[Viruses present in the environment: virological considerations and examples of their impact on human health]

Animal viruses are present in most human environments. Their viability in these media is very variable and the most important element that conditions this viability is the existence or not of a phospholipid envelope surrounding the nucleocapsid. After some general considerations on the structure of viruses, their multiplication cycle and their resistance to different physico-chemical agents, some examples of the impact of animal viruses present in the environment on human health will be presented. The situations that are related concern recent epidemiological events: circulation of type 2 polioviruses derived from the Sabin vaccine strain in the wastewater of New York, London and Jerusalem; risk of transmission of Sars-CoV-2 during the spreading of sludge from wastewater treatment plants on agricultural land in the era of the Covid-19 pandemic; « new » forms of food-borne poisoning of viral origin (hepatitis E, tick-borne encephalitis, Nipah virus infection); contamination by epidemic viruses of mobile phones used by pediatricians; role of fomites in the spread of orthopoxvirus infections (smallpox, cowpox, monkeypox). The risk attached to animal viruses present in the environment must be assessed in a measured way without overestimating or underestimating their potential consequences for human health.