EPIDEMIC TOXOPLASMOSIS ASSOCIATED WITH INFECTED CATS

In October, 1977, an outbreak of toxoplasmosis occurred in patrons of a riding stable in Atlanta, Georgia; 37 became ill with toxoplasmosis or had serologic evidence by indirect fluorescent-antibody test of acute infection with Toxoplasma gondii (titer ≥1:4096 or a positive fluorescent-antibody test for toxoplasma antibodies). Forty-nine additional patrons did not become ill. Two of the three adult cats from the stable were seropositive for toxoplasma, which was also recovered from the tissues of two kittens and four mice trapped near the stable. Patrons who spent most of their time at the end of the stable where a cat had defecated had the highest incidence of infection. Patrons who attended the stable daily had a higher attack rate than those who attended less frequently. No common meals were consumed, and dietary history eliminated meat as the source of infection. The data suggest that toxoplasma oocysts were the source of the infection. (N Engl J Med 300:695–699, 1979) BOTH infection and disease are well documented for persons who have consumed toxoplasma in raw or inadequately cooked meat.1,2 More recently, the role of cats shedding toxoplasma oocysts as a source of human and animal infection has been widely publicized.3 Although most investigators acknowledge that oocysts are probably infectious for human beings, there is little evidence linking infection by oocysts with clinical disease in human beings.4 Background On November 11, 1977, a physician in Atlanta, Georgia, informed us about a patient with high fever and headache whom he had recently diagnosed as having toxoplasmosis. This patient informed us that she. © 1979, Massachusetts Medical Society. All rights reserved.