The replication of two strains of La Crosse (LAC) virus, prototype and an unpassaged field isolate, was followed in intrathoracically inoculated male and venereally infected female Aedes triseriatus mosquitoes. The venereal infection rate following induced mating was 13.6% of 44 females inseminated by males inoculated with prototype virus, and 26.3% of 38 females inseminated by males inoculated with an unpassaged field strain. The males consistently contained concentrations of virus in reproductive tracts equal to or greater than those in salivary glands (SG). In contrast, venereally infected females generally contained the highest concentrations of virus in SG. Prototype LAC virus was demonstrable in nearly all organs of the infected females by 10 days following mating; the unpassaged field strain was detectable in all organ systems tested by day 6. There appeared to be no significant differences in replication between the prototype and field isolate viruses.
Present address: Department of Biomedical and Environmental Health Sciences, School of Public Health, University of California, Berkeley, California 94720.