Hepatitis A virus and environmental quality indicators in aquatic ecosystems for oyster farming in the Northeast of the State of Pará, Brazil

Abstract - Research into the occurrence of microbiological contaminants, including hepatitis A virus (HAV), in river waters intended for oyster farming is of extreme importance for public health. This study aimed to detect the occurrence of HAV in the aquatic environment for ostreiculture in northeastern Pará, Brazil, and correlate with microbiological, physico-chemical and climatological variables. The HAV research was based on the method of water concentration by filtration membrane adsorption-elution and in the organic flocculation method with skim milk, followed by Nested-PCR. Quantification of coliforms, Enterococci and heterotrophic bacteria was performed. The physico-chemical variables were measured with multiparametric probe and spectrophotometry. Positive samples were purified and submitted to sequencing. From March 2017 to December 2018, 203 samples of river water were collected and analyzed in the municipalities of Augusto Corrêa, Curuçá, Salinópolis and São Caetano de Odivelas. In 10.8% of the analyzed samples the HAV RNA was detected, in all localities the HAV was classified in genotype IB. There was no significant difference between the concentration methods of the water samples. The only physicochemical variable that most influenced HAV detection was dissolved oxygen. Regarding the bacterial indicators, the highest statistical significance occurred with thermotolerant coliforms and Escherichia coli. The detection of HAV in the four municipalities studied shows that the virus is circulating in the aquatic environment and, therefore, in the community. In this context, more effective hygienic-sanitary measures are necessary in these communities dedicated to oyster farming