In our article, we will talk about a disease such as dirofilariasis. The disease was previously common in tropical countries. But now he is confidently moving to the northern states. The causative agent of the disease has already adapted to cold temperatures. Therefore, the disease is more often registered in the states of Eurasian content. Pet owners need to know how to recognize the disease, as well as how dogs are treated for dirofilariasis. But first, we will consider the disease itself and its stages.
Biological and general characteristics of nematodes. Disease Description
Dirofilariasis is a zoonotic, vector-borne, invasive disease. The disease is characterized by heart, liver and pulmonary complications. In this case, helminths do not affect the intestines. The causative agents of the disease are nematodes of the Onchocercidae family:
- Dirofilaria immitis. As a rule, it parasitizes in the vena cava, the right ventricle of the heart, as well as the pulmonary artery.
- Dirofilaria repens. Usually parasitizes in the subcutaneous tissue of different parts of the body.
The carriers of dirofilaria repens and dirofilaria immitis in dogs are mosquitoes. Infection occurs through a bite. All breeds are affected, regardless of size, age and gender. Mosquitoes are intermediate carriers of helminths.
In the intestine of the insect, helminths are found for a day. Then they move into the malpighian vessels. After which, within 16 days, the development process takes place. Then microfilariae invade the mosquito's body, lingering on the lower lip. After that, the larva reaches a length of up to 0.9 mm and through the proboscis of the mosquito enters the blood of a warm-blooded animal (in this case, the dog).
Stages of the disease and its types
After a few weeks, a larva develops already in the subcutaneous space of the infected beast. Now the helminth is transformed into an invasive individual, which can already move to a new organism. In the fifth stage, the parasite can penetrate the heart and blood vessels of the dog. And after another six months, active reproduction of the helminth begins within the body.
The maximum size of an adult parasite is 30 centimeters. Due to the spread of helminths in the body of an animal, the functioning of internal systems and organs is disrupted. If the treatment of dirofilariasis in a dog has not been started in a timely manner, then it will simply die.
If we talk about which form of the disease is milder, then it is skin. In this case, death usually does not occur. The skin form of the disease manifests itself: itching, skin rashes in the neck and muzzle.
Symptoms of the disease
How to understand that a dog has heartworms? How the disease manifests depends on how much the parasite resides in the body of the animal. As it develops, the helminth moves into the internal organs, after which it begins to grow in them. If it parasitizes in vessels, penetrating through them into the heart, then the blood flow is disturbed in the animal, as a result of this, heart failure can develop. Dirofilariasis in dogs may be suspected of the following symptoms:
- dyspnea;
- swelling of the extremities;
- mild cough;
- labored breathing;
- instead of sputum, blood discharge is observed.
Also, with such an ailment, loss of appetite, papular dermatitis on the legs and head, as well as general malaise are observed. You can also notice the rapid fatigue and lethargy of the animal. Periodically, the dog has a low-grade fever, as well as fever. A similar condition in an animal occurs due to the negative impact on the body of the waste products of parasites.
The danger of the disease and possible complications in the treatment of the animal
What is the disease dangerous and what can be the consequences of dirofilariasis in a dog? With such an ailment, the animal develops tachycardia, the arteries of the lungs are deformed. The disease is fraught with the development of irreversible processes in the vessels, heart and lungs:
- There are noises in the heart.
- Tachycardia is observed.
- Pulmonary arteries enlarge and deform.
- The right departments of the heart expand, thereby interfering with the normal functioning of the organ.
- Density of pulmonary arteries increases.
- The blood supply to the lungs is disturbed.
- The central pulmonary artery protrudes.
- Gradually, complications such as hepatic and renal failure develop.
Of particular danger is the death of helminth in the body of an animal. The dead parasite decomposes, shifts to the distal borders of the pulmonary arteries. The presence of their fragments in the vessels leads to the accumulation of platelets and pulmonary thromboembolism.
About 15% of dogs that have this parasite inside suffer from diseases such as glomerulonephritis. Helminths can also penetrate the abdominal cavity, brain and spinal cord, as well as into the eyes.
Methods for diagnosing a disease in a dog
There may be a suspicion of infection with this helminth if the animal visits the endemic area during the summer. Those who like to travel to warm countries with a pet expose him and himself to the risk of infection. At the same time, you can not suspect a pet's illness for several months or even years. Due to the variability of symptoms, the process of detecting a disease is complicated. To make an accurate diagnosis at home certainly will not work.
For this you need to undergo various medical examinations. These procedures include:
- smear analysis according to the Romanovsky-Giemsa method;
- echocardiography;
- immunological tests for dirofilariasis in dogs
- X-ray
- peripheral blood antigen test;
- electrocardiography;
- Schuffner blood test;
- electrocardiography. It makes it possible to identify heart problems.
If we talk about immunological analysis, then in it the main tool is a one-time test for rapid diagnosis. They can identify a protein - an antigen that is secreted by adult female parasites. The accuracy of the test largely depends on the number of individuals in the body of the animal. If one instance is detected, then the sensitivity of the test will be no more than 64%.
If the fact of the presence of microfilariae in the blood is confirmed, then it is necessary to further establish what kind of helminth belongs to. It is determined using histochemical staining.
