The mosquito sucks blood from an affected dog, thus ingesting the microfilaria (baby worms)
Within the mosquito these microfilaria change into infective larvae
The mosquito then infects a healthy dog when feeding
These larvae develop into adult worms which migrate to the heart and large blood vessels
The adult female worms will start producing more microfilaria and allow the cycle to repeat
The first symptoms of disease include coughing, breathing difficulty, weakness and exercise intolerance. As the number of adult heartworms increase they interfere with the normal functioning of the heart. Consequently congestive heart failure and death can occur.
A sample of blood is taken and tested for adult heartworm. If your pet has tested positive to Heartworm you will need to discuss treatment options with the veterinary surgeon.
Heartworm is easier to prevent that cure. There are two choices:
If a dog has not started heart worm prevention by 6 months of age a Heartworm test will be required. If you forget to give the prevention tablets or the injection is overdue, discuss with the veterinarian for advice regarding need for a blood test.
Treatment is expensive and can be risky. Prevention is much better, cheaper and kinder to your dog. A positive test can mean either INFECTION (the worms are present but not yet causing clinical signs) or DISEASE (symptoms of coughing, exercise intolerance, weakness or breathing difficulty may be evident).
The disease is staged by the veterinarian and a treatment plan is devised. Generally, treatment involves a strong chemical (IMMITICIDE) being injected into the lumbar muscles of the dog, 2 injections, 24 hours apart. Your dog will have to be hospitalized for treatment as we need to monitor the dog for any possible reaction to the drug or to the dying worms.
The vet may or may not prescribe other supportive drugs before and after these injections.
Post Treatment Care/Plan:
After you collect your dog from the clinic, it is important that it receives absolute rest i.e. NO EXERCISE and NO PLAYING for several weeks after treatment. If you allow your dog to be active then the heart will beat faster causing dead worms to create blockages in blood vessels, kidneys or other organs. REST IS ESSENTIAL
One month after treatment you will need to visit the clinic for one further injection and to start preventative medicine to stop re-infection. Six months after treatment we need to repeat the heartworm test to ensure the infection has been cleared.