The tiny immature heartworms (Dirofilaria immitis) are transmitted through the bite of a mosquito. At first, the parasites move into the dog's tissues, but eventually they occupy the dog's heart. As the worm grows and reproduces, more immature worms are released into the dog's blood stream. When other mosquitoes bite the infected dog they pick up this microfilarias and transmit them to the next dog they bite.

    Once in the heart of your dog heartworms interfere with the normal flow of blood from the right side of the heart to the vessels serving the lungs.

    If left untreated, canine heartworm disease can significantly reduce your dog's quality of life, cause congestive failure of the heart and other organs, and ultimately can lead to death. At first an infected dog may show few signs of infection, but as the heartworm grows and matures, they cause increasing damage.     The dog become listless, tires easily after exercise, develops an occasional to persistent cough and becomes anemic.

    In advances cases, dogs often suffer congestive heart failure. Complications may develop in the liver and kidneys. The blood supply to the lungs and other major organs may become blocked.

Heartworm Prevention
Heartguard Plus (Ivermectin/pyrantel) is a preventive medicine that is safe for puppies 6 weeks of age and older and very effective eliminating the tissue stages of the heartworm larvae for a month. It is easy to use since it is a tasty chewable that your pet will eat like a treat. It is recommended year round in Florida. It also prevents and controls other intestinal parasites like Roundworm and Hookworms.
Revolution is a new preventative that is applied topically, besides heartworm prevention it also prevents fkeas, ticks, intestinal parasites, ear mites. It is use once a month on the skin between shoulder blades, it is absorbed in one hour .

Treatment
A complete physical and medical examination is necessary to determine the health status of your pet and the severity of the disease. Laboratory tests and possibly radiographs may be part of the complete work-up that will be undertaken to assure treatment tailored to the patient's condition.

Heatworms can be treated with a new drug (Immiticide) that is the most effective development for adult heartworm control in recent years. Most worm infected dogs need two injections, given 24 hours apart. The dog needs to be kept in the hospital for the procedure, and his health will be carefully monitored. Supportive medication will be administrated if necessary depending on each individual case.