Seasonal Activity of Adult Mosquitoes (Diptera: Culicidae) in a Focus of Dirofilariasis and West Nile Infection in Northern Iran

BACKGROUND: Mosquito-borne arboviruses such as West Nile, dengue, Rift Valley fever, and Sindbis viruses and the nematode Dirofilaria are reported in Iran, but there is little information on the seasonal activity of their vectors in the country. We aimed to determine the seasonal activity of adult mosquitoes (Diptera: Culicidae) in a focus of dirofilariasis and West Nile infection in Guilan Province, northern Iran. METHODS: Collections were carried out using light traps in seven counties at least two times from random sites and every two weeks from a fixed site (Pareh Village, Rudbar County) during Aug–Dec 2015 and Apr–Oct 2016. RESULTS: Overall, 16327 adult mosquitoes comprising 18 species representing seven genera were identified. The most prevalent species were Cx. theileri (23.59%), Cx. tritaeniorhynchus (20.75%), Cx. pipiens (19.37%), Ae. vexans (18.18%), An. pseudopictus (10.92%) and An. maculipennis s.l. (5.48%). Aedes pulcritarsis and Cx. perexiguus were found for the first time in Guilan Province. The active season of adult mosquitoes extended from early May to early Oct in the fixed site. There was no significant regression between the abundance of adult mosquitoes and the meteorological data during active season in the fixed site (P> 0.05, R(2)= 0.31). CONCLUSION: Though no significant regression between the abundance of mosquitoes and the meteorological data was observed during active season, temperature and rice fields had a great influence in starting and ending active season in the region.