The Role of Viruses in Enteric Disease of Farm Animals

Abstract

It is generally accepted that viruses are a frequent cause of diarrhoea in animals and man. They do not inevitably cause disease, however; most of the enteropathogenic viruses are ubiquitous and subclinical infections are common. This article examines reasons for disease outbreaks and the problem of accurate diagnosis. Evidence is presented that subclinical infections can be beneficial as they stimulate protective immunity in the young. Two unexpected observations are given which serve as a reminder that we should remain open-minded in spite of recent advances. The conclusions drawn are that the causes of enteric disease are often complex and that there is still some way to go before we fully understand why outbreaks occur when they do.