EXPERIMENTAL TRANSMISSION OF EASTERN EQUINE ENCEPHALITIS-VIRUS BY STRAINS OF AEDES-ALBOPICTUS AND A-TAENIORHYNCHUS (DIPTERA, CULICIDAE)

The vector competence of Aedes taeniorhynchus (Wiedemann) and four str ains of Aedes albopictus (Skuse) was assessed for eastern equine encep halitis (EEE) virus isolated from Ae. albopictus collected in Polk Cou nty, Florida. Both species became infected with and transmitted EEE vi rus by bite after feeding on 1-d-old chicks that had been inoculated w ith EEE virus (viremia = 10(10.1) plaque-forming units [PFU] per ml of blood). However, when fed on an older chick with a lower viremia (vir emia = 10(6.1) PFU per ml of blood), Ae. albopictus was significantly more susceptible to infection (90%, n = 61) than was Ae. taeniorhynchu s (15%, n = 40). Transmission was also significantly more efficient by Ae. albopictus (36%, n = 44), than by Ae. taeniorhynchus (0%, n = 14) . These data, combined with the recent isolation of EEE virus from Ae. albopictus and its opportunistic feeding behavior, indicate that Ae. albopictus could function as a bridge vector between the enzootic Culi seta melanura (Coq.)-avian cycle and susceptible mammalian hosts.