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Holzschuh A, Ewnetu Y, Carlier L, Lerch A, Gerlovina I, Baker SC, Yewhalaw D, Haileselassie W, Berhane N, Lemma W, Koepfli C. Plasmodium falciparum transmission in the highlands of Ethiopia is driven by closely related and clonal parasites. Mol Ecol 2024; 33:e17292. [PMID: 38339833 DOI: 10.1111/mec.17292] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 12/28/2023] [Accepted: 01/30/2024] [Indexed: 02/12/2024]
Abstract
Malaria cases are frequently recorded in the Ethiopian highlands even at altitudes above 2000 m. The epidemiology of malaria in the Ethiopian highlands, and, in particular, the role of importation by human migration from the highly endemic lowlands is not well understood. We sequenced 187 Plasmodium falciparum samples from two sites in the Ethiopian highlands, Gondar (n = 159) and Ziway (n = 28), using a multiplexed droplet digital PCR (ddPCR)-based amplicon sequencing method targeting 35 microhaplotypes and drug resistance loci. Here, we characterize the parasite population structure and genetic relatedness. We identify moderate parasite diversity (mean HE : 0.54) and low infection complexity (74.9% monoclonal). A significant percentage of infections share microhaplotypes, even across transmission seasons and sites, indicating persistent local transmission. We identify multiple clusters of clonal or near-clonal infections, highlighting high genetic relatedness. Only 6.3% of individuals diagnosed with P. falciparum reported recent travel. Yet, in clonal or near-clonal clusters, infections of travellers were frequently observed first in time, suggesting that parasites may have been imported and then transmitted locally. 31.1% of infections are pfhrp2-deleted and 84.4% pfhrp3-deleted, and 28.7% have pfhrp2/3 double deletions. Parasites with pfhrp2/3 deletions and wild-type parasites are genetically distinct. Mutations associated with resistance to sulphadoxine-pyrimethamine or suggested to reduce sensitivity to lumefantrine are observed at near-fixation. In conclusion, genomic data corroborate local transmission and the importance of intensified control in the Ethiopian highlands.
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Affiliation(s)
- Aurel Holzschuh
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Yalemwork Ewnetu
- Department of Medical Biotechnology, University of Gondar, Gondar, Ethiopia
| | - Lise Carlier
- Trinity Centre for Global Health, Trinity College Dublin, Dublin, Ireland
- Noul Inc., Seoul, Republic of Korea
| | - Anita Lerch
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Inna Gerlovina
- Department of Medicine, Division of HIV, ID and Global Medicine, EPPIcenter Research Program, University of California, San Francisco, California, USA
| | - Sarah Cate Baker
- Trinity Centre for Global Health, Trinity College Dublin, Dublin, Ireland
| | - Delenasaw Yewhalaw
- Tropical and Infectious Disease Research Center, Jimma University, Jimma, Ethiopia
| | | | - Nega Berhane
- Department of Medical Biotechnology, University of Gondar, Gondar, Ethiopia
| | - Wossenseged Lemma
- Department of Medical Biotechnology, University of Gondar, Gondar, Ethiopia
| | - Cristian Koepfli
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
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Holzschuh A, Lerch A, Fakih BS, Aliy SM, Ali MH, Ali MA, Bruzzese DJ, Yukich J, Hetzel MW, Koepfli C. Using a mobile nanopore sequencing lab for end-to-end genomic surveillance of Plasmodium falciparum: A feasibility study. PLOS Glob Public Health 2024; 4:e0002743. [PMID: 38300956 PMCID: PMC10833559 DOI: 10.1371/journal.pgph.0002743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 12/20/2023] [Indexed: 02/03/2024]
Abstract
Genomic epidemiology holds promise for malaria control and elimination efforts, for example by informing on Plasmodium falciparum genetic diversity and prevalence of mutations conferring anti-malarial drug resistance. Limited sequencing infrastructure in many malaria-endemic areas prevents the rapid generation of genomic data. To address these issues, we developed and validated assays for P. falciparum nanopore sequencing in endemic sites using a mobile laboratory, targeting key antimalarial drug resistance markers and microhaplotypes. Using two multiplexed PCR reactions, we amplified six highly polymorphic microhaplotypes and ten drug resistance markers. We developed a bioinformatics workflow that allows genotyping of polyclonal malaria infections, including minority clones. We validated the panels on mock dried blood spot (DBS) and rapid diagnostic test (RDT) samples and archived DBS, demonstrating even, high read coverage across amplicons (range: 580x to 3,212x median coverage), high haplotype calling accuracy, and the ability to explore within-sample diversity of polyclonal infections. We field-tested the feasibility of rapid genotyping in Zanzibar in close collaboration with the local malaria elimination program using DBS and routinely collected RDTs as sample inputs. Our assay identified haplotypes known to confer resistance to known antimalarials in the dhfr, dhps and mdr1 genes, but no evidence of artemisinin partial resistance. Most infections (60%) were polyclonal, with high microhaplotype diversity (median HE = 0.94). In conclusion, our assays generated actionable data within a few days, and we identified current challenges for implementing nanopore sequencing in endemic countries to accelerate malaria control and elimination.
