If the animal controls the infection, a lymphocytic infiltration into the periphery of the distended interlobular septa is followed by fibroblasts. Eventually, the interlobular septa become thick, white bands of connective tissue. While this process is advancing, a connective-tissue capsule develops around the necrotic area of lung to form a sequestrum. One distinguishing feature of CBPP lesions is coagulative necrosis rather than the liquefaction necrosis seen in many other pneumonias in cattle. In some severe cases of CBPP, the animals will develop septicemia, and the CBPP agent will localize and grow in joints.
Affected joints become very enlarged by proliferated connective tissue and exudate.
This form of the disease is seen mostly in calves.