Assessment of Culicidae collection methods for xenomonitoring lymphatic filariasis in malaria co-infection context in Burkina Faso

Abstract

BackgroundEntomological surveillance of lymphatic filariasis (LF) and malaria infections play an important role in the decision-making of national programs, to control or eliminate these both diseases. In order to corroborate infections in the human population, sampling large numbers of mosquitoes is necessary. To overcome this challenge, this study was design to assess the efficiency of four mosquito collection methods for monitoring LF and malaria infections in mosquito population. Methodology/Principle FindingsMosquito collections were performed between August and September 2018 in four villages (Koulpissy, Seiga, and Peribgan, Saptan), distributed in East and South-West health regions of Burkina Faso. Different collection methods were used: Human Landing Catches (HLC) executed indoor and outdoor, Window Exit-Trap, Double Net Trap (DNT) and Pyrethrum Spray Catches (PSC). Molecular analyses were performed to identify Anopheles gambiae s.l. sibling species and to detect Wuchereria bancrofti and Plasmodium falciparum infection in mosquitoes. A total of 3,322 mosquitoes were collected among this, Anopheles gambiaes.l. was the vector caught in largest proportion (63.82%). An. gambiae s.l. sibling species molecular characterization showed that Anopheles gambiae was the dominant specie in all health regions. The Human Landing Catches (indoor and outdoor) collected the highest proportion of mosquitoes (between 61.5%and 82.79%). For sampling vectors infected to W. bancrofti and P. falciparum, PSC, HLC and Window Exit-Trap were been find as the most effective collection methods. Conclusions/SignificanceThis study revealed that HLC indoor and outdoor remained the most effective collection methods. Likewise, the results showed the probability to use Window Exit-Trap and PSC collection methods to sample Anopheles infected and can be useful for xenomonitoring for both LF and malaria. Author summaryIn Burkina Faso the monitoring and evaluation scheme to assess the impact of LF and malaria interventions is only focusing on parasitological tests. While nowadays, the most simple and direct measure of vector borne diseases is xenomonitoring. Thus, in order to confirm both diseases infection rate in the human population, sampling large numbers of mosquitoes is necessary. This study was undertaken in this context to assess the efficiency of four mosquito collection methods for xenomonitoring LF and malaria. Mosquito collections were performed between August and September 2018 in four villages, distributed in East and South-West health regions of Burkina Faso. Human Landing Catches (HLC), Window Exit-Trap, Double Net Trap (DNT) and Pyrethrum Spray Catches (PSC) were evaluated. The results showed that HLC remained the most effective collection method by collecting the highest number of Anopheles (2,388; 71.88% of total). Across the study, mosquito infection rate for Wuchereria bancrofti and Plasmodium falciparum were 0.004 and 0.13 respectively. To collect vectors infected it was found that Window Exit-Trap and PSC were efficiencies. In conclusion, HLC has shown to be appropriate for collect large number of mosquitoes. Likewise, Window Exit-Trap and PSC can be useful for xenomonitoring for both LF and malaria.