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Affiliation(s)
- Aurel Holzschuh
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
| | - Anita Lerch
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Bakar S. Fakih
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Safia Mohammed Aliy
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Mohamed Haji Ali
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Mohamed Ali Ali
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Daniel J. Bruzzese
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Joshua Yukich
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, United States of America
| | - Manuel W. Hetzel
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
| | - Cristian Koepfli
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
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Mkali HR, Lalji SM, Al-Mafazy AW, Joseph JJ, Mwaipape OS, Ali AS, Abbas FB, Ali MH, Hassan WS, Reaves EJ, Kitojo C, Serbantez N, Kabula BI, Nyinondi SS, McKay M, Cressman G, Ngondi JM, Reithinger R. How Real-Time Case-Based Malaria Surveillance Helps Zanzibar Get a Step Closer to Malaria Elimination: Description of Operational Platform and Resources. Glob Health Sci Pract 2023; 11:e2200522. [PMID: 37903584 PMCID: PMC10615242 DOI: 10.9745/ghsp-d-22-00522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 09/26/2023] [Indexed: 11/01/2023]
Abstract
Testing and treating asymptomatic populations have the potential to reduce the population's parasite reservoir and reduce malaria transmission. Zanzibar's malaria case notification (MCN) platform collects detailed sociodemographic and epidemiological data from all confirmed malaria cases to inform programmatic decision-making. We describe the design and operationalization process of the platform and other malaria surveillance resources that are enabling Zanzibar's progress toward malaria elimination.The MCN platform consists of an interactive short message service (SMS) system for case notification, a software application for Android mobile devices, a visual question set and workflow manager, a back-end database server, and a web browser-based application for data analytics, configuration, and management. Malaria case data were collected from August 2012 to December 2021 and reported via SMS from all public and private health facilities to a central database and then to district malaria surveillance officers' mobile devices. Data included patient names, shehia (administrative area), and date of diagnosis, enabling officers to track patients, ideally within 24 hours of reporting. Patients' household members were tested for malaria using conventional rapid diagnostic tests (RDTs). Treatment using artemisinin-based combination therapy was provided for persons testing positive.Between 2012 and 2021, a total of 48,899 index malaria cases were confirmed at health facilities, 22,152 (45.3%) within 24 hours of reporting; 41,886 (85.7%) cases were fully investigated and followed up to the household level. A total of 111,811 additional household members were tested with RDTs, of whom 10,602 (9.5%) were malaria positive.The MCN platform reports malaria case data in near real time, enabling prompt follow-up of index cases and prompt testing and treatment of members in index case households. Along with routine testing and treatment and other preventive interventions, the MCN platform is foundational to the programmatic efforts in further reducing malaria and ultimately eliminating autochthonous malaria transmission in Zanzibar.
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Affiliation(s)
| | - Shabbir M Lalji
- RTI International, Dar es Salaam, United Republic of Tanzania
| | | | - Joseph J Joseph
- RTI International, Dar es Salaam, United Republic of Tanzania
| | - Osia S Mwaipape
- RTI International, Dar es Salaam, United Republic of Tanzania
| | - Abdullah S Ali
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Faiza B Abbas
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Mohamed H Ali
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Wahida S Hassan
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Erik J Reaves
- U.S. President's Malaria Initiative, U.S. Centers for Disease Control and Prevention, Dar es Salaam, United Republic of Tanzania
| | - Chonge Kitojo
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Dar es Salaam, United Republic of Tanzania
| | - Naomi Serbantez
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Dar es Salaam, United Republic of Tanzania
| | - Bilali I Kabula
- RTI International, Dar es Salaam, United Republic of Tanzania
| | | | - Mike McKay
- RTI International, Research Triangle Park, USA
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Fakih BS, Holzschuh A, Ross A, Stuck L, Abdul R, Al-Mafazy AWH, Irema I, Mbena A, Thawer SG, Shija SJ, Aliy SM, Ali A, Fink G, Yukich J, Hetzel MW. Risk of imported malaria infections in Zanzibar: a cross-sectional study. Infect Dis Poverty 2023; 12:80. [PMID: 37641152 PMCID: PMC10464242 DOI: 10.1186/s40249-023-01129-5] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 08/11/2023] [Indexed: 08/31/2023] Open
Abstract
BACKGROUND Zanzibar has made substantial progress in malaria control with vector control, improved diagnosis, and artemisinin-based combination therapy. Parasite prevalence in the population has remained around 1% but imported infections from mainland Tanzania contribute to sustained local transmission. Understanding travel patterns between mainland Tanzania and Zanzibar, and the risk of malaria infection, may help to control malaria importation to Zanzibar. METHODS A rolling cross-sectional survey linked to routine reactive case detection of malaria was carried out in Zanzibar between May 2017 and October 2018. Households of patients diagnosed with malaria at health facilities were surveyed and household members were tested for malaria using rapid diagnostic tests and a sub-sample by quantitative PCR (qPCR). Interviews elicited a detailed travel history of all household members who had travelled within the past two months, including trips within and outside of Zanzibar. We estimated the association of malaria infection with travel destinations in pre-defined malaria endemicity categories, trip duration, and other co-variates using logistic regression. RESULTS Of 17,891 survey participants, 1177 (7%) reported a recent trip, of which 769 (65%) visited mainland Tanzania. Among travellers to mainland Tanzania with travel destination details and a qPCR result available, 241/378 (64%) reported traveling to districts with a 'high' malaria endemicity and for 12% the highest endemicity category was 'moderate'. Travelers to the mainland were more likely to be infected with malaria parasites (29%, 108/378) than those traveling within Zanzibar (8%, 16/206) or to other countries (6%, 2/17). Among travellers to mainland Tanzania, those visiting highly endemic districts had a higher odds of being qPCR-positive than those who travelled only to districts where malaria-endemicity was classified as low or very low (adjusted odd ratio = 7.0, 95% confidence interval: 1.9-25.5). Among travellers to the mainland, 110/378 (29%) never or only sometimes used a mosquito net during their travel. CONCLUSIONS Strategies to reduce malaria importation to Zanzibar may benefit from identifying population groups traveling to highly endemic areas in mainland Tanzania. Targeted interventions to prevent and clear infections in these groups may be more feasible than attempting to screen and treat all travellers upon arrival in Zanzibar.
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Affiliation(s)
- Bakar S Fakih
- Ifakara Health Institute, Dar es Salaam, Tanzania.
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.
