Entomological impact of indoor residual spraying with pirimiphos-methyl: a pilot study in an area of low malaria transmission in Senegal

Sy, Ousmane; Niang, El Hadji Amadou; Ndiaye, Magatte; Konaté, Lassana; Diallo, Abdoulaye; Ba, Elhadji; Tairou, Fassiath; Diouf, Elhadji; Cissé, Badara; Gaye, Oumar; Faye, Ousmane

doi:10.1186/s12936-018-2212-x

Cited by 25 publications

(37 citation statements)

References 15 publications

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“…This is in line with the ultimate goal of IRS which is to reduce the lifespan of mosquitoes, hence the parity rate. A similar observation was made in neighbor Senegal during a pirimiphos-methyl based IRS campaign [26].…”

Section: Discussionsupporting

confidence: 77%

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Performance of pirimiphos-methyl based Indoor Residual Spraying on entomological parameters of malaria transmission in the pyrethroid resistance region of Koulikoro, Mali.

KEITA¹,

Sogoba

Traoré

et al. 2020

Preprint

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Background:Vector control relies heavily on Long-lasting insecticidal nets ( (LLINs) and Indoor Residual Spraying (IRS) in selected districts in Mali including Koulikoro district. As part of strengthening vector control strategies in the district, IRS was initiated by the National Malaria Control Program (NMCP) with the support of the US President's Malaria Initiative (PMI) since 2008. LLINs coverage was 93.3% and 98.2% for IRS in Koulikoro, the only district of the region where IRS was supported by PMI. Following mosquito vector resistance to both pyrethroid and carbamates, organophosphate (pirimiphos-methyl) was used for the IRS campaigns of 2015 and 2016 in the district of Koulikoro. In this study, we assessed the effect of IRS on malaria transmission by comparing entomological indices in of the district of Koulikoro, where IRS was implemented and its neighbored district of Banamba, where IRS had never been implemented. Methods:The study was conducted in two villages of each district (Koulikoro and Banamba). Pyrethrum spray catches and entry window trapping were used to collect mosquitoes on a monthly basis. WHO tube tests were carried out to assess mosquito susceptibility to insecticides. Mosquitoes were identified to species level by PCR and their infection to P. falciparum was detected by ELISA.Results:Of the 527 specimens identified, An. coluzzii was the most frequent species (95%) followed by An. gambiae (4%) and An. arabiensis (1%). Its density was rainfall dependent in the no-IRS area, and almost independent in the IRS area. The infection rate (IR) in the no-IRS area was 0.96%, while it was null in the IRS area. In the no-IRS area, the entomological inoculation rates (EIR) was 0.21 infective bites /person month with a peak in September. High resistance to pyrethroids and carbamates and susceptibility to organophosphates was observed at all sites.Conclusion:The introduction of pirimiphos-methyl based IRS in the area resulted in a significant decrease in malaria transmission. An.gambiae s.l., the main malaria vector of the area, was resistant to pyrethroids and carbamates, and remained susceptible to the organophosphates.

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Section: Discussionsupporting

confidence: 77%

“…gambiae s.l. densities between the two areas could be explained by the residual effect of the IRS campaign [25,26].…”

Section: Discussionmentioning

confidence: 99%

Performance of pirimiphos-methyl based Indoor Residual Spraying on entomological parameters of malaria transmission in the pyrethroid resistance region of Koulikoro, Mali.

KEITA¹,

Sogoba

Traoré

et al. 2020

Preprint

View full text Add to dashboard Cite

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“…gambiae s.l. population allowing it to escape control interventions as reported in Senegal during an IRS campaign using pirimiphos-methyl [25].…”

Section: Discussionmentioning

confidence: 99%

Performance of pirimiphos-methyl based Indoor Residual Spraying on entomological parameters of malaria transmission in the pyrethroid resistance region of Koulikoro, Mali.

