Seasonal and Temporal Distribution of Anopheles Melas in Djeg Badji, a Coastal Lagoon Village of Southwestern Benin

Background

The complex Anopheles gambiae includes the most effective vectors of malaria in the world. The identification of these vector species and their seasonal and temporal distribution are essential for effective control of malaria. In Benin, this complex Anopheles gambiae is represented by Anopheles coluzzii, Anopheles gambiae, Anopheles arabiensis and Anopheles melas which occur near the lakes and lagoons of southern Benin. The present study provides information on the seasonal and temporal variation of Anopheles melas, the predominant malaria vector in Djegbadji, a coastal lagoon town of Benin.

Methods 

Sampling of adult mosquitoes was performed at Djegbadji by night inside and outside of homes using human landing catches (from May 2013 to February 2015) and morning indoor residual spray catches (from January 2014 to December 2014). The collected mosquitoes were identified morphologically and Anopheles melas specimens were separated from other vectors by the palps biometrics technique.

Results

The results showed that the collected mosquitoes belonged to 5 genera and 8 species. It included: Anopheles gambiae sensu lato, Aedes aegypti, Culex quinquefasciatus, Culex decens, Culex nebulosus, Culex fatigans and Mansonia africana. Among the different species identified, Anopheles gambiae sensu lato had the highest abundance. At Djegbadji, Anopheles melas was the predominant malaria vector in dry season (90%), in rainy season (73.43%) and during flood periods (76.47%). In times of recession, there is a reduction of Anopheles melas density by 30.76% with a predominance of Anopheles gambiae sensu stricto (69.24%). The two methods used for the collection of Anopheles melas gave similar results (p = 0.35).

Conclusion

This study allowed us to update the data on malaria vector species in coastal lagoon areas of Benin. It also demonstrated that the predominant species of malaria vectors in this area was Anopheles melas. These findings will guide planning strategies against malaria vectors in the coastal lagoon areas of Benin