Dirofalariosi – «Cardiac worm disease»

Author: Veterinary Doctor – Dr. Carmen Voda

Dirofalariosis is the disease caused by the infestations of the worm of the Dirofilaria genre. In dogs, a form is also called «Heart worm disease«And it is caused by the parasitic species Dirofilaria Ruthless. Although they are called heart worms, parasites enter the heart only in the final stages of the disease, when driven by the main lung artery (where they are), retrograde, in the heart (in the right ventricle and then in the right atrium).

Life cycle of this parasite begins when a mosquito biting a haunted dog e microfilalar anger («chicks» in Dirofalarii) who are in the blood. Microfilaria develops in the mosquito in the larvae (up to phase L3). At this stage, they are weed larvae And they can complete their maturation when entering a dog. The weeds enter the dog’s body when the mosquito bits a dog and for saliva is transmitted in the blood. These weed larvae migrate into the bloodstream and move to the lung arteries and later in the heart, reach in the phase of adult In 6-7 monthsThen be able to mate and reproduce (→ microfilages).

Microfilations need mosquitoes to develop in adults, otherwise they remain at this stage of the «chicks» (The duration of life is ~ 2 years).

Adult worms have impressive dimensions: females have a length of 15 – 36 cm And a width of 3 mm and the males have about half of the size of the females.

A dog can have Up to 300 worms present when diagnosed.

Adult worms can live up to 5-7. During this period, the females produce millions of microfilaments that live mainly in small blood flow pots.

► Clinical disease symptoms / signs ◄

In the early stages of the disease, many dogs have few symptoms or not at all.

The signs of this disease in a more advanced phase can include a file cough EASY persistence, reluctance in the exercise, fatigue after a moderate activityreduction of appetite, weight loss.

All these signs are more evident when the disease is in a very advanced phase (the worms +/- are already in the heart), it seems respectively Obviously effortA DUPA minimum effortthe dog They do not get upIt can occur ude +/- Syncopa (loss of consciousness) or tachipnea (FREQUENCYÞa raised respiratoryA) In rest/sleep times (When it is possible that the right heart is very high due to the worms in it and compromise the left side of the heart so that the blood can no longer be sent correctly in the systemic circulation and the tissues are no longer supplied with oxygen).

Adult worms cause fibrosis and relaxation of the blood vessels and can block the blood flow leading to lung thrombosis (CLUTS IN THE STRENGTH) and heart failure. It can also lead to liver or kidney failure.

► diagnosis ◄

I For detection Microfalarii:

– A grapping of blood – Basically take a drop of venous blood, put on a blade above which a blade is positioned and examined under a microscope. ADVANTAGE is that it is a quick and cheap method but Disadvantages These are the frequent negative results (they are not microfilages in the sample or adults have not reproduced. 35% of infested dogs have no circulating microfille) and cannot be differentiated from the microfilarium produced by another species: Difilaria retens (which determines subcutaneous nodules). Microfilations can also be received during transfusions or between the mother (therefore they do not have adults).

– The Knott test -1 ml of venous blood + 10 ml of buffer format, centrifuges 1500 rpm 3-5 min. The Sirnant is extracted from the tube and the sediment is mixed in equal parts with the blue of methylene 1: 1000. The sediment is positioned on the blade, covered with a blade and examined under a microscope. ADVANTAGE is that the species of microfilages can be differentiated, disadvantage: The difficulty of finding a specialist capable of correctly differentiating the species.

II For detection adult:

– Snap 4DX test – With the mention that the antigen produced by the uterus of females is detected, which means that a greater number of females increases the sensitivity of the test. It’s fast to do, More often recommended and used to detect adults.

– PCR, Elisa test – More expensive and lasts longer until a result is received.

III Methods that can lead to suspected infestation and/or can help determine GThe ravine ravine secondary infestation and creation of a appropriate treatment:

– Thoracic radiographs – I can show an advanced phase of the disease when the changes in the lung arteries +/- increase in the volume of the right heart.

Thoracic X -ray (VD) – Allaroal heart + modified pulmonary artery

– Cardiac ultrasound It allows to evaluate the size of the heart, the relaxation of the main pulmonary artery (in which adults are initially), the presence of the worms in it or in the right heart, the secondary hemodynamic changes.

!!! A blood test (more recommended: Snap 4DX) is always necessary for a diagnosis of certaintyEspecially when the worms are not evident in the heart.

Cardiac ultrasound – Longitudinal section – Cord as a dilated, worms present in the right ventricle and in the atrium. The left ventricle chamber is reduced in size due to the pressure made by the right width in volume, with consequent inadequate expulsion of the blood flow on the aorta and the appearance of the tachipne.

► Treatment ◄

It can be medicinal or surgical, depending on the stadium in which the patient is found, each involves serious risks.

!! Prevention is always the safest variant !!

► Prevention ◄

Always use Repellents against mosquitoes For pets when it is the mosquito season. Also Internal deworming with Millbemicin products destroy the larvae of microfilages and weeds.

When you do blood blood or blood tests, take a test Snap 4DX; Among other things, the presence of the species of Dirofilaria Immitis can identify.

No form of prevention can provide 100%protection, which is why it is good We test periodically Our fur to make sure everything goes well.

And in case you wonder – yes, e cats They can also be influenced by this disease, but not at the same level.

Cats that develop adults (very rare cases) usually have one or three worms. Although this means that the disease of heart worms often remains not diagnosed in cats, it is important to understand that even immature worms cause real damage in the form of a condition known as respiratory disease associated with cardiac worms (hard). In addition, medicines used to treat infestations with heart worms cannot be used in cats, so prevention is the only means to protect cats from the effects of heart workers.