1.25 mg PQ base for infants aged 6-11 months because they have the highest rate of baseline anaemia and the highest risks of AHA and CSA. We modelled an anthropometric database of 661,979 African individuals aged ≥6 months (549,127 healthy individuals, 28,466 malaria patients and 84,386 individuals with other infections/illnesses) by the Box-Cox transformation power exponential and tested PQ doses of 1-15 mg base, selecting dosing groups based on calculated mg/kg PQ doses. RESULTS From the Box-Cox transformation power exponential model, five age categories were selected: (i) 6-11 months (n = 39,886, 6.03%), (ii) 1-5 years (n = 261,036, 45.46%), (iii) 6-9 years (n = 20,770, 3.14%), (iv) 10-14 years (n = 12,155, 1.84%) and (v) ≥15 years (n = 328,132, 49.57%) to receive 1.25, 2.5, 5, 7.5 and 15 mg PQ base for corresponding median (1st and 99th centiles) mg/kg PQ base of: (i) 0.16 (0.12-0.25), (ii) 0.21 (0.13-0.37), (iii) 0.25 (0.16-0.38), (iv) 0.26 (0.15-0.38) and (v) 0.27 (0.17-0.40). The proportions of individuals predicted to receive optimal therapeutic PQ doses were: 73.2 (29,180/39,886), 93.7 (244,537/261,036), 99.6 (20,690/20,770), 99.4 (12,086/12,155) and 99.8% (327,620/328,132), respectively. CONCLUSIONS We plan to test the safety of this age-based dosing regimen in a large randomised placebo-controlled trial (ISRCTN11594437) of uncomplicated falciparum malaria in G6PDd African children aged 0.5 - 11 years. If the regimen is safe and demonstrates adequate pharmacokinetics, it should be used to support malaria elimination.
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Affiliation(s)
- W Robert Taylor
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Mahidol University, 420/6 Rajvithi Road, Rajthevee, Bangkok, 10400, Thailand.
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
- Division of Tropical and Humanitarian Medicine, University Hospitals of Geneva, Geneva, Switzerland.
| | - Htee Khu Naw
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Mahidol University, 420/6 Rajvithi Road, Rajthevee, Bangkok, 10400, Thailand
| | - Kathryn Maitland
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
- Wellcome Trust Centre for Clinical Tropical Medicine and Department of Paediatrics, Faculty of Medicine, Imperial College, London, UK
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
- Wellcome Trust Centre for Clinical Tropical Medicine and Department of Paediatrics, Faculty of Medicine, Imperial College, London, UK
| | - Melissa Kapulu
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Umberto D'Alessandro
- MRC Unit, Fajara, Banjul, The Gambia
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - James A Berkley
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | - Philip Bejon
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- KEMRI-Wellcome Trust Research Programme, Centre for Geographic Medicine Research-Coast, Kilifi, Kenya
| | | | | | | | | | | | | | - Muhindo Mavoko
- Department of Tropical Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Pascal Lutumba
- Department of Tropical Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Junior Matangila
- Department of Tropical Medicine, University of Kinshasa, Kinshasa, Democratic Republic of Congo
| | | | - Patrice Piola
- Institut Pasteur de Madagascar, BP 1274, Antananarivo, Madagascar
| | | | - Estrella Lasry
- Kinshasa Mahidol Oxford Research Unit, Kinshasa, Democratic Republic of Congo
| | - Caterina Fanello
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Kinshasa School of Public Health, Kinshasa, Democratic Republic of Congo
| | - Marie Onyamboko
- Kinshasa Mahidol Oxford Research Unit, Kinshasa, Democratic Republic of Congo
- Kinshasa School of Public Health, Kinshasa, Democratic Republic of Congo
| | | | - Zolia Yah
- National Malaria Control Programme, Monrovia, Sierra Leone
| | - Joel Jones
- National Malaria Control Programme, Monrovia, Sierra Leone
| | - Rick M Fairhurst
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | | | | | - Malcolm Molyneux
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | | | | | | | - Abraham Aseffa
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | | | | | - Grant Dorsey
- Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Chandy John
- Department of Pediatrics, Indiana University, Indianapolis, IN, USA
| | - Sodiomon B Sirima
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | - Karen I Barnes
- Division of Clinical Pharmacology, Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - Peter Kremsner
- Institute of Tropical Medicine, University of Tubingen, Tubingen, Germany
| | - Nicholas P Day
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Mahidol University, 420/6 Rajvithi Road, Rajthevee, Bangkok, 10400, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Nicholas J White
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Mahidol University, 420/6 Rajvithi Road, Rajthevee, Bangkok, 10400, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Mavuto Mukaka
- Mahidol Oxford Tropical Medicine Research Unit (MORU), Mahidol University, 420/6 Rajvithi Road, Rajthevee, Bangkok, 10400, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
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21
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Bastiaens GJH, Tiono AB, Okebe J, Pett HE, Coulibaly SA, Gonçalves BP, Affara M, Ouédraogo A, Bougouma EC, Sanou GS, Nébié I, Bradley J, Lanke KHW, Niemi M, Sirima SB, d’Alessandro U, Bousema T, Drakeley C. Safety of single low-dose primaquine in glucose-6-phosphate dehydrogenase deficient falciparum-infected African males: Two open-label, randomized, safety trials. PLoS One 2018; 13:e0190272. [PMID: 29324864 PMCID: PMC5764271 DOI: 10.1371/journal.pone.0190272] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 12/05/2017] [Indexed: 12/11/2022] Open
Abstract
Background Primaquine (PQ) actively clears mature Plasmodium falciparum gametocytes but in glucose-6-phosphate dehydrogenase deficient (G6PDd) individuals can cause hemolysis. We assessed the safety of low-dose PQ in combination with artemether-lumefantrine (AL) or dihydroartemisinin-piperaquine (DP) in G6PDd African males with asymptomatic P. falciparum malaria. Methods and findings In Burkina Faso, G6PDd adult males were randomized to treatment with AL alone (n = 10) or with PQ at 0.25 (n = 20) or 0.40 mg/kg (n = 20) dosage; G6PD-normal males received AL plus 0.25 (n = 10) or 0.40 mg/kg (n = 10) PQ. In The Gambia, G6PDd adult males and boys received DP alone (n = 10) or with 0.25 mg/kg PQ (n = 20); G6PD-normal males received DP plus 0.25 (n = 10) or 0.40 mg/kg (n = 10) PQ. The primary study endpoint was change in hemoglobin concentration during the 28-day follow-up. Cytochrome P-450 isoenzyme 2D6 (CYP2D6) metabolizer status, gametocyte carriage, haptoglobin, lactate dehydrogenase levels and reticulocyte counts were also determined. In Burkina Faso, the mean maximum absolute change in hemoglobin was -2.13 g/dL (95% confidence interval [CI], -2.78, -1.49) in G6PDd individuals randomized to 0.25 PQ mg/kg and -2.29 g/dL (95% CI, -2.79, -1.79) in those receiving 0.40 PQ mg/kg. In The Gambia, the mean maximum absolute change in hemoglobin concentration was -1.83 g/dL (95% CI, -2.19, -1.47) in G6PDd individuals receiving 0.25 PQ mg/kg. After adjustment for baseline concentrations, hemoglobin reductions in G6PDd individuals in Burkina Faso were more pronounced compared to those in G6PD-normal individuals receiving the same PQ doses (P = 0.062 and P = 0.022, respectively). Hemoglobin levels normalized during follow-up. Abnormal haptoglobin and lactate dehydrogenase levels provided additional evidence of mild transient hemolysis post-PQ. Conclusions Single low-dose PQ in combination with AL and DP was associated with mild and transient reductions in hemoglobin. None of the study participants developed moderate or severe anemia; there were no severe adverse events. This indicates that single low-dose PQ is safe in G6PDd African males when used with artemisinin-based combination therapy. Trial registration Clinicaltrials.gov NCT02174900 Clinicaltrials.gov NCT02654730
