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Ramesh A, Oliveira P, Cameron M, Castanha PMS, Walker T, Lenhart A, Impoinvil L, Alexander N, Medeiros Z, Sá A, Rocha A, Souza WV, Maciel A, Braga C. Postintervention Immunological and Entomological Survey of Lymphatic Filariasis in the City of Olinda, Brazil, 2015-2016. Am J Trop Med Hyg 2024; 110:470-482. [PMID: 38350158 PMCID: PMC10919178 DOI: 10.4269/ajtmh.23-0174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 11/05/2023] [Indexed: 02/15/2024] Open
Abstract
Lymphatic filariasis (LF) is a leading cause of disability due to infectious disease worldwide. The Recife Metropolitan Region (RMR) is the only remaining focus of LF in Brazil, where the parasite Wuchereria bancrofti is transmitted solely by the mosquito Culex quinquefasciatus. This study reports the results of transmission assessment surveys and molecular xenomonitoring in the city of Olinda, RMR, after nearly 15 years (2015-2016) of interventions for LF elimination. Participants were screened for W. bancrofti antigen via immunochromatographic card tests (ICT) in: 1) door-to-door surveys conducted for all children aged 5-7 years from 4 out of 17 intervention areas treated with at least five annual doses of mass drug administration (MDA), and 2) a two-stage cluster sampling survey of residents aged 5 years and older in non-MDA areas. Mosquitoes were collected via handheld aspirators in four MDA areas, differentiated by species, sex, and physiological status, pooled into groups of up to 10 blood-fed, semigravid, and gravid mosquitoes, and screened for W. bancrofti infection by real-time quantitative polymerase chain reaction (RT-qPCR). All 1,170 children from MDA areas and the entire population sample of 990 residents in non-MDA areas were ICT negative. In MDA areas, a total of 3,152 female Cx. quinquefasciatus mosquitoes in 277 households (range, 0-296 mosquitoes per house) were collected via aspiration. RT-qPCR of 233 pools of mosquitos were negative for W. bancrofti RNA; an independent reference laboratory confirmed these results. These results provide evidence that LF transmission has been halted in this setting.
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Affiliation(s)
- Anita Ramesh
- Department of Parasitology, Instituto Aggeu Magalhães/Fundação Oswaldo Cruz (FIOCRUZ), Recife, Brazil
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Paula Oliveira
- National Reference Service for Lymphatic Filariasis, Department of Parasitology, Instituto Aggeu Magalhães/FIOCRUZ, Recife, Brazil
| | - Mary Cameron
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Priscila M. S. Castanha
- Faculty of Medical Science, University of Pernambuco, Recife, Brazil
- School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Thomas Walker
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
- School of Life Sciences, The University of Warwick, Coventry, United Kingdom
| | - Audrey Lenhart
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Lucy Impoinvil
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Neal Alexander
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Zulma Medeiros
- Department of Parasitology, Instituto Aggeu Magalhães/Fundação Oswaldo Cruz (FIOCRUZ), Recife, Brazil
| | - André Sá
- Collective Health Department, Instituto Aggeu Magalhães/FIOCRUZ
| | - Abraham Rocha
- National Reference Service for Lymphatic Filariasis, Department of Parasitology, Instituto Aggeu Magalhães/FIOCRUZ, Recife, Brazil
| | - Wayner V. Souza
- Collective Health Department, Instituto Aggeu Magalhães/FIOCRUZ
| | - Amélia Maciel
- Department of Tropical Medicine, Federal University of Pernambuco, Recife, Brazil
| | - Cynthia Braga
- Department of Parasitology, Instituto Aggeu Magalhães/Fundação Oswaldo Cruz (FIOCRUZ), Recife, Brazil
