Porcine Haemophilus pleuropneumonia epizootic in southwestern Ontario: clinical, microbiological, pathological and some epidemiological findings.

A fibrinous necrotizing pleuropneumonia with a predominant mononuclear cell infiltrate commenced January 1978. The pneumonia, caused by Haemophilus pleuropneumoniae assumed epizootic proportions and affected mainly feeder pigs in the intensive pig rearing area of southwestern Ontario. A few abortions occurred. Winter storms, recent transportation and other potentially stressful situations were associated with herd outbreaks. Broad spectrum antibiotics were usually effective in stopping deaths.