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Martello E, Yogeswaran G, Reithinger R, Leonardi-Bee J. Mosquito aquatic habitat modification and manipulation interventions to control malaria. Cochrane Database Syst Rev 2022; 11:CD008923. [PMID: 36367444 PMCID: PMC9651131 DOI: 10.1002/14651858.cd008923.pub3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Larval source management (LSM) may help reduce Plasmodium parasite transmission in malaria-endemic areas. LSM approaches include habitat modification (permanently or temporarily reducing mosquito breeding aquatic habitats); habitat manipulation (temporary or recurrent change to environment); or use of chemical (e.g. larviciding) or biological agents (e.g. natural predators) to breeding sites. We examined the effectiveness of habitat modification or manipulation (or both), with and without larviciding. This is an update of a review published in 2013. OBJECTIVES 1. To describe and summarize the interventions on mosquito aquatic habitat modification or mosquito aquatic habitat manipulation, or both, on malaria control. 2. To evaluate the beneficial and harmful effects of mosquito aquatic habitat modification or mosquito aquatic habitat manipulation, or both, on malaria control. SEARCH METHODS We used standard, extensive Cochrane search methods. The latest search was from January 2012 to 30 November 2021. SELECTION CRITERIA Randomized controlled trials (RCT) and non-randomized intervention studies comparing mosquito aquatic habitat modification or manipulation (or both) to no treatment or another active intervention. We also included uncontrolled before-after (BA) studies, but only described and summarized the interventions from studies with these designs. Primary outcomes were clinical malaria incidence, malaria parasite prevalence, and malaria parasitaemia incidence. DATA COLLECTION AND ANALYSIS We used standard Cochrane methods. We assessed risk of bias using the Cochrane RoB 2 tool for RCTs and the ROBINS-I tool for non-randomized intervention studies. We used a narrative synthesis approach to systematically describe and summarize all the interventions included within the review, categorized by the type of intervention (habitat modification, habitat manipulation, combination of habitat modification and manipulation). Our primary outcomes were 1. clinical malaria incidence; 2. malaria parasite prevalence; and 3. malaria parasitaemia incidence. Our secondary outcomes were 1. incidence of severe malaria; 2. anaemia prevalence; 3. mean haemoglobin levels; 4. mortality rate due to malaria; 5. hospital admissions for malaria; 6. density of immature mosquitoes; 7. density of adult mosquitoes; 8. sporozoite rate; 9. entomological inoculation rate; and 10. HARMS We used the GRADE approach to assess the certainty of the evidence for each type of intervention. MAIN RESULTS Sixteen studies met the inclusion criteria. Six used an RCT design, six used a controlled before-after (CBA) study design, three used a non-randomized controlled design, and one used an uncontrolled BA study design. Eleven studies were conducted in Africa and five in Asia. Five studies reported epidemiological outcomes and 15 studies reported entomological outcomes. None of the included studies reported on the environmental impacts associated with the intervention. For risk of bias, all trials had some concerns and other designs ranging from moderate to critical. Ten studies assessed habitat manipulation (temporary change to the environment). This included water management (spillways across streams; floodgates; intermittent flooding; different drawdown rates of water; different flooding and draining regimens), shading management (shading of drainage channels with different plants), other/combined management approaches (minimal tillage; disturbance of aquatic habitats with grass clearing and water replenishment), which showed mixed results for entomological outcomes. Spillways across streams, faster drawdown rates of water, shading drainage canals with Napier grass, and using minimal tillage may reduce the density of immature mosquitoes (range of effects from 95% reduction to 1.7 times increase; low-certainty evidence), and spillways across streams may reduce densities of adult mosquitoes compared to no intervention (low-certainty evidence). However, the effect of habitat manipulation on malaria parasite prevalence and clinical malaria incidence is uncertain (very low-certainty evidence). Two studies assessed habitat manipulation with larviciding. This included reducing or removal of habitat sites; and drain cleaning, grass cutting, and minor repairs. It