Lifecycle of a Mosquito
Dog heartworm is an important parasite of dogs. Dog heartworm disease is caused when a tiny parasitic worm enters the bloodstream of a dog through a mosquito bite. The juvenile worm migrates to the dog’s heart and grows there. An infected dog may have as many as 20 heartworms, each up to 11 inches long.
Dogs should regularly be treated for heartworm to prevent this potentially fatal disease.