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Alenou LD, Nwane P, Mbakop LR, Piameu M, Ekoko W, Mandeng S, Bikoy EN, Toto JC, Onguina H, Etang J. Burden of mosquito-borne diseases across rural versus urban areas in Cameroon between 2002 and 2021: prospective for community-oriented vector management approaches. Parasit Vectors 2023; 16:136. [PMID: 37076896 PMCID: PMC10114431 DOI: 10.1186/s13071-023-05737-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 03/12/2023] [Indexed: 04/21/2023] Open
Abstract
BACKGROUND Over the past two decades, Cameroon has recorded one of the highest rates of urban population growth in sub-Saharan Africa. It is estimated that more than 67% of Cameroon's urban population lives in slums, and the situation is far from improving as these neighbourhoods are growing at an annual rate of 5.5%. However, it is not known how this rapid and uncontrolled urbanization affects vector populations and disease transmission in urban versus rural areas. In this study, we analyse data from studies conducted on mosquito-borne diseases in Cameroon between 2002 and 2021 to determine the distribution of mosquito species and the prevalence of diseases they transmit with regards to urban areas versus rural areas. METHODS A search of various online databases, such as PubMed, Hinari, Google and Google Scholar, was conducted for relevant articles. A total of 85 publications/reports were identified and reviewed for entomological and epidemiological data from the ten regions of Cameroon. RESULTS Analysis of the findings from the reviewed articles revealed 10 diseases transmitted by mosquitoes to humans across the study regions. Most of these diseases were recorded in the Northwest Region, followed by the North, Far North and Eastern Regions. Data were collected from 37 urban and 28 rural sites. In the urban areas, dengue prevalence increased from 14.55% (95% confidence interval [CI] 5.2-23.9%) in 2002-2011 to 29.84% (95% CI 21-38.7%) in 2012-2021. In rural areas, diseases such as Lymphatic filariasis and Rift valley fever, which were not present in 2002-2011, appeared in 2012-2021, with a prevalence of 0.4% (95% CI 0.0- 2.4%) and 10% (95% CI 0.6-19.4%), respectively. Malaria prevalence remained the same in urban areas (67%; 95% CI 55.6-78.4%) between the two periods, while it significantly decreased in rural areas from 45.87% (95% CI 31.1-60.6%) in 2002-2011 to 39% (95% CI 23.7-54.3%) in the 2012-2021 period (*P = 0.04). Seventeen species of mosquitoes were identified as involved in the transmission of these diseases, of which 11 were involved in the transmission of malaria, five in the transmission of arboviruses and one in the transmission of malaria and lymphatic filariasis. The diversity of mosquito species was greater in rural areas than in urban areas during both periods. Of the articles reviewed for the 2012-2021 period, 56% reported the presence of Anopheles gambiae sensu lato in urban areas compared to 42% reported in 2002-2011. The presence of Aedes aegypti increased in urban areas in 2012-2021 but this species was absent in rural areas. Ownership of long-lasting insecticidal nets varied greatly from one setting to another. CONCLUSIONS The current findings suggest that, in addition to malaria control strategies, vector-borne disease control approaches in Cameroon should include strategies against lymphatic filariasis and Rift Valley fever in rural areas, and against dengue and Zika viruses in urban areas.
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Affiliation(s)
- Leo Dilane Alenou
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, P.O. Box 2701, Douala, Cameroon.
- Malaria Research Laboratory, Yaoundé Research Institute (IRY), Organization for the Coordination of Endemic Diseases' Control in Central Africa (OCEAC), P.O. Box 288, Yaoundé, Cameroon.
