Background: There has been a rapid emergence in insecticide resistance among mosquito population to commonly used public health insecticides. This situation presents a challenge to chemicals that are currently used to control mosquitoes in sub-Saharan African. Furthermore, there is limited information on insecticide susceptibility status of human-biting mosquitoes in some areas of Tanzania. This study aimed to determine insecticide susceptibility status of human biting mosquitoes in a rural area of north-eastern Tanzania.
Methods: The study was conducted in two villages in Muheza district, Tanzania. Insecticide susceptibility bioassays were performed according to the World Health Organization standard operating procedures on two to five-day old human biting mosquitoes. The mosquitoes of each species were exposed to four classes of insecticides commonly used for malaria vector control. Mosquito mortality rates (%) were determined after 24 hours post insecticide exposure.
Results: Mosquito species tested were
Anopheles gambiae
s.l.,
An. funestus
,
Aedes aegypti
, and
Culex quinquefasciatus
species. Real-time PCR have showed that the main sibling species of
An. gambiae complex and
An. funestus group were
An. gambiae s. s. (58.2%) and
An. funestus s. s. (91.1%), respectively. All mosquitoes, except
Ae. aegypti formosus were susceptible to pirimiphos-methyl (0.25%).
An. gambiae s. l. was found to be resistant to permethrin (0.75%) but showed possibility of resistance to DDT (4%) and bendiocarb (0.1%). Our findings have shown that,
An. funestus was fully susceptible to all insecticide tested.
Conclusion: The present study has revealed different levels of insecticide susceptibility status to four classes of commonly used insecticides in the most common mosquito vectors of human diseases in north-eastern Tanzania. The findings of the present study call for integrated vector control interventions.
