What are the dog heartworm vectors?

• A. Ae. notoscriptus, Ae. sierriensis
• B. Ae. tahoensis
• C. Ae. taeniorynchus
• D. Ae. vexans

Answer: (A)

Dog heartworm is spread when a mosquito serves as a vector, picking up microfilariae from an infected dog, letting them develop to the infective stage inside the mosquito, and then transmitting them to another dog during a later bite. Not all mosquitoes can do this effectively; only species that bite dogs and support the parasite’s development become vectors.

Aedes notoscriptus and Aedes sierrensis are documented vectors in the regions where they occur, meaning they both feed on dogs and provide the right conditions for Dirofilaria immitis to mature to the infective stage and be transmitted in a subsequent bite. This is why they’re identified as dog heartworm vectors.

Other species listed aren’t established as primary heartworm vectors in the context of this question—either due to regional distribution, feeding habits, or lack of evidence showing they reliably support transmission—so they’re not considered the vectors in this scenario.