Posted by Vector and Vector-borne Disease Committee
May 26, 2022
Tiffany D. Tran,1 Brittany M. Nelms,2 Michelle L. Koschik,2 Jamesina J. Scott,2 Tara Thiemann1
1University of the Pacific, Biological Sciences, Stockton, CA 95211, U.S.A.
2Lake County Vector Control District, 410 Esplanade St., Lakeport, CA 95453, U.S.A.
Abstract [paraphrased]. Mosquitoes collected in Lake County, CA, in 2014 were tested for filarial parasite DNA using standard PCR. Filarial parasites were detected in 23 out of 1,008 total pools. Dirofilaria immitis, dog heartworm, was detected in Aedes increpitus (MIR=4.62), Aedes sierrensis (MIR=6.72), Anopheles freeborni (MIR=1.08), and Culex tarsalis (MIR=0.10). Setaria yehi, deer body worm, was detected in Ae. sierrensis (MIR=13.42), Anopheles franciscanus (MIR=0.55), An. freeborni (MIR=2.69), and Culex stigmatosoma (MIR=0.41). The avian parasite Splendidofilaria could not be identified to species but was detected in Cx. tarsalis (MIR=0.20). DNA was also detected for three unidentified filarial parasites in Culex.
Comment: This research confirms that Aedes sierrensis is an important vector of dog heartworm, but indicates that previous studies using dissection techniques most likely over estimated infection rates that were confounded because of frequent infection with deer body worm. Further research is needed to elucidate the vector competence of these naturally infected species.