SlimDoggy Health Check : Heartworm Pt.2
Recently we introduced our new SlimDoggy Health Check series and took a closer look at heartworm and its prevalence throughout the US. Today we want to focus on the causes, symptoms, diagnosis, treatment and prevention of the disease.
We all know that heartworm is a serious disease that causes severe lung & heart problems and potentially other organ failure if not treated quickly. The disease is caused by a parasitic worm called Dirofilaria immitis that is spread through the bite of a mosquito. It is called heartworm because the worms – planted by the mosquito – live in the heart, lungs and other vital organs of the host (mainly dogs, cats & ferrets).
The mosquito is the secondary host and carries the microfilia (worm eggs) from host to host – spreading the disease. (See Lifecycle photo).
Heartworm Lifecycle #4
In the early stages of the disease, many dogs show few symptoms or no symptoms at all. The longer the infection persists, the more likely symptoms will develop. Active dogs, dogs heavily infected with heartworms, or those with other health problems often show pronounced clinical signs.
Signs of heartworm disease may include a mild persistent cough, reluctance to exercise, fatigue after moderate activity, decreased appetite, and weight loss. As heartworm disease progresses, pets may develop heart failure and the appearance of a swollen belly due to excess fluid in the abdomen. Dogs with large numbers of heartworms can develop a sudden blockages of blood flow within the heart leading to a life-threatening form of cardiovascular collapse. This is called caval syndrome, and is marked by a sudden onset of labored breathing, pale gums, and dark bloody or coffee-colored urine. Without prompt surgical removal of the heartworm blockage, few dogs survive.
American Heartworm Society
Heartworm diagnosis & treatment:
Given the severity of heartworm, the need for early detection is critical. The diagnosis is made through a simple antigen blood test administered by your vet. If your dogs tests positive, more tests may be required to determine the stage of the disease in order to prepare a treatment plan. If adult heartworms are present your dog may be hospitalized and given medication designed to kill the adult worms.
There are two drugs approved by the U.S. Food and Drug Administration (FDA) for the treatment of heartworm disease in dogs. Both drugs contain arsenic and are effective at killing adult heartworms. Caparsolate Sodium (arsenamide sodium), the older of the two drugs, is injected into a vein. It is not currently manufactured or marketed in the United States. The newer drug, Immiticide (melarsomine hydrochloride), is given by a deep injection into the back muscles to treat dogs with stabilized class 1, 2, and 3 heartworm disease.
US Food & Drug Administration
Preventing heartworm is as simple as administering a preventive medication each month. It’s important to test your dog for heartworm before starting a regular adminstration of the preventive medication and should always be done under the guidance and the direction of your veterinarian.