- University of Basel, Basel, Switzerland.
| | - Aurel Holzschuh
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, USA
| | - Amanda Ross
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Logan Stuck
- Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
- Amsterdam Institute for Global Health and Development, Amsterdam, Netherlands
| | - Ramadhan Abdul
- Ifakara Health Institute, Dar es Salaam, Tanzania
- Amsterdam Institute for Global Health and Development, Amsterdam, Netherlands
| | | | - Imani Irema
- Ifakara Health Institute, Dar es Salaam, Tanzania
| | | | - Sumaiyya G Thawer
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Shija J Shija
- Zanzibar Malaria Elimination Programme, Zanzibar, United Republic of Tanzania
| | - Safia M Aliy
- Zanzibar Malaria Elimination Programme, Zanzibar, United Republic of Tanzania
| | - Abdullah Ali
- Zanzibar Malaria Elimination Programme, Zanzibar, United Republic of Tanzania
| | - Günther Fink
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Joshua Yukich
- Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
| | - Manuel W Hetzel
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
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Holzschuh A, Lerch A, Gerlovina I, Fakih BS, Al-Mafazy AWH, Reaves EJ, Ali A, Abbas F, Ali MH, Ali MA, Hetzel MW, Yukich J, Koepfli C. Multiplexed ddPCR-amplicon sequencing reveals isolated Plasmodium falciparum populations amenable to local elimination in Zanzibar, Tanzania. Nat Commun 2023; 14:3699. [PMID: 37349311 PMCID: PMC10287761 DOI: 10.1038/s41467-023-39417-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [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: 01/05/2023] [Accepted: 06/13/2023] [Indexed: 06/24/2023] Open
Abstract
Zanzibar has made significant progress toward malaria elimination, but recent stagnation requires novel approaches. We developed a highly multiplexed droplet digital PCR (ddPCR)-based amplicon sequencing method targeting 35 microhaplotypes and drug-resistance loci, and successfully sequenced 290 samples from five districts covering both main islands. Here, we elucidate fine-scale Plasmodium falciparum population structure and infer relatedness and connectivity of infections using an identity-by-descent (IBD) approach. Despite high genetic diversity, we observe pronounced fine-scale spatial and temporal parasite genetic structure. Clusters of near-clonal infections on Pemba indicate persistent local transmission with limited parasite importation, presenting an opportunity for local elimination efforts. Furthermore, we observe an admixed parasite population on Unguja and detect a substantial fraction (2.9%) of significantly related infection pairs between Zanzibar and the mainland, suggesting recent importation. Our study provides a high-resolution view of parasite genetic structure across the Zanzibar archipelago and provides actionable insights for prioritizing malaria elimination efforts.
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Affiliation(s)
- Aurel Holzschuh
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Indiana, IN, USA.
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland.
| | - Anita Lerch
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Indiana, IN, USA
| | - Inna Gerlovina
- EPPIcenter Research Program, Division of HIV, ID and Global Medicine, Department of Medicine, University of California, San Francisco, CA, USA
| | - Bakar S Fakih
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | | | - Erik J Reaves
- U.S. Centers for Disease Control and Prevention, President's Malaria Initiative, Dar es Salaam, United Republic of Tanzania
| | - Abdullah Ali
- Zanzibar Malaria Elimination Programme, Zanzibar, United Republic of Tanzania
| | - Faiza Abbas
- Zanzibar Malaria Elimination Programme, Zanzibar, United Republic of Tanzania
| | - Mohamed Haji Ali
- Zanzibar Malaria Elimination Programme, Zanzibar, United Republic of Tanzania
| | - Mohamed Ali Ali
- Zanzibar Malaria Elimination Programme, Zanzibar, United Republic of Tanzania
| | - Manuel W Hetzel
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Joshua Yukich
- School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA
| | - Cristian Koepfli
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Indiana, IN, USA.
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Ali MH, Kitau J, Ali AS, Al-Mafazy AW, Tegegne SG, Ussi O, Musanhu C, Shija SJ, Khatib BO, Mkali H, Mkude S, Makenga G, Kasagama E, Molteni F, Kisoka N, Kitojo C, Serbantez N, Reaves E, Yoti Z. Malaria elimination in Zanzibar: where next? Pan Afr Med J 2023; 45:7. [PMID: 37538363 PMCID: PMC10395111 DOI: 10.11604/pamj.supp.2023.45.1.39804] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 06/12/2023] [Indexed: 08/05/2023] Open
Abstract
In 2018, Zanzibar developed a national malaria strategic plan IV (2018-2023) to guide elimination of malaria by 2023. We assessed progress in the implementation of malaria activities as part of the end-term review of the strategic plan. The review was done between August and October 2022 following the WHO guideline to assess progress made towards malaria elimination, effectiveness of the health systems in delivering malaria case management; and malaria financing. A desk review examined available malaria data, annual work plans and implementation reports for evidence of implemented malaria activities. This was complemented by field visits to selected health facilities and communities by external experts, and interviews with health management teams and inhabitants to authenticate desk review findings. A steady increase in the annual parasite incidence (API) was observed in Zanzibar, from 2.7 (2017) to 3.6 (2021) cases per 1,000 population with marked heterogeneity between areas. However, about 68% of the detected malaria cases were imported into Zanzibar. Malaria case follow-up and investigation increased from <70% in 2017 to 94% and 96% respectively, in 2021. The review noted a 3.7-fold increase of the health allocation in the country's budget, from 31.7 million USD (2017/18) to 117.3 million USD (2022/23) but malaria allocation remained low (<1%). The varying transmission levels in the islands suggest a need for strategic re-orientation of the elimination attempts from a national-wide to a sub-national agenda. We recommend increasing malaria allocation from the health budget to ensure sustainability of malaria elimination interventions.