is uncertain whether drain cleaning, grass cutting, and minor repairs reduces malaria parasite prevalence compared to no intervention (odds ratio 0.59, 95% confidence interval (CI) 0.42 to 0.83; very low-certainty evidence). Two studies assessed combination of habitat manipulation and permanent change (habitat modification). This included drainage canals, filling, and planting of papyrus and other reeds for shading near dams; and drainage of canals, removal of debris, land levelling, and filling ditches. Studies did not report on epidemiological outcomes, but entomological outcomes suggest that such activities may reduce the density of adult mosquitoes compared to no intervention (relative risk reduction 0.49, 95% CI 0.47 to 0.50; low-certainty evidence), and preventing water stagnating using drainage of canals, removal of debris, land levelling, and filling ditches may reduce the density of immature mosquitoes compared to no intervention (ranged from 10% to 55% reductions; low-certainty evidence). Three studies assessed combining manipulation and modification with larviciding. This included filling or drainage of water bodies; filling, draining, or elimination of rain pools and puddles at water supply points and stream bed pools; and shoreline work, improvement and maintenance to drainage, clearing vegetation and undergrowth, and filling pools. There were mixed effect sizes for the reduction of entomological outcomes (moderate-certainty evidence). However, filling or draining water bodies probably makes little or no difference to malaria parasite prevalence, haemoglobin levels, or entomological inoculation rate when delivered with larviciding compared to no intervention (moderate-certainty evidence). AUTHORS' CONCLUSIONS Habitat modification and manipulation interventions for preventing malaria has some indication of benefit in both epidemiological and entomological outcomes. While the data are quite mixed and further studies could help improve the knowledge base, these varied approaches may be useful in some circumstances.
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Affiliation(s)
- Elisa Martello
- Centre for Evidence Based Healthcare, Division of Epidemiology and Public Health, Clinical Sciences Building Phase 2, University of Nottingham, Nottingham, UK
| | - Gowsika Yogeswaran
- Centre for Evidence Based Healthcare, Division of Epidemiology and Public Health, Clinical Sciences Building Phase 2, University of Nottingham, Nottingham, UK
| | | | - Jo Leonardi-Bee
- Centre for Evidence Based Healthcare, Division of Epidemiology and Public Health, Clinical Sciences Building Phase 2, University of Nottingham, Nottingham, UK
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Chanyalew T, Natea G, Amenu D, Yewhalaw D, Simma EA. Composition of mosquito fauna and insecticide resistance status of Anopheles gambiae sensu lato in Itang special district, Gambella, Southwestern Ethiopia. Malar J 2022; 21:125. [PMID: 35436961 PMCID: PMC9014582 DOI: 10.1186/s12936-022-04150-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 04/04/2022] [Indexed: 11/10/2022] Open
Abstract
Background Anopheles arabiensis, member species of the Anopheles gambiae complex, is the primary vector of malaria and is widely distributed in Ethiopia. Anopheles funestus, Anopheles pharoensis and Anopheles nili are secondary vectors occurring with limited distribution in the country. Indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) are pillars for the interventions against malaria control and elimination efforts in Ethiopia. However, the emergence and widespread of insecticide resistance in An. gambiae sensu lato (s.l.), might compromise the control efforts of the country. The aim of this study was to investigate composition of mosquito fauna and insecticide resistance status of An. gambiae s.l. in Itang special district ( woreda), Gambella, southwestern Ethiopia. Methods Adult mosquitoes were sampled from September 2020 to February 2021 using the CDC light trap and pyrethrum spray catch (PSC). CDC light traps were placed in three selected houses for two consecutive days per month to collect mosquitoes indoor and outdoor from 6:00 P.M. to 06:00 A.M. and PSC was used to collect indoor resting mosquitoes from ten selected houses once in a month from October 2020 to February 2021. Moreover, mosquito larvae were also collected from different breeding sites and reared to adults to assess susceptibility status of populations of An. gambiae s.l. in the study area. Susceptibility tests were conducted on two to three days old non blood fed female An. gambiae s.l. using insecticide impregnated papers