Overview

Feline panleukopenia virus, feline infectious enteritis virus, feline plague virus, feline panleukopenia virus (FPV) caused by infectious diseases with high fever, vomiting, severe leukopenia and enteritis . Feline infectious enteritis from the thirties of this century was found by European and American scholars. But the virus was first isolated in 1957 (Bilin). Later, Johnson (1964) isolated from the spleen of a leopard with similar symptoms of feline infectious enteritis isolated the same virus, and identified as parvovirus, before the study of this disease has made significant progress. It has been shown that FPV infects many species of animals such as tigers, leopards, lions and raccoons under natural conditions, but most of the smaller felines, including minks, are susceptible to infection by a variety of animal-like disease pathogens. FPV is currently the virus in the most extensive range of infection, pathogenicity of the strongest one. Therefore, this is one of the main virus.

Morphology and physicochemical characteristics of feline panleukopenia virus

Feline panleukopenia virus is the same as other viruses, the virus on the outside world has a strong resistance. Can withstand heat treatment at 66 ℃ for 30 minutes. 50% Glycerin in the toxic tissue, in the ordinary refrigerator can be stored 35 to 138 days. The virus titer was not reduced after 5 days of storage at 25 ° C. Earle liquid containing toxic tissue, whether placed at 4 ℃ or 25 ℃, after 13 months, the toxicity is not reduced. For ether, chloroform and other lipid solvents and trypsin resistance. 0.5% formalin can effectively kill the virus, is a good disinfectant.

Blood coagulation: Feline panleukopenia virus is the blood clotting in the weak one, only at 4 ℃ on the red blood cells of monkeys and pigs have agglutination, this point in the virus identification has some significance.

Ecology

During about one week of viremia, sick animals, feces, urine and a variety of secretions contain viruses. Contaminated food, utensils and clothing can cause disease transmission, mainly oral, but also by droplet infection. Rehabilitation cat detoxification period for several months to a year. In addition to horizontal transmission, it has been confirmed that the fetus can occur in the vertical transmission of the fetus. Since viremia occurs in sick animals for as long as five days or more, it is presumed that transmission of blood-sucking insects such as fleas is possible.

To cultivate

The virus can proliferate in the culture of the kidney, lung, testis, spleen, heart, diaphragm, adrenal gland, bone marrow and lymph nodes of the cats, among which the cells of the first three organs are more commonly used. In addition to the cells of the cat, but also in the mink and ferrets derived from the tissue cells proliferation. With this is the same as other viruses, to form a single layer of cells before the inoculation of the virus, in order to achieve the purpose of a large number of viral proliferation. Although can produce cytopathic lesions, but not in the stained specimen is difficult to identify, for this, can be placed in the flask of coverslips (fly) regularly removed by H.E. or Giemsa staining after microscopic examination. When the dose of large doses, the 10 to 12 hours, the first nucleolus enlargement, the outer around a clear halo ring. After 24 hours, a small number of cells appeared nuclear inclusions, began to eosinophilic, and gradually become basophilic. Morphological changes in cells are often transient, when the virus periodically proliferated after several times, the cell appearance may return to normal. However, some researchers report that they have seen a significant cytopathic effect. This may be related to the strain, concentration, cell type, nutrient solution and inoculation time and other factors. According to Johnson data (1967), there are many calves, pigs, horses, dogs serum, containing the virus proliferation and the formation of cytopathic heat-resistant substances, when the cell culture medium containing the serum, Decreased by about a thousand times, of course, cell lesions will be significantly affected.

Immunization

Rehabilitation of animals in the blood of neutralizing antibodies slowly increased continuously, the cat is usually 8 days after infection began to neutralize antibodies, 15 days titer of 1: 16 ~ 1: 60, 30 days up to 1: 150. Actual observation shows that the disease's immunity is strong and durable, because in natural circumstances, rarely see the animals infected by the second infection. Newborn kittens can be obtained from the colostrum and neutralizing antibodies, this passive immunity for 3 to 12 weeks.

Surveys of sera from cats in Europe and the United States showed that the positive rate was as high as 70% (titer from 1: 5). However, in natural conditions, and no such cat incidence, because most of the adult cat is a subclinical infection, although not significant symptoms, but the immune response.

Diagnosis

According to clinical symptoms, histopathological changes (bone marrow was liquid, semi-liquid, small intestine epithelial cells within the inclusion body) and leukopenia, can make a preliminary diagnosis. Diagnosis depends on viral isolation or immunological serological tests.

Diagnosis depends on viral isolation or immunological serological tests.