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SEROLOGICAL RESPONSES TO CRYPTOSPORIDIUM ANTIGENS AMONG USERS OF SURFACE VERSUS UNDERGROUND DRINKING WATER SOURCES
Citation:
Frost, F. J., T. Kunde, T. Muller, G. F. Craun, R L. Calderon, M. Katz Louis, AND A. J. Hibbard. SEROLOGICAL RESPONSES TO CRYPTOSPORIDIUM ANTIGENS AMONG USERS OF SURFACE VERSUS UNDERGROUND DRINKING WATER SOURCES. EPIDEMIOLOGY AND INFECTION 131(3):1131-1138, (2003).
Impact/Purpose:
To explore reasons for not finding elevated health risks following detection of oocysts in drinking water
Description:
Cryptosporidium oocysts have been detected in source and treated drinking waters in the United States and elsewhere. Enhanced enteric disease surveillance, initiated following detection of oocysts, has not often detected elevated rates of infection or of symptoms compatible with infection at the time. Reasons for not finding elevated health risks in these exposed communities are unclear. A prior study suggested that a low rate of drinking-water-attributable infection (e.g. 1/1000 per year) along with difficulties in diagnosing and reporting cases of cryptosporidiosis likely accounts for low rates of detectable disease.
It is possible that many oocysts detected in drinking water are not viable or infectious for humans. Alternatively, Cryptosporidium infections may not result in overt or clinically detectable illness for substantial proportion of the population. If people are regularly exposed to drinking water with low concentrations of oocysts, the risk of symptomatic illness or the severity of illness from infection may be reduced because of protective immunity. Since surveillance systems for Cryptosprodium infections generally focus on the regocnition of clinically detected disease (cryptosporidiosis), little information is available on the occurence of unrecognized and asymptomatic infections.