Reptile- and Amphibian-associated Salmonellosis in Childcare Centers, United States

during the clinical stage of the disease, and in 1 case, at the preclinical or asymptomatic stage. Our fi ndings suggest that PrPSc is likely to be detected in the saliva of BSE-affected cattle during the clinical stage of disease, after accumulation of PrPSc in the brain. PrPSc was found in the salivary glands of BSE-affected cattle at the terminal stage of infection (1). Therefore, once the infectious agent reaches the central nervous system, it may spread centrifugally from the brain to the salivary glands through the autonomic nervous system. Infectivity of saliva and the presence of PrPSc in saliva have been reported in other ruminants affected with transmissible spongiform encephalopathy. Infectivity of saliva was demonstrated in deer with chronic wasting disease (3) and in scrapieaffected sheep (4); the immunolabeled PrPSc accumulated in the salivary glands of scrapie-affected sheep (5). A low level of PrPSc was detected in concentrated buccal swab samples of preclinical scrapie-infected sheep by using sPMCA (6,7). These results suggest that small amounts of PrPSc may accumulate in the salivary glands and are then secreted into saliva. The presence of infectious prions in saliva may explain the facile horizontal transmission of scrapie in sheep (4–6) and chronic wasting disease in deer (4,8). There has been no epidemiologic evidence, however, that saliva, milk, blood, and cerebrospinal fl uid from BSE-infected cattle are infectious (9). Nonetheless, the potential risk for BSE transmission by body fl uids or excretions from BSE-infected cattle is cannot be ruled out by the current data.