The clinical signs of hog cholera vary with the severity of the infection. There are three forms of the disease:
Acute Hog Cholera
The acute form of hog cholera is highly virulent (severe), causing persistent fevers that can raise body temperatures to as high as 107°F. Other signs of the acute form include convulsions and lack of appetite. Affected pigs will pile or huddle up together. Signs of hog cholera may not be apparent for several days following infection. Death usually occurs within 5 to 14 days following the onset of infection.
Chronic Hog Cholera
The chronic form causes similar clinical signs in affected swine, but the signs are less severe than in the acute form. Discoloration of the abdominal skin and red splotches around the ears and extremities often occur. Pigs with chronic hog cholera can live for more than 100 days after the onset of infection.
Mild Hog Cholera
The mild, or clinically unapparent, form of hog cholera seldom results in noticeable clinical signs. Affected pigs suffer from short periods of illness, which are often followed by periods of recovery. Eventually, a terminal relapse occurs. The mild strain may cause small litter size, stillbirths, and other reproductive failures. High mortality during weaning may also indicate the presence of this mild strain of the disease.