Canine cardiac filariasis

This disease is a kind of filariasis caused by circulatory disturbance, dyspnea and anemia caused by canine cardiac filariasis parasitic on the right ventricle and pulmonary artery (rarely in chest and bronchus). In addition to infected dogs, cats and other wild carnivores can also be infected. The disease is widely distributed in China, from Shenyang in the north to Guangzhou in the south.

[pathogen and its life history]

Canine heart filariasis (also known as canine filariasis) is yellow and white in the shape of slender vermicelli. The male worm is 120mm long and 160mm long, the tail is spirally curled, and the female worm is 250mm 300mm long. The viviparous larvae are called microfilariae, parasitic in the blood, 307 to 322 microns in length and unsheathed.

Canine heart filariasis needs dog flea, Anopheles or Culex pipiens as intermediate host to complete its life cycle. The female parasitic in the right ventricle produces microfilariae that can move freely and enters the blood. when fleas and mosquitoes suck blood, microfilariae are inhaled into the body and develop into infectious larvae and enter the beak of fleas and mosquitoes. the larvae escape from the beak into the skin of the final host and circulate through subcutaneous lymph or blood to the heart and large blood vessels.

[main points of diagnosis]

(1) Clinical symptoms: the earliest symptoms are chronic cough, but no other symptoms of upper respiratory tract infection, aggravation during exercise, or fatigue of sick dogs during exercise. With the development of the disease, the sick dog developed hyperpalpitation, weak pulse and intermittent murmur in the heart. Palpation pain in the liver area, hepatomegaly. Hydrothorax and abdominal cavity, edema all over the body. dyspnea. In cases of long-term infection, pulmonary heart disease is very obvious. At the end of the year, he died as a result of general weakness or collapse during exercise. Diseased dogs are often associated with nodular dermatosis, characterized by itching and multiple focal nodules that tend to break. The skin nodule is suppurative granulomatosis in the center of blood vessels, and microfilariae are often found in the blood vessels around suppurative granuloma. X-ray showed dilatation of right ventricle, aorta and pulmonary artery.

(2) Laboratory microscopic examination: a preliminary diagnosis can be made according to medical history investigation and clinical symptom observation, and the final diagnosis should be made by microscopic examination of peripheral blood at night to find microfilariae.

[prevention and control measures]

(1) deworming: ① was used to kill adults: sodium thioarsine amide was used at a dose of 2.2mg / kg body weight, intravenously, twice a day for two days. Intravenous injection should be slowly injected, the liquid should not leak out of the blood vessels, so as not to cause tissue inflammation and necrosis. Or dichlorophenyl arsine hydrochloride, at a dose of 2.5 mg / kg body weight, is injected intravenously every 5 days, which has strong deworming effect and low toxicity. ② drive microfilariae: levimidazole was taken orally at a dosage of 10 mg / kg body weight for 15 days. The blood was tested after the sixth day of treatment. When microfilariae could not be detected in the blood, the treatment was stopped. Or use ivermectin (trade name to kill Ivomec), the dosage is 0.05-0.1mg / kg body weight, one intradermal injection. Or use parathion, subcutaneously inject 0.2 milliliters of 7% solution per kilogram of body weight, repeating once or twice every 2 weeks if necessary. Symptomatic treatment should also be carried out according to the condition.

(2) Prevention and elimination of intermediate hosts: prevention and elimination of fleas and mosquitoes are important measures to prevent the disease. Drug prophylaxis can also be used. The oral dose of diethylamine is 6.6 mg / kg body weight, which should be used continuously in mosquitoes and flies during the active season. For microfilariasis positive dogs, the use of diethylamine is strictly prohibited. Only after killing adults and microfilariae can we begin to use ethamizine for prevention.