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Affiliation(s)
- Guido J. H. Bastiaens
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
- * E-mail:
| | - Alfred B. Tiono
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Joseph Okebe
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia
| | - Helmi E. Pett
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
- Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Sam A. Coulibaly
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Bronner P. Gonçalves
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Muna Affara
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia
| | - Alphonse Ouédraogo
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Edith C. Bougouma
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Guillaume S. Sanou
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Issa Nébié
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - John Bradley
- MRC Tropical Epidemiology Group, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Kjerstin H. W. Lanke
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Mikko Niemi
- Department of Clinical Pharmacology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Sodiomon B. Sirima
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Umberto d’Alessandro
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia
- Department of Disease Control, Faculty of infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, the Netherlands
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
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Mwesigwa J, Achan J, Di Tanna GL, Affara M, Jawara M, Worwui A, Hamid-Adiamoh M, Kanuteh F, Ceesay S, Bousema T, Drakeley C, Grietens KP, Lindsay SW, Van geertruyden JP, D’Alessandro U. Residual malaria transmission dynamics varies across The Gambia despite high coverage of control interventions. PLoS One 2017; 12:e0187059. [PMID: 29095834 PMCID: PMC5667860 DOI: 10.1371/journal.pone.0187059] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 10/12/2017] [Indexed: 01/08/2023] Open
Abstract
Over the last decades, malaria has declined substantially in The Gambia but its transmission has not been interrupted. In order to better target control interventions, it is essential to understand the dynamics of residual transmission. This prospective cohort study was conducted between June 2013 and April 2014 in six pairs of villages across The Gambia. Blood samples were collected monthly during the transmission season (June-December) from all residents aged ≥6 months (4,194 individuals) and then in April (dry season). Entomological data were collected monthly throughout the malaria transmission season. Ownership of Long-Lasting Insecticidal Nets was 71.5% (2766/3869). Incidence of malaria infection and clinical disease varied significantly across the country, with the highest values in eastern (1.7/PYAR) than in central (0.2 /PYAR) and western (0.1/PYAR) Gambia. Malaria infection at the beginning of the transmission season was significantly higher in individuals who slept outdoors (HR = 1.51, 95% CI: 1.02-2.23, p = 0.04) and in those who had travelled outside the village (HR = 2.47, 95% CI: 1.83-3.34, p <0.01). Sub-patent infections were more common in older children (HR = 1.35, 95% CI: 1.04-1.6, p <0.01) and adults (HR = 1.53, 95% CI: 1.23-1.89, p<0.01) than in younger children. The risk of clinical malaria was significantly higher in households with at least one infected individual at the beginning of the transmission season (HR = 1.76, p<0.01). Vector parity was significantly higher in the eastern part of the country, both in the south (90.7%, 117/129, p<0.01) and the north bank (81.1%, 227/280, p<0.01), than in the western region (41.2%, 341/826), indicating higher vector survival. There is still significant residual malaria transmission across The Gambia, particularly in the eastern region. Additional interventions able to target vectors escaping Long-Lasting Insecticidal Nets and indoor residual spraying are needed to achieve malaria elimination.
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Affiliation(s)
- Julia Mwesigwa
- Medical Research Council Unit The Gambia, Banjul, The Gambia
- Department of Global Health, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Jane Achan
- Medical Research Council Unit The Gambia, Banjul, The Gambia
| | - Gian Luca Di Tanna
- Centre for Primary Care and Public Health, Queen Mary University of London, London, United Kingdom
| | - Muna Affara
- Medical Research Council Unit The Gambia, Banjul, The Gambia
| | - Musa Jawara
- Medical Research Council Unit The Gambia, Banjul, The Gambia
| | | | - Majidah Hamid-Adiamoh
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell & Molecular Biology University of Ghana, Accra, Ghana
| | | | - Sainey Ceesay
- Medical Research Council Unit The Gambia, Banjul, The Gambia
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Chris Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Koen Peeters Grietens
- Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
- Amsterdam Institute for Social Science Research, University of Amsterdam, Amsterdam, The Netherlands
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
| | - Steve W. Lindsay
- School of Biological & Biomedical Sciences, Durham University, Durham, United Kingdom
| | - Jean-Pierre Van geertruyden
- Department of Global Health, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Umberto D’Alessandro
- Medical Research Council Unit The Gambia, Banjul, The Gambia
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
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23
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Mira-Martínez S, van Schuppen E, Amambua-Ngwa A, Bottieau E, Affara M, Van Esbroeck M, Vlieghe E, Guetens P, Rovira-Graells N, Gómez-Pérez GP, Alonso PL, D'Alessandro U, Rosanas-Urgell A, Cortés A. Expression of the Plasmodium falciparum Clonally Variant clag3 Genes in Human Infections. J Infect Dis 2017; 215:938-945. [PMID: 28419281 PMCID: PMC5407054 DOI: 10.1093/infdis/jix053] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 01/20/2017] [Indexed: 11/13/2022] Open
Abstract
Background Many genes of the malaria parasite Plasmodium falciparum show clonally variant expression regulated at the epigenetic level. These genes participate in fundamental host-parasite interactions and contribute to adaptive processes. However, little is known about their expression patterns during human infections. A peculiar case of clonally variant genes are the 2 nearly identical clag3 genes, clag3.1 and clag3.2, which mediate nutrient uptake and are linked to resistance to some toxic compounds. Methods We developed a procedure to characterize the expression of clag3 genes in naturally infected patients and in experimentally infected human volunteers. Results We provide the first description of clag3 expression during human infections, which revealed mutually exclusive expression and identified the gene predominantly expressed. Adaptation to culture conditions or selection with a toxic compound resulted in isolate-dependent changes in clag3 expression. We also found that clag3 expression patterns were reset during transmission stages. Conclusions Different environment conditions select for parasites with different clag3 expression patterns, implying functional differences between the proteins encoded. The epigenetic memory is likely erased before parasites start infection of a new human host. Altogether, our findings support the idea that clonally variant genes facilitate the adaptation of parasite populations to changing conditions through bet-hedging strategies.
