EFFECT OF SALT CONCENTRATION IN LARVAL REARING WATER ON SUSCEPTIBILITY OF AEDES MOSQUITOS (DIPTERA, CULICIDAE) TO EASTERN EQUINE AND VENEZUELAN EQUINE ENCEPHALITIS VIRUSES

The effect of salt concentration in larval rearing water on the suscep tibility of adult Aedes taeniorhynchus; (Wiedemann) and Aedes sollicit ans (Skuse) to infection with eastern equine encephalomyelitis (EEE) v irus was tested in the laboratory. Ae. sollicitans was more susceptibl e to infection (79%, n = 82) and viral dissemination (16%) with EEE vi rus 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 unit s/ml; however, infection rates in adults were not affected by rearing in salt concentrations ranging from fresh water to brackish water cont aining 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 (Skus e), reared in fresh water, became infected. Similarly, Venezuelan equi ne encephalitis viral infection or dissemination rates did not vary am ong Ae. taeniorhynchus adults that were reared in water containing 0, 1, or 2% sea salts.