Dirofilaria immitis also known as heartworm was originally known as a regional disease common in southern climates, but now it has spread in all 50 states of America and all over the world, except Antarctica. It is most common in dogs but it can affect a large variety of animals and even humans.
The problem with heartworm infection is that it shows very little symptoms and most of them appear only in the final stages of the disease. Areas with high mosquito population are the most affected with this parasite. Left untreated, this disease will eventually kill the host. However, testing, treatment and prevention of heartworm is very easy. Heartworms can be discovered by doing a simple blood test and can be seen as adults in x-rays.
Dirofilaria immitis parasite goes through different stages and through different hosts until reaching the adult form. The first stage is the larvae or microfilariae which is usually carried by mosquitoes. After the mosquito bites a dog the larvae is transmitted to the new host and in six to seven months reaches the adult stage and moves to the heart of the dog. This is the time when the symptoms start to appear. Here the worms multiply and block the right chamber of the heart and blood flow to other organs.
Treatment of the infection with dirofilaria immitis parasite is successful if the stage of the disease is not to evolved. The adult heartworm can be removed using arsenic compound. In about one month the adult worm is killed, however another month or so of treatment is needed to remove the microfilariae as well. During this treatment the dog is put under a lot of stress and side effects may occur. In case of final stages of the disease surgical removal of the heartworm may be needed.
There are a lot of heartworm prevention treatments on the market. Most of them are available on prescription only and should be given once a month. The best one in my opinion is interceptor for dogs, which can be orally administered monthly. Prevention treatments can be used either year round either in the mosquito seasons only.