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Affiliation(s)
- Sofía Mira-Martínez
- Institute of Tropical Medicine, Antwerp, Belgium.,Barcelona Institute for Global Health (ISGlobal), Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Evi van Schuppen
- Barcelona Institute for Global Health (ISGlobal), Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | | | | | - Muna Affara
- Medical Research Council Unit, Fajara, The Gambia
| | | | | | | | - Núria Rovira-Graells
- Barcelona Institute for Global Health (ISGlobal), Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Gloria P Gómez-Pérez
- Barcelona Institute for Global Health (ISGlobal), Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Pedro L Alonso
- Barcelona Institute for Global Health (ISGlobal), Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Umberto D'Alessandro
- Institute of Tropical Medicine, Antwerp, Belgium.,Medical Research Council Unit, Fajara, The Gambia.,London School of Hygiene and Tropical Medicine, United Kingdom
| | | | - Alfred Cortés
- Barcelona Institute for Global Health (ISGlobal), Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,ICREA, Barcelona, Spain
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24
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Mbaye A, Gaye A, Dieye B, Ndiaye YD, Bei AK, Affara M, Deme AB, Yade MS, Diongue K, Ndiaye IM, Ndiaye T, Sy M, Sy N, Koita O, Krogstad DJ, Volkman S, Nwakanma D, Ndiaye D. Ex vivo susceptibility and genotyping of Plasmodium falciparum isolates from Pikine, Senegal. Malar J 2017; 16:250. [PMID: 28615016 PMCID: PMC5471902 DOI: 10.1186/s12936-017-1897-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 06/06/2017] [Indexed: 01/21/2023] Open
Abstract
Background The monitoring of Plasmodium falciparum sensitivity to anti-malarial drugs is a necessity for effective case management of malaria. This species is characterized by a strong resistance to anti-malarial drugs. In Senegal, the first cases of chloroquine resistance were reported in the Dakar region in 1988 with nearly 7% population prevalence, reaching 47% by 1990. It is in this context that sulfadoxine–pyrimethamine temporarily replaced chloroquine as first line treatment in 2003, pending the introduction of artemisinin-based combination therapy in 2006. The purpose of this study is to assess the ex vivo sensitivity to different anti-malarial drugs of the P. falciparum population from Pikine. Methods Fifty-four samples were collected from patients with non-complicated malaria and aged between 2 and 20 years in the Deggo health centre in Pikine in 2014. An assay in which parasites are stained with 4′, 6-di-amidino-2-phenylindole (DAPI), was used to study the ex vivo sensitivity of isolates to chloroquine, amodiaquine, piperaquine, pyrimethamine, and dihydroartemisinin. High resolution melting was used for genotyping of pfdhps, pfdhfr, pfmdr1, and pfcrt genes. Results The mean IC50s of chloroquine, amodiaquine, piperaquine, dihydroartemisinin, and pyrimethamine were, respectively, 39.44, 54.02, 15.28, 2.23, and 64.70 nM. Resistance mutations in pfdhfr gene, in codon 437 of pfdhps gene, and an absence of mutation at position 540 of pfdhps were observed. Mutations in codons K76T of pfcrt and N86Y of pfmdr1 were observed at 51 and 11% population prevalence, respectively. A relationship was found between the K76T and N86Y mutations and ex vivo resistance to chloroquine. Conclusion An increase in sensitivity of isolates to chloroquine was observed. A high sensitivity to dihydroartemisinin was observed; whereas, a decrease in sensitivity to pyrimethamine was observed in the parasite population from Pikine.
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Affiliation(s)
- Aminata Mbaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal.
| | - Amy Gaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Baba Dieye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Yaye D Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Amy K Bei
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal.,Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
| | - Muna Affara
- Medical Research Council Unit, The Gambia, Fajara, Gambia
| | - Awa B Deme
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Mamadou S Yade
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Khadim Diongue
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Ibrahima M Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Tolla Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Mouhamed Sy
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | - Ngayo Sy
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal
| | | | | | - Sarah Volkman
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
| | - Davis Nwakanma
- Medical Research Council Unit, The Gambia, Fajara, Gambia
| | - Daouda Ndiaye
- Laboratory of Parasitology/Mycology HALD, Cheikh Anta Diop University of Dakar, PO Box 5005, Dakar, Senegal.,Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, USA
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Mwesigwa J, Achan J, Jawara M, Ditanna G, Worwui A, Affara M, Geertruyden JP, D'Alessandro U. SPATIAL-TEMPORAL DYNAMICS IN HETEROGENEITY OF MALARIA INFECTION IN A SETTING WITH SEASONAL TRANSMISSION: A LONGITUDINAL STUDY IN THE GAMBIA. BMJ Glob Health 2017. [DOI: 10.1136/bmjgh-2016-000260.67] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Moneke-Anyanwoke N, Mwesigwa J, Affara M, Momodou J, Clarke E, D'Alessandro U, Scott S. EFFECT OF COMMUNITY-BASED SCHEDULED SCREENING AND TREATMENT (CSST) OF MALARIA IN PREGNANCY ON INFANT MALARIA INFECTION IN A SEASONAL MALARIA TRANSMISSION SETTING. BMJ Glob Health 2017. [DOI: 10.1136/bmjgh-2016-000260.76] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Claessens A, Affara M, Assefa SA, Kwiatkowski DP, Conway DJ. Culture adaptation of malaria parasites selects for convergent loss-of-function mutants. Sci Rep 2017; 7:41303. [PMID: 28117431 PMCID: PMC5259787 DOI: 10.1038/srep41303] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 12/19/2016] [Indexed: 12/30/2022] Open
Abstract
Cultured human pathogens may differ significantly from source populations. To investigate the genetic basis of laboratory adaptation in malaria parasites, clinical Plasmodium falciparum isolates were sampled from patients and cultured in vitro for up to three months. Genome sequence analysis was performed on multiple culture time point samples from six monoclonal isolates, and single nucleotide polymorphism (SNP) variants emerging over time were detected. Out of a total of five positively selected SNPs, four represented nonsense mutations resulting in stop codons, three of these in a single ApiAP2 transcription factor gene, and one in SRPK1. To survey further for nonsense mutants associated with culture, genome sequences of eleven long-term laboratory-adapted parasite strains were examined, revealing four independently acquired nonsense mutations in two other ApiAP2 genes, and five in Epac. No mutants of these genes exist in a large database of parasite sequences from uncultured clinical samples. This implicates putative master regulator genes in which multiple independent stop codon mutations have convergently led to culture adaptation, affecting most laboratory lines of P. falciparum. Understanding the adaptive processes should guide development of experimental models, which could include targeted gene disruption to adapt fastidious malaria parasite species to culture.
