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Entomological Characteristics of Malaria Transmission across Benin: An Essential Element for Improved Deployment of Vector Control Interventions

SIMPLE SUMMARY: With limited resources to properly perform geographic surveillance of malaria vectors, Benin, through its National Malaria Control Program (NMCP), conducted a study on vector dynamics and transmission across the country’s departments in order to generate an entomological transmission...

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Autores principales: Tokponnon, Tatchémè Filémon, Ossè, Razaki, Padonou, Germain Gil, Affoukou, Cyriaque Dossou, Sidick, Aboubakar, Sewade, Wilfried, Fassinou, Arsène, Koukpo, Côme Z., Akinro, Bruno, Messenger, Louisa A., Okê, Mariam, Tchévoédé, Alexis, Ogouyemi-Hounto, Aurore, Gazard, Dorothée Kinde, Akogbeto, Martin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9864170/
https://www.ncbi.nlm.nih.gov/pubmed/36661980
http://dx.doi.org/10.3390/insects14010052
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author Tokponnon, Tatchémè Filémon
Ossè, Razaki
Padonou, Germain Gil
Affoukou, Cyriaque Dossou
Sidick, Aboubakar
Sewade, Wilfried
Fassinou, Arsène
Koukpo, Côme Z.
Akinro, Bruno
Messenger, Louisa A.
Okê, Mariam
Tchévoédé, Alexis
Ogouyemi-Hounto, Aurore
Gazard, Dorothée Kinde
Akogbeto, Martin
author_facet Tokponnon, Tatchémè Filémon
Ossè, Razaki
Padonou, Germain Gil
Affoukou, Cyriaque Dossou
Sidick, Aboubakar
Sewade, Wilfried
Fassinou, Arsène
Koukpo, Côme Z.
Akinro, Bruno
Messenger, Louisa A.
Okê, Mariam
Tchévoédé, Alexis
Ogouyemi-Hounto, Aurore
Gazard, Dorothée Kinde
Akogbeto, Martin
author_sort Tokponnon, Tatchémè Filémon
collection PubMed
description SIMPLE SUMMARY: With limited resources to properly perform geographic surveillance of malaria vectors, Benin, through its National Malaria Control Program (NMCP), conducted a study on vector dynamics and transmission across the country’s departments in order to generate an entomological transmission profile. Per department, 2 communes (i.e., 24 across twelve departments) were chosen for this study, taking into account geographical and ecological diversity. We selected two villages per commune and four households (HH) per village to collect mosquitoes using human landing catches (HLCs). In each HH, an indoor and outdoor HLC session took place between 7 p.m. and 7 a.m. on two consecutive nights between July and September 2017. Captured Anopheles were identified and ovaries were dissected for parity. Heads and thoraxes were tested for Plasmodium falciparum sporozoites by ELISA, and entomological inoculation rate (EIR) was calculated. Analyses revealed low, medium, and high transmission communes distributed throughout the country. Heterogeneity in malaria transmission in Benin was observed, which is not evident when assessing entomological surveillance from sentinel sites alone. The NMCP will use the study findings in the future to stratify and plan vector control interventions in high transmission districts to better protect the most at-risk populations. ABSTRACT: Entomological surveillance in Benin has historically been limited to zones where indoor residual spraying was performed or where long-standing sentinel surveillance sites existed. However, there are significant country-wide gaps in entomological knowledge. The National Malaria Control Program (NMCP) assessed population dynamics of Anopheles vectors and malaria transmission in each of Benin’s 12 departments to create an entomological risk profile. Two communes per department (24/77 communes) were chosen to reflect diverse geographies, ecologies and malaria prevalence. Two villages per commune were selected from which four households (HH) per village were used for human landing catches (HLCs). In each HH, an indoor and outdoor HLC occurred between 7 p.m. and 7 a.m. on two consecutive nights between July–September 2017. Captured Anopheles were identified, and ovaries were dissected to determine parous rate. Heads and thoraces were tested for Plasmodium falciparum sporozoites by ELISA. The Entomological Inoculation Rate (EIR) was calculated as the product of mosquito bite rate and sporozoite index. Bite rates from An. gambiae s.l., the primary vector species complex, differed considerably between communes; average sporozoite infection index was 3.5%. The EIR ranged from 0.02 infectious bites (ib) per human per night in the departments of Ouémé and Plateau to 1.66 ib/human/night in Collines. Based on transmission risk scales, Avrankou, Sakété and Nikki are areas of low transmission (0 < EIR < 3 ib/human/year), Adjarra, Adja Ouèrè, Zè, Toffo, Bopa, Pehunco, Pèrèrè and Kandi are of medium transmission (3 < EIR < 30 ib/human/year), and the other remaining districts are high transmission (EIR > 30 ib/human/year). The heterogeneous and diverse nature of malaria transmission in Benin was not readily apparent when only assessing entomological surveillance from sentinel sites. Prospectively, the NMCP will use study results to stratify and deploy targeted vector control interventions in districts with high EIRs to better protect populations most at-risk.
