Although dogs are considered the unequivocal host for heartworms (Dirofilaria immitis), other mammals such as coyotes, foxes, domestic cats, ferrets, as well as wolves and other canids are all susceptible as hosts, as are humans.

Heartworm in dogs are spread through mosquitoes carrying heartworm larvae. When the mosquito bites the dog it transmits the infection to the animal where the larvae grow and eventually migrate throughout the body over a period of moths until they eventually become mature worms. These typically reside in the heart, lungs and connected blood vessels. These worms then release their own offspring into the host animal’s bloodstream.

It takes about six months from the time the heartworm larvae enter the dog’s bloodstream until the offspring can be detected when blood tests are taken. The adult heartworms, however, aren’t detected as they will have grown to around 12 inches during this time. Unfortunately, heartworms in dogs live for between five and seven years!

How severe the dog’s condition will be is reflected in the number of adult heartworms in the dog, how long the infestation has been ongoing and the dog’s activity levels. As one would expect, dogs with a high number of heartworms living within them are more likely to suffer severe heart and lung disease.

Symptoms of Heartworms in Dogs

Interceptor is a popular heartworm treatment

The most common symptoms of heartworm in dogs are coughing, abnormal sounds from the lungs when the dog breathes and a reluctance to take normal exercise. If the condition is severe then the dog may also suffer difficulty breathing and temporary loss of consciousness (caused by poor blood flow to the brain). Unfortunately, in severe cases, death will often follow quickly. If you can imagine your heart filled with strands of spaghetti then you’ll appreciate the difficulty a dog’s heart that’s infested with heartworm will have when pumping blood. Clots are also easily formed when blood sticks to the worms in the blood vessels. These then break away and can travel to the lungs and other organs.

Unfortunately, dogs with a small number of heartworms may not show any clear symptoms although the heart, lungs, liver and kidneys could be damaged.

An x-ray or ultrasound is needed in order to access the extent of the damage to the dog.

It’s also important to understand the difference between a heartworm infestation and heartworm disease. A dog with heartworm disease will be ill whereas this isn’t necessarily the case for those with just an infestation.

Treatment and Prevention of Heartworm in Dogs

Revolution is a commonly prescribed heartworm medication

Luckily, most dogs that suffer heartworms can be treated although treatments aren’t without complications, including coughing, depression, loss of appetite (anorexia), fever, vomiting, and excess salivating.

The idea is to kill both the adult worms and their offspring with two different medications but, as with most health problems, the earlier the heartworm infestation is caught, the greater the chance of treatment working rapidly and without severe side effects for the dog.

Prevention is, of course, both better and more cost effective than cure and fortunately there are a number of products available that are designed to help prevent heartworms in dogs.

Interceptor is one such product that prevents female heartworms from reproducing as well as killing microfilariae (the offspring). However, as with many such products, Interceptor should never be given to dogs that have heartworm disease as this can cause an adverse shock reaction.

Revolution is another preventative although this works somewhat differently to Interceptor in that it causes paralysis in the heartworms that eventually leads to their death.

A heartworm infestation is never nice and can be lethal so it’s important you speak to your veterinary for advice on this matter. Remember, prevention is better than cure but if prevention’s too late, you MUST act quickly if your dog is to have a chance of survival.

Tags: dogs, heartgard, heartworm, interceptor, pet meds, revolution, therapy

This entry was posted on Monday, June 8th, 2009 at 4:29 pm and is filed under Guides, Heartworm Care, Prevention, Treatment Methods. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.