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Affiliation(s)
- Antoine Claessens
- London School of Hygiene and Tropical Medicine, London, UK.,Medical Research Council Unit The Gambia, Atlantic Road, Fajara, P.O. Box 273, Banjul, The Gambia
| | - Muna Affara
- Medical Research Council Unit The Gambia, Atlantic Road, Fajara, P.O. Box 273, Banjul, The Gambia
| | | | | | - David J Conway
- London School of Hygiene and Tropical Medicine, London, UK
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Goheen MM, Wegmüller R, Bah A, Darboe B, Danso E, Affara M, Gardner D, Patel JC, Prentice AM, Cerami C. Anemia Offers Stronger Protection Than Sickle Cell Trait Against the Erythrocytic Stage of Falciparum Malaria and This Protection Is Reversed by Iron Supplementation. EBioMedicine 2016; 14:123-130. [PMID: 27852523 PMCID: PMC5161422 DOI: 10.1016/j.ebiom.2016.11.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 11/05/2016] [Accepted: 11/07/2016] [Indexed: 11/28/2022] Open
Abstract
Background Iron deficiency causes long-term adverse consequences for children and is the most common nutritional deficiency worldwide. Observational studies suggest that iron deficiency anemia protects against Plasmodium falciparum malaria and several intervention trials have indicated that iron supplementation increases malaria risk through unknown mechanism(s). This poses a major challenge for health policy. We investigated how anemia inhibits blood stage malaria infection and how iron supplementation abrogates this protection. Methods This observational cohort study occurred in a malaria-endemic region where sickle-cell trait is also common. We studied fresh RBCs from anemic children (135 children; age 6–24 months; hemoglobin < 11 g/dl) participating in an iron supplementation trial (ISRCTN registry, number ISRCTN07210906) in which they received iron (12 mg/day) as part of a micronutrient powder for 84 days. Children donated RBCs at baseline, Day 49, and Day 84 for use in flow cytometry-based in vitro growth and invasion assays with P. falciparum laboratory and field strains. In vitro parasite growth in subject RBCs was the primary endpoint. Findings Anemia substantially reduced the invasion and growth of both laboratory and field strains of P. falciparum in vitro (~ 10% growth reduction per standard deviation shift in hemoglobin). The population level impact against erythrocytic stage malaria was 15.9% from anemia compared to 3.5% for sickle-cell trait. Parasite growth was 2.4 fold higher after 49 days of iron supplementation relative to baseline (p < 0.001), paralleling increases in erythropoiesis. Interpretation These results confirm and quantify a plausible mechanism by which anemia protects African children against falciparum malaria, an effect that is substantially greater than the protection offered by sickle-cell trait. Iron supplementation completely reversed the observed protection and hence should be accompanied by malaria prophylaxis. Lower hemoglobin levels typically seen in populations of African descent may reflect past genetic selection by malaria. Funding National Institute of Child Health and Development, Bill and Melinda Gates Foundation, UK Medical Research Council (MRC) and Department for International Development (DFID) under the MRC/DFID Concordat. P. falciparum laboratory and field strains invade and grow less efficiently in RBCs from anemic children. Deficits in invasion and growth for erythrocytic stage P. falciparum are reversed when RBCs are used from anemic children receiving iron supplementation for 49 and 84 days. The population level impact of protection against malaria from anemia was greater than that for sickle-cell trait.
The long-term consequences of anemia are severe, and it is easily treatable. However, concerns remain about the safety of iron supplements, particularly for children in malaria-endemic countries lacking adequate access to health services. We used RBCs from Gambian children before, during, and after 12 weeks of daily iron supplementation for in vitro P. falciparum assays. P. falciparum invasion and growth was decreased in anemic RBCs and increased after 49 days of iron supplementation relative to baseline (p < 0.001), paralleling increases in young RBCs, which the parasite prefers. The parasite growth protection from anemia was substantial, providing greater population level impact than sickle-cell trait.
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Affiliation(s)
- M M Goheen
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, CB# 7435, Chapel Hill, NC 27599-7435, USA.
| | - R Wegmüller
- MRC Unit The Gambia, MRC International Nutrition Group, Keneba, P.O. Box 273, Banjul, Gambia
| | - A Bah
- MRC Unit The Gambia, MRC International Nutrition Group, Keneba, P.O. Box 273, Banjul, Gambia
| | - B Darboe
- MRC Unit The Gambia, MRC International Nutrition Group, Keneba, P.O. Box 273, Banjul, Gambia
| | - E Danso
- MRC Unit The Gambia, MRC International Nutrition Group, Keneba, P.O. Box 273, Banjul, Gambia
| | - M Affara
- MRC Unit The Gambia, MRC International Nutrition Group, Keneba, P.O. Box 273, Banjul, Gambia
| | - D Gardner
- University of North Carolina School of Medicine, CB# 9535, Chapel Hill, NC 27599-9535, USA
| | - J C Patel
- Department of Epidemiology, University of North Carolina Gillings School of Global Public Health, CB# 7435, Chapel Hill, NC 27599-7435, USA
| | - A M Prentice
- MRC Unit The Gambia, MRC International Nutrition Group, Keneba, P.O. Box 273, Banjul, Gambia; London School of Hygiene & Tropical Medicine, Keppel Street, WC1E 7HT London, UK
| | - C Cerami
- MRC Unit The Gambia, MRC International Nutrition Group, Keneba, P.O. Box 273, Banjul, Gambia
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Okebe J, Bousema T, Affara M, Di Tanna GL, Dabira E, Gaye A, Sanya-Isijola F, Badji H, Correa S, Nwakanma D, Van Geertruyden JP, Drakeley C, D'Alessandro U. The Gametocytocidal Efficacy of Different Single Doses of Primaquine with Dihydroartemisinin-piperaquine in Asymptomatic Parasite Carriers in The Gambia: A Randomized Controlled Trial. EBioMedicine 2016; 13:348-355. [PMID: 27825738 PMCID: PMC5264436 DOI: 10.1016/j.ebiom.2016.10.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 10/14/2016] [Accepted: 10/19/2016] [Indexed: 11/23/2022] Open
Abstract
Background Asymptomatic low-density gametocyte carriers represent the majority of malaria-infected individuals. However, the impact of recommended treatment with single low dose of primaquine and an artemisinin-based combination therapy to reduce transmission in this group is unknown. Methods This was a four-arm, open label, randomized controlled trial comparing the effect of dihydroartemisinin-piperaquine (DHAP) alone or combined with single dose of primaquine (PQ) at 0.20 mg/kg, 0.40 mg/kg, or 0.75 mg/kg on Plasmodium falciparum gametocytaemia, infectiousness to mosquitoes and hemoglobin change in asymptomatic, malaria-infected, glucose-6-phosphate dehydrogenase (G6PD) normal individuals. Randomization was done using a computer-generated sequence of uneven block sizes with codes concealed in sequentially numbered opaque envelopes. The primary endpoint was the prevalence of P. falciparum gametocytemia at day 7 of follow-up determined by quantitative nucleic acid sequence based assay and analysis was by intention to treat. The trial has been concluded (registration number: NCT01838902; https://clinicaltrials.gov/ct2/show/NCT01838902). Results A total of 694 asymptomatic, malaria-infected individuals were enrolled. Gametocyte prevalence at day 7 was 37.0% (54/146; 95% CI 29.2–45.4), 19.0% (27/142; 95% CI 12.9–26.4), 17.2% (25/145; 95% CI 11.0–23.5) and 10.6% (15/141; 95% CI 6.1–16.9) in the DHAP alone, 0.20 mg/kg, 0.40 mg/kg, and 0.75 mg/kg PQ arms, respectively. The main adverse events reported include headache (130/471, 27.6%), cough (73/471, 15.5%), history of fever (61/471, 13.0%) and abdominal pain (57/471, 12.1%). There were five serious adverse events however, none was related to the interventions. Interpretation A single course of PQ significantly reduces gametocyte carriage in malaria-infected asymptomatic, G6PD-normal individuals without increasing the risk of clinical anemia. The limited number of successful mosquito infections suggests that post-treatment transmission potential in this asymptomatic population is low. Treatment with primaquine and an artemisinin-based combination therapy is part of malaria elimination strategies. Its slow uptake, despite specific recommendations highlights the need for evidence on primaquine's efficacy and safety. About 50% of asymptomatic P. falciparum-infected individuals carry gametocytes detectable by sensitive molecular methods. Primaquine reduced gametocyte prevalence at day 7 and carriage time in the study population at all doses tested.
