Everyone who lives with a dog has surely heard of dog heartworm (or filariasis). It is a parasitic nematode, a roundworm, that infests animals and occasionally humans. Knowing about heartworm is certainly the best way to prevent its damage.
What is dog heartworm?
When we talk about dog heartworm (or filariasis), we refer specifically to two species: Dirofilaria repens and Dirofilaria immitis. We can find the former worm under the skin or occasionally in the eye. It affects dogs, cats, and humans. The latter is located in the heart chambers of dogs and occasionally cats. This type of filariasis is the most severe. As is probably known to many, heartworm is transmitted through mosquito bites, particularly from two species: Culex pipiens (common mosquito typical of summer evenings) and Aedes albopictus (tiger mosquito also present during the day), which are widespread in the Po Valley, where it is often strongly recommended to vaccinate dogs.
The symptoms
How can we determine if a bite has caused our dog to contract filariasis? Unfortunately, the symptoms, especially at the beginning, are almost nonexistent and mostly invisible, as the parasite primarily affects the heart. The most common effects include respiratory problems, but also blood clots and embolisms. Therefore, the parasite's effects are more noticeable in the late stages of infection: dogs may become intolerant to physical activity, have cyanotic mucous membranes (i.e., bluish in color), and experience breathing difficulties.
Preventing heartworm
The good news is that there are two ways to manage filariasis through prevention: with a pill or an injection. Every month, you must regularly administer the pill, which is a tablet. The drug has a one-month retroactive effect, meaning it kills all microfilariae (the larvae) that the dog may have contracted through a mosquito bite the previous month. The injection, on the other hand, varies depending on the dog's weight and protects our four-legged friend for the entire year. It also has a retroactive effect of about 4 months.
Note that there are two tests to determine if our dog has contracted heartworm: thick drop tests, which require a drop of blood, and rapid antigen tests. However, for any doubts, it is always advisable to contact a veterinarian, as these tests are not always reliable.
Can heartworm be treated?
Heartworm is treatable, but the treatment is extremely strenuous for our dogs, which is why prevention is crucial. Generally, we use an arsenic-based drug, but we also have surgical options via a coronary endoscope. Even in this case, the procedure is not the simplest, further demonstrating that prevention is always the best course of action when it comes to filariasis.
Is heartworm dangerous for humans?
Humans can contract an infection with Dirofilaria repens. However, this is not a common occurrence but rather an occasional one. Dirofilaria repens prefers our pets as its victims. Dirofilaria immitis, on the other hand, is not transmissible to humans.
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