North American Culex pipiens and Culex quinquefasciatus are competent vectors for Usutu virus.

Results indicate that members of the Cx. pipiens complex are susceptible to USUV and competent for its transmission potential in North America in the event of its introduction. In contrast, Ae. albopictus were highly refractory to USUV infection, suggesting that this species is unlikely to contribute to USUV transmission in North America.