Potential mosquito vectors of Dirofilaria immitis in Bernalillo County, New Mexico

The susceptibility of Aedes vexans, Culex quinquefasciatus, and Culex tarsalis to Dirofilaria immitis infections was evaluated in Bernalillo Co., New Mexico. Mosquitoes that had taken a blood meal from a D. immitis-infected dog were dissected and observed for developing larvae. Infection rates for Ae. vexans, Cx. quinquefasciatus, and Cx. tarsalis were 68.9, 40.6, and 30.2%, respectively. Infective D. immitis larvae developed after a minimum of 8 days in Ae. vexans vs. 14 days in both Cx. quinquefasciatus and Cx. tarsalis. Vector efficiency of Ae. vexans was 20.4%, with a mean of 5.9 infective larvae developing from a mean of 29 microfilariae ingested per mosquito. Vector efficiency in Cx. quinquefasciatus and Cx. tarsalis was 2.7 and 0.4%, respectively. These results suggest that Ae. vexans has the greatest potential for D. immitis transmission.