**2.6 Viruses and bacteria**

The occurrence of human pathogenic viruses in wastewater is a usual occurrence, and newly discovered cases that were not associated with wastewater previously, are now considered as wastewater pollutants. Viral and bacterial infections from waterborne outbreaks are usually connected with environments associated with the discharge of wastewater [37, 38]. Enteric viruses are known to cause gastroenteritis infections, hepatitis, and respiratory tract infections. Enteric viruses such as noroviruses, rotaviruses, enteroviruses, sapoviruses, astroviruses, bocaviruses, hepatitis A virus, hepatitis E virus, Aichi virus, Human polyomaviruses (PyVs), papillomaviruses, a plant virus called pepper mild mottle virus (PMMoV), and enteric bacteria such as bacteriophages, fecal coliforms and *Escherichia coli* are found in wastewater, and the full details of their occurrence and concentration in untreated and treated wastewater by continents can be seen in a review by Farkas et al., [37]. The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus related to the COVID-19 pandemic has been discovered in wastewater with entry through human feaces into sewer systems as other viruses [39, 40]. Research is on-going on the effect of SARS-CoV-2 on aquatic habitats and its resulting long-term effect.