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Affiliation(s)
- Mohamed Haji Ali
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, Tanzania
| | - Jovin Kitau
- World Health Organization, Country office, Dar-es-Salaam, Tanzania
| | | | - Abdul-wahid Al-Mafazy
- Second Vice President Office-Zanzibar Country Coordinating Mechanism, Zanzibar, Tanzania
| | | | - Omar Ussi
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, Tanzania
| | | | - Shija Joseph Shija
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, Tanzania
| | - Bakari Omar Khatib
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, Tanzania
| | - Humphrey Mkali
- Population Services International, Dar-es-Salaam, Tanzania
| | - Sigsbert Mkude
- Population Services International, Dar-es-Salaam, Tanzania
| | | | | | - Fabrizio Molteni
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
| | - Noela Kisoka
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
| | - Chonge Kitojo
- US President´s Malaria Initiative, United States Agency for International Development, Dar-es-Salaam, United Republic of Tanzania
| | - Naomi Serbantez
- US President´s Malaria Initiative, United States Agency for International Development, Dar-es-Salaam, United Republic of Tanzania
| | - Erik Reaves
- United States Centers for Disease Control, Dar-es-Salaam, Tanzania
| | - Zabulon Yoti
- World Health Organization, Country office, Dar-es-Salaam, Tanzania
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7
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Aidoo EK, Aboagye FT, Botchway FA, Osei-Adjei G, Appiah M, Duku-Takyi R, Sakyi SA, Amoah L, Badu K, Asmah RH, Lawson BW, Krogfelt KA. Reactive Case Detection Strategy for Malaria Control and Elimination: A 12 Year Systematic Review and Meta-Analysis from 25 Malaria-Endemic Countries. Trop Med Infect Dis 2023; 8:tropicalmed8030180. [PMID: 36977181 PMCID: PMC10058581 DOI: 10.3390/tropicalmed8030180] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/23/2023] [Accepted: 03/09/2023] [Indexed: 03/30/2023] Open
Abstract
Reactive case detection (RACD) is the screening of household members and neighbors of index cases reported in passive surveillance. This strategy seeks asymptomatic infections and provides treatment to break transmission without testing or treating the entire population. This review discusses and highlights RACD as a recommended strategy for the detection and elimination of asymptomatic malaria as it pertains in different countries. Relevant studies published between January 2010 and September 2022 were identified mainly through PubMed and Google Scholar. Search terms included "malaria and reactive case detection", "contact tracing", "focal screening", "case investigation", "focal screen and treat". MedCalc Software was used for data analysis, and the findings from the pooled studies were analyzed using a fixed-effect model. Summary outcomes were then presented using forest plots and tables. Fifty-four (54) studies were systematically reviewed. Of these studies, 7 met the eligibility criteria based on risk of malaria infection in individuals living with an index case < 5 years old, 13 met the eligibility criteria based on risk of malaria infection in an index case household member compared with a neighbor of an index case, and 29 met the eligibility criteria based on risk of malaria infection in individuals living with index cases, and were included in the meta-analysis. Individuals living in index case households with an average risk of 2.576 (2.540-2.612) were more at risk of malaria infection and showed pooled results of high variation heterogeneity chi-square = 235.600, (p < 0.0001) I2 = 98.88 [97.87-99.89]. The pooled results showed that neighbors of index cases were 0.352 [0.301-0.412] times more likely to have a malaria infection relative to index case household members, and this result was statistically significant (p < 0.001). The identification and treatment of infectious reservoirs is critical to successful malaria elimination. Evidence to support the clustering of infections in neighborhoods, which necessitates the inclusion of neighboring households as part of the RACD strategy, was presented in this review.
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Affiliation(s)
- Ebenezer Krampah Aidoo
- Department of Medical Laboratory Technology, Accra Technical University, Accra GP 561, Ghana
| | - Frank Twum Aboagye
- Biomedical and Public Health Research Unit, Council for Scientific and Industrial Research-Water Research Institute, Accra AH 38, Ghana
| | - Felix Abekah Botchway
- Department of Medical Laboratory Technology, Accra Technical University, Accra GP 561, Ghana
| | - George Osei-Adjei
- Department of Medical Laboratory Technology, Accra Technical University, Accra GP 561, Ghana
| | - Michael Appiah
- Department of Medical Laboratory Technology, Accra Technical University, Accra GP 561, Ghana
| | - Ruth Duku-Takyi
- Department of Medical Laboratory Technology, Accra Technical University, Accra GP 561, Ghana
| | - Samuel Asamoah Sakyi
- Department of Molecular Medicine, Kwame Nkrumah University of Science & Technology, University Post Office, Kumasi AK 039, Ghana
| | - Linda Amoah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra LG 581, Ghana
| | - Kingsley Badu
- Department of Theoretical & Applied Biology, Kwame Nkrumah University of Science & Technology, University Post Office, Kumasi AK 039, Ghana
| | - Richard Harry Asmah
- Department of Biomedical Sciences, School of Basic and Biomedical Science, University of Health & Allied Sciences, Ho PMB 31, Ghana
| | - Bernard Walter Lawson
- Department of Theoretical & Applied Biology, Kwame Nkrumah University of Science & Technology, University Post Office, Kumasi AK 039, Ghana
| | - Karen Angeliki Krogfelt
- Department of Science and Environment, Unit of Molecular and Medical Biology, The PandemiX Center, Roskilde University, 4000 Roskilde, Denmark
- Department of Virus and Microbiological Special Diagnostics, Statens Serum Institut, 2300 Copenhagen, Denmark
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8
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Hergott DEB, Owalla TJ, Balkus JE, Apio B, Lema J, Cemeri B, Akileng A, Seilie AM, Chavtur C, Staubus W, Chang M, Egwang TG, Murphy SC. Feasibility of community at-home dried blood spot collection combined with pooled reverse transcription PCR as a viable and convenient method for malaria epidemiology studies. Malar J 2022; 21:221. [PMID: 35836179 PMCID: PMC9284728 DOI: 10.1186/s12936-022-04239-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [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: 04/06/2022] [Accepted: 06/26/2022] [Indexed: 01/08/2023] Open
Abstract
Background Many Plasmodium infections in endemic regions exist at densities below the limit of detection of standard diagnostic tools. These infections threaten control efforts and may impact vaccine and therapeutic drug studies. Simple, cost-effective methods are needed to study the natural history of asymptomatic submicroscopic parasitaemia. Self-collected dried blood spots (DBS) analysed using pooled and individual quantitative reverse transcription polymerase chain reaction (qRT-PCR) provide such a solution. Here, the feasibility and acceptability of daily at-home DBS collections for qRT-PCR was studied to better understand low-density infections. Methods Rapid diagnostic test (RDT)-negative individuals in Katakwi District, northeastern Uganda, were recruited between April and May 2021. Venous blood samples and clinic-collected DBS were taken at enrollment and at four weekly clinic visits. Participants were trained in DBS collection and asked to collect six DBS weekly between clinic visits. Opinions about the collection process were solicited using daily Diary Cards and a Likert scale survey at the final study visit. Venous blood and DBS were analysed by Plasmodium 18S rRNA qRT-PCR. The number of participants completing the study, total DBS collected, and opinions of the process were analysed to determine compliance and acceptability. The human internal control mRNA and Plasmodium 18S rRNA were evaluated for at-home vs. clinic-collected DBS and venous blood to assess quality and accuracy of at-home collected samples. Results One-hundred two adults and 29 children were enrolled, and 95 and 26 completed the study, respectively. Three individuals withdrew due to pain or inconvenience of procedures. Overall, 96% of participants collected ≥ 16 of 24 at-home DBS, and 87% of DBS contained ≥ 40 µL of blood. The procedure was well tolerated and viewed favourably by participants. At-home collected DBS were acceptable for qRT-PCR and showed less than a one qRT-PCR cycle threshold shift in the human control mRNA compared to clinic-collected DBS. Correlation between Plasmodium falciparum 18S rRNA from paired whole blood and DBS was high (R = 0.93). Conclusions At-home DBS collection is a feasible, acceptable, and robust method to obtain blood to evaluate the natural history of low-density Plasmodium infections by qRT-PCR. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04239-x.