Adding a single dose (0.75 mg/kg) of primaquine to the treatment of uncomplicated falciparum malaria was recommended in 2010 on the basis of weak evidence. Primaquine, at doses as low as 0.20 mg/kg, can reduce substantially gametocyte carriage in asymptomatic, malaria-infected individuals, representing the majority of the human reservoir of infection. Post-treatment transmission potential is low with artemisinin-based combination alone or with the 0.20 mg/kg dose but may occur despite reductions in gametocyte carriage.
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Affiliation(s)
- Joseph Okebe
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia; Epidemiology for Global Health Institute, Faculty of Medicine & Health Sciences, University of Antwerp, Antwerp, Belgium.
| | - Teun Bousema
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Muna Affara
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia.
| | - Gian Luca Di Tanna
- Pragmatic Clinical Trials Unit, Centre for Primary Care and Public Health, Queen Mary University of London, United Kingdom.
| | - Edgard Dabira
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia.
| | - Abdoulaye Gaye
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia.
| | - Frank Sanya-Isijola
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia.
| | - Henry Badji
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia.
| | - Simon Correa
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia.
| | - Davis Nwakanma
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia.
| | - Jean-Pierre Van Geertruyden
- Epidemiology for Global Health Institute, Faculty of Medicine & Health Sciences, University of Antwerp, Antwerp, Belgium.
| | - Chris Drakeley
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
| | - Umberto D'Alessandro
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia; Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium.
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Dieye B, Affara M, Sangare L, Joof F, Ndiaye YD, Gomis JF, Ndiaye M, Mbaye A, Diakite M, Sy N, Mbengue B, Deme AB, Daniels R, Ahouidi AD, Dieye T, Abdullahi A, Doumbia S, Ndiaye JL, Diarra A, Ismaela A, Coulibaly M, Welty C, Ngwa AA, Shaffer J, D'Alessandro U, Volkman SK, Wirth DF, Krogstad DJ, Koita O, Nwakanma D, Ndiaye D. West Africa International Centers of Excellence for Malaria Research: Drug Resistance Patterns to Artemether-Lumefantrine in Senegal, Mali, and The Gambia. Am J Trop Med Hyg 2016; 95:1054-1060. [PMID: 27549635 DOI: 10.4269/ajtmh.16-0053] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 06/29/2016] [Indexed: 01/09/2023] Open
Abstract
In 2006, artemether-lumefantrine (AL) became the first-line treatment of uncomplicated malaria in Senegal, Mali, and the Gambia. To monitor its efficacy, between August 2011 and November 2014, children with uncomplicated Plasmodium falciparum malaria were treated with AL and followed up for 42 days. A total of 463 subjects were enrolled in three sites (246 in Senegal, 97 in Mali, and 120 in Gambia). No early treatment failure was observed and malaria infection cleared in all patients by day 3. Polymerase chain reaction (PCR)-adjusted adequate clinical and parasitological response (ACPR) was 100% in Mali, and the Gambia, and 98.8% in Senegal. However, without PCR adjustment, ACPR was 89.4% overall; 91.5% in Mali, 98.8% in Senegal, and 64.3% in the Gambia (the lower value in the Gambia attributed to poor compliance of the full antimalarial course). However, pfmdr1 mutations were prevalent in Senegal and a decrease in parasite sensitivity to artesunate and lumefantrine (as measured by ex vivo drug assay) was observed at all sites. Recrudescent parasites did not show Kelch 13 (K13) mutations and AL remains highly efficacious in these west African sites.
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Affiliation(s)
- Baba Dieye
- Cheikh Anta Diop University, Dakar, Senegal
| | | | | | | | | | | | | | | | | | - Ngayo Sy
- Cheikh Anta Diop University, Dakar, Senegal
| | | | - Awa B Deme
- Cheikh Anta Diop University, Dakar, Senegal
| | - Rachel Daniels
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts
| | | | | | | | | | | | | | | | | | | | | | | | - Umberto D'Alessandro
- Medical Research Council, The Gambia.,London School of Hygiene and Tropical Medicine, London, United Kingdom.,Institute of Tropical Medicine, Antwerp, Belgium
| | - Sarah K Volkman
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,The Broad Institute of MIT and Harvard, Cambridge, Massachusetts.,Simmons College School of Nursing and Health Sciences, Boston, Massachusetts
| | - Dyann F Wirth
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts.,The Broad Institute of MIT and Harvard, Cambridge, Massachusetts
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Mwesigwa J, Okebe J, Affara M, Di Tanna GL, Nwakanma D, Janha O, Opondo K, Grietens KP, Achan J, D'Alessandro U. On-going malaria transmission in The Gambia despite high coverage of control interventions: a nationwide cross-sectional survey. Malar J 2015; 14:314. [PMID: 26268225 PMCID: PMC4535679 DOI: 10.1186/s12936-015-0829-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 08/03/2015] [Indexed: 11/13/2022] Open
Abstract
Background As indicators of burden of malaria have substantially decreased in The Gambia, reaching a pre-elimination status may be attainable. Achieving this goal requires in-depth understanding of the current burden of Plasmodium falciparum infection. Methods A nationwide cross-sectional survey was conducted in 2012 to determine the prevalence of P.falciparum infection, and to describe its heterogeneity and associated risk factors. Finger-prick blood samples were collected for microscopy, species-specific PCR and haemoglobin measurement. Results A total of 9,094 participants were included and median
age was 11.9 years (IQR 5, 28). Overall prevalence of P. falciparum was 16.01 % with marked heterogeneity between sites (4.32–36.75 %) and within villages in each site (1.63–49.13 %). Across all sites, 51.17 % (745/1,456) of infections were asymptomatic and 35.61 % (448/1,258) were sub-microscopic. The odds of P. falciparum infection were higher in older children; 5–15 years (OR = 1.90; 95 % CI 1.60–2.26), adults (OR = 1.48; 95 % CI 1.24–1.78) and participants with moderate anaemia (OR = 1.62; 95 % CI 1.32–1.99). Conclusions The current malaria control interventions are not sufficient to interrupt transmission in The Gambia as malaria prevalence is still relatively high in the eastern part of the country. New interventions aiming at interrupting transmission are needed and should be urgently evaluated.
