acute infection caused by the microorganism Streptobacillus moniliformis, transmitted to humans by rat bite or by the ingestion of contaminated foods and characterized by the sudden onset of chills, fever, and vomiting followed by the development of a skin rash and inflammation of the joints. An ulcerative lesion may be observed at the site of the rat bite. Formation of abscesses in the brain, heart muscle, and other tissues is a rare but serious complication. The infection responds well to penicillin. It was first described in Haverhill, Mass., U.S., in 1926; some 86 persons were infected then, apparently by the ingestion of contaminated raw and unpasteurized milk. Haverhill fever sometimes refers only to cases in which there is no history of rodent bite. See also rat-bite fever.