The causative agent of this pathology is Dirofilaria immitis , a parasite that can appear anywhere in Spain with the help of a “vehicle”: various types of mosquitoes. As in the case of leishmaniasis, filariasis depends on the action of a (non-specific) mosquito for the transmission of the disease.
The parasite responsible for heartworm disease (or dirofilariosis) is a nematode that can measure from 12 to 30 cm in adulthood, with females being larger than males.
Its usual “destination place” is the right ventricle of the heart and the pulmonary artery .
In the case of filariasis, the disease can be spread by multiple species of mosquitoes, something that undoubtedly differentiates this disease from leishmaniasis in which the transmitting agent is not so variable.
Animals sick with heartworm disease will have the juvenile forms of the parasite (microfilariae) circulating in their blood, which penetrate the body of the mosquito after its bite in order to feed on blood; the parasite develops inside the mosquito for about 8 to 18 days.
When a mosquito introduces parasites (microfilariae) into its body, it becomes a dangerous transmitter of the disease , because when it settles on healthy animals and bites them, it will introduce the filariae that have been developing inside them for a few days.
Once inside our pet, the parasites “take a break” in the muscles or fat, where they develop. After about three months of “rest”, they begin their journey to the heart and nearby vessels (arteries and veins).
The effects of the filaria in our animal are due to the presence of the adult forms (12 – 30 cm.) in the pulmonary arteries, heart, kidney and liver. Microfilariae, although they are very abundant within the bloodstream of the sick pet, are of little importance in the lesions of this disease. However, the presence of adult parasites triggers two serious situations:
- Pulmonary arterial hypertension
- Congestive failure of the right side of the heart
In the first place, we must remember the existence of animals that do not present symptoms or present discreet symptoms despite having parasites.
Those who do manifest the disease may have some or most of these symptoms : cough, shortness of breath, refusal to exercise, coughing up blood (hemoptysis), weight loss, nosebleeds (epistasis), increased heart rate (tachycardia) , increased respiratory rate (tachypnea) and finally heart failure.
Other symptoms, although rare, are: blindness, intolerant of light (photophobia), lumps under the skin (subcutaneous nodules) and salivary gland problems.
To achieve clear success after the application of preventive treatments , we must follow the recommendations of the veterinarian and the laboratories to the letter.
The success of the treatment will depend on the correct dosage of the drug, as well as its administration for as long as necessary.
It is always advisable before using any preventive treatment to diagnose the possible disease, since if our pet is parasitized we should eliminate the existing parasites before administering any preventive treatment.
Treatment is not easy since we do not have a drug that effectively “attacks” all forms and ages of the parasite, so we will need several drugs for treatment to be successful.
In addition, we must know perfectly the real state of our animal before proceeding with the treatment: if the state of our pet is not adequate, we must treat it previously, so that its body is put in sufficient conditions to resist the “attacks” From both sides.
Once the animal is in a correct state, we will first attack the adult parasites, secondly we will dedicate ourselves to eradicating the microfilariae, and when we are sure that we have finished with these parasitic forms, we will apply treatments that prevent the new appearance of the problem (preventive treatment).
We must not forget that this is only one of the treatment possibilities, since it can vary depending on the number of parasites, the severity of the animal and of course according to the veterinarian’s criteria.
On many occasions, the number of parasites in the heart and adjacent vessels is such that prior surgical treatment is required to extract as many of the adult forms as possible; If we kill these parasites, and their number is high, the lifeless parasitic forms could cause serious circulatory problems (“jams”) that could lead to the death of the animal.
It is for everything that has been said that in the event that our good friend suffers from filariasis, we must put ourselves in the hands of an expert professional so that, after the diagnosis and assessment of the specific pathology suffered by the animal, they apply the appropriate treatment to eliminate all parasitic forms. with the least vital risk for the animal.