| | - Philippe Nwane
- Malaria Research Laboratory, Yaoundé Research Institute (IRY), Organization for the Coordination of Endemic Diseases' Control in Central Africa (OCEAC), P.O. Box 288, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Lili Ranaise Mbakop
- Malaria Research Laboratory, Yaoundé Research Institute (IRY), Organization for the Coordination of Endemic Diseases' Control in Central Africa (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Michael Piameu
- Malaria Research Laboratory, Yaoundé Research Institute (IRY), Organization for the Coordination of Endemic Diseases' Control in Central Africa (OCEAC), P.O. Box 288, Yaoundé, Cameroon
- School of Health Sciences, Catholic University of Central Africa, P.O. Box 1110, Yaounde, Cameroon
| | - Wolfgang Ekoko
- Malaria Research Laboratory, Yaoundé Research Institute (IRY), Organization for the Coordination of Endemic Diseases' Control in Central Africa (OCEAC), P.O. Box 288, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, University of Bamenda, Bambili, P.O. Box 39, Douala, Cameroon
| | - Stanislas Mandeng
- Malaria Research Laboratory, Yaoundé Research Institute (IRY), Organization for the Coordination of Endemic Diseases' Control in Central Africa (OCEAC), P.O. Box 288, Yaoundé, Cameroon
- Department of Animal Biology and Physiology, Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Elisabeth Ngo Bikoy
- Department of Animal Biology and Physiology, Faculty of Sciences, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
| | - Jean Claude Toto
- Malaria Research Laboratory, Yaoundé Research Institute (IRY), Organization for the Coordination of Endemic Diseases' Control in Central Africa (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Hugues Onguina
- Malaria Research Laboratory, Yaoundé Research Institute (IRY), Organization for the Coordination of Endemic Diseases' Control in Central Africa (OCEAC), P.O. Box 288, Yaoundé, Cameroon
| | - Josiane Etang
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, P.O. Box 2701, Douala, Cameroon.
- Malaria Research Laboratory, Yaoundé Research Institute (IRY), Organization for the Coordination of Endemic Diseases' Control in Central Africa (OCEAC), P.O. Box 288, Yaoundé, Cameroon.
- Department of Insect Biotechnology in Plant Protection, Institute for Insect Biotechnology, Faculty 09-Agricultural Sciences, Nutritional Sciences and Environmental Management, Justus-Liebig-University Gießen, Winchester Str. 2, 35394, Giessen, Germany.
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Beng AA, Esum ME, Deribe K, Njouendou AJ, Ndongmo PWC, Abong RA, Fru J, Fombad FF, Nchanji GT, Amambo G, Gandjui NTV, Biholong B, Nko'Ayissi G, Mbia P, Akame J, Enyong PI, Reid SD, Tougoue JJ, Zhang Y, Wanji S. Mapping lymphatic filariasis in Loa loa endemic health districts naïve for ivermectin mass administration and situated in the forested zone of Cameroon. BMC Infect Dis 2020; 20:284. [PMID: 32299374 PMCID: PMC7164349 DOI: 10.1186/s12879-020-05009-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 04/01/2020] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND The control of lymphatic filariasis (LF) caused by Wuchereria bancrofti in the Central African Region has been hampered by the presence of Loa loa due to severe adverse events that arise in the treatment with ivermectin. The immunochromatographic test (ICT) cards used for mapping LF demonstrated cross-reactivity with L. loa and posed the problem of delineating the LF map. To verify LF endemicity in forest areas of Cameroon where mass drug administration (MDA) has not been ongoing, we used the recently developed strategy that combined serology, microscopy and molecular techniques. METHODS This study was carried out in 124 communities in 31 health districts (HDs) where L. loa is present. At least 125 persons per site were screened. Diurnal blood samples were investigated for circulating filarial antigen (CFA) by FTS and for L. loa microfilariae (mf) using TBF. FTS positive individuals were further subjected to night blood collection for detecting W. bancrofti. qPCR was used to detect DNA of the parasites. RESULTS Overall, 14,446 individuals took part in this study, 233 participants tested positive with FTS in 29 HDs, with positivity rates ranging from 0.0 to 8.2%. No W. bancrofti mf was found in the night blood of any individuals but L. loa mf were found in both day and night blood of participants who were FTS positive. Also, qPCR revealed that no W. bancrofti but L.loa DNA was found with dry bloodspot. Positive FTS results were strongly associated with high L. loa mf load. Similarly, a strong positive association was observed between FTS positivity and L loa prevalence. CONCLUSIONS Using a combination of parasitological and molecular tools, we were unable to find evidence of W. bancrofti presence in the 31 HDs, but L. loa instead. Therefore, LF is not endemic and LF MDA is not required in these districts.
