Population Fluctuations and Abundance Indices of Mosquitoes (Diptera: Culicid), as the Potential Bridge Vectors of Pathogens to Humans and Animals in Mazandaran Province, Northern Iran

Background: Seasonal activity patterns of mosquitoes are essential as baseline knowledge to understand the transmis­sion dynamics of vector-borne diseases. This study was conducted to evaluate the monthly dynamics of the mosquito populations and their relation to meteorological factors in Mazandaran Province, north of Iran. Methods: Mosquito adults and larvae were collected from 16 counties of Mazandaran Province using different sam­pling techniques, once a month from May to December 2014. “Index of Species Abundance” (ISA) along with “Stand­ardized ISA” (SISA) was used for assessing the most abundant species of mosquitoes based on the explanations of Rob­ert and Hsi. Pearson’s correlation coefficient (R) was used to assess the relationships between the monthly population fluctuations and meteorological variables. Results: Overall, 23750 mosquitoes belonging to four genera and nineteen species were collected and identified. The highest population density of mosquitoes was in July and the lowest in May. The ISA/SISA indices for Culex pipiens were both 1 for larvae and 1.25/0.973 for adults in total catch performed in human dwellings. For Cx. tritaeniorhynchus, the ISA/SISA were 1.68/0.938 in pit shelter method. A significant positive correlation was observed between population fluctuations of Cx. tritaeniorhynchus and mean temperature (R: 0.766, P< 0.027). Conclusions: The results indicated that the mosquitoes are more active in July, and Cx. pipiens and Cx. tritaeniorhyn­chus were the most abundant species. Considering the potential of these species as vectors of numerous pathogens, con­trol programs can be planed based on their monthly activity pattern in the area.