Other viruses causing gastroenteritis.

Besides the viruses producing the majority of human viral gastroenteritis, other viruses infect more rarely but are sometimes able to cause epidemics. In particular, they cause chronic infection in the immunocompromised. Some of these viruses discussed in this chapter are toroviruses, picobirnaviruses, enteroviruses, human immunodeficiency virus (HIV), herpesviruses, and coronaviruses. Toroviruses make up a genus of the Coronaviridae family. They are a well-described cause of diarrhea in calves and horses but may also infect sheep, goats, and pigs. Picobirnaviruses are related to members of the Birnaviridae family. They are found in the feces of HIV-infected patients with diarrhea more frequently than in HIV-infected patients without diarrhea, but a virus-specific immune response was not measurable. The genus is of the Picornaviridae family. All enteroviruses infect man via the gastrointestinal tract where they have their first site of replication, probably in lymphoid tissues of the pharynx and gut. HIV, the causative agent of the acquired immunodeficiency syndrome (AIDS), is a member of the genus of the Retroviridae family. Cytomegalovirus (CMV) and herpes simplex viruses, members of the Herpesviridae family, are found as the cause of colitis and esophagitis, mainly in HIV-infected patients. is another genus of the Coronaviridae family. Coronaviruses infect the respiratory and gastrointestinal tracts. They are a recognized cause of the common cold in man.