A highly virulent togavirus-like agent associated with the fulminating disease of guinea fowl.

During a 1986 natural lethal outbreak of fulminating disease in guinea poult flocks in southwestern France, enveloped virus particles were consistently observed in the gut contents of infected birds. For the present study, a protocol was developed for the purification of these particles. Sucrose-banded virus obtained from birds infected experimentally with virus from the outbreak was found to have a buoyant density of 1.18 g/ml. The purified virus showed hemagglutinating activity, was shown by electron microscopy to have a togavirus-like morphology, and also was shown to be transmissible and pathogenic through oral ingestion. In addition, other enveloped particles have been occasionally detected in gut contents of both infected and uninfected birds; the improbability of the viral nature of these interfering particles is discussed.