Comparison of surveillance methods applied to a situation of low malaria prevalence at rural sites in The Gambia and Guinea Bissau

Abstract Background Health record-based observations from several parts of Africa indicate a major decline in malaria, but up-to-date information on parasite prevalence in West-Africa is sparse. This study aims to provide parasite prevalence data from three sites in the Gambia and Guinea Bissau, res...

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Published in:Malaria Journal
Main Authors: Corran Patrick, Correa Simon, Oriero Eniyou C, Nwakanma Davis, Drakeley Christopher, Walther Brigitte, Satoguina Judith, Conway David J, Walther Michael
Format: Article in Journal/Newspaper
Language:English
Published: BMC 2009
Subjects:
Online Access:https://doi.org/10.1186/1475-2875-8-274
https://doaj.org/article/56e872daa0544596a5bee4c77bc4f93d
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spelling ftdoajarticles:oai:doaj.org/article:56e872daa0544596a5bee4c77bc4f93d 2023-05-15T15:16:06+02:00 Comparison of surveillance methods applied to a situation of low malaria prevalence at rural sites in The Gambia and Guinea Bissau Corran Patrick Correa Simon Oriero Eniyou C Nwakanma Davis Drakeley Christopher Walther Brigitte Satoguina Judith Conway David J Walther Michael 2009-12-01T00:00:00Z https://doi.org/10.1186/1475-2875-8-274 https://doaj.org/article/56e872daa0544596a5bee4c77bc4f93d EN eng BMC http://www.malariajournal.com/content/8/1/274 https://doaj.org/toc/1475-2875 doi:10.1186/1475-2875-8-274 1475-2875 https://doaj.org/article/56e872daa0544596a5bee4c77bc4f93d Malaria Journal, Vol 8, Iss 1, p 274 (2009) Arctic medicine. Tropical medicine RC955-962 Infectious and parasitic diseases RC109-216 article 2009 ftdoajarticles https://doi.org/10.1186/1475-2875-8-274 2022-12-31T08:06:04Z Abstract Background Health record-based observations from several parts of Africa indicate a major decline in malaria, but up-to-date information on parasite prevalence in West-Africa is sparse. This study aims to provide parasite prevalence data from three sites in the Gambia and Guinea Bissau, respectively, and compares the usefulness of PCR, rapid diagnostic tests (RDT), serology and slide-microscopy for surveillance. Methods Cross-sectional surveys in 12 villages at three rural sites were carried out in the Gambia and Guinea Bissau in January/February 2008, shortly following the annual transmission season. Results A surprisingly low microscopically detectable parasite prevalence was detected in the Gambia (Farafenni: 10.9%, CI95%: 8.7-13.1%; Basse: 9.0%, CI95%: 7.2-10.8%), and Guinea Bissau (Caio: 4%, CI95%: 2.6-5.4%), with low parasite densities (geometric mean: 104 parasites/μl, CI95%: 76-143/μl). In comparison, PCR detected a more than three times higher proportion of parasite carriers, indicating its usefulness to sensitively identify foci where malaria declines, whereas the RDT had very low sensitivity. Estimates of force of infection using age sero-conversion rates were equivalent to an EIR of approximately 1 infectious bite/person/year, significantly less than previous estimates. The sero-prevalence profiles suggest a gradual decline of malaria transmission, confirming their usefulness in providing information on longer term trends of transmission. A greater variability in parasite prevalence among villages within a site than between sites was observed with all methods. The fact that serology equally captured the inter-village variability, indicates that the observed heterogeneity represents a stable pattern. Conclusion PCR and serology may be used as complementary tools to survey malaria in areas of declining malaria prevalence such as the Gambia and Guinea Bissau. Article in Journal/Newspaper Arctic Directory of Open Access Journals: DOAJ Articles Arctic Malaria Journal 8 1 274
institution Open Polar
collection Directory of Open Access Journals: DOAJ Articles
op_collection_id ftdoajarticles
language English
topic Arctic medicine. Tropical medicine
RC955-962
Infectious and parasitic diseases
RC109-216
spellingShingle Arctic medicine. Tropical medicine
RC955-962
