Background: Aedes aegypti is present year round in several cities of the Republic of Benin. This study aims to assess the seasonal distribution of this mosquito at Dandji, in southern Benin.
Method: A cross seasonal entomological study on larvae and adults of Ae. aegypti was carried out from May 2013 to April 2014 in southern Benin (Dandji). The study was based on sampling Ae. aegypti immature stages (larvae/pupae) from domestic, peri-domestic and natural water sources and were reared to adults. The collections were made during the dry and rainy seasons. Addional Ae. aegypti were collected by Human Landing Catches (HLC), Indoor Pyrethrum Spray Catches (PSC), Biogents (BG) sentinel trap and Gravid traps (GT).
Results: During the year of study, a total number of 18,658 mosquitoes were collected where 15,204 were collected by HLC; 303 with BG trap, 3,038 with PSC, 48 with the GT. Among the 18, 593 of Ae. aegypti collected, the female populations (13,834) was significantly higher than the male populations (p<0.05). From the 13,834 females, 1,380 were blood-fed.
Adult's collection was high during the two rainy seasons (June to July and October to November) but declined in the two dry seasons (December to March and August to September).
At Dandji, the average of Human Biting Rates (HBR) obtained during the rainy seasons (79.6 bites/p/n) was significantly higher than those obtained during the dry seasons (58.62 bites/p/n) (p < 0.05).
Conclusion: These findings showed the presence of Aedes aegypti year round at Dandji in southern Benin. This presence is strengthening with the trade of second hand tires which are good breeding sites for the development of Ae. aegypti. Data on blood feeding patterns of Ae. aegypti collected during this study will certainly provide valuable information about potential Dengue virus (DENV) hosts others than humans and will help to get a greater understanding about DENV ecology in Benin. It is therefore crucial for health authorities of Benin to develop a program to fight against this mosquito in order to avoid an outbreak of DENV as it was the case in many sub Saharan Africa countries recently.