Potential for evolution of California serogroup bunyaviruses by genome reassortment in Aedes albopictus.

Aedes albopictus was introduced into the United States in used tires in 1985. Its successful colonization of the upper Midwest has potential to alter the current epidemiology of bunyaviruses that circulate in the region. It is permissive for the replication of several arboviruses, including La Crosse (LACV) and Jamestown Canyon (JCV) bunyaviruses. In this study, we demonstrate the ability of LACV and JCV to coinfect Ae. albopictus mosquitoes and to form all six possible reassortant genotypes. All reassortant viruses infect Ae. albopictus orally and can be transmitted to suckling mice. All reassortants are neurovirulent in mice. However, reassortant viruses carrying the LACV M segment in the foreign genetic background of JCV are more neuroinvasive than JCV, or any other reassortant genotype. In addition, these reassortants can replicate in gerbils and infect Ae. triseriatus, characteristics of LACV, but not JCV. Because Ae. albopictus is spreading into new geographic areas and feeds on a variety of mammals, including humans, it has the potential to transmit new, emerging bunyaviruses in nature.