Difficulties in diagnosing this disease
There are false negative results in the diagnosis of the disease. Why is this happening? Errors can occur for a number of reasons:
- The absence of parasites in the blood due to rapid penetration into the pulmonary artery.
- The population consists of males.
- The number of helminths is very small.
It is possible to obtain a false negative test result due to the fact that the animal was given an anthelmintic drug.
Danger to people
Is there a threat to humans if a dog develops dirofilariasis? People can also become infected with this disease, but only through a mosquito bite. In the process of caring for a sick animal, there is no risk of infection.
The first stage of treatment of the animal
If heartworms are found in a dog, then treatment should be started immediately. The treatment consists of two stages. The first is the destruction of parasites. In this case, special medicines are used. What drugs are used to treat dirofilariasis in dogs? The drug "Filarsen" kills adult parasites. Give the drug for ten days. Dosage: 0.001 g per 1 kg of body weight three times a day.
Also used is Levamisole. The instructions indicate that the drug is effective in the early stages of the disease. It destroys the means of larvae and males, but it does not affect females at all. The instructions of Levamisole indicate that the drug is administered subcutaneously at a dose of 1.0 ml per 10 kg of animal weight.
Diethylcarbamazine is also used to treat dirofilariasis in dogs. The medicine is quite effective on larvae. The duration of treatment is 1 month. Dosage - 0.025 g of the drug per 1 kg of animal weight 3 times a day.
The drug "Ivermectin"
Also, Ivermectin is used for treatment. The following dosage is indicated in the instructions for use - 0.2 ml per 1 kilogram of weight. The injection of the drug is done subcutaneously 1 time per month. The instructions for use of Ivermectin also indicate that the drug is very effective. It destroys microfilaria within 24 hours.
The drug "Thiacetarsamide"
There is another drug that is used for dirofilariasis - this is “Thiacetarsamide". It is prescribed in the following dosage - 1 mg per 1 kg of dog weight. It is necessary to administer the drug twice a day intravenously. The duration of the course of therapy is 15 days. After a few months, it needs to be repeated, since the drug only affects adult parasites that die during the first week. "Thiacetarsamide" is considered quite effective against this type of helminth. But after the first course, a complete cure is unlikely to happen. At least two are needed, while it is necessary to periodically monitor the effectiveness of therapy using serological methods and blood tests.
Note that a drug such as Thiacetarsamide is toxic. It can cause hepatorenal dysfunction, skin necrosis and pulmonary embolism with dead worms. Therefore, the following blood biochemical parameters should be monitored: serum creatinine, liver enzyme activity, blood urea nitrogen. Also, periodically you need to do a urine test to control. To prevent tissue necrosis at the injection site, lotions are made with dimexide (1: 6 with water).
Second stage of therapy
The second stage of treatment of dirofilariasis in dogs is aimed at reducing the pathological effects of parasites, as well as overcoming hypoxia. In especially severe cases, it takes three to four days to hold the animal under an oxygen mask. If the internal organs are severely affected, then surgery is usually used. During surgery, parasites can be removed in two ways. In the first case, the procedure is carried out with special forceps. It is also possible to carry out surgery through the vena cava.
To prevent thromboembolic complications (blood clots), acetylsalicylic acid with heparin, dipyridamole or ticlopidine is added to the animal during the treatment period.
If the animal has a skin form of the disease, then macrolides are used in small doses. The duration of treatment of dirofilariasis in dogs is from eight months to three years. That is, until the moment when all adult individuals are destroyed. If skin reactions are observed, then specific drugs are prescribed for symptomatic treatment.
During the treatment period, it is desirable to isolate the sick pet in a separate enclosure and room. During treatment, short walks are allowed, but without special physical exertion.
Therapy prognosis
If treatment is started in a timely manner, then serious complications can be avoided. In this case, the forecast will be favorable. Note that with pulmonary form, there are serious complications that sometimes lead to the death of the animal. But with timely therapy, there is a chance to cure the dog.
Disease prevention
Infection with the disease is very easy. But to prevent this is simple, you just need to carry out preventive measures. It is necessary to treat the animal with one of the drugs:
- "Selamectin";
- Ivermetin (Baymek, Ivomek, etc.);
- Milbemycin;
- Moxidectin.
They belong to the macrolide group, are effective and at the same time safe for the animal. Prevention can be carried out for dogs older than 2 months. Before vaccination at seven months, a diagnosis should be made for the presence of these parasites in the animal.
Components such as moxidectin and imidacloprid are contained in a popular drug like Advocaat (drops on the withers). The tool has an effect on the larvae.
Additional measures are the treatment of animals with repellents, as well as the use of fumigators and mosquito nets in the premises.
It is advisable in the warm season to do a test for dirofilariasis for your pets in order to identify an ailment at an early stage and prevent pathological changes from developing. Then the treatment will be much easier.
Little conclusion
Now you know how dirofilariasis is manifested in dogs, what is the danger of this disease. In our article, we examined in detail the treatment options for this ailment. Remember that early diagnosis avoids the consequences. Therefore, do not forget to check your dogs for parasites or at least monthly (during the period of the appearance of mosquitoes) it is worthwhile to carry out preventive treatment.