filariasis is a parasitic disease caused by filaria. The complication of this condition is that the adult forms of this parasite are installed in the right part of the heart, so they can cause considerable damage and even its elimination will be complex.
Therefore, it is best to follow the appropriate prevention measures and thus avoid infestation. In this article on our site we will provide all the information that caregivers need to know about heartworm in dogs, symptoms and treatment, how it affects the body, how it is cured and Above all, how can it be prevented?
Canine filariasis
As we said, it is important to know that the heartworm is going to settle in our dog's heart and that, furthermore, it is transmitted by mosquito bites. Heartworm in dogs can occur worldwide, although with different rates of contagion, and dogs living outdoors are more affected.
The dog becomes infested when a mosquito bites it, carrying infective heartworm larvae in its mouth, which enter its body at that moment. The larvae are capable of burrowing into the skin and undergo different modifications until they reach maturity. They can be tackled with various drugs, depending on the life stage they are in.
Immature worms enter the bloodstream and travel to end up in one of the chambers of the heart, the right ventricle, and the arteries lungs, where they continue their maturation. When the number of worms is very high, they can also move to the right atrium and even to the vena cava and hepatic veins Through the pulmonary arteries they can affect the your circulation, obstructing blood flow and forming clots, which can also happen after treatment.
This condition is known as " pulmonary thromboembolism" and can lead to heart failure. In addition, worms near the heart valves can interfere with their function, making the dog appear to have valve disease. Worms in the vena cava or hepatic veins are responsible for vena cava syndrome, which causes liver failure that can present with jaundice, ascites, or anemia
Approximately six months after the filariae enter the dog, they become adults, reaching a size of up to 30 centimeters They can live for several years. Females generate microfilariae that are also able to survive for years in the circulatory system.
If a mosquito bites the dog again, it can ingest the blood contaminated with them. In the mosquito they will undergo modifications for 10-15 days, depending on the climate, and will move to their oral organs to become infestive again, thus restarting the cycle as soon as the mosquito bites another animal. As we can see, filariasis in dogs can have serious consequences, hence the importance of promoting its prevention.
Canine heartworm symptoms
The clinical manifestations of heartworm in dogs will depend on the number of worms that are causing the infestation, as well as the size of the dog. A minimum number of filariae is needed for symptoms to be visible. With few specimens, the dog will remain without symptoms.
The symptoms of heartworm in dogs are:
- Fatigue
- Lack of willingness to do physical activity
- Slimming
- Cough
- Accelerated breathing
- Fainting, especially before exercise
- Dogs with liver or lung involvement can collapse and die
Diagnosis of canine filariasis
If a dog shows any of these symptoms and is in an area where filariasis is common, it should be included in the differential diagnosis. It is essential to go to our veterinarian, who will be able to detect the presence of heartworms in the blood using various methods. Sometimes there are difficulties in confirming the diagnosis due to the number of parasites, the life cycle phase they are in, etc.
In addition, you can resort to the X-ray, which will show the damage that the parasites have caused in the heart and lungs, which allows knowing the severity of the dog's condition. The electrocardiogram can also provide valuable information, as can the blood tests, which detect anemia, as well as possible liver or kidney disorders.
Treatment of canine filariasis
The treatment of heartworm in dogs will depend on the condition of the animal and the degree of infestation, hence the importance of carrying out the necessary tests to have the greatest possible knowledge of the dog's clinical situation. Based on all this, a distinction is made between dogs for which a high risk of thromboembolism is expected during treatment, as we have already mentioned, and others with a low risk of this complication occurring. Each of these groups has the following characteristics:
- Low risk: would correspond to dogs with a low parasite burden and no more injuries. Normally they do not present symptoms and do not have other diseases. The radiograph is normal, and the filariae are not seen on examination. In addition, you can rest during treatment, as this carries risks.
- High risk: these are dogs that present symptoms and alterations in their radiographic examination. Parasites are observed and there are concomitant diseases. The dog's activity cannot be restricted during treatment.
In any case, the treatment must be administered under strict veterinary control and take into account the moment of the life cycle of the filaria, since that we will find more or less adult individuals in the same dog. Adult filariae are usually removed in a staggered manner to try to avoid the risk of thromboembolism. For the same reason physical activity is restricted
There is also the possibility of removing the worms surgically, in some cases. Months after the end of the treatment, it is advisable to test the dog again to verify that the cure has been complete.
Prevention measures for filariasis in dogs
We have already seen that filaria in dogs causes important disorders that can become fatal and, also, the complications that its treatment. For all these reasons, the importance of prevention must be stressed to prevent our dog from becoming infested.
There are several products on the market that can be used for this purpose. They are usually monthly application and begin to be used one month before the period of maximum risk and their use is prolonged until one month after this interval. These drugs usually prevent the development of larvae.
It will be our veterinarian who will guide us on the best preventive options according to the area in which we live. It is important to maintain precautions throughout the dog's life. In areas with a high presence of heartworms, it would be advisable to carry out a test to check whether the dog is infested or not before starting prophylaxis. The ideal prevention would also include the control of mosquitoes, since they are the ones that transmit parasites. Although this aspect is impossible, we can follow some preventive measures such as avoiding walks late in the afternoon or at night, since this is when the mosquitoes go to feed.
If the dog lives outside, it is advisable to close it during the months of greatest risk of bites. You can also avoid the breeding areas of these mosquitoes, eliminate stagnant water or use a repellent product. Don't forget to externally and internally deworm your dogs and, if you consider it convenient, also use a homemade mosquito repellent for dogs.
Is heartworm contagious in dogs?
As we have seen, heartworm in dogs needs the intermediary of a mosquito to develop. This means that a dog cannot, by itself, infect another. On the other hand, if it so happens that an infested dog is bitten by a mosquito and this, in turn, bites another dog just having the infective heartworms in its oral organs, this second dog yes it could be infected
In that case the first dog would have worked as a reservoir. In such a situation contagion from humans is rare. For all this, prevention and treatment of affected dogs is essential to avoid creating reservoirs.