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Affiliation(s)
- Julia Mwesigwa
- Medical Research Council Unit, PO Box 273, Banjul, The Gambia.
| | - Joseph Okebe
- Medical Research Council Unit, PO Box 273, Banjul, The Gambia.
| | - Muna Affara
- Medical Research Council Unit, PO Box 273, Banjul, The Gambia.
| | | | - Davis Nwakanma
- Medical Research Council Unit, PO Box 273, Banjul, The Gambia.
| | - Omar Janha
- Medical Research Council Unit, PO Box 273, Banjul, The Gambia.
| | - Kevin Opondo
- Medical Research Council Unit, PO Box 273, Banjul, The Gambia.
| | - Koen Peeters Grietens
- Institute of Tropical Medicine, Antwerp, Belgium. .,School of International Health Development, Nagasaki University, Nagasaki, Japan. .,Partners for Applied Social Sciences (PASS) International, Tessenderlo, Belgium.
| | - Jane Achan
- Medical Research Council Unit, PO Box 273, Banjul, The Gambia.
| | - Umberto D'Alessandro
- Medical Research Council Unit, PO Box 273, Banjul, The Gambia. .,London School of Hygiene and Tropical Medicine, London, UK. .,Institute of Tropical Medicine, Antwerp, Belgium.
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Ceesay SJ, Koivogui L, Nahum A, Taal MA, Okebe J, Affara M, Kaman LE, Bohissou F, Agbowai C, Tolno BG, Amambua-Ngwa A, Bangoura NF, Ahounou D, Muhammad AK, Duparc S, Hamed K, Ubben D, Bojang K, Achan J, D'Alessandro U. Malaria Prevalence among Young Infants in Different Transmission Settings, Africa. Emerg Infect Dis 2015; 21:1114-21. [PMID: 26079062 PMCID: PMC4480393 DOI: 10.3201/eid2107.142036] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The prevalence and consequences of malaria among infants are not well characterized and may be underestimated. A better understanding of the risk for malaria in early infancy is critical for drug development and informed decision making. In a cross-sectional survey in Guinea, The Gambia, and Benin, countries with different malaria transmission intensities, the overall prevalence of malaria among infants <6 months of age was 11.8% (Guinea, 21.7%; The Gambia, 3.7%; and Benin, 10.2%). Seroprevalence ranged from 5.7% in The Gambia to 41.6% in Guinea. Mean parasite densities in infants were significantly lower than those in children 1-9 years of age in The Gambia (p<0.0001) and Benin (p = 0.0021). Malaria in infants was significantly associated with fever or recent history of fever (p = 0.007) and anemia (p = 0.001). Targeted preventive interventions, adequate drug formulations, and treatment guidelines are needed to address the sizeable prevalence of malaria among young infants in malaria-endemic countries.
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Okebe J, Bousema T, Affara M, DiTanna G, Eziefula AC, Jawara M, Nwakanma D, Amambua-Ngwa A, Van Geertruyden JP, Drakeley C, D'Alessandro U. The gametocytocidal efficacy of primaquine in malaria asymptomatic carriers treated with dihydroartemisinin-piperaquine in The Gambia (PRINOGAM): study protocol for a randomised controlled trial. Trials 2015; 16:70. [PMID: 25887344 PMCID: PMC4349754 DOI: 10.1186/s13063-015-0597-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 02/10/2015] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Finding efficacious tools to decrease and interrupt malaria transmission is essential to sustain the gains in malaria control and contain the emergence of artemisinin resistance. Primaquine is effective against Plasmodium falciparum gametocytes and recommended for treatment campaigns in (pre-)elimination settings. Safety concerns preclude its use in endemic African countries with variable proportions of glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals. The efficacy of the current recommended dose needs to be evaluated, particularly in individuals with an asymptomatic malaria infection. METHODS/DESIGN This is a four-arm, open label, randomized controlled trial that aims to determine and compare the effect of three different single doses of primaquine combined with dihydroartemisinin-piperaquine, an artemisinin-based combination therapy, on gametocyte carriage in asymptomatic, malaria infected, G6PD-normal individuals. Approximately 1,200 participants are enrolled and followed for 42 days, with the primary endpoint being the prevalence of Plasmodium falciparum gametocyte carriage at day 7 of follow-up determined by quantitative nucleic acid sequence based amplification assay. Direct membrane feeding experiments to determine infectiousness to mosquitoes are conducted as a biological secondary endpoint. DISCUSSION Sub-Saharan Africa, with a relatively high but poorly characterized G6PD prevalence, could potentially benefit from the use of primaquine to further reduce or interrupt malaria transmission. However, G6PD screening may not be feasible given the cost and difficulties in interpreting test results in terms of risk of haemolysis. Because the haemolytic effect of primaquine is dose-dependent, determining the minimal gametocytocidal and transmission-blocking dose of primaquine is extremely important to help address public health concerns over its safety and validate the efficacy of lower than recommended dosages. By including infectiousness to mosquitoes, the trial provides complementary evidence for the potential of the drug to interrupt transmission to mosquitoes. TRIAL REGISTRATION ClinicalTrials.gov: NCT01838902 (12 April 2013).
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Affiliation(s)
- Joseph Okebe
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia.
| | - Teun Bousema
- Immunology and Infection Department, London School of Hygiene and Tropical Medicine, London, UK.
| | - Muna Affara
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia.
| | - GianLuca DiTanna
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population health, London School of Hygiene and Tropical Medicine, London, UK.
| | - Alice C Eziefula
- Immunology and Infection Department, London School of Hygiene and Tropical Medicine, London, UK.
| | - Musa Jawara
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia.
| | - Davis Nwakanma
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia.
| | - Alfred Amambua-Ngwa
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia.
| | | | - Chris Drakeley
- Immunology and Infection Department, London School of Hygiene and Tropical Medicine, London, UK.
| | - Umberto D'Alessandro
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia.
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
- Department of Public health, Institute of Tropical Medicine, Antwerp, Belgium.
