Heartworm is a deadly disease that is transmitted by mosquitos. It more often affects dogs, but cats can also be infected.

Heartworm larvae live in the bloodstream, so when a mosquito bites an infected dog and then bites another dog, the disease is transmitted. The larvae then migrate to the heart where they grow into adult worms and cause heart failure.

Heartworm can be quite easily prevented in dogs with either an annual heartworm injection or a good quality monthly heartworm product.