Detection of echovirus 7 in effluent sewage treatment plant Ahvaz city, Iran

The enteroviruses may lead to conditions such as aseptic meningitis, encephalitis, acute flaccid myelitis, epidemic pleurodynia (Bornholm disease), hemorrhagic conjunctivitis, and myopericarditis among pediatric populations. The present study was undertaken to identify the presence of enteroviruses within sewage treatment systems.

24 composite effluent sewage samples (500 ml each) were collected, centrifuged (1000 rpm for 30 minutes), and the first supernatant was saved. The precipitate was resuspended in 10 ml of supernatant, treated with 10% chloroform, and centrifuged again (1000 rpm for 5 minutes) to collect a second supernatant. The first and second supernatants were combined, treated with 2.2% sodium chloride and 7% polyethylene glycol 6000, and the mixture was agitated at 4°C overnight before being centrifuged for two hours at 2000 g. After discarding the supernatant, the pellet was resuspended at a 1:100 dilution. Each sample was then inoculated into RD and HeLa cells for virus isolation, followed by detection via RT-PCR. A phylogenetic tree was constructed to determine the genotypes of the isolated enteroviruses.

Enterovirus was detected in 10 of 24 (41.7%) sewage effluent samples. Phylogenetic analysis of five randomly chosen positive samples identified echovirus 7.

The removal of enteroviruses during the sewage treatment process is of paramount importance, necessitating heightened attention to this critical phase of wastewater management.