Prevalence of filarial parasites in field-caught mosquitoes in northwestern California.

Mosquitoes were collected in Lake County, CA, in 2014 and tested using standard polymerase chain reaction for filarial parasite DNA. Filarial parasites were detected in 23 out of 1,008 total pools. DNA from the parasite causing dog heartworm, was detected in (MIR=4.62), (MIR=6.72), (MIR=1.08), and (MIR=0.10). deer body worm, was detected in (MIR=13.42), (MIR=0.55), (MIR=2.69), and (MIR=0.41). The avian parasite could not be identified to species but was detected in (MIR=0.20). DNA was also detected for three unidentified filarial parasites in . Filarial-positive pools spanned May-August, with earlier in the season and later. For , MIR tended to be highest in June, when the 130 HDU development threshold was reached. Interestingly, was also detected prior to the HDU threshold, and was not detected August-September, though HDU remained high enough for development. This suggests that there are other factors influencing dog heartworm transmission in the area.