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Affiliation(s)
- Dianna E B Hergott
- Department of Laboratory Medicine and Pathology, University of Washington, 750 Republican St., F870, Seattle, WA, 98109, USA.,Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA, USA
| | - Tonny J Owalla
- Med Biotech Laboratories, P.O. Box 9364, Kampala, Uganda
| | - Jennifer E Balkus
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA, USA
| | | | - Jimmy Lema
- Med Biotech Laboratories, P.O. Box 9364, Kampala, Uganda
| | - Barbara Cemeri
- Med Biotech Laboratories, P.O. Box 9364, Kampala, Uganda
| | - Andrew Akileng
- Med Biotech Laboratories, P.O. Box 9364, Kampala, Uganda
| | - Annette M Seilie
- Department of Laboratory Medicine and Pathology, University of Washington, 750 Republican St., F870, Seattle, WA, 98109, USA.,Center for Emerging and Re-Emerging Infectious Diseases, University of Washington, Seattle, WA, USA
| | - Chris Chavtur
- Department of Laboratory Medicine and Pathology, University of Washington, 750 Republican St., F870, Seattle, WA, 98109, USA.,Center for Emerging and Re-Emerging Infectious Diseases, University of Washington, Seattle, WA, USA
| | - Weston Staubus
- Department of Laboratory Medicine and Pathology, University of Washington, 750 Republican St., F870, Seattle, WA, 98109, USA.,Center for Emerging and Re-Emerging Infectious Diseases, University of Washington, Seattle, WA, USA
| | - Ming Chang
- Department of Laboratory Medicine and Pathology, University of Washington, 750 Republican St., F870, Seattle, WA, 98109, USA.,Center for Emerging and Re-Emerging Infectious Diseases, University of Washington, Seattle, WA, USA
| | | | - Sean C Murphy
- Department of Laboratory Medicine and Pathology, University of Washington, 750 Republican St., F870, Seattle, WA, 98109, USA. .,Center for Emerging and Re-Emerging Infectious Diseases, University of Washington, Seattle, WA, USA. .,Department of Microbiology, University of Washington, Seattle, WA, USA.
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9
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Oyegoke OO, Akoniyon OP, Ogunsakin RE, Ogunlana MO, Adeleke MA, Maharaj R, Okpeku M. A Systematic Review and Meta-Analysis of Malaria Test Positivity Outcomes and Programme Interventions in Low Transmission Settings in Southern Africa, 2000-2021. Int J Environ Res Public Health 2022; 19. [PMID: 35682356 DOI: 10.3390/ijerph19116776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 04/27/2022] [Accepted: 05/04/2022] [Indexed: 02/01/2023]
Abstract
Malaria is one of the most significant causes of mortality and morbidity globally, especially in sub-Saharan Africa (SSA) countries. It harmfully disturbs the public’s health and the economic growth of many developing countries. Despite the massive effect of malaria transmission, the overall pooled proportion of malaria positivity rate in Southern Africa is still elusive. Therefore, the objective of this systematic review and meta-analysis is to pool estimates of the incidence of the malaria positivity rate, which is the first of its kind in South African countries. A literature search is performed to identify all published articles reporting the incidence of malaria positivity in Southern Africa. Out of the 3359 articles identified, 17 studies meet the inclusion for systematic review and meta-analysis. In addition, because substantial heterogeneity is expected due to the studies being extracted from the universal population, random-effects meta-analyses are carried out to pool the incidence of the malaria positivity rate from diverse diagnostic methods. The result reveals that between-study variability is high (τ2 = 0.003; heterogeneity I2 = 99.91% with heterogeneity chi-square χ2 = 18,143.95, degree of freedom = 16 and a p-value < 0.0001) with the overall random pooled incidence of 10% (95%CI: 8−13%, I2 = 99.91%) in the malaria positivity rate. According to the diagnostic method called pooled incidence estimate, the rapid diagnostic test (RDT) is the leading diagnostic method (17%, 95%CI: 11−24%, I2 = 99.95%), followed by RDT and qPCR and RDT and loop mediated isothermal amplification (LAMP), respectively, found to be (3%, 95%CI: 2−3%, I2 = 0%) and (2%, 95%CI: 1−3%, I2 = 97.94%).Findings of the present study suggest high malaria positive incidence in the region. This implies that malaria control and elimination programmes towards malaria elimination could be negatively impacted and cause delays in actualising malaria elimination set dates. Further studies consisting of larger samples and continuous evaluation of malaria control programmes are recommended.