with deltamethrin (0.05%), alpha-cypermethrin (0.05%), propoxur (0.1%), pirimiphos-methyl (0.25%) and bendiocarb (0.1%) following World Health Organization (WHO) standard susceptibility test procedure. Molecular diagnostics were done for the identification of member species of An. gambiae s.l. and detection of knockdown resistance (kdr) allele using species specific polymerase chain reaction (PCR) and allele specific PCR. Results In total, 468 adult mosquitoes were collected from different houses. Culex mosquitoes were the most dominant (80.4%) followed by Anopheles mosquitoes. Three species of Anopheles (Anopheles coustani, An. pharoensis, and An. gambiae s.l.) were identified, of which An. coustani was the dominant (8.1%) species. Higher number of mosquitoes (231) were collected outdoor by CDC light traps. Out of 468 adult mosquitoes, 294 were blood fed, 46 were half-gravid and gravid whereas the remaining 128 were unfed. WHO bioassay tests revealed that the populations of An. gambiae s.l. in the study area are resistant against alpha-cypermethrin and deltamethrin, but susceptible to bendiocarb, pirimiphos-methyl and propoxur. Of the total 86 An. gambiae s.l. specimens assayed, 79 (92%) successfully amplified and identified as An. arabiensis. West African kdr (L1014F) mutation was detected with high kdr allele frequency ranging from 67 to 88%. Conclusion The detection of target site mutation, kdr L1014F allele, coupled with the phenotypic resistance against alpha-cypermethrin and deltamethrin call for continuous resistance monitoring.
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Olkeba BK, Goethals PLM, Boets P, Duchateau L, Degefa T, Eba K, Yewhalaw D, Mereta ST. Mesocosm Experiments to Quantify Predation of Mosquito Larvae by Aquatic Predators to Determine Potential of Ecological Control of Malaria Vectors in Ethiopia. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18136904. [PMID: 34199088 PMCID: PMC8296878 DOI: 10.3390/ijerph18136904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 11/20/2022]
Abstract
Malaria parasites are transmitted to humans by infectious female Anopheles mosquitoes. Chemical-insecticide-based mosquito control has been successful in reducing the burden of malaria. However, the emergence of insecticide resistance in malaria vectors and concerns about the effect of the chemicals on the environment, human health, and non-target organisms present a need for new or alternative vector control intervention tools. Biocontrol methods using aquatic invertebrate predators have emerged as a potential alternative and additional tool to control mosquito populations. Ecological control specifically makes use of species insights for improving the physical habitat conditions of competitors and predators of vectors. A first step towards this is to gain knowledge on the predation potential of several typically present macroinvertebrates. Hence, this study aimed at (1) examining the influence of the predation of hemipterans on the number of emerging adult mosquitoes and (2) detecting Anopheles mosquito DNA in the gut of those predators. The prey and predators were collected from a range of water bodies located in the Gilgel Gibe watershed, southwest Ethiopia. A semi-field study was carried out using mesocosms which were constructed using plastic containers mimicking the natural aquatic habitat of immature Anopheles mosquitoes. Adult mosquitoes that emerged from the mesocosms were collected using a mechanical aspirator. At the end of the experiment, predators were withdrawn from the mesocosms and identified to genus level. Polymerase Chain Reaction (PCR) was employed to identify sibling species of Anopheles gambiae s.l. and to detect Anopheles mosquito DNA in the gut of the predators. Data were analysed using R software. Giant water bugs (belostomatids) were the most aggressive predators of Anopheles larvae, followed by backswimmers (notonectids) and water boatmen (corixids). All female Anopheles gambiae s.l. emerged from the mesocosms were identified as Anopheles arabiensis. Anopheles arabiensis DNA was detected in the gut content of hemipteran specimens analysed from the three families. The number of the adult mosquitoes emerging from the mesocosms was affected by the presence of predators. The findings of this study provide evidence of the potential use of aquatic macroinvertebrate predators as biocontrol agents against immature Anopheles mosquitoes and their potential to be considered as a component of integrated vector management for insecticide resistance and the combined restoration of aquatic ecosystems via smart ecological engineering.
