An outbreak of mucosal disease in cattle caused by <i>Pestivirus H</i>

Abstract

An outbreak of infection caused by Pestivirus H (virus of bovine viral diarrhea – mucosal disease of the third kind, BVDV-3) in a dairy farm with high morbidity and mortality in animals of different ages is described. In some sick animals a full complex of pronounced symptoms characteristic of "classical" bovine mucosal disease was registered: erosions and ulcers on the nasal mirror and tongue, foaming from the mouth, serous discharge from the nose, hemorrhagic inflammation and pronounced longitudinal erosions on the mucosa of the esophagus, rennet stomach and intestine. Cows miscarried at different stages of pregnancy. The coefficient of effective insemination decreased to 20%. The course of the disease was complicated by the involvement of the bovine herpes virus type 4, bacteria of the family Pasteurellaceae and Clostridium spp. in the infectious process. The BVDV-3 genome was found in a wide range of internal organs of aborted fetuses, calves, and adult animals. According to sequencing data, the pathogen was classified as subtype 3a. Phylogenetic analysis of the 5'-untranslated region of the virus genome (5'-UTR) showed its close relationship to the strains isolated in Italy and Brazil, most of which were previously identified as contaminants of fetal bovine serum and live vaccines against viral infections of cattle. No specific prophylaxis against BVDV-3 infection has been developed at this time, therefore, it is necessary to update and improve diagnostic methods, optimize control measures to prevent the spread of virulent strains of the pathogen, and control the safety of the vaccines used.