Background
Enteric viruses are viruses that are primarily transmitted via the faecal-oral route, and that cause enteric disease (with symptoms e.g. nausea, diarrhea, vomiting, and abdominal pain). Many families of viruses are enteric viruses, including, for example, calicivirus (including norovirus and sapovirus), adenoviruses, astroviruses, rotaviruses, hepatitis viruses, and enteroviruses. Most enteric viruses cause only relatively mild symptoms in healthy individuals, some enteric viruses (e.g. poliovirus) can have serious health effect, with symptoms including meningitis and paralysis. Enteric viruses have been known to cause epidemics, for example, outbreaks of hepatitis A and coxsackieviruses have been reported worldwide within the latest decade.
In the below paragraphs, we provide more detail regarding some examples of enteric viruses.
Noroviruses belong to the Caliciviruses family. The norovirus GG2 is more commonly known as the “winter vomiting disease virus”. Cases are typically seasonal, with peaks in winter. It is often spread between people in environments where individuals come into close contact, such as hospitals, nurseries, schools, and cruise ships. To read more about GG2, see resources by folkhälsomyndigheten, for example.
Hepatitis A (HAV) and hepatitis E (HEV) are other examples of enteric viruses. The other four human hepatitis viruses are not transmitted via the faecal–oral route. Outbreaks of hepatitits A, caused by transmission in contaminated food or water, occur regularly. Read more about the 2022 outbreak in our emerging pathogens section.
The Enteroviruses comprise of a group of around one hundred viruses of the Picornaviridae family. Examples include Enterovirus A-D (which includes Poliovirus (typ 1-3)) and Coxsackievirus (group A and B). All three Polioviruses can cause poliomyelitis, more commonly known as polio. There was a major polio epidemic in the early 20th century, polio vaccines were created in the 1950s in response, and mass vaccination programs were quickly implemented. In Sweden, the polio vaccine became part of the routine vaccination program for children in the mid-1960s and there have been no reported cases since the late 1970s. More information about the mass vaccination program is available (in Swedish) from Folkälsomyndigheten, along with more information about ongoing efforts with polio virus globally. Most non-polio enteroviruses will only cause a mild illness, with patients reporting symptoms similar to the common cold with a fever, runny nose, a cough, and muscle aches. Most people recover easily without medical intervention, or with only mild ‘over the counter’ remedies. A number of outbreaks of non-polio enteroviruses, such as coxsackieviruses, have been reported within the latest decade. Information about the surveillance for outbreaks of non-polio enteroviruses is available from American Centers for Disease Control and Prevention (CDC).
Adenoviruses are part of the Adenoviridae family. There are seven human adenoviruses (A to G) and >60 (sero)types, some of which are water-borne. These viruses commonly cause gastroenteritis among children younger than 5.
Astroviruses, part of the Astroviridae family comprise of eight serotypes (HAst1-8) causing gastrointenstinal symptoms. Most enteric viruses do not give immunity, but astroviruses are an exception, with healthy individuals generally acquiring immunity after infection, making reinfection rare. The National Respiratory and Enteric Virus Surveillance System (NREVSS) is an American surveillance program that monitors many enteric viruses. They monitor respiratory syncytial virus (RSV), human parainfluenza viruses (HPIV), human metapneumovirus (HMPV), respiratory adenoviruses, human coronavirus (excluding SARS-CoV-2), rotavirus, and norovirus.