Which statement about dog heartworm is true?

• A. It is the most common mosquito-borne disease in Maryland and is not a human health concern.
• B. It is transmitted by ticks.
• C. It has been eradicated in Maryland.
• D. It is not transmitted by mosquitoes.

Answer: (A)

Dog heartworm is a parasite that mosquitoes transmit to dogs when they take a blood meal. Dogs are the main hosts, and the disease can cause serious heart and lung damage in them. Humans are not natural hosts for heartworm, so it’s not a common or direct human health concern. That makes the statement that heartworm is mosquito-borne and not a human health concern the most accurate take-home point for this question.

It isn’t transmitted by ticks, it hasn’t been eradicated in Maryland, and it is indeed spread by mosquitoes, not some other vector. So the key idea is recognizing the mosquito as the vector and understanding that the public health impact for people is minimal, even though heartworm is a major veterinary issue.