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Affiliation(s)
- Andrew A Beng
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Mathias E Esum
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Kebede Deribe
- Centre for Global Health Research, Brighton and Sussex Medical School, Brighton, BN1 9PS, UK.
- School of Public Health, College of Health Sciences, Addis Ababa University, P.O. Box 9086, Addis Ababa, Ethiopia.
| | - Abdel J Njouendou
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Patrick W C Ndongmo
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Raphael A Abong
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Jerome Fru
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Fanny F Fombad
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Gordon T Nchanji
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Glory Amambo
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Narcisse T V Gandjui
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | | | | | | | - Julie Akame
- Helen Keller International, Yaoundé, Cameroon
| | - Peter I Enyong
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | | | | | - Yaobi Zhang
- Helen Keller International, New York, NY, USA
- Helen Keller International, Regional Office for Africa, Dakar, Senegal
| | - Samuel Wanji
- Department of Microbiology and Parasitology, Parasites and Vector Biology Research Unit (PAVBRU), University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
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4
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Nchoutpouen E, Talipouo A, Djiappi-Tchamen B, Djamouko-Djonkam L, Kopya E, Ngadjeu CS, Doumbe-Belisse P, Awono-Ambene P, Kekeunou S, Wondji CS, Antonio-Nkondjio C. Culex species diversity, susceptibility to insecticides and role as potential vector of Lymphatic filariasis in the city of Yaoundé, Cameroon. PLoS Negl Trop Dis 2019; 13:e0007229. [PMID: 30943198 PMCID: PMC6464241 DOI: 10.1371/journal.pntd.0007229] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 04/15/2019] [Accepted: 02/10/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Culex species are widespread across Cameroon and responsible for high burden of nuisance in most urban settings. However, despite their high nuisance, they remain less studied compared to anophelines. The present study aimed to assess Culex species distribution, susceptibility to insecticide, bionomics and role in Lymphatic Filariasis (LF) transmission in the city of Yaoundé. METHODS Mosquito collections were conducted from March to December 2017 using Centre for Disease Control light traps (CDC-LT), human landing catches (HLC) and larval collections. Mosquitoes were identified using morphological identification keys. Mosquitoes from the Culex pipiens complex were further identified using Polymerase Chain Reaction (PCR) to assess the presence of sibling species. Bioassays were conducted with 2-5 day-old unfed females to assess mosquito susceptibility to DDT, permethrin, deltamethrin and bendiocarb following WHO guidelines. Dead, control and surviving mosquitoes from bioassays were screened by PCR to detect the presence of knockdown resistance (kdr) alleles. Pools of mosquitoes were examined by PCR to detect the presence of Wuchereria bancrofti. RESULTS A total of 197,956 mosquitoes belonging to thirteen species were collected. The density of mosquito collected varied according to the collection methods, districts and seasons. Culex quinquefasciatus emerged as the most abundant and the only species of the Culex pipiens complex in Yaoundé. Culex species were found breeding in different types of breeding sites including polluted and unpolluted sites. All Culex species including Cx antennatus, Cx duttoni, Cx perfuscus and Cx tigripes were found to be highly resistant to permethrin, deltamethrin and DDT. Culex quinquefasciatus was also found to be resistant to bendiocarb. A high frequency of the West Africa kdr allele was recorded in resistant Cx. quinquefasciatus. Out of the 247 pooled samples of 25 Culex spp. examined for the presence of Wuchereria bancrofti, none was found infected. CONCLUSION The study confirms the high adaptation of Culex species particularly Culex quinquefasciatus to the urban environment and no implication of this species in the transmission of LF in Yaoundé Cameroon. Culex species predominance in urban settings highlight potential transmission risk of West Nile and rift valley fever in Yaoundé.