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Olaosebikan R, Ernest K, Bojang K, Mokuolu O, Rehman AM, Affara M, Nwakanma D, Kiechel JR, Ogunkunle T, Olagunju T, Murtala R, Omefe P, Lambe T, Bello S, Ibrahim O, Olorunsola B, Ojuawo A, Greenwood B, Milligan P. A Randomized Trial to Compare the Safety, Tolerability, and Effectiveness of 3 Antimalarial Regimens for the Prevention of Malaria in Nigerian Patients With Sickle Cell Disease. J Infect Dis 2015; 212:617-25. [PMID: 25701866 PMCID: PMC4512609 DOI: 10.1093/infdis/jiv093] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 02/06/2015] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Malaria prophylaxis is recommended for persons with sickle cell disease (SCD), but the value of this has been questioned. The aim of this study was to find out whether intermittent preventive treatment (IPT) with a fixed-dose combination of mefloquine-artesunate (MQAS) or sulfadoxine-pyrimethamine plus amodiaquine (SPAQ) was more effective than daily proguanil for malaria prevention in subjects with SCD. METHODS Patients with SCD were randomized to receive daily treatment with proguanil or IPT with either MQAS or SPAQ once every 2 months at routine clinic visits. Patients were followed up for 14 months. FINDINGS A total of 270 patients with SCD were studied, with 90 in each group. Adherence to the IPT regimens was excellent, but 57% of patients took <75% of their daily doses of proguanil. IPT was well tolerated; the most common side effects were vomiting and abdominal pain. Protective efficacy against malaria, compared with daily proguanil, was 61% (95% confidence interval, 3%-84%) for MQAS and 36% (40%-70%) for SPAQ. There were fewer outpatient illness episodes in children who received IPT than those who received proguanil. CONCLUSIONS IPT with MQAS administered to patients with SCD during routine clinic visits was well tolerated and more effective in preventing malaria than daily prophylaxis with proguanil. CLINICAL TRIALS REGISTRATION NCT01319448 and ISRCTN46158146.
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Affiliation(s)
- Rasaq Olaosebikan
- University of Ilorin Teaching Hospital, Nigeria Medical Research Council Unit, Banjul, Gambia University of Nebraska Medical Centre, Omaha
| | | | | | | | - Andrea M Rehman
- London School of Hygiene and Tropical Medicine, United Kingdom
| | - Muna Affara
- Medical Research Council Unit, Banjul, Gambia
| | | | | | | | | | | | - Peter Omefe
- University of Ilorin Teaching Hospital, Nigeria
| | - Tosin Lambe
- University of Ilorin Teaching Hospital, Nigeria
| | | | | | | | | | - Brian Greenwood
- London School of Hygiene and Tropical Medicine, United Kingdom
| | - Paul Milligan
- London School of Hygiene and Tropical Medicine, United Kingdom
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Okebe J, Affara M, Correa S, Muhammad AK, Nwakanma D, Drakeley C, D’Alessandro U. School-based countrywide seroprevalence survey reveals spatial heterogeneity in malaria transmission in the Gambia. PLoS One 2014; 9:e110926. [PMID: 25338083 PMCID: PMC4206471 DOI: 10.1371/journal.pone.0110926] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 09/25/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND As the geographical distribution of malaria transmission becomes progressively clustered, identifying residual pockets of transmission is important for research and for targeting interventions. Malarial antibody-based surveillance is increasingly recognised as a valuable complement to classic methods for the detection of infection foci especially at low transmission levels. The study presents serological evidence for transmission heterogeneity among school children in The Gambia measured during the dry, non-transmission season. METHODS Healthy primary school children were randomly selected from 30 schools across the country and screened for malaria infection (microscopy) and antimalarial antibodies (MSP119). Antibody distribution was modelled using 2-component finite mixture model with cut-off for positivity from pooled sera set at 2-standard deviation from the mean of the first component. Factors associated with a positive serological status were identified in a univariate model and then combined in a multilevel mixed-effects logistic regression model, simultaneously adjusting for variations between individuals and school. RESULTS A total of 4140 children, 1897 (46%) boys, were enrolled with mean age of 10.2 years (SD 2.6, range 4-20 years). Microscopy results available for 3640 (87.9%) children showed that 1.9% (69) were positive for Plasmodium falciparum infections, most of them (97.1%, 67/69) asymptomatic. The overall seroprevalence was 12.7% (527/4140) with values for the schools ranging from 0.6% to 43.8%. Age (OR 1.12, 95% CI 1.07-1.16,) and parasite carriage (OR 3.36, 95% CI 1.95-5.79) were strongly associated with seropositivity. CONCLUSION Serological responses to malaria parasites could identify individuals who were or had been infected, and clusters of residual transmission. Field-adapted antibody tests able to guide mass screening and treatment campaigns would be extremely useful.
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Affiliation(s)
- Joseph Okebe
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia
- * E-mail:
| | - Muna Affara
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia
| | - Simon Correa
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia
| | - Abdul Khalie Muhammad
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia
| | - Davis Nwakanma
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia
| | - Chris Drakeley
- Department of Immunology and Infection, London school of Hygiene and Tropical Medicine, London, United Kingdom
| | - Umberto D’Alessandro
- Disease Control & Elimination Theme, Medical Research Council Unit, Fajara, The Gambia
- Department of Disease Control, Faculty of infectious and Tropical Diseases, London school of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Public health, Institute of Tropical Medicine, Antwerp, Belgium
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Okebe J, Amambua-Ngwa A, Parr J, Nishimura S, Daswani M, Takem EN, Affara M, Ceesay SJ, Nwakanma D, D'Alessandro U. The prevalence of glucose-6-phosphate dehydrogenase deficiency in Gambian school children. Malar J 2014; 13:148. [PMID: 24742291 PMCID: PMC3999733 DOI: 10.1186/1475-2875-13-148] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Accepted: 04/13/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Primaquine, the only available drug effective against Plasmodium falciparum sexual stages, induces also a dose-dependent haemolysis, especially in glucose-6-phosphate dehydrogenase deficient (G6PDd) individuals. Therefore, it is important to determine the prevalence of this deficiency in areas that would potentially benefit from its use. The prevalence of G6PD deficiency by genotype and enzyme activity was determined in healthy school children in The Gambia. METHODS Blood samples from primary school children collected during a dry season malaria survey were screened for G6PDd and malaria infection. Genotypes for allele mutations reported in the country; 376, 202A-, 968A- and 542 were analysed while enzyme activity (phenotype) was assayed using a semi-quantitative commercial test kit. Enzyme activity values were fitted in a finite mixture model to determine the distribution and calculate a cut-off for deficiency. The association between genotype and phenotype for boys and girls as well as the association between mutant genotype and deficient phenotype was analysed. RESULTS Samples from 1,437 children; 51% boys were analysed. The prevalence of P. falciparum malaria infection was 14%. The prevalence of the 202A-, 968 and 542 mutations was 1.8%, 2.1% and 1.0%, respectively, and higher in boys than in girls. The prevalence of G6PDd phenotype was 6.4% (92/1,437), 7.8% (57/728) in boys and 4.9% (35/709) in girls with significantly higher odds in the former (OR 1.64, 95% CI 1.05, 2.53, p = 0.026). The deficient phenotype was associated with reduced odds of malaria infection (OR 0.77, 95% CI 0.36, 1.62, p = 0.49). CONCLUSIONS There is a weak association between genotype and phenotype estimates of G6PDd prevalence. The phenotype expression of deficiency represents combinations of mutant alleles rather than specific mutations. Genotype studies in individuals with a deficient phenotype would help identify alleles responsible for haemolysis.
