Bancroftian filariasis in Nigeria is endemic with 22.1% of the population at risk of infection. The main mosquito genera implicated with the transmission are Anopheles and Culex. To compare the infectivity rates and transmission potentials after long - lasting insecticide - treated bed net (LLIN) intervention, we conducted study on the vectors between the high transmission (rainy) and the low transmission (dry) seasons. Mosquitoes were caught from houses in six sentinel villages (3 each from Ohaukwu and Abakiliki Local Government Areas of Ebonyi State, Nigeria). Day resting indoor collection (DRI) by Pyrethrum knock down (PKD) was used to collect mosquitoes between 7:00am and 11:00am. After morphological identification, female parous mosquitoes were dissected in search for infective (L3) larvae of Wuchereria bancrofti. A total of 3,938 mosquitoes were dissected/examined for parous, infection/infectivity status. Facilitation only in the couple An. gambiae sl/W.bancrofti continued with insignificant difference in the overall infectivity rate (P>0.05). The infectivity rates were 3.18% and 3.06% for Ohaukwu whereas in Abakiliki these were 0.15% and 0.25% respectively. Similarly, no significant difference in the total/average Transmission potentials were found between the seasons (P>0.05). Evaluation of entomologic indices herein provides inexpensive alternative to blood smear analysis and the need for LLIN usage in synergy with other vector control measures is suggested.

Keywords: Long lasting insecticide-treated net, Rainy and Dry Season, transmitting vectors, Wuchereria bancrofti, Transmission risk.