Susceptibility of Anopheles hermsi to Plasmodium vivax

Two outbreaks of Plasmodium vivax malaria have occurred recently in southern California, and Anopheles hermsi, a newly described species closely related to A freeborni, has been implicated as the vector. To assess the competence of A. hermsi as a vector, its susceptibility to P. vivax was compared with that of the efficient vector A. freeborni by allowing 150 females of each species to feed to repletion on infected squirrel monkeys. Oocyst density was greater in A. hermsi than in A. freeborni, and the frequency and density of sporozoites were similar. A. hermsi was susceptible to P. vivax and readily supported development to the sporozoite stage.