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Affiliation(s)
- Elysee Nchoutpouen
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Abdou Talipouo
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Borel Djiappi-Tchamen
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Vector Borne Infectious Disease Unit of the Laboratory of Applied Biology and Ecology (VBID-LABEA), Department of Animal Biology, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Landre Djamouko-Djonkam
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Vector Borne Infectious Disease Unit of the Laboratory of Applied Biology and Ecology (VBID-LABEA), Department of Animal Biology, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Edmond Kopya
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Carmene Sandra Ngadjeu
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Patricia Doumbe-Belisse
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Parfait Awono-Ambene
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
| | | | - Charles Sinclair Wondji
- Vector Biology Liverpool School of Tropical medicine Pembroke Place, Liverpool, United Kingdom
| | - Christophe Antonio-Nkondjio
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Vector Biology Liverpool School of Tropical medicine Pembroke Place, Liverpool, United Kingdom
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5
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Wanji S, Esum ME, Njouendou AJ, Mbeng AA, Chounna Ndongmo PW, Abong RA, Fru J, Fombad FF, Nchanji GT, Ngongeh G, Ngandjui NV, Enyong PI, Storey H, Curtis KC, Fischer K, Fauver JR, Lew D, Goss CW, Fischer PU. Mapping of lymphatic filariasis in loiasis areas: A new strategy shows no evidence for Wuchereria bancrofti endemicity in Cameroon. PLoS Negl Trop Dis 2019; 13:e0007192. [PMID: 30849120 PMCID: PMC6436748 DOI: 10.1371/journal.pntd.0007192] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 03/27/2019] [Accepted: 01/28/2019] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Mapping of lymphatic filariasis (LF) caused by Wuchereria bancrofti largely relies on the detection of circulating antigen using ICT cards. Several studies have recently shown that this test can be cross-reactive with sera of subjects heavily infected with Loa loa and thus mapping results in loiasis endemic areas may be inaccurate. METHODOLOGY/PRINCIPAL FINDINGS In order to develop an LF mapping strategy for areas with high loiasis prevalence, we collected day blood samples from 5,001 subjects residing in 50 villages that make up 6 health districts throughout Cameroon. Antigen testing using Filarial Test Strip (FTS, a novel platform that uses the same reagents as ICT) revealed an overall positivity rate of 1.1% and L. loa microfilaria (Mf) rates of up to 46%. Among the subjects with 0 to 8,000 Mf/ml in day blood, only 0.4% were FTS positive, while 22.2% of subjects with >8,000 Mf/ml were FTS positive. A Mf density of >8,200 Mf/ml was determined as the cut point at which positive FTS results should be excluded from the analysis. No FTS positive samples were also positive for W. bancrofti antibodies as measured by two different point of care tests that use the Wb123 antigen not found in L. loa. Night blood examination of the FTS positive subjects showed a high prevalence of L. loa Mf with densities up to 12,710 Mf/ml. No W. bancrofti Mf were identified, as confirmed by qPCR. Our results show that high loads of L. loa Mf in day blood are a reliable indicator of FTS positivity, and Wb123 rapid test proved to be relatively specific. CONCLUSIONS/SIGNIFICANCE Our study provides a simple day blood-based algorithm for LF mapping in loiasis areas. The results indicate that many districts that were formerly classified as endemic for LF in Cameroon are non-endemic and do not require mass drug administration for elimination of LF.
