Heartworm disease in dogs, the climate favors its spread

Heartworm disease in dogs is on the rise due to the climate crisis and the spread of mosquito vectors.In these cases, prophylaxis is essential

• Heartworm disease is an often fatal disease for dogs spread by some types of mosquitoes.
• The climate crisis and the consequent increase in insect colonies is causing the disease to spread.
• To protect our dogs, careful prophylaxis and the advice of our trusted veterinarian are necessary.

There heartworm disease it is a subtle and often lethal disease that can be contracted by our people dogs both in metropolitan and extra-urban areas.The vectors responsible for the transmission of the disease are mosquitoes of different genres, including the Aedes albopictus, the so-called tiger mosquito, now rooted in the national territory.Climate changes, both natural and man-made, and the movement of animals, both domestic and wild, have increased the infectious potential of heartworm disease.In fact, if the vectors increase and expand their territory, the number of infested animals will continue to increase.To try to better understand filariasis and the mechanisms that establish its spread among the canine population, we asked the doctor's opinion Chiara Dissegna, veterinary doctor.

Heartworm disease is on the rise

For filariasis to spread, a climate with adequate temperatures and humidity is necessary, which are essential to keep mosquito colonies alive and allow the maturation of the microfilariae within the vector itself.It is no coincidence that a few years ago the disease was more widespread among hunting dogs that frequented marshy areas where it was easier to come into contact with vector insects.But now, thanks to climate change, the transmission of filariasis also occurs in metropolitan areas.An example?The spread of the tiger mosquito in the city, which can also reproduce in small containers, such as saucers on balconies and terraces.

And there is another detail to take into account.Urbanization and overbuilding has allowed the development of areas that retain heat during the day, creating microclimates which facilitate the development of heartworm larvae inside the vector mosquito even in the coldest months, thus lengthening the transmission season.Heartworm is a very common disease in dogs.On the contrary, the pathology affects i cats with a prevalence of 20% less than dogs.Infested felines have fewer adult parasites than those found in the canine species and preventive treatment to prevent the cat from developing heartworm adults is usually not necessary, as the parasite load is low.

The transmission of heartworm disease is reduced in the winter months, but the risk of transmission is now never zero throughout the year.To date, the greatest challenge to reduce the spread of filariasis is the fight against the vector.There chemoprophylaxis in dogs it is still fundamental because it reduces the reservoir for the parasite, but with the climate crisis and the consequent modification of many natural habitats that allow the development of mosquitoes, the danger becomes increasingly pressing and present for our four-legged friends.

Prevention is an obligation

For the prophylaxis of heartworm disease, drugs prescribed by the veterinary surgeon must be used with the obligation of a specific medical prescription.If the medical history is "silent", i.e. if it is not known whether treatments against heartworm have been carried out previously (perhaps because you have just adopted an adult dog), it is advisable to carry out a test to evaluate the presence of antigen and microfilariae.In this way, delays in the diagnosis of any subclinical infections are avoided and the most suitable therapy can be started immediately.

The most used drugs (ivermycetin, moxidectin, selamectin, milbemycin oxime) belong to the class of so-called macrolic lactones.Their action on precardiac larvae is obtained with repeated administration at very low doses and for this reason they have a very good toxic/therapeutic relationship.If used following the instructions on the information leaflet, and if the instructions of your doctor are scrupulously followed, these medicines can be considered safe medicines.However, their administration must take place orally or via periodic injection carried out by the attending veterinarian.

Be careful, though.Some dogs (like collie, i bobtail, i border collie), which have an altered functionality of the P glycoprotein  due to a genetic mutation, they are extremely sensitive to various drugs used to prevent heartworm disease, including macrolic lactones.It is therefore advisable to decide together with the veterinary doctor which drug to administer in these cases to avoid even serious problems for our four-legged friend.