Estimating dispersal and survival of Anopheles gambiae and Anopheles funestus along the Kenyan coast by using mark-release-recapture methods

Abstract

Mark-release-recapture (MRR) experiments were conducted with emerging Anopheles gambiae s.l. and Anophelesfunestus Giles at Jaribuni and Mtepeni in Kilifi, along the Kenyan Coast. Of 739 and 1246 Anopheles released at Jaribuni and Mtepeni, 24.6 and 4.33% were recaptured, respectively. The daily survival probability was 0.96 for An. funestus and 0.95 for An. gambiae in Jaribuni and 0.83 and 0.95, respectively, in Mtepeni. The maximum flight distance recorded was 661 m. The high survival probability of An. gambiae and An. funestus estimated accounts for the continuous transmission of malaria along the Kenyan coast. This study also shows that the release of young, emergent female Anopheles improves the recapture rates and may be a better approach to MRR studies.

Figures

Fig. 1

Map of the study area, showing Kilifi District and the two study sites along the Kenyan Coast. Site 1, Jaribuni; Site 2, Mtepeni. Boxes 1 and 2 on the right show the spatial location of the larval habitats where larvae were collected and of compounds where adult r ecapture collections were made.

Fig. 2

Regression of the daily number (Log n+1) of marked An. gambiae (A) and An. funestus (B) females recaptured after release at Jaribuni.

Fig. 3

Regression of the daily number (Log n+1) of marked An. funestus (A) and An. gambiae (B) females recaptured after release at Mtepeni.

Fig. 4

Distance moved as a function of days after release. (A) An.gambiae, and (B) An. funestus at Jaribuni; (C) An. gambiae at Mtepeni.