posted 05-19-2003 07:58 AM
Heartworms are named thus because they are parasitic worms that cause heart failure. Heartworms are not fatal themselves but they cause serious infections that are fatal. These worms live inside the dog's heart. Immature or larvae of heartworms are called microfilariae. Heartworms are transmitted via the mosquito as the carrier host. Dogs, cats and foxes can be infected by the bite of a mosquito carrying the infective larvae.
The infected dog then becomes the host of these heartworms. Some of the clinical signs of infection are chronic cough, lack of stamina and lack of energy for exercise.
Adult heartworms may interfere in the heart's functions and blood can't be pumped properly for the circulation. The right heart will swell, followed by damage to the lungs, liver, kidneys, abdomen, chest and lastly limbs.
The period of incubation in the dog host varies. Some dogs remain infected for a long time before showing any clinical signs of the disease. All dogs are susceptible to heartworm infection. Dogs with outdoor kennels are very likely to be bitten by mosquitoes and thus are exposed to higher risks of contacting heartworm disease.
If there are large masses of heartworms near the liver, this will cause serious illnesses in the liver. The dog will experience loss of appetite, liver disease, blood pigments in the urine, yellowing skin, jaundice and eventually the dog dies.
When worms of only 1 sex or immature worms are inside a dog, there are no microfilariae in its blood circulation. However, this type of heartworm disease affects this dog and mosquitoes feeding on its blood do not carry microfilariae to infect other animals.
Treatment of heartworm disease is successful if the disease is still in its infancy stage. Victims of severe heartworm disease do not have good chances of recovery due to the extensive damage already done to the organs.
Your vet will prescribe drugs to kill the adult heartworms in the heart. Then he will administer preventive medication drugs to kill the microfilariae. Follow-up drugs are also used to prevent recontamination by mosquito bites.