Viral hepatitis and hydraulic parameters: an alternative hypothesis.

Point source outbreaks of viral hepatitis have been associated with the consumption of contaminated food and water, yet epidemiologic analysis of the disease in the general population usually provides strong correlations with sub-standard socioeconomic conditions. However, statistical analysis of municipal public health records in Worcester, Massachusetts showed that significant correlations existed between the incidence of viral hepatitis and certain water and sewer parameters. A 5-yr period spanning the epidemic outbreak of 1969 to 1970 was analyzed. Significantly higher incidences of the disease occurred in those areas of the city served by old water and sewer pipes, combined sewers and the low pressure water distribution system. Based on this epidemiologic evidence, the authors propose that an alternate hypothesis, based on hydraulic arguments, can be made which will explain the observations. Although neither hypothesis, socioeconomic or hydraulic, can be excluded solely on the basis of epidemiologic results, this new hypothesis may prove useful in the design of methods for environmental control of viral hepatitis.