Infectious and parasitic diseases
RC109-216
Corran Patrick
Correa Simon
Oriero Eniyou C
Nwakanma Davis
Drakeley Christopher
Walther Brigitte
Satoguina Judith
Conway David J
Walther Michael
Comparison of surveillance methods applied to a situation of low malaria prevalence at rural sites in The Gambia and Guinea Bissau
topic_facet Arctic medicine. Tropical medicine
RC955-962
Infectious and parasitic diseases
RC109-216
description Abstract Background Health record-based observations from several parts of Africa indicate a major decline in malaria, but up-to-date information on parasite prevalence in West-Africa is sparse. This study aims to provide parasite prevalence data from three sites in the Gambia and Guinea Bissau, respectively, and compares the usefulness of PCR, rapid diagnostic tests (RDT), serology and slide-microscopy for surveillance. Methods Cross-sectional surveys in 12 villages at three rural sites were carried out in the Gambia and Guinea Bissau in January/February 2008, shortly following the annual transmission season. Results A surprisingly low microscopically detectable parasite prevalence was detected in the Gambia (Farafenni: 10.9%, CI95%: 8.7-13.1%; Basse: 9.0%, CI95%: 7.2-10.8%), and Guinea Bissau (Caio: 4%, CI95%: 2.6-5.4%), with low parasite densities (geometric mean: 104 parasites/μl, CI95%: 76-143/μl). In comparison, PCR detected a more than three times higher proportion of parasite carriers, indicating its usefulness to sensitively identify foci where malaria declines, whereas the RDT had very low sensitivity. Estimates of force of infection using age sero-conversion rates were equivalent to an EIR of approximately 1 infectious bite/person/year, significantly less than previous estimates. The sero-prevalence profiles suggest a gradual decline of malaria transmission, confirming their usefulness in providing information on longer term trends of transmission. A greater variability in parasite prevalence among villages within a site than between sites was observed with all methods. The fact that serology equally captured the inter-village variability, indicates that the observed heterogeneity represents a stable pattern. Conclusion PCR and serology may be used as complementary tools to survey malaria in areas of declining malaria prevalence such as the Gambia and Guinea Bissau.
format Article in Journal/Newspaper
author Corran Patrick
Correa Simon
Oriero Eniyou C
Nwakanma Davis
Drakeley Christopher
Walther Brigitte
Satoguina Judith
Conway David J
Walther Michael
author_facet Corran Patrick
Correa Simon
Oriero Eniyou C
Nwakanma Davis
Drakeley Christopher
Walther Brigitte
Satoguina Judith
Conway David J
Walther Michael
author_sort Corran Patrick
title Comparison of surveillance methods applied to a situation of low malaria prevalence at rural sites in The Gambia and Guinea Bissau
title_short Comparison of surveillance methods applied to a situation of low malaria prevalence at rural sites in The Gambia and Guinea Bissau
title_full Comparison of surveillance methods applied to a situation of low malaria prevalence at rural sites in The Gambia and Guinea Bissau
title_fullStr Comparison of surveillance methods applied to a situation of low malaria prevalence at rural sites in The Gambia and Guinea Bissau
title_full_unstemmed Comparison of surveillance methods applied to a situation of low malaria prevalence at rural sites in The Gambia and Guinea Bissau
title_sort comparison of surveillance methods applied to a situation of low malaria prevalence at rural sites in the gambia and guinea bissau
publisher BMC
publishDate 2009
url https://doi.org/10.1186/1475-2875-8-274
https://doaj.org/article/56e872daa0544596a5bee4c77bc4f93d
geographic Arctic
geographic_facet Arctic
genre Arctic
genre_facet Arctic
op_source Malaria Journal, Vol 8, Iss 1, p 274 (2009)
op_relation http://www.malariajournal.com/content/8/1/274
https://doaj.org/toc/1475-2875
doi:10.1186/1475-2875-8-274
1475-2875
https://doaj.org/article/56e872daa0544596a5bee4c77bc4f93d
op_doi https://doi.org/10.1186/1475-2875-8-274
container_title Malaria Journal
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