Effect of salt concentration in larval rearing water on susceptibility of Aedes Mosquitoes (Diptera: Culicidae) to eastern equine and Venezuelan equine encephalitis viruses.

The effect of salt concentration in larval rearing water on the susceptibility of adult Aedes taeniorhynchus (Wiedemann) and Aedes sollicitans (Skuse) to infection with eastern equine encephalomyelitis (EEE) virus was tested in the laboratory. Ae. sollicitans was more susceptible to infection (79%, n = 82) and viral dissemination (16%) with EEE virus than was Ae. taeniorhynchus (42%, n = 184) and (5%), respectively, when fed on a chick with a viremia of 10(7) +/- 0.1 plaque-forming units/ml; however, infection rates in adults were not affected by rearing in salt concentrations ranging from fresh water to brackish water containing 2.4% sea salts (1 part fresh water and 2 parts seawater). When fed on the same viremic 6-d-old chicken, all 48 Aedes albopictus (Skuse), reared in fresh water, became infected. Similarly, Venezuelan equine encephalitis viral infection or dissemination rates did not vary among Ae. taeniorhynchus adults that were reared in water containing 0, 1, or 2% sea salts.