Heartworm disease occurs when a dog becomes infested with a roundworm called Dirofilaria immitis. It was first identified in the United States in 1856 and occurred most frequently on the seacoast in the southeastern United States. Heartworms are parasitic worms, which inhabit the heart muscle and lungs of infected dogs. Heartworm disease can cause serious health problems including death due to heart failure or pneumonia. Dogs are considered the definitive host for heartworms. However, heartworms may infect more than 30 species of animals (e. g. , coyotes, foxes, wolves and other wild canids, domestic cats and wild felids, ferrets, sea lions, etc. ) and humans as well.
Heartworms belong to the same class of worms as roundworms. In fact, they look a bit like roundworms, but that is where the similarity ends. When a mosquito carrying infective heartworm larvae bites a dog and transmits the infection, the larvae grow, develop, and migrate in the body over a period of several months to become *** mature male and female worms. These reside in the heart, lungs, and associated blood vessels. Even as immature adults, the worms mate and the females release their offspring (microfilariae) into the blood stream. The time elapsed from when the larvae enter the dog until the minute offspring can be detected in the blood (pre-patent period) is about six to seven months.
The severity and onset of clinical signs relate to 3 things: the number of worms, the duration of the infection and the dog's response. Many dogs infected with heartworms may not show any evidence of the infection in the early stages of the disease. Signs can eventually appear and will worsen with increased numbers of worms and with lengthy infections, making early detection and prevention programs an important part of managing your pet's health.
Initially dogs tend to develop a cough and experience difficulty breathing. They may also exhibit a decreased tolerance to exercise, develop fainting episodes or suffer severe weight loss. Since the heart and lungs are affected, many of the clinical signs seen or observed are typical of heart failure, pneumonia or other debilitating diseases.
Dog heartworm disease can be treated by medications. These medications are :
- Melarsomine dihydrochloride (Immiticide®, Merial)
Dog heartworm disease can be prevented by medications. These medications are :
- Macrocyclic Lactone (ML)
- Ivermectin (Heartgard®, Heartgard Plus®, Merial, IverhartTM Plus, Virbac)
Find out more information about dog heartworm disease at http://dogheartwormdisease.com