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Affiliation(s)
- Beekam Kebede Olkeba
- Department of Animal Sciences and Aquatic Ecology, Ghent University, Coupure Links 653, Building F, 9000 Ghent, Belgium; (P.L.M.G.); (P.B.)
- Department of Environmental Health Science and Technology, Jimma University, Jimma P.O. Box 378, Ethiopia; (K.E.); (S.T.M.)
- Department of Environmental Health Science, Hawassa University, Hawassa P.O. Box 1560, Ethiopia
- Correspondence:
| | - Peter L. M. Goethals
- Department of Animal Sciences and Aquatic Ecology, Ghent University, Coupure Links 653, Building F, 9000 Ghent, Belgium; (P.L.M.G.); (P.B.)
| | - Pieter Boets
- Department of Animal Sciences and Aquatic Ecology, Ghent University, Coupure Links 653, Building F, 9000 Ghent, Belgium; (P.L.M.G.); (P.B.)
- Provincial Centre of Environmental Research, Godshuizenlaan 95, 9000 Ghent, Belgium
| | - Luc Duchateau
- Biometrics Research Centre, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium;
| | - Teshome Degefa
- School of Medical Laboratory Sciences, Jimma University, Jimma P.O. Box 378, Ethiopia; (T.D.); (D.Y.)
| | - Kasahun Eba
- Department of Environmental Health Science and Technology, Jimma University, Jimma P.O. Box 378, Ethiopia; (K.E.); (S.T.M.)
- Biometrics Research Centre, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium;
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Jimma University, Jimma P.O. Box 378, Ethiopia; (T.D.); (D.Y.)
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma P.O. Box 378, Ethiopia
| | - Seid Tiku Mereta
- Department of Environmental Health Science and Technology, Jimma University, Jimma P.O. Box 378, Ethiopia; (K.E.); (S.T.M.)
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Cross DE, Thomas C, McKeown N, Siaziyu V, Healey A, Willis T, Singini D, Liywalii F, Silumesii A, Sakala J, Smith M, Macklin M, Hardy AJ, Shaw PW. Geographically extensive larval surveys reveal an unexpected scarcity of primary vector mosquitoes in a region of persistent malaria transmission in western Zambia. Parasit Vectors 2021; 14:91. [PMID: 33522944 PMCID: PMC7849156 DOI: 10.1186/s13071-020-04540-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 12/11/2020] [Indexed: 11/10/2022] Open
Abstract
Background The Barotse floodplains of the upper Zambezi River and its tributaries are a highly dynamic environment, with seasonal flooding and transhumance presenting a shifting mosaic of potential larval habitat and human and livestock blood meals for malaria vector mosquitoes. However, limited entomological surveillance has been undertaken to characterize the vector community in these floodplains and their environs. Such information is necessary as, despite substantial deployment of insecticide-treated nets (ITNs) and indoor residual spraying (IRS) against Anopheles vectors, malaria transmission persists across Barotseland in Zambia’s Western Province. Methods Geographically extensive larval surveys were undertaken in two health districts along 102 km of transects, at fine spatial resolution, during a dry season and following the peak of the successive wet season. Larvae were sampled within typical Anopheles flight range of human settlements and identified through genetic sequencing of cytochrome c oxidase I and internal transcribed spacer two regions of mitochondrial and nuclear DNA. This facilitated detailed comparison of taxon-specific abundance patterns between ecological zones differentiated by hydrological controls. Results An unexpected paucity of primary vectors was revealed, with An. gambiae s.l. and An. funestus representing < 2% of 995 sequenced anophelines. Potential secondary vectors predominated in the vector community, primarily An. coustani group species and An. squamosus. While the distribution of An. gambiae s.l. in the study area was highly clustered, secondary vector species were ubiquitous across the landscape in both dry and wet seasons, with some taxon-specific relationships between abundance and ecological zones by season. Conclusions The diversity of candidate vector species and their high relative abundance observed across diverse hydro-ecosystems indicate a highly adaptable transmission system, resilient to environmental variation and, potentially, interventions that target only part of the vector community. Larval survey results imply that residual transmission of malaria in Barotseland is being mediated predominantly by secondary vector species, whose known tendencies for crepuscular and outdoor biting renders them largely insensitive to prevalent vector control methods.![]()
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Affiliation(s)
- Dónall Eoin Cross
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, SY23 3FG, UK
| | - Chris Thomas
- Lincoln Centre for Water and Planetary Health, School of Geography, College of Science, Think Tank, University of Lincoln, Ruston Way, Lincoln, LN6 7DW, UK.