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Affiliation(s)
- Samuel Wanji
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
- * E-mail:
| | - Mathias Eyong Esum
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Abdel Jelil Njouendou
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Amuam Andrew Mbeng
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Patrick W. Chounna Ndongmo
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Raphael Awah Abong
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Jerome Fru
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Fanny F. Fombad
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Gordon Takop Nchanji
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Glory Ngongeh
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Narcisse V. Ngandjui
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Peter Ivo Enyong
- Parasites and Vector Biology research unit (PAVBRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation for Tropical Diseases and the Environment (REFOTDE), Buea, Cameroon
| | - Helen Storey
- Diagnostics Program, PATH, Seattle, Washington, United States of America
| | - Kurt C. Curtis
- Infectious Diseases Division, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Kerstin Fischer
- Infectious Diseases Division, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Joseph R. Fauver
- Infectious Diseases Division, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Daphne Lew
- Division of Biostatistics, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Charles W. Goss
- Division of Biostatistics, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Peter U. Fischer
- Infectious Diseases Division, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
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Garchitorena A, Raza-Fanomezanjanahary EM, Mioramalala SA, Chesnais CB, Ratsimbasoa CA, Ramarosata H, Bonds MH, Rabenantoandro H. Towards elimination of lymphatic filariasis in southeastern Madagascar: Successes and challenges for interrupting transmission. PLoS Negl Trop Dis 2018; 12:e0006780. [PMID: 30222758 PMCID: PMC6160210 DOI: 10.1371/journal.pntd.0006780] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 09/27/2018] [Accepted: 08/23/2018] [Indexed: 11/21/2022] Open
Abstract
Introduction A global strategy of mass drug administration (MDA) has greatly reduced the burden of lymphatic filariasis (LF) in endemic countries. In Madagascar, the National Programme to eliminate LF has scaled-up annual MDA of albendazole and diethylcarbamazine across the country in the last decade, but its impact on LF transmission has never been reported. The objective of this study was to evaluate progress towards LF elimination in southeastern Madagascar. Methods Three different surveys were carried out in parallel in four health districts of the Vatovavy Fitovinany region in 2016: i) a school-based transmission assessment survey (TAS) in the districts of Manakara Atsimo, Mananjary, and Vohipeno (following a successful pre-TAS in 2013); ii) a district-representative community prevalence survey in Ifanadiana district; and iii) a community prevalence survey in sentinel and spot-check sites of these four districts. LF infection was assessed using the Alere Filariasis Test Strips, which detect circulating filarial antigens (CFA) of adult worms. A brief knowledge, attitudes and practices questionnaire was included in the community surveys. Principal findings None of the 1,825 children sampled in the TAS, and only one in 1,306 children from sentinel and spot-check sites, tested positive to CFA. However, CFA prevalence rate in individuals older than 15 years was still high in two of these three districts, at 3.5 and 9.7% in Mananjary and Vohipeno, respectively. Overall CFA prevalence in sentinel and spot-check sites of these three districts was 2.80% (N = 2,707), but only two individuals had detectable levels of microfilaraemia (0.06%). Prevalence rate estimates for Ifanadiana were substantially higher in the district-representative survey (15.8%; N = 545) than in sentinel and spot-check sites (0.8%; N = 618). Only 51.2% of individuals surveyed in these four districts reported taking MDA in the last year, and 42.2% reported knowing about LF. Conclusions Although TAS results suggest that MDA can be stopped in three districts of southeastern Madagascar, the adult population still presents high CFA prevalence levels. This discordance raises important questions about the TAS procedures and the interpretation of their results. Lymphatic filariasis is a neglected disease with chronic disabling consequences. Endemic countries have reduced lymphatic filariasis transmission through a strategy of annual rounds of mass drug administration (MDA), but the impact of such strategy has not yet been reported for Madagascar. In this study we conducted three different surveys and used rapid diagnostic tests to evaluate lymphatic filariasis transmission in four health districts of southeastern Madagascar. This included a school-based transmission assessment survey (TAS), the international gold standard to help national programmes confirm that they have interrupted lymphatic filariasis transmission, and two complementary community-based surveys. Our TAS results suggested that MDA could be stopped in three districts, confirming the consistent decline in lymphatic filariasis observed in recent years. However, the other two surveys revealed that the adult population still had high prevalence levels. This discordance raises questions about the TAS procedures and the interpretation of their results in contexts where, like in Madagascar, implementation of MDA is different for school age children than for the rest of the population.
