[Isolation of a cytopathogenic rotavirus from calves].

A cytopathic rotavirus was isolated from calves with symptoms of diarrhea and underwent 15 passages in bovine embryo kidney cell culture. The specificity of the isolate was confirmed by the neutralization test, immunofluorescence, electron microscopy. The CPE of the isolated in bovine embryo kidney cells was similar to that of the reference strain.

[Study of the virus carrier state in chicken influenza].

The problems of virus carrier state in influenza are connected with two aspects of the disease: the duration of virus antigen persistence in convalescents and changes of influenza virus properties in the course of persistence. In the present study, natural influenza infection in chickens caused by influenza A/chicken/USSR/336/74 virus (Hav6H3--N2) was used to determine the duration of virus antigen persistence (up to 60 days) and the entire period of virus isolation from the survivers (up to 30 days). Administration of hydrocortisone on the 50th day of convalescence permitted to obtain from the chickens several influenza A virus isolates antigenically unrelated to the epizootic strain either in hemagglutinin or in neuraminidase.