B. Pasteurellosis

Clinical Findings. Pneumonic Pasteurellosis of cattle is characterized by a sudden onset of high fever (104 to 106°F or 40 to 41°C), depression, anorexia and dyspnoea, with coughing and a slight mucopurulent nasal discharge. Auscultation is used to reveal the presence of bronchopneumonia and pleuritis especially in the anterior and ventral parts of the lungs. If cases are seen in the early stages, there is often only a general increase in the vesicular murmur, but an increase in the rate and depth of respiration will be observed. An ocular discharge and diarrhea may be present but these vary a great deal between outbreaks.

The course in the majority of animals is known to be variable, depending upon the degree of pulmonary involvement, and deaths occur at any time up to 3 weeks after the onset of the disease. The disease responds well to treatment, and even without it some animals recover in 3 to 7 days.

Pasteurellosis of Swine, Sheep and Goats. Pasteurellosis causes heavy losses in pigs and sheep in most parts of the world, both through deaths and depression of body weight gains. Morbidity and mortality rates are considered to be up to 40 per cent and 5 per cent respectively in both species. In sheep at pasture, the disease tends to spread slowly and the morbidity rate is lower that in feeder lambs and pigs maintained in small areas.

As in pneumonic pasteurellosis of cattle, transmission occurs probably by the inhalation or ingestion of infected material.

In pigs an acute bronchopneumonia, accompanied by fever and

toxemia, causes a clinical syndrome similar to that of pneumonic pasteurellosis. There is marked tendency for the disease to become chronic resulting in reduced weight gains and frequent relapses.