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Affiliation(s)
- Andres Garchitorena
- UMR 224 MIVEGEC, Institut de Recherche pour le Développement, Montpellier, France
- PIVOT, Ifanadiana, Madagascar
- * E-mail:
| | - Estelle M. Raza-Fanomezanjanahary
- Institut National de la Sante Publique et Communautaire, – Ministère de la Santé Publique, Ministère de l’Enseignement Supérieur et de la Recherche Scientifique, Antananarivo, Madagascar
| | - Sedera A. Mioramalala
- Direction de lutte contre le paludisme, – Ministère de la Santé Publique, Antananarivo, Madagascar
| | - Cédric B. Chesnais
- UMI 233, Institut de Recherche pour le Développement (IRD), Université Montpellier, INSERM Unité 1175, Montpellier, France
| | - Claude A. Ratsimbasoa
- Direction de lutte contre le paludisme, – Ministère de la Santé Publique, Antananarivo, Madagascar
| | - Herinirina Ramarosata
- Institut National de la Sante Publique et Communautaire, – Ministère de la Santé Publique, Ministère de l’Enseignement Supérieur et de la Recherche Scientifique, Antananarivo, Madagascar
| | - Matthew H. Bonds
- PIVOT, Ifanadiana, Madagascar
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Holivololona Rabenantoandro
- Service de Lutte contre les Maladies Epidémiques et Négligées – Ministère de la Santé Publique, Antananarivo, Madagascar
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Koroma JB, Sesay S, Conteh A, Paye J, Bah M, Sonnie M, Hodges MH, Zhang Y. Progress on elimination of lymphatic filariasis in Sierra Leone. Parasit Vectors 2018; 11:334. [PMID: 29866207 PMCID: PMC5987388 DOI: 10.1186/s13071-018-2915-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 05/24/2018] [Indexed: 11/18/2022] Open
Abstract
Background A baseline survey in 2007–2008 found lymphatic filariasis (LF) to be endemic in Sierra Leone in all 14 districts and co-endemic with onchocerciasis in 12 districts. Mass drug administration (MDA) with ivermectin started in 2006 for onchocerciasis and was modified to add albendazole in 2008 to include LF treatment. In 2011, after three effective MDAs, a significant reduction in microfilaraemia (mf) prevalence and density was reported at the midterm assessment. After five MDAs, in 2013, mf prevalence and density were again measured as part of a pre-transmission assessment survey (pre-TAS) conducted per WHO guidelines. Methods For the pre-TAS survey, districts were paired to represent populations of one million for impact assessment. One sentinel site selected from baseline and one spot check site purposefully selected based upon local knowledge of patients with LF were surveyed per pair (two districts). At each site, 300 people over five years of age provided mid-night blood samples and mf prevalence and density were determined using thick blood film microscopy. Results are compared with baseline and midterm data. Results At pre-TAS the overall mf prevalence was 0.54% (95% CI: 0.36–0.81%), compared to 0.30% (95% CI: 0.19–0.47) at midterm and 2.6% (95% CI: 2.3–3.0%) at baseline. There was a higher, but non-significant, mf prevalence among males vs females. Eight districts (four pairs) had a prevalence of mf < 1% at all sites. Two pairs (four districts) had a prevalence of mf > 1% at one of the two sites: Koinadugu 0.98% (95% CI: 0.34–2.85%) and Bombali 2.67% (95% CI: 1.41–5.00%), and Kailahun 1.56% (95% CI: 0.72–3.36%) and Kenema 0% (95% CI: 0.00–1.21%). Conclusions Compared to baseline, there was a significant reduction of LF mf prevalence and density in the 12 districts co-endemic for LF and onchocerciasis after five annual LF MDAs. No statistically significant difference was seen in either measure compared to midterm. Eight of the 12 districts qualified for TAS. The other four districts that failed to qualify for TAS had historically high LF baseline prevalence and density and had regular cross-border movement of populations. These four districts needed to conduct two additional rounds of LF MDA before repeating the pre-TAS. The results showed that Sierra Leone continued to make progress towards the elimination of LF as a public health problem.