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10
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Holzschuh A, Koepfli C. Tenfold difference in DNA recovery rate: systematic comparison of whole blood vs. dried blood spot sample collection for malaria molecular surveillance. Malar J 2022; 21:88. [PMID: 35292038 DOI: 10.1186/s12936-022-04122-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 03/07/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Molecular and genomic surveillance is becoming increasingly used to track malaria control and elimination efforts. Blood samples can be collected as whole blood and stored at - 20 °C until DNA extraction, or as dried blood spots (DBS), circumventing the need for a cold chain. Despite the wide use of either method, systematic comparisons of how the method of blood sample preservation affects the limit of detection (LOD) of molecular diagnosis and the proportion of DNA recovered for downstream applications are lacking. METHODS Extractions based on spin columns, magnetic beads, Tween-Chelex, and direct PCR without prior extraction were compared for whole blood and dried blood spots (DBS) using dilution series of Plasmodium falciparum culture samples. Extracted DNA was quantified by qPCR and droplet digital PCR (ddPCR). RESULTS DNA recovery was 5- to 10-fold higher for whole blood compared to DBS, resulting in a 2- to 3-fold lower LOD for both extraction methods compared to DBS. For whole blood, a magnetic bead-based method resulted in a DNA recovery rate of 88-98% when extracting from whole blood compared to 17-33% for a spin-column based method. For extractions from DBS, the magnetic bead-based method resulted in 8-20% DNA recovery, while the spin-column based method resulted in only 2% DNA recovery. The Tween-Chelex method was superior to other methods with 15-21% DNA recovery, and even more sensitive than extractions from whole blood samples. The direct PCR method was found to have the lowest LOD overall for both, whole blood and DBS. CONCLUSIONS Pronounced differences in LOD and DNA yield need to be considered when comparing prevalence estimates based on molecular methods and when selecting sampling protocols for other molecular surveillance applications.
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11
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Onken A, Haanshuus CG, Miraji MK, Marijani M, Kibwana KO, Abeid KA, Mørch K, Reimers M, Langeland N, Müller F, Jenum PA, Blomberg B. Malaria prevalence and performance of diagnostic tests among patients hospitalized with acute undifferentiated fever in Zanzibar. Malar J 2022; 21:54. [PMID: 35183188 PMCID: PMC8858509 DOI: 10.1186/s12936-022-04067-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 01/31/2022] [Indexed: 12/04/2022] Open
Abstract
Background Control efforts in Zanzibar reduced the burden of malaria substantially from 2000 to 2015, but re-emergence of falciparum malaria has been observed lately. This study evaluated the prevalence of malaria and performance of routine diagnostic tests among hospitalized fever patients in a 1.5 years period in 2015 and 2016. Methods From March 2015 to October 2016, paediatric and adult patients hospitalized with acute undifferentiated fever at Mnazi Mmoja Hospital, Zanzibar were included. The malaria prevalence, and performance of rapid diagnostic test (RDT) and microscopy, were assessed using polymerase chain reaction (PCR) as gold standard. Results The malaria prevalence was 9% (63/731). Children under 5 years old had lower malaria prevalence (5%, 14/260) than older children (15%, 20/131, p = 0.001) and persons aged 16 to 30 years (13%, 15/119, p = 0.02), but not different from persons over 30 years old (6%, 14/217, p = 0.7). All cases had Plasmodium falciparum infection, except for one case of Plasmodium ovale. Ten malaria patients had no history of visiting mainland Tanzania. The RDT had a sensitivity of 64% (36/56) and a specificity of 98% (561/575), and microscopy had a sensitivity of 50% (18/36) and a specificity of 99% (251/254), compared to PCR. The malaria parasitaemia was lower in patients with false negative results on RDT (median 7 × 103 copies/µL, interquartile range [IQR] 2 × 103 – 8 × 104, p = 0.002) and microscopy (median 9 × 103 copies/µL, IQR 8 × 102 – 7 × 104, p = 0.006) compared to those with true positive RDT (median 2 × 105 copies/µL, IQR 3 × 104 – 5 × 105) and microscopy (median 2 × 105 copies/µL, IQR 6 × 104 – 5 × 105). Conclusions The study emphasizes that malaria was a frequent cause of febrile illness in hospitalized patients in Zanzibar in the years 2015-2016, particularly among school age children and young adults. We found evidence of autochthonous malaria transmission in Zanzibar. Compared to PCR, both RDT and microscopy had low sensitivity, and false negative results were associated with low parasitaemia. While low parasitaemia identified only by PCR in a semi-immune individual could be coincidental and without clinical relevance, clinicians should be aware of the risk of false negative results on routine tests.
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12
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Pujo JM, Houcke S, Lemmonier S, Portecop P, Frémery A, Blanchet D, Djossou F, Kallel H, Demar M. Accuracy of SD Malaria Ag P.f/Pan® as a rapid diagnostic test in French Amazonia. Malar J 2021; 20:369. [PMID: 34535137 PMCID: PMC8447521 DOI: 10.1186/s12936-021-03902-z] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 09/02/2021] [Indexed: 12/04/2022] Open
Abstract
Background French Guiana (FG) is a French overseas territory where malaria is endemic. The current incidence rate is 0.74‰ inhabitants, and Plasmodium vivax is widely predominating even though Plasmodium falciparum is still present due to imported cases mainly from Africa. In FG, rapid diagnostic test (SD Malaria Ag P.f/Pan®) is based on the detection of pan-pLDH, PfHRP2, and PfHRP3 antigens, while in South America, the share of deletion of PfHRP2 gene is significantly increasing. Accordingly, the study questions the reliability of RDTs in the Amazonian context. Methods The study is retrospective. It is conducted over 4 years and analysed 12,880 rapid diagnostic tests (RDTs) compared to concomitant Blood Film Tests (BFTs) sampled for malaria diagnosis. Results The global assessment of the accuracy of SD Malaria Ag P.f/Pan® in the diagnostic of malaria shows both Positive and Negative Predictive Values (PPV and NPV) higher than 95%, except for PPV in the diagnosis of malaria to P. falciparum (88%). Overall, the concordance rate between RDT and BFT (positive/positive; negative/negative) was 99.5%. The PPV of the RDT in the follow-up of patients diagnosed with P. falciparum was the lowest during the first 28 days. The PPV of the RDT in the follow-up of patients diagnosed with P. vivax was the lowest during the first 21 days. The global sensitivity of SD Malaria Ag P.f/Pan® test was, on average, 96% (88.2–100) for P. falciparum and 93% (90.6–94.2) for P. vivax. The global specificity was 99.8% (99.5–100) for all included species. Conclusion SD Malaria Ag P.f/Pan® is a reliable rapid test used for the first-line diagnosis in remote healthcare centres. The test results should be interpreted in the light of patient’s recent medical history and the date of arrival to FG.
