Biological properties of bovine parvovirus and its role in cattle pathology

Basing on analysis of extensive investigations in many countries, the properties and prevalence of bovine parvovirus are described. The isolates of bovine parvovirus I from the United States, Europe, North America, Africa, and Australia are identical on antigenic properties, but differ from other animal and human parvoviruses. Japanese isolates which differ from bovine parvovirus I on antigenic patterns are referred to the bovine parvovirus II. Bovine parvovirus can agglutinate the human and Guinea pig red cells. This is a DNA-containing virus with the virion size of 23 nm. Virus replication and the assembling occur in the cell nucleus. The highest titеrs (10 6.75-10 8.00 TCID 50/ml) are produced by parvovirus I cultivation in primary cell cultures of lung, kidney, spleen, testis and adrenals from cattle embryos. To isolate parvovirus I, the cattle fetal serum free of specific antibodies must be used. Oral or intravenous infection of the newborn calves or the calves who were not fed with сolostrum resultes in the diarrhea syndrome within 24-48 hours. The virus is commonly found in the intestines, blood leukocytes, lymph nodes, spleen, thymus and in the adrenal cells. In cows it persists for a long time and penetrates through the placental barrier causing abortions and embryo mortality. The virus was found in the thymus, lungs and spleen of mummified fetuses. The rate of seropositive animals in different herds in the UK, Australia, Germany, Austria, Italy, Algeria, etc. varies from 14 to 100 %. According to our data, 26.6 to 58.4 % of pregnant cows and calves from nine regions of the Middle Volga are positive on antibodies to parvovirus in ELISA. This percentage was higher in the herds with imported cattle. Parvovirus is involved in mixed respiratory and intestinal infections in calves and the reproduction abnormalities in adult cattle. To control the infections caused by bovine parvovirus in the national cattle husbandry, the enzyme immunoassay (EIA) diagnostic kit and the inactivated associated vaccine with a wide range of specific activity have been developed. The patented EIA test meets the international standards, and the vaccine is also patentable.