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Affiliation(s)
- Joseph B Koroma
- Family Health International 360, Ghana Country Office, Accra, Ghana
| | - Santigie Sesay
- National Neglected Tropical Disease Control Programme, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Abdul Conteh
- National Neglected Tropical Disease Control Programme, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | - Jusufu Paye
- Helen Keller International, Freetown, Sierra Leone
| | - Mohamed Bah
- Helen Keller International, Freetown, Sierra Leone
| | | | | | - Yaobi Zhang
- Helen Keller International, Regional Office for Africa, Dakar, Senegal.
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Titaley CR, Damayanti R, Soeharno N, Mu'asyaroh A, Bradley M, Lynam T, Krentel A. Assessing knowledge about lymphatic filariasis and the implementation of mass drug administration amongst drug deliverers in three districts/cities of Indonesia. Parasit Vectors 2018; 11:315. [PMID: 29801511 PMCID: PMC5970490 DOI: 10.1186/s13071-018-2881-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 04/29/2018] [Indexed: 11/29/2022] Open
Abstract
Background This research assesses knowledge amongst drug deliverers about the implementation of mass drug administration (MDA) for lymphatic filariasis (LF) in Agam District (West Sumatera Province), the City of Depok (West Java Province) and the City of Batam (Kepulauan Riau Province), Indonesia. Methods A cross-sectional survey was conducted from January to March 2015 at these three sites. Respondents were identified using purposive sampling (i.e. cadre, health worker or community representatives). A total of 318 questionnaires were accepted for analysis. Three outcomes were assessed: knowledge about LF; knowledge about MDA implementation; and was informed about MDA coverage. Logistic regression analyses were employed to examine factors associated with these three outcomes. Results Less than half of respondents were charactersised as having a high level of LF knowledge and less than half a high level of knowledge about MDA. The odds of having a high level of knowledge of LF was significantly lower in Batam City than Agam District, yet higher amongst health workers than cadres. Deliverers living in urban areas reported more feedback on MDA outcomes than in the rural district. Health workers received more feedback than cadres (P < 0.001). Deliverers perceived the difference between coverage (drug receipt) and compliance (drug ingestion) in the community. Conclusions There are variations in knowledge about LF and MDA as well as feedback across drug deliverers in MDA across geographical areas. Adaptation of the MDA guidelines, supportive supervision, increasing the availability of supporting materials and directly-observed therapy might be beneficial to improve coverage and compliance in all areas.
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Affiliation(s)
- Christiana R Titaley
- Center for Health Research Universitas Indonesia. Faculty of Public Health Universitas Indonesia, Depok, West Java Province, Indonesia.
| | - Rita Damayanti
- Center for Health Research Universitas Indonesia. Faculty of Public Health Universitas Indonesia, Depok, West Java Province, Indonesia
| | - Nugroho Soeharno
- Center for Health Research Universitas Indonesia. Faculty of Public Health Universitas Indonesia, Depok, West Java Province, Indonesia
| | - Anifatun Mu'asyaroh
- Center for Health Research Universitas Indonesia. Faculty of Public Health Universitas Indonesia, Depok, West Java Province, Indonesia
| | - Mark Bradley
- NTD's Global Health Programs, GSK, Brentford, UK
| | - Tim Lynam
- Reflecting Society Pty Ltd., Townsville, Queensland, Australia
| | - Alison Krentel
- Bruyere Research Institute, Ottawa, Canada.,London School of Hygiene and Tropical Medicine, London, UK
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