| | - Niall McKeown
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, SY23 3FG, UK
| | - Vincent Siaziyu
- Limulunga District Health Office, P.O. Box 910022, Mongu, Zambia
| | - Amy Healey
- Lincoln Centre for Water and Planetary Health, School of Geography, College of Science, Think Tank, University of Lincoln, Ruston Way, Lincoln, LN6 7DW, UK
| | - Tom Willis
- School of Geography, University of Leeds, Leeds, LS2 9JT, UK
| | - Douglas Singini
- Provincial Health Office, Western Province, P.O. Box 910022, Mongu, Zambia.,School of Public Health and Health Systems, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | - Francis Liywalii
- Provincial Health Office, Western Province, P.O. Box 910022, Mongu, Zambia
| | | | - Jacob Sakala
- Provincial Health Office, Western Province, P.O. Box 910022, Mongu, Zambia
| | - Mark Smith
- School of Geography, University of Leeds, Leeds, LS2 9JT, UK
| | - Mark Macklin
- Lincoln Centre for Water and Planetary Health, School of Geography, College of Science, Think Tank, University of Lincoln, Ruston Way, Lincoln, LN6 7DW, UK
| | - Andy J Hardy
- Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, SY23 3DB, UK
| | - Paul W Shaw
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, SY23 3FG, UK.,Department of Ichthyology and Fisheries Science, Rhodes University, Grahamstown, South Africa
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Goupeyou-Youmsi J, Rakotondranaivo T, Puchot N, Peterson I, Girod R, Vigan-Womas I, Paul R, Ndiath MO, Bourgouin C. Differential contribution of Anopheles coustani and Anopheles arabiensis to the transmission of Plasmodium falciparum and Plasmodium vivax in two neighbouring villages of Madagascar. Parasit Vectors 2020; 13:430. [PMID: 32843082 PMCID: PMC7447585 DOI: 10.1186/s13071-020-04282-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 08/03/2020] [Indexed: 02/01/2023] Open
Abstract
Background Malaria is still a heavy public health concern in Madagascar. Few studies combining parasitology and entomology have been conducted despite the need for accurate information to design effective vector control measures. In a Malagasy region of moderate to intense transmission of both Plasmodium falciparum and P. vivax, parasitology and entomology have been combined to survey malaria transmission in two nearby villages. Methods Community-based surveys were conducted in the villages of Ambohitromby and Miarinarivo at three time points (T1, T2 and T3) during a single malaria transmission season. Human malaria prevalence was determined by rapid diagnostic tests (RDTs), microscopy and real-time PCR. Mosquitoes were collected by human landing catches and pyrethrum spray catches and the presence of Plasmodium sporozoites was assessed by TaqMan assay. Results Malaria prevalence was not significantly different between villages, with an average of 8.0% by RDT, 4.8% by microscopy and 11.9% by PCR. This was mainly due to P. falciparum and to a lesser extent to P. vivax. However, there was a significantly higher prevalence rate as determined by PCR at T2 (\documentclass[12pt]{minimal}
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\begin{document}$$\chi_{2}^{2}$$\end{document}χ22 = 7.46, P = 0.025). Likewise, mosquitoes were significantly more abundant at T2 (\documentclass[12pt]{minimal}
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\begin{document}$$\chi_{2}^{2}$$\end{document}χ22 = 64.8, P < 0.001), especially in Ambohitromby. At T1 and T3 mosquito abundance was higher in Miarinarivo than in Ambohitromby (\documentclass[12pt]{minimal}
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\begin{document}$$\chi_{2}^{2}$$\end{document}χ22 = 14.92, P < 0.001). Of 1550 Anopheles mosquitoes tested, 28 (1.8%) were found carrying Plasmodium sporozoites. The entomological inoculation rate revealed that Anopheles coustani played a major contribution in malaria transmission in Miarinarivo, being responsible of 61.2 infective bites per human (ib/h) during the whole six months of the survey, whereas, it was An. arabiensis, with 36 ib/h, that played that role in Ambohitromby. Conclusions Despite a similar malaria prevalence in two nearby villages, the entomological survey showed a different contribution of An. coustani and An. arabiensis to malaria transmission in each village. Importantly, the suspected secondary malaria vector An. coustani, was found playing the major role in malaria transmission in one village. This highlights the importance of combining parasitology and entomology surveys for better targeting local malaria vectors. Such study should contribute to the malaria pre-elimination goal established under the 2018–2022 National Malaria Strategic Plan. ![]()
