A Hemagglutinating Virus Producing Encephalomyelitis in Baby Pigs.

Abstract

A viral type of encephalomyelitis in baby pigs has been known to occur in Ontario for at least three years (1, 2). Studies have been undertaken in an effort to identify the cause or causes of this apparently infectious condition (3, 4). During the course of this work feces and brain tissue from piglets showing histopathological evidence of viral polioencephalomyelitis have been seeded into monolayer cell cultures of pig kidney origin in an attempt to isolate an infectious agent. Some of the results have been previously reported in regard to the isolation of enteroviruses (4). Recently three outbreaks of encephalomyelitis in different parts of Eastern Ontario have been investigated. In each case a cytopathogenic microorganism markedly different to the enteroviruses previously described (4) has been isolated. These agents proved to be hemagglutinating viruses and were shown to be pathogenic for baby pigs. This report describes preliminary investigations conducted with these hemagglutinating encephalomyelitic viruses (HEV) and discusses their relationship to porcine encephalomyelitis in Ontario.