Are Dog Heartworms Contagious?

Dog heartworms can be a fatal condition, and the worms are frequently discovered when the dog is severely ill. Some canine worms are zoonotic and may be transmitted from the dog to humans and other species. Heartworms are parasites that may only be transmitted to other dogs and cats. However, the heartworms cannot be transmitted from an infested dog to another through direct contact. The worms will be transmitted through an intermediary: the mosquito.

Heartworms Are Contagious to Other Dogs and Felines

Heartworms are contagious and may be contracted indirectly from an infested dog. In order to be transmitted, the infected dog has to be bitten by a mosquito, which will be a carrier of the heartworm larvae. The mosquito carrying the heartworm larvae can bite healthy dogs and transmit the infection. When the heartworm larvae reach a new host, these will be able to mature and develop into a serious heartworm infection. The heartworms may also be transmitted to felines, if the mosquito carrying the larvae bites a cat.

Heartworms Are Not Contagious to Humans

Heartworms may only be transmitted from dog to dog, dog to cat or vice versa, indirectly through mosquitoes. However, the heartworm infection cannot be transmitted from dogs to humans, not even through intermediaries.

Heartworm Symptoms

The presence of heartworms may not show any symptoms in pets for as long as 12 months after the larvae are transmitted. For this reason, it's virtually impossible to detect the heartworm infection from the early stages and apply treatment. Some dogs will display symptoms such as:

  • Coughing, especially during nighttime when the worms are active or after exercising
  • Exercise resistance
  • Vomiting of worms
  • Lack of appetite
  • Lack of energy
  • Anemia
  • Coughing up blood
  • Congestive heart failure (in advanced cases)

Some dogs may display no symptoms at all. Very often, heartworms are only detected during routine vet exams that involve a blood sample analysis or chest x-rays.

Heartworm Treatment

A dog with heartworms may be treated only if the infection is detected in the early stages. In more advanced stages, the worms may do a lot of irreparable damage and the prognosis is poor. The medications that are prescribed for canine heartworms may be dangerous and have serious side effects. The side effects of the treatment can often be fatal. In some cases, heart surgery may be possible, but this can be a risky operation.

Heartworm Prevention

Heartworm prevention is possible through the administration of medication. There are preventive drugs which can be administered each month or less often. You can be cautious and get regular veterinary checkups if you suspect your pet has been bitten by a mosquito, especially if you know of cats or dogs infested with heartworms in your area. If you live in an area where there are no mosquitoes, your pet is protected from the heartworm infestation.