Frontiers in Marine Science (Jun 2014)
Detection and quantification of Hepatitis A and E vírus in wastewater from Tunisia <br />
Abstract
Enteric viruses contaminating the environment represent a danger for public health. They are present quite frequently in wastewater and transmitted to humans by the fecal-oral route. The aim of our study was to detect hepatitis A and E viruses (HAV and HEV) in wastewater samples collected from 6 different Tunisian sewage treatment plants during thirteen months. A total of 325 samples were analyzed by real time reverse transcriptase-polymerase chain reaction (RT-qPCR). Results showed the presence of HAV contamination in 36% of the samples. Msaken (58.9%) and SidiBouzid (51.85%) regions showed the highest contamination, followed by Ouerdanine (35.2%), Kasserine (38.9%), Sbitla (23.6%) and El Jem (7.7%) regions. Contamination with HEV was significantly lower (4.9%), being detected HEV positive samples in SidiBouzid (9.25%), El Jem (5.76%), Kasserine (3.7%), Ouerdanine (3.7%), Sbitla (3.63%) and Msaken (3.6%) regions. On the another hand, our research found that, in entry points, 54% of wastewater samples were contaminated with HAV, whereas, in exit points a percentage of 17.9% was found. HAV values were also analyzed by plant showing percentages of positive samples in entry points between 15.38% and 85.18%, while in exit points values ranged from 3.57% to 57.14%. HAV was detected in exit points of all plants except El Jem region. Concerning HEV, the average percentage of contaminated wastewater at entry was 6.75% which was reduced until 3.1% at exit. By plant, HEV positive samples were detected only in three plants, Kasserine, El Jem and Sidi Bouzid at rates of 3.7% 3.84% and 11.11%, respectively. These results support previous findings on the stability of enteric viruses in wastewater and the inefficiency of the procedures employed in the sewage treatment plants. On the other hand, molecular procedures proved to be very sensitive to detect viral genomes in this type of samples. In conclusion, wastewater treatments employed in Tunisian plants can reduce the number of viral particles of hepatitis A and E but do not remove all of them, which constitute a potential risk for human health.
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