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Affiliation(s)
- Jessy Goupeyou-Youmsi
- Immunology of Infectious Diseases Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar. .,Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France. .,Doctoral School "Complexité du Vivant", Sorbonne University, Paris, France.
| | - Tsiriniaina Rakotondranaivo
- G4 Malaria Group, Institut Pasteur de Madagascar, Antananarivo, Madagascar.,Doctoral School "Génie du vivant et modélisation" Mahajanga University, Mahajanga, Madagascar
| | - Nicolas Puchot
- Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique UMR2000, Institut Pasteur, Paris, France
| | - Ingrid Peterson
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Romain Girod
- Medical Entomology Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Inès Vigan-Womas
- Immunology of Infectious Diseases Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Richard Paul
- Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France.,Centre National de la Recherche Scientifique UMR2000, Institut Pasteur, Paris, France
| | | | - Catherine Bourgouin
- Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France. .,Centre National de la Recherche Scientifique UMR2000, Institut Pasteur, Paris, France.
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Goupeyou-Youmsi J, Rakotondranaivo T, Puchot N, Peterson I, Girod R, Vigan-Womas I, Paul R, Ndiath MO, Bourgouin C. Differential contribution of Anopheles coustani and Anopheles arabiensis to the transmission of Plasmodium falciparum and Plasmodium vivax in two neighbouring villages of Madagascar. Parasit Vectors 2020; 13:430. [PMID: 32843082 DOI: 10.1101/787432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 08/03/2020] [Indexed: 05/21/2023] Open
Abstract
BACKGROUND Malaria is still a heavy public health concern in Madagascar. Few studies combining parasitology and entomology have been conducted despite the need for accurate information to design effective vector control measures. In a Malagasy region of moderate to intense transmission of both Plasmodium falciparum and P. vivax, parasitology and entomology have been combined to survey malaria transmission in two nearby villages. METHODS Community-based surveys were conducted in the villages of Ambohitromby and Miarinarivo at three time points (T1, T2 and T3) during a single malaria transmission season. Human malaria prevalence was determined by rapid diagnostic tests (RDTs), microscopy and real-time PCR. Mosquitoes were collected by human landing catches and pyrethrum spray catches and the presence of Plasmodium sporozoites was assessed by TaqMan assay. RESULTS Malaria prevalence was not significantly different between villages, with an average of 8.0% by RDT, 4.8% by microscopy and 11.9% by PCR. This was mainly due to P. falciparum and to a lesser extent to P. vivax. However, there was a significantly higher prevalence rate as determined by PCR at T2 ([Formula: see text] = 7.46, P = 0.025). Likewise, mosquitoes were significantly more abundant at T2 ([Formula: see text] = 64.8, P < 0.001), especially in Ambohitromby. At T1 and T3 mosquito abundance was higher in Miarinarivo than in Ambohitromby ([Formula: see text] = 14.92, P < 0.001). Of 1550 Anopheles mosquitoes tested, 28 (1.8%) were found carrying Plasmodium sporozoites. The entomological inoculation rate revealed that Anopheles coustani played a major contribution in malaria transmission in Miarinarivo, being responsible of 61.2 infective bites per human (ib/h) during the whole six months of the survey, whereas, it was An. arabiensis, with 36 ib/h, that played that role in Ambohitromby. CONCLUSIONS Despite a similar malaria prevalence in two nearby villages, the entomological survey showed a different contribution of An. coustani and An. arabiensis to malaria transmission in each village. Importantly, the suspected secondary malaria vector An. coustani, was found playing the major role in malaria transmission in one village. This highlights the importance of combining parasitology and entomology surveys for better targeting local malaria vectors. Such study should contribute to the malaria pre-elimination goal established under the 2018-2022 National Malaria Strategic Plan.
