Vertical Transmission of La Crosse Virus (California Encephalitis Group): Transovarial and Filial Infection Rates in Aedes Triseriatus (Diptera: Culicidae)1

Abstract

La Crosse (LAC) virus remained infective to warm-blooded hosts after 8 successive transovarial passages in the mosquito Aedes triseriatus. Virtually all transovarially infected females (98%) transmitted LAC virus to their offspring, and the mean percentage of infected offspring from an infected female was 71%, a rate that remained essentially constant from one generation to the next. These results indicate that the virus can persist 4 years or longer in the absence of horizontal amplification in vertebrate hosts and the data provide a basis for estimating, during anyone season, the amount of amplification necessary to maintain the virus at existing endemic levels.