A pig farm has several sick and dying adult pigs. Affected animals are febrile and depressed.

Some seem constipated and others have diarrhea. A few are ataxic.

A necropsy on one of the dead pigs shows widespread petechial and ecchymotic hemorrhages in the kidneys ("turkey egg kidneys"), bladder, spleen, and larynx.

Which one of the following choices is the most likely diagnosis?

Sorry.  You chose A, but the correct answer is C. Classical swine fever

Hemorrhages on the kidneys and other organs are characteristic of both classical swine fever (CSF, also called "hog cholera") and African swine fever (ASF).

African swine fever cannot be differentiated from classical swine fever based on clinical and postmortem signs alone.

Confirmation is based on either PCR or ELISA antigen testing.

Both are reportable diseases. Classical swine fever was last reported in North America in the 1970s.

Click here to see more images of CSF.

Erysipelas is characterized by fever, painful joints, and sometimes, urticarial diamond-shaped skin lesions.

Hemagglutinating encephalomyelitis (vomiting and wasting disease) and Glaesserella parasuis (formerly Haemophilus parasuis; cause of Glasser's disease) both occur mainly in young piglets.

Pigs with postweaning multisystemic wasting syndrome (PMWS) typically have enlarged, pale lymph nodes, growth retardation, wasting, and dyspnea.

Ref: Jackson and Cockcroft, Handbook of Pig Medicine, pp. 182-4.

Images courtesy, USDA and the Center for Food Security and Public Health.