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Affiliation(s)
- Jessy Goupeyou-Youmsi
- Immunology of Infectious Diseases Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar.
- Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France.
- Doctoral School "Complexité du Vivant", Sorbonne University, Paris, France.
| | - Tsiriniaina Rakotondranaivo
- G4 Malaria Group, Institut Pasteur de Madagascar, Antananarivo, Madagascar
- Doctoral School "Génie du vivant et modélisation" Mahajanga University, Mahajanga, Madagascar
| | - Nicolas Puchot
- Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France
- Centre National de la Recherche Scientifique UMR2000, Institut Pasteur, Paris, France
| | - Ingrid Peterson
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Romain Girod
- Medical Entomology Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Inès Vigan-Womas
- Immunology of Infectious Diseases Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Richard Paul
- Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France
- Centre National de la Recherche Scientifique UMR2000, Institut Pasteur, Paris, France
| | | | - Catherine Bourgouin
- Functional Genetics of Infectious Diseases Unit, Institut Pasteur, Paris, France.
- Centre National de la Recherche Scientifique UMR2000, Institut Pasteur, Paris, France.
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Jones RT, Tusting LS, Smith HMP, Segbaya S, Macdonald MB, Bangs MJ, Logan JG. The impact of industrial activities on vector-borne disease transmission. Acta Trop 2018; 188:142-151. [PMID: 30165072 DOI: 10.1016/j.actatropica.2018.08.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 07/25/2018] [Accepted: 08/25/2018] [Indexed: 10/28/2022]
Abstract
Industrial activities have produced profound changes in the natural environment, including the mass removal of trees, fragmentation of habitats, and creation of larval mosquito breeding sites, that have allowed the vectors of disease pathogens to thrive. We conducted a review of the literature to assess the impact of industrial activities on vector-borne disease transmission. Our study shows that industrial activities may be coupled with significant changes to human demographics that can potentially increase contact between pathogens, vectors and hosts, and produce a shift of parasites and susceptible populations between low and high disease endemic areas. Indeed, where vector-borne diseases and industrial activities intersect, large numbers of potentially immunologically naïve people may be exposed to infection and lack the knowledge and means to protect themselves from infection. Such areas are typically associated with inadequate access to quality health care, thus allowing industrial development and production sites to become important foci of transmission. The altered local vector ecologies, and the changes in disease dynamics that changes affect, create challenges for under-resourced health care and vector-control systems.
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Affiliation(s)
- Robert T Jones
- ARCTEC, London School of Hygiene & Tropical Medicine, London, United Kingdom.
| | - Lucy S Tusting
- Big Data Institute, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Hugh M P Smith
- ARCTEC, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | | | - Michael J Bangs
- International SOS, Ltd., Papua Province, Indonesia; International SOS, Ltd., Lualaba Province, Democratic Republic of Congo
| | - James G Logan
- ARCTEC, London School of Hygiene & Tropical Medicine, London, United Kingdom; Department of Disease Control, London School of Hygiene & Tropical Medicine, United Kingdom
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