KEITA¹,

Sogoba

Traoré

et al. 2020

Preprint

View full text Add to dashboard Cite

Background: Following mosquito vector resistance to both pyrethroid and carbamates, organophosphate (pirimiphos-methyl) was used for the Indoor Residual Spray campaigns performed in 2015 to 2016 in the district of Koulikoro. In this context, we assessed the effect of IRS on malaria transmission by comparing entomological indices in two localities: Koulikoro (LLINs+IRS), and Banamba (LLINs -only) districts. Methods: The study was conducted in two villages of each district (Koulikoro and Banamba). Pyrethrum spray catches and entry window trapping were used to collect mosquitoes on a monthly basis. WHO tube tests were carried out to assess mosquito susceptibility to insecticides. Mosquitoes were identified to species level by PCR and their infection to P. falciparum was detected by ELISA. Results: An. coluzii was the most frequent species. Its density was rainfall dependent in the no-IRS area, and almost independent in the IRS area. The infection rate (IR) in the no-IRS area was 0.96%, while it was null in the IRS area. In the no-IRS area, the entomological inoculation rates (EIR) was 0.21 infective bites /person month with a peak in September. High resistance to pyrethroids and carbamates and susceptibility to organophosphates was observed at all sites. Conclusion: The introduction of pirimiphos-methyl based IRS in the area resulted to a significant decrease in malaria transmission. An.gambiae s.l., the main malaria vector of the area, was resistant to pyrethroids and carbamates, and remained susceptible to the organophosphates.

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“…Thus, this spatial heterogeneity may contribute to the persistence of transmission at a significant level [3]. The detection of heterogeneity patterns in malaria endemic areas is therefore becoming an important element in recent approaches that seek to identify transmission bottlenecks [4][5][6][7][8][9][10][11][12][13]. Variations in heterogeneity have been observed even at a very local scale-for example, within 8-km radius areas in Kenya [7], at the village level in Senegal (KeurSocé) [14], and at the household level in Tanzania (Korogwe District) and Mali (Bandiagara) [9,15].…”

Section: Introductionmentioning

confidence: 99%

Spatio-temporal variation of malaria hotspots in central Senegal, 2008-2012

Dieng

Bâ²,

Cissé

et al. 2020

Preprint

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Background: In malaria endemic areas, identifying spatio-temporal hotspots is becoming an important element of innovative control strategies targeting transmission bottlenecks. The aim of this work was to describe the spatio-temporal variation of malaria hotspots in central Senegal and to identify the meteorological, environmental, and preventive factors that influence this variation.Methods: This study analysed the weekly incidence of malaria cases recorded from 2008 to 2012 in 575 villages of central Senegal (total population approximately 500,000) as part of a trial of seasonal malaria chemoprevention (SMC). Data on weekly rainfall and annual vegetation types were obtained for each village through remote sensing. The time series of weekly malaria incidence for the entire study area was divided into periods of high and low transmission using change-point analysis. Malaria hotspots were detected during each transmission period with the SaTScan method. The effects of rainfall, vegetation type, and SMC intervention on the spatio-temporal variation of malaria hotspots were assessed using a General Additive Mixed Model.Results : The malaria incidence for the entire area varied between 0 and 115.34 cases/100,000 person weeks during the study period. During high transmission periods, the cumulative malaria incidence rate varied between 7.53 and 38.1 cases/100,000 person-weeks, and the number of hotspot villages varied between 62 and 147. During low transmission periods, the cumulative malaria incidence rate varied between 0.83 and 2.73 cases/100,000 person-weeks, and the number of hotspot villages varied between 10 and 43. Villages with SMC were less likely to be hotspots (OR=0.48, IC95%: 0.33-0.68). The association between rainfall and hotspot status was non-linear and depended on both vegetation type and amount of rainfall. The association between village location in the study area and hotspot status was also shown.Conclusion : In our study, malaria hotspots varied over space and time according to a combination of meteorological, environmental, and preventive factors. By taking into consideration the environmental and meteorological characteristics common to all hotspots, monitoring of these factors could lead targeted public health interventions at the local level. Moreover, spatial hotspots and foci of malaria persisting during LTPs need to be further addressed.Trial registrationThe data used in this work were obtained from a clinical trial registered at www.clinicaltrials.gov under # NCT 00712374.

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Entomological impact of indoor residual spraying with pirimiphos-methyl: a pilot study in an area of low malaria transmission in Senegal

Cited by 25 publications

References 15 publications

Performance of pirimiphos-methyl based Indoor Residual Spraying on entomological parameters of malaria transmission in the pyrethroid resistance region of Koulikoro, Mali.

Performance of pirimiphos-methyl based Indoor Residual Spraying on entomological parameters of malaria transmission in the pyrethroid resistance region of Koulikoro, Mali.

Performance of pirimiphos-methyl based Indoor Residual Spraying on entomological parameters of malaria transmission in the pyrethroid resistance region of Koulikoro, Mali.

Spatio-temporal variation of malaria hotspots in central Senegal, 2008-2012

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