Causes, Prevention and Treatment of Heartworms in Dogs.

Heartworms are a danger to dogs of any age and breed. These parasitic roundworms infect the lungs and heart of dogs, cats and other mammals, causing heartworm disease. Left untreated, the disease is potentially fatal.
The disease, once thought to be a problem only in warmer climates, has become a worldwide problem. Cases have been reported in all 50 US states.
How Heartworm Infection Occurs
The infection cycle begins when female heartworms releases their young, called microfilariae, into an infected animal’s bloodstream. Mosquitoes then become infected with microfilariae while taking blood from the infected dog. The microfilariae mature to the infective larval stage within the mosquito over the next 10-14 days.
The mosquito then bites another dog, and the larvae enter through the bite wound. The larvae mature into adult heartworms over the next 6 months and can live for up to 7 years. Microfilariae cannot mature into adult heartworms without first passing through a mosquito.
Heartworms: Warning Signs
The early stages of a heartworm infestation are difficult to spot, with recently infected dogs showing no signs of the disease at all. This is because an infestation tends to accumulate gradually over several months, sometimes years, and after repeated mosquito bites.
Where the dog is heavily infected the clinical signs will be a mild, persistent cough, general lethargy, loss of appetite, weight loss, and fatigue after even moderate exercise.
Other symptoms may include vomiting and diarrhea, blood in the stool, jaundice, poor coat condition, and blindness.
If any of these are present in your dog, get him to the vet immediately.
Heartworms: Prevention and Treatment
Canine heartworm infection is usually detected by blood tests. However, the results of these tests may not be reliable until the infection is relatively advanced.
Heartworm can also occasionally be detected by ultrasound and/or x-ray, although this method of testing is usually only used in dogs that are known to be infected.
Most cases of heartworm disease in dogs are treatable, but treatment can be complicated and expensive, taking weeks before the infected dog recovers fully. The process involves a series of injections to the muscles, and hospitalization is usually recommended.
By contrast, preventative heartworm medication is safe, easy and inexpensive.
Preventative medicine can be administered either monthly or daily, by injection, tablet, or topical treatment. All of these methods are highly effective in disrupting the heartworm development cycle and preventing the adult worms from infecting the heart and lungs.
Provided you maintain the prevention program your dog need never be infected with heartworms.