Detection of Dirofilaria immitis (Nematoda: Filarioidea) by Polymerase Chain Reaction in Aedes albopictus, Anopheles punctipennis, and Anopheles crucians (Diptera: Culicidae) From Georgia, USA

Potential mosquito vectors of Dirofilaria immitis (Leidy) (Nematoda: Filarioidea), the causative agent of dog heartworm in the southeastern region of the United States, were collected with CDC light traps and gravid traps in seven counties in the state of Georgia, USA. The presence of D. immitis in these mosquitoes was detected by polymerase chain reaction using species-specific primers for the D. immitis surface or cuticular antigen. Overall, 1,574 mosquitoes of 13 species in seven genera were collected; 92% of the specimens were Aedes albopictus (Skuse), Aedes vexans (Meigen), or Anopheles punctipennis (Say). Ae. albopictus, An. punctipennis, and Anopheles crucians Wiedemann were positive for D. immitis DNA. Ae. albopictus had the highest maximum likelihood rate of infection (2.30%; 95% confidence interval [CI] = 1.15–4.00%) followed by An. crucians (1.38%: 95% CI = 0.04–6.93%), and An. punctipennis (0.85%: 95% CI 0.03–4.29%). The detection of D. immitis DNA in the heads and thoraxes of Ae. albopictus (0.40%; 95% CI = 0.12–2.02%) indicates that these mosquitoes can support the development of D. immitis to the infective stage 3 larvae.