<i>Anopheles leesoni</i>Evans 1931, a Member of the <i>Anopheles funestus</i>Group, Is a Potential Malaria Vector in Cameroon

Background: Understanding the biology of Anopheles malaria vector species is essential to planning effective and sustainable malaria control strategies in endemic countries. This study reported the implication of Anopheles leesoni in malaria transmission in Cameroon, Central Africa. Methods: Mosquitoes were collected in three localities from May 2015 to March 2018 using electric aspirators and Centers for Disease Control light traps (CDC-LT). Anopheles funestus sensu lato (s.l.) mosquitoes were identified as species using polymerase chain reaction assay (PCR). Furthermore, Plasmodium falciparum infection status was determined using the enzyme-linked immunosorbent assay (ELISA) method. Results: A total of 12,744 Anopheles mosquitoes were collected by electric aspirator (N = 4844) and CDC-LT (N = 7900). Anopheles funestus s.l. (86.95%) was the major species and the main malaria vector in rural savannah and rural forest sites followed by A. gambiae s.l. (13.05%) whereas in urban areas, A. gambiae s.l. was by far the most abundant representing 91.45% of Anopheles mosquitoes collected. Two members of the A. funestus group were identified among 1389 analysed by PCR: 1307 A. funestus sensu stricto (s.s.) (94.10%) and 82 A. leesoni (5.9%). Plasmodium falciparum infection rate was 21.04% in A. funestus s.s. For the first time, A. leesoni was found positive for P. falciparum (infection rate: 10.98%) in Cameroon. Conclusion: A very high P. falciparum infection rate was observed in this study in A. funestus s.s., highlighting its high implication in malaria transmission in Cameroon. Furthermore, the detection of P. falciparum infection in A. leesoni calls for more attention towards this neglected vector species.

Spatial distribution of Anopheles gambige sensu lato larvae in the urban environment of Yaounde,Cameroon

Background:The rapid and unplanned urbanization of African cities is considered to increase the risk of urban malaria transmission.The present study objective was to assess factors influencing the spatio-temporal distribution of Anopheles gombioe s.l.larvae in the city of Yaounde,Cameroon.Methods:All water bodies were checked once every 2 months for the presence of mosquito larvae from March 2017 to May 2018 in 32 distrias of Yaounde.Physico-chemical characteristics including the size,depth,turbidity,pH,temperature,conductivity,sulfates,organophosphates,hydrogen peroxide(H2O2),conductivity,iron and calcium were recorded and analyzed according to anopheline larvae presence or absence.High resolution satellite images from landsat sentinel Enhanced Thematic Mapper were used for spatial mapping of both field and environmental variables.Bivariate and multivariate logistic regression models were used to identify variables closely associated with anopheline larvae distribution.Results:A total of 18696 aquatic habitats were checked and only 2942 sites(15.7%)contained anopheline larvae.A high number of sites with anopheline larvae(>69%)presented late instar larvae(L3,L4 and pupae).Anopheline mosquito larvae were sampled from a variety of breeding sites including puddles(51.6%),tire prints(12.9%),wells(11.7%)and drains(11.3%).Bivariate logistic regression analyses associated anopheline larvae presence with the absence of predators,absence of algae,absence of vegetation and depth of less than 1 m.Conductivity,turbidity,organophosphates,H2O2 and temperature were significantly high in breeding sites with anopheline larvae than in breeding sites without these larvae(P<0.1).Anopheline species colleaed included An.coluzzii(91.1%)and An.gombioe s.s.(8.9%).GIS mapping indicated a heterogeneous distribution of anopheline breeding habitats in the city of Yaounde.Land cover analysis indicated high variability of the city of Yaounde's landscape.Conclusions:The data confirms adaptation of An.gombioe s.l.to the urban domain in the city of Yaounde and calls for urgent actions to improve malaria vector control.