Background: Culex quinquefasciatus is a vector of lymphatic filariasis and a biting nuisance in many developing countries with a warm and humid climate. In north eastern part of Tanzania, the burden of chronic lymphatic filariasis disease is still high. There is limited information on the factors that contribute to higher abundance of this mosquito species in rural areas. This study was therefore aimed at assessing the seasonal variation of Cx. quinquefasciatus abundance in pit latrines in rural areas in Muheza.

Methods: A cross-sectional study was conducted in rural settings of Muheza district for the duration of 11 months consecutively in 24 villages which were randomly selected. Collection of adult Culex mosquitoes emerged from wet pit latrines was done by using emergence traps. In each village three houses were selected basing on the presence of pit latrines.

Results: A total of 12,762 mosquitoes consisting of Culex quinquefasciatus (12%) and Culex cinereus (88%) species were collected from 24 villages. Majority of Cx. quinquefasciatus mosquitoes were collected during cool and dry season followed by long rains season with 48.52% (n=722) and 41.53% (n=618), respectively. Only one Cx. quinquefasciatus (0.07%) was collected during hot and dry season.

Conclusion: The present study has revealed the variation in the densities of Cx. quinquefasciatus emerged from pit latrines across the seasons. Wet pit latrines were found to be potential breeding sites for Cx. quinquefasciatus. The present study has provided important information on mosquito seasonality density in rural setting for employing alternative vector control such as larviciding in wet pit latrines.