Failure to spread bovine virus diarrhoea virus infection from primarily infected calves despite concurrent infection with bovine coronavirus.

摘要: Previous reports on the spread of bovine virus diarrhoea (BVDV) from animals primarily infected with agent are contradictory. In this study, possibility transmission BVDV calves simultaneously subjected to acute and coronavirus (BCV) infection was investigated. Ten were inoculated intranasally Type 1. Each 10 then randomly allocated one two groups. each group there four additional calves, resulting in five susceptible per group. Virulent BCV actively introduced groups by means a transmitter calf. Two both BCV, kept separate group, as controls. All ten became shown seroconversions, six them also shed nasal secretions. However, none other eight (four each) seroconverted agent. contrast, it proved impossible prevent between experimental consequently all 20 study virus. Following infection, detected secretions faeces and, after three weeks had including controls, showed at least following clinical signs during days 3-15 trial started: fever (> or =40 degrees C), depressed general condition, diarrhoea, cough. The that cattle, even when co-infected an enteric respiratory pathogen, inefficient transmitters BVDV. This finding supports principle Scandinavian control programmes elimination cattle populations can be achieved identifying removing persistently (PI) animals, i.e. long-term circulation without presence PI is highly unlikely.