Vector competence of two species of mosquitoes (Diptera : Culicidae) from southern California for Dirofilaria immitis (Filariidea : Onchocercidae)

Two species of mosquitoes reared to adults from field-collected larvae or e gg rafts in or near Los Angeles County, CA, were exposed to dogs with known levels of Dirofilaria immitis (Leidy) microfilariae per 20 cubic millimete rs of blood Aedes taeniorhynchus (Wiedemann) readily blood fed on an infect ed dog ingested microfilariae but did not become infected. Culiseta inciden s (Thomson) also fed on an infected dog became infected, and 10% of the mic rofilariae developed to the L-3 stage. Cs. incidens is a peridomestic speci es broadly distributed in Los Angeles County and abundant from February thr ough December. The wide distribution of this species as well as its long an nual period of reproductive activity in Los Angeles County may contribute t o its potential as a vector of D. immitis.