Rotavirus B (RVB) is a double‑stranded RNA virus that belongs to the genus Rotavirus (family Sedoreoviridae). It has eleven genome segments and primarily infects pigs but can cause outbreaks of severe gastroenteritis in humans, particularly adults.
Virology and epidemiology
RVB particles are triple‑layered and encode structural and non‑structural proteins on eleven genome segments. Classification of rotaviruses is based on antigenicity of the VP6 protein. Group B viruses are less common than group A viruses and represent a distinct species. Pigs are considered the main reservoir, but viruses have been detected in rats, cattle, goats, sheep and humans. The first recognized human outbreak occurred in 1982–1983 in China, when adult diarrhoea rotavirus caused severe gastroenteritis in thousands of people. Subsequent outbreaks were reported in India, Bangladesh, Nepal and Myanmar. Surveys indicate that immunity to group B viruses is low in countries where the virus has not circulated. Human infections are rare outside Asia, and most detected strains are associated with animal reservoirs. Because the virus is difficult to cultivate in vitro, many aspects of its biology remain poorly understood. Illness resembles other rotavirus infections but often affects adults, causing watery diarrhoea, abdominal cramps, nausea and fever. No licensed vaccine targets RVB; prevention relies on sanitation and reducing contact with infected animals.
Outbreaks and host species
The 1982–1983 epidemic in China involved a strain later called adult diarrhoea rotavirus (ADRV). An endemic strain known as CAL was subsequently identified. Outbreaks in India and Bangladesh occurred in rural areas with limited sanitation. Molecular studies have detected RVB in rodents and several domestic animals, suggesting a broad host range. Pigs are the principal reservoir, and infection has been documented in pig herds worldwide. Because the virus has not been isolated in cell culture, surveillance depends on polymerase‑chain‑reaction assays to detect viral RNA. Monitoring animal reservoirs and improving hygiene in pig farming are important strategies to prevent zoonotic spill‑over.
Rotavirus B is a lesser‑known but important cause of gastroenteritis. Its ability to infect multiple species and occasional capacity to cause large human outbreaks highlight the need for continued surveillance. Improved detection, sanitary practices and understanding of its ecology may reduce the risk of future epidemics in both animals and humans.
Related Terms: Rotavirus A, Rotavirus C, Rotavirus H, Gastroenteritis, Reoviridae