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Affiliation(s)
- Joseph Okebe
- Medical Research Council Unit, Atlantic Boulevard, Fajara, The Gambia.
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Affara M, Sanders D, Araki H, Tamada Y, Dunmore BJ, Humphreys S, Imoto S, Savoie C, Miyano S, Kuhara S, Jeffries D, Print C, Charnock-Jones DS. Vasohibin-1 is identified as a master-regulator of endothelial cell apoptosis using gene network analysis. BMC Genomics 2013; 14:23. [PMID: 23324451 PMCID: PMC3570387 DOI: 10.1186/1471-2164-14-23] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 12/07/2012] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Apoptosis is a critical process in endothelial cell (EC) biology and pathology, which has been extensively studied at protein level. Numerous gene expression studies of EC apoptosis have also been performed, however few attempts have been made to use gene expression data to identify the molecular relationships and master regulators that underlie EC apoptosis. Therefore, we sought to understand these relationships by generating a Bayesian gene regulatory network (GRN) model. RESULTS ECs were induced to undergo apoptosis using serum withdrawal and followed over a time course in triplicate, using microarrays. When generating the GRN, this EC time course data was supplemented by a library of microarray data from EC treated with siRNAs targeting over 350 signalling molecules.The GRN model proposed Vasohibin-1 (VASH1) as one of the candidate master-regulators of EC apoptosis with numerous downstream mRNAs. To evaluate the role played by VASH1 in EC, we used siRNA to reduce the expression of VASH1. Of 10 mRNAs downstream of VASH1 in the GRN that were examined, 7 were significantly up- or down-regulated in the direction predicted by the GRN.Further supporting an important biological role of VASH1 in EC, targeted reduction of VASH1 mRNA abundance conferred resistance to serum withdrawal-induced EC death. CONCLUSION We have utilised Bayesian GRN modelling to identify a novel candidate master regulator of EC apoptosis. This study demonstrates how GRN technology can complement traditional methods to hypothesise the regulatory relationships that underlie important biological processes.
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Affiliation(s)
- Muna Affara
- Department of Obstetrics and Gynaecology, University of Cambridge, The Rosie Hospital, Robinson Way, Cambridge CB2 0SW, UK
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Hurley D, Araki H, Tamada Y, Dunmore B, Sanders D, Humphreys S, Affara M, Imoto S, Yasuda K, Tomiyasu Y, Tashiro K, Savoie C, Cho V, Smith S, Kuhara S, Miyano S, Charnock-Jones DS, Crampin EJ, Print CG. Gene network inference and visualization tools for biologists: application to new human transcriptome datasets. Nucleic Acids Res 2011; 40:2377-98. [PMID: 22121215 PMCID: PMC3315333 DOI: 10.1093/nar/gkr902] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Gene regulatory networks inferred from RNA abundance data have generated significant interest, but despite this, gene network approaches are used infrequently and often require input from bioinformaticians. We have assembled a suite of tools for analysing regulatory networks, and we illustrate their use with microarray datasets generated in human endothelial cells. We infer a range of regulatory networks, and based on this analysis discuss the strengths and limitations of network inference from RNA abundance data. We welcome contact from researchers interested in using our inference and visualization tools to answer biological questions.
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Affiliation(s)
- Daniel Hurley
- Auckland Bioengineering Institute, Department of Molecular Medicine and Pathology, School of Medical Sciences, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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Affara M, Dunmore B, Savoie C, Imoto S, Tamada Y, Araki H, Charnock-Jones DS, Miyano S, Print C. Understanding endothelial cell apoptosis: what can the transcriptome, glycome and proteome reveal? Philos Trans R Soc Lond B Biol Sci 2007; 362:1469-87. [PMID: 17569639 PMCID: PMC2440409 DOI: 10.1098/rstb.2007.2129] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Endothelial cell (EC) apoptosis may play an important role in blood vessel development, homeostasis and remodelling. In support of this concept, EC apoptosis has been detected within remodelling vessels in vivo, and inactivation of EC apoptosis regulators has caused dramatic vascular phenotypes. EC apoptosis has also been associated with cardiovascular pathologies. Therefore, understanding the regulation of EC apoptosis, with the goal of intervening in this process, has become a current research focus. The protein-based signalling and cleavage cascades that regulate EC apoptosis are well known. However, the possibility that programmed transcriptome and glycome changes contribute to EC apoptosis has only recently been explored. Traditional bioinformatic techniques have allowed simultaneous study of thousands of molecular signals during the process of EC apoptosis. However, to progress further, we now need to understand the complex cause and effect relationships among these signals. In this article, we will first review current knowledge about the function and regulation of EC apoptosis including the roles of the proteome transcriptome and glycome. Then, we assess the potential for further bioinformatic analysis to advance our understanding of EC apoptosis, including the limitations of current technologies and the potential of emerging technologies such as gene regulatory networks.
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Affiliation(s)
- Muna Affara
- Department of Pathology, Cambridge UniversityTennis Court Road, Cambridge CB2 1QP, UK
| | - Benjamin Dunmore
- Department of Obstetrics and Gynaecology, Cambridge UniversityThe Rosie Hospital, Cambridge CB2 2SW, UK
| | - Christopher Savoie
- GNI Ltd. Kasumigaseki IHF Building 3-5-1Kasumigaseki, Chiyoda-ku, 100-0013 Toyko, Japan
| | - Seiya Imoto
- Human Genome Centre, Institute of Medical Science, University of Tokyo4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Yoshinori Tamada
- Department of Obstetrics and Gynaecology, Cambridge UniversityThe Rosie Hospital, Cambridge CB2 2SW, UK
- Bioinformatics Centre, Institute for Chemical Research, Kyoto UniversityGokasho, Uji, Kyoto 611-0011, Japan
| | - Hiromitsu Araki
- GNI Ltd. Kasumigaseki IHF Building 3-5-1Kasumigaseki, Chiyoda-ku, 100-0013 Toyko, Japan
| | - D. Stephen Charnock-Jones
- Department of Obstetrics and Gynaecology, Cambridge UniversityThe Rosie Hospital, Cambridge CB2 2SW, UK
| | - Satoru Miyano
- Human Genome Centre, Institute of Medical Science, University of Tokyo4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Cristin Print
- Department of Molecular Medicine and Pathology, University of Auckland85 Park Road, Private Bag 92019, Auckland, New Zealand
- Author for correspondence ()
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