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spelling pubmed-98641702023-01-22 Entomological Characteristics of Malaria Transmission across Benin: An Essential Element for Improved Deployment of Vector Control Interventions Tokponnon, Tatchémè Filémon Ossè, Razaki Padonou, Germain Gil Affoukou, Cyriaque Dossou Sidick, Aboubakar Sewade, Wilfried Fassinou, Arsène Koukpo, Côme Z. Akinro, Bruno Messenger, Louisa A. Okê, Mariam Tchévoédé, Alexis Ogouyemi-Hounto, Aurore Gazard, Dorothée Kinde Akogbeto, Martin Insects Article SIMPLE SUMMARY: With limited resources to properly perform geographic surveillance of malaria vectors, Benin, through its National Malaria Control Program (NMCP), conducted a study on vector dynamics and transmission across the country’s departments in order to generate an entomological transmission profile. Per department, 2 communes (i.e., 24 across twelve departments) were chosen for this study, taking into account geographical and ecological diversity. We selected two villages per commune and four households (HH) per village to collect mosquitoes using human landing catches (HLCs). In each HH, an indoor and outdoor HLC session took place between 7 p.m. and 7 a.m. on two consecutive nights between July and September 2017. Captured Anopheles were identified and ovaries were dissected for parity. Heads and thoraxes were tested for Plasmodium falciparum sporozoites by ELISA, and entomological inoculation rate (EIR) was calculated. Analyses revealed low, medium, and high transmission communes distributed throughout the country. Heterogeneity in malaria transmission in Benin was observed, which is not evident when assessing entomological surveillance from sentinel sites alone. The NMCP will use the study findings in the future to stratify and plan vector control interventions in high transmission districts to better protect the most at-risk populations. ABSTRACT: Entomological surveillance in Benin has historically been limited to zones where indoor residual spraying was performed or where long-standing sentinel surveillance sites existed. However, there are significant country-wide gaps in entomological knowledge. The National Malaria Control Program (NMCP) assessed population dynamics of Anopheles vectors and malaria transmission in each of Benin’s 12 departments to create an entomological risk profile. Two communes per department (24/77 communes) were chosen to reflect diverse geographies, ecologies and malaria prevalence. Two villages per commune were selected from which four households (HH) per village were used for human landing catches (HLCs). In each HH, an indoor and outdoor HLC occurred between 7 p.m. and 7 a.m. on two consecutive nights between July–September 2017. Captured Anopheles were identified, and ovaries were dissected to determine parous rate. Heads and thoraces were tested for Plasmodium falciparum sporozoites by ELISA. The Entomological Inoculation Rate (EIR) was calculated as the product of mosquito bite rate and sporozoite index. Bite rates from An. gambiae s.l., the primary vector species complex, differed considerably between communes; average sporozoite infection index was 3.5%. The EIR ranged from 0.02 infectious bites (ib) per human per night in the departments of Ouémé and Plateau to 1.66 ib/human/night in Collines. Based on transmission risk scales, Avrankou, Sakété and Nikki are areas of low transmission (0 < EIR < 3 ib/human/year), Adjarra, Adja Ouèrè, Zè, Toffo, Bopa, Pehunco, Pèrèrè and Kandi are of medium transmission (3 < EIR < 30 ib/human/year), and the other remaining districts are high transmission (EIR > 30 ib/human/year). The heterogeneous and diverse nature of malaria transmission in Benin was not readily apparent when only assessing entomological surveillance from sentinel sites. Prospectively, the NMCP will use study results to stratify and deploy targeted vector control interventions in districts with high EIRs to better protect populations most at-risk. MDPI 2023-01-05 /pmc/articles/PMC9864170/ /pubmed/36661980 http://dx.doi.org/10.3390/insects14010052 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Tokponnon, Tatchémè Filémon
Ossè, Razaki
Padonou, Germain Gil
Affoukou, Cyriaque Dossou
Sidick, Aboubakar
Sewade, Wilfried
Fassinou, Arsène
Koukpo, Côme Z.
Akinro, Bruno
Messenger, Louisa A.
Okê, Mariam
Tchévoédé, Alexis
Ogouyemi-Hounto, Aurore
Gazard, Dorothée Kinde
Akogbeto, Martin
Entomological Characteristics of Malaria Transmission across Benin: An Essential Element for Improved Deployment of Vector Control Interventions
title Entomological Characteristics of Malaria Transmission across Benin: An Essential Element for Improved Deployment of Vector Control Interventions
title_full Entomological Characteristics of Malaria Transmission across Benin: An Essential Element for Improved Deployment of Vector Control Interventions
title_fullStr Entomological Characteristics of Malaria Transmission across Benin: An Essential Element for Improved Deployment of Vector Control Interventions
title_full_unstemmed Entomological Characteristics of Malaria Transmission across Benin: An Essential Element for Improved Deployment of Vector Control Interventions
title_short Entomological Characteristics of Malaria Transmission across Benin: An Essential Element for Improved Deployment of Vector Control Interventions
title_sort entomological characteristics of malaria transmission across benin: an essential element for improved deployment of vector control interventions
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9864170/
https://www.ncbi.nlm.nih.gov/pubmed/36661980
http://dx.doi.org/10.3390/insects14010052
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