Noroviruses are members of the Caliciviridae family and can cause a variety of diseases in a wide range of species. Human noroviruses cause viral gastroenteritis, with millions of cases per year worldwide. Most common symptoms include diarrhea, vomiting, and abdominal cramps. The illness lasts on average 28 to 60 hours. Infection is most common in health care institutions such as hospitals and long-term-care facilities, but outbreaks are often reported in schools, restaurants, cruise ships, and military bases. About 20% of Caucasians have reduced susceptibility to infection with noroviruses.
Transmission is via contact with feces or vomit, which occurs mainly through direct person-to-person contact or contaminated food and water. Recreational water users can also be exposed to infection with norovirus as the result of fecal pollution.
Human noroviruses have recently been isolated from pet dogs, raising concerns about potential zoonotic infections. Dogs produce an immune response to numan noroviruses, implying productive infection. Studies show that seropositivity to norovirus in humans is higher if there is a dog in the household. The fact that norovirus may be transmissible between dogs and humans is of considerable public health concern.
- Evidence for Human Norovirus Infection of Dogs in the United Kingdom. Sarah L. Caddy et al.