Division D CHRONIC FORMS

Chronic forms of the disease are rare. In chronic forms, secondary bacterial infections can be observed. As clinical signs of chronic ASF are rather non-specific, many other diseases must be considered for differential diagnosis. Increased body temperature is not necessarily present in every animal, but in an infected holding fever can be detected at least in some pigs.

Clinical symptoms of chronic ASF may include respiratory problems, abortions, arthritis, chronic skin ulcers or necrosis, not resembling the typical clinical picture of ASF virus infections. The lesions may be minimal or absent. Histopathological findings are characterised by enlarged lymph nodes and spleen, pleuritis and fibrinous pericarditis and infiltrated pneumonitis. Focal caseous necrosis and mineralisation of the lung have also been described.