Conventional wastewater treatment may not eliminate hepatitis A virus, posing a potential public health hazard in secondary effluents.
May signal incomplete HAV removal by standard treatment; leaves open need for enhanced surveillance and method validation.
The present study investigates the presence of hepatitis A virus (HAV) in wastewater both before and after conventional treatment. Two different procedures are used to concentrate the viruses: by precipitation and by filtration. The reverse transciptase-polymerase chain reaction (RT-PCR) followed by hybridization are applied to detect HAV. The flocculation of 1 L of wastewater using the aluminum hydroxide adsorption–precipitation method gave two negative samples out of the nine processed; that is, 22% of the samples were HAV negative. The filtration method, using an immersible CX-30 ultrafiltration unit, showed 10% of the samples to be negative. However, the Chi2 test gave no statistically significant differences for these results with respect to the method of concentration used. All of the samples of raw wastewater were HAV positive, a finding which reflects a high prevalence among the population. Furthermore, although conventional wastewater treatment reduces all other microbiological indicators by more than 99%, HAV was found to remain positive in our samples of treated water. This means that when primary influents are contaminated with HAV, the secondary effluent may constitute a public health hazard in the transmission of HAV.
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Espigares et al. (1999) studied this question.