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Affiliation(s)
- Jean Marc Pujo
- Emergency Department, Cayenne General Hospital, Cayenne, French Guiana.
| | - Stéphanie Houcke
- Intensive Care Unit, Cayenne General Hospital, Cayenne, French Guiana
| | - Sarah Lemmonier
- Emergency Department, Cayenne General Hospital, Cayenne, French Guiana
| | - Patrick Portecop
- Emergency Department, Guadeloupe University Hospital, Les Abymes, Guadeloupe
| | - Alexis Frémery
- Emergency Department, Cayenne General Hospital, Cayenne, French Guiana
| | - Denis Blanchet
- Academic Laboratory of Parasitology-Mycology, Cayenne General Hospital, Cayenne, French Guiana.,Tropical Biome and Immunophysiopathology (TBIP), Université de Guyane, Cayenne, 97300, French Guiana.,Université de Lille, CNRS, Inserm, Institut Pasteur de Lille, U1019-UMR9017-CIIL Centre d'Infection Et d'Immunité de Lille, 59000, Lille, France
| | - Felix Djossou
- Infectious and Tropical Diseases Unit, Cayenne General Hospital, Cayenne, French Guiana
| | - Hatem Kallel
- Intensive Care Unit, Cayenne General Hospital, Cayenne, French Guiana.,Tropical Biome and Immunophysiopathology (TBIP), Université de Guyane, Cayenne, 97300, French Guiana.,Université de Lille, CNRS, Inserm, Institut Pasteur de Lille, U1019-UMR9017-CIIL Centre d'Infection Et d'Immunité de Lille, 59000, Lille, France
| | - Magalie Demar
- Academic Laboratory of Parasitology-Mycology, Cayenne General Hospital, Cayenne, French Guiana.,Tropical Biome and Immunophysiopathology (TBIP), Université de Guyane, Cayenne, 97300, French Guiana.,Université de Lille, CNRS, Inserm, Institut Pasteur de Lille, U1019-UMR9017-CIIL Centre d'Infection Et d'Immunité de Lille, 59000, Lille, France
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13
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Mavridis K, Michaelidou K, Vontas J. Highly sensitive droplet digital PCR-based diagnostics for the surveillance of malaria vector populations in low transmission and incipient resistance settings. Expert Rev Mol Diagn 2021; 21:1105-1114. [PMID: 34328051 DOI: 10.1080/14737159.2021.1963234] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Sensitive monitoring of Plasmodium infective mosquitoes in low malaria transmission settings is of high priority for disease control. Early detection of insecticide resistance at low frequencies is also key for vector monitoring nowadays, when new insecticides are launched to control vector populations. RESEARCH DESIGN AND METHODS An. gambiae mosquitoes with predetermined infection and resistance status were used to produce populations with various malaria infection rates and mutant allelic frequencies (MAFs) of target site insecticide resistance traits. Total RNA and gDNA were isolated and used in droplet Digital PCR (ddPCR) and Reverse Transcription (RT) ddPCR performed in the QX200 ddPCR System. RESULTS We developed a novel ddPCR for detecting P. falciparum DNA in pooled mosquito head-thoraces with infective rate as low as 1.0%. A dissection-free RT-ddPCR assay for specific infective-stage detection was additionally developed and validated (accuracy = 100%) in mosquito pools with infective rates down to 1.0%. A novel ddPCR assay for insecticide resistant alleles, which was able to reliably quantify MAFs as low as 0.050% in pooled mosquito specimens, is also reported. CONCLUSIONS We developed highly sensitive and efficient (RT-) ddPCR assays for contemporary operational needs that require monitoring of low malaria transmission and emerging insecticide resistance.
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Affiliation(s)
- Konstantinos Mavridis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
| | - Kleita Michaelidou
- Laboratory of Translational Oncology, School of Medicine, University of Crete, Heraklion, Greece
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece.,Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, Athens, Greece
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14
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Kavanaugh MJ, Azzam SE, Rockabrand DM. Malaria Rapid Diagnostic Tests: Literary Review and Recommendation for a Quality Assurance, Quality Control Algorithm. Diagnostics (Basel) 2021; 11:768. [PMID: 33922917 DOI: 10.3390/diagnostics11050768] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 01/24/2023] Open
Abstract
Malaria rapid diagnostic tests (RDTs) have had an enormous global impact which contributed to the World Health Organization paradigm shift from empiric treatment to obtaining a parasitological diagnosis prior to treatment. Microscopy, the classic standard, requires significant expertise, equipment, electricity, and reagents. Alternatively, RDT’s lower complexity allows utilization in austere environments while achieving similar sensitivities and specificities. Worldwide, there are over 200 different RDT brands that utilize three antigens: Plasmodium histidine-rich protein 2 (PfHRP-2), Plasmodium lactate dehydrogenase (pLDH), and Plasmodium aldolase (pALDO). pfHRP-2 is produced exclusively by Plasmodium falciparum and is very Pf sensitive, but an alternative antigen or antigen combination is required for regions like Asia with significant Plasmodium vivax prevalence. RDT sensitivity also decreases with low parasitemia (<100 parasites/uL), genetic variability, and prozone effect. Thus, proper RDT selection and understanding of test limitations are essential. The Center for Disease Control recommends confirming RDT results by microscopy, but this is challenging, due to the utilization of clinical laboratory standards, like the College of American Pathologists (CAP) and the Clinical Lab Improvement Act (CLIA), and limited recourses. Our focus is to provide quality assurance and quality control strategies for resource-constrained environments and provide education on RDT limitations.
