PREVALENCE AND FATE OF HEPATITIS-A VIRUS IN WATER

Hepatitis A virus (HAV) is a major waterborne disease agent with world wide distribution. The main transmission route of HAV is direct person -to-person contact. However, hepatitis A (HA) outbreaks associated wit h the consumption and use of fecally contaminated water were reported from many countries. Studies on the environmental behavior of HAV were feasible only after developing techniques for its cultivation and enu meration in tissue culture. This study reviews data on the extent of H AV prevalence and persistence in the environment and water. HA is high ly prevalent in low socioeconomic populations as determined by seroepi demiologic studies. HAV is excreted for long periods by infected indiv iduals, but it is also shed by healthy persons. HAV has been detected in concentrated wastewater and natural waters. However, in most cases the natural waters were monitored for the presence of HAV after the oc currence of HA outbreak. HAV persists for months at temperatures below 10 degrees C and for at least 1 month at ambient temperature (20 to 2 5 degrees C). Physical, biological, and chemical factors that influenc e the survival of enteric viruses - such as temperature, pH, salt conc entration, microbial activity, and humidity - have similar effects on HAV. Drinking water treatment processes such as coagulation, high rate filtration, and disinfection seem to be effective in removing HAV fro m water.