Identifying Dog Heartworm Symptoms

The dog heartworm disease is a serious condition that may be fatal. The disease is caused by the Dirofilaria immitis parasites, which can be transmitted through mosquito bites and will affect the heart. The heartworm disease may show no or very subtle symptoms while the worms are not mature; when mature, the worms should cause a few clinical signs.

Heartworm Stages of Development

The heartworm dog symptoms will depend greatly on the stages of development of the Dirofilaria immitis worms. The heartworms have a number of life stages; when the worms become adults, they will affect the heart of the dog.

The worms are transmitted through mosquito bites. The mosquitoes carry the heartworm larvae, which start developing once they are transmitted to the host (the dog). The larvae will initially start to develop under the dog’s skin and will spread towards the muscles 1 week after the bite; then the larvae will migrate towards the chest and the stomach of the dog, where they will stay for up to 9 weeks.

Approximately 16 weeks after the infection, the worms are not yet mature, but they will get in the blood stream and affect the heart and the pulmonary artery. The worms will reach maturity when they are between 9 and 12 inches long. This may happen 6 to 7 months after the mosquito bite. At this stage, the heartworms will start to reproduce and create the microfilariae, which will be present in the blood stream.

Symptoms of Heartworms in Dogs

During the stages of the heartworm immaturity, the dog will be less likely to display any clinical signs. Consequently, it may take 6 to 7 months for the dog to start showing symptoms of heartworm disease. In rare cases, the larvae may circulate in the blood stream and affect the optical nerve, causing blindness or affect the brain or the limbs of the dog, causing confusion or lameness.

After the worms reach maturity, the dog will start showing symptoms such as:

  • Lethargy
  • Depression
  • Dry cough; the dog may cough up blood
  • Resistance to exercise and coughing after exercising
  • Longer sleep hours
  • Vomiting, in advanced cases
  • Lack of appetite and weight loss
  • Fainting or sudden collapse
  • Confusion
  • Breathing problems

In some cases, infected dogs may not show any symptoms, not even after the worms have reached maturity.

Dog Medicine for Heartworms

Heartworms may only be detected after they have reached maturity. It is important to get some tests to identify the worms as soon as the dog shows some of the above mentioned symptoms; if the condition is left untreated, the dog may suffer from a congestive heart failure.

The treatment for heartworms in dogs will consist of an arsenic medicine, which can destroy the worms. If the heart and the pulmonary artery are severely affected, the dog may require surgery.

The occurrence of heartworms may be prevented with dog heartworm medication.