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15
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Searle KM, Katowa B, Musonda M, Pringle JC, Hamapumbu H, Matoba J, Lubinda M, Shields T, Kobayashi T, Stevenson JC, Norris DE, Thuma PE, Wesolowski A, Moss WJ, For The Southern And Central Africa International Center Of Excellence For Malaria Research. Sustained Malaria Transmission despite Reactive Screen-and-Treat in a Low-Transmission Area of Southern Zambia. Am J Trop Med Hyg 2020; 104:671-679. [PMID: 33236715 PMCID: PMC7866307 DOI: 10.4269/ajtmh.20-0947] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [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: 08/03/2020] [Accepted: 09/28/2020] [Indexed: 12/30/2022] Open
Abstract
Malaria elimination strategies are designed to more effectively identify and treat infected individuals to interrupt transmission. One strategy, reactive screen-and-treat, starts with passive detection of symptomatic cases at health facilities. Individuals residing within the index case and neighboring households are screened with a malaria rapid diagnostic test (RDT) and treated if positive. However, it is unclear to what extent this strategy is effective in reducing transmission. Reactive screen-and-treat was implemented in Choma district, Southern Province, Zambia, in 2013, in which residents of the index case and neighboring households within 140 m were screened with an RDT. From March 2016 to July 2018, the screening radius was extended to 250-m, and additional follow-up visits at 30 and 90 days were added to evaluate the strategy. Plasmodium falciparum parasite prevalence was measured using an RDT and by quantitative PCR (qPCR). A 24-single nucleotide polymorphism molecular bar-code assay was used to genotype parasites. Eighty-four index case households with 676 residents were enrolled between March 2016 and March 2018. Within each season, parasite prevalence declined significantly in index households at the 30-day visit and remained low at the 90-day visit. However, parasite prevalence was not reduced to zero. Infections identified by qPCR persisted between study visits and were not identified by RDT. Parasites identified within the same household were most genetically related; however, overall parasite relatedness was low and similar across time and space. Thus, despite implementation of a reactive screen-and-treat program, parasitemia was not eliminated, and persisted in targeted households for at least 3 months.
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Affiliation(s)
- Kelly M Searle
- Division of Epidemiology and Community Health, University of Minnesota School of Public Health, Minneapolis, Minnesota
| | | | | | - Julia C Pringle
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | | | | | - Timothy Shields
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Tamaki Kobayashi
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Jennifer C Stevenson
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.,Macha Research Trust, Macha, Zambia
| | - Douglas E Norris
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Philip E Thuma
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.,Macha Research Trust, Macha, Zambia
| | - Amy Wesolowski
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - William J Moss
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.,W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
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16
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Stuck L, Fakih BS, Al-Mafazy AWH, Hofmann NE, Holzschuh A, Grossenbacher B, Bennett A, Cotter C, Reaves E, Ali A, der Horst TV, Felger I, Hetzel MW, Yukich J. Malaria infection prevalence and sensitivity of reactive case detection in Zanzibar. Int J Infect Dis 2020; 97:337-346. [PMID: 32534138 PMCID: PMC8450816 DOI: 10.1016/j.ijid.2020.06.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [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: 04/17/2020] [Revised: 06/04/2020] [Accepted: 06/05/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Reactive case detection (RCD) is a commonly used strategy for malaria surveillance and response in elimination settings. Many approaches to RCD assume detectable infections are clustered within and around homes of passively detected cases (index households), which has been evaluated in a number of settings with disparate results. METHODS Household questionnaires and diagnostic testing were conducted following RCD investigations in Zanzibar, Tanzania, including the index household and up to 9 additional neighboring households. RESULTS Of 12,487 participants tested by malaria rapid diagnostic test (RDT), 3·2% of those residing in index households and 0·4% of those residing in non-index households tested positive (OR = 8·4; 95%CI: 5·7, 12·5). Of 6,281 participants tested by quantitative polymerase chain reaction (qPCR), 8·4% of those residing in index households and 1·3% of those residing in non-index households tested positive (OR = 7·1; 95%CI: 6·1, 10·9). Within households of index cases defined as imported, odds of qPCR-positivity amongst members reporting recent travel were 1·4 times higher than among those without travel history (95%CI: 0·2, 4·4). Amongst non-index households, odds of qPCR-detectable infection were no different between households located within 50 m of the index household as compared with those located farther away (OR = 0·8, 95%CI: 0·5, 1·4). Sensitivity of RDT to detect qPCR-detectable infections was 34% (95%CI: 26·4, 42·3). CONCLUSIONS Malaria prevalence in index households in Zanzibar is much higher than in non-index households, in which prevalence is very low. Travelers represent a high-risk population. Low sensitivity of RDTs due to a high prevalence of low-density infections results in an RCD system missing a large proportion of the parasite reservoir.
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Affiliation(s)
- Logan Stuck
- Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA.
| | - Bakar S Fakih
- Ifakara Health Institute, Dar es Salaam, United Republic of Tanzania
| | - Abdul-Wahid H Al-Mafazy
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Natalie E Hofmann
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Aurel Holzschuh
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Benjamin Grossenbacher
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Adam Bennett
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, CA, USA
| | - Chris Cotter
- Malaria Elimination Initiative, Global Health Group, University of California, San Francisco, CA, USA
| | - Erik Reaves
- U.S. President's Malaria Initiative, Malaria Branch, U.S. Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Abdullah Ali
- Zanzibar Malaria Elimination Programme, Ministry of Health, Zanzibar, United Republic of Tanzania
| | - Tina van der Horst
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Ingrid Felger
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Manuel W Hetzel
- Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland
| | - Joshua Yukich
- Tulane School of Public Health and Tropical Medicine, New Orleans, LA, USA
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17
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Affiliation(s)
- Manuel W Hetzel
- Swiss Tropical and Public Health Institute, 4002 Basel, Switzerland; University of Basel, Basel, Switzerland.
| | - Nakul Chitnis
- Swiss Tropical and Public Health Institute, 4002 Basel, Switzerland; University of Basel, Basel, Switzerland
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