Salivirus A is a small, positive-sense single-stranded RNA virus in the family Picornaviridae and the only known species in the genus Salivirus. It was first identified in stool samples from children and chimpanzees and is not clearly linked to human disease.
Explanation
Salivirus A virions are non-enveloped and roughly 30 nm in diameter, with pseudo‑T=3 icosahedral symmetry typical of picornaviruses. The genome is a positive-sense RNA strand of about 7.98–8.02 kilobases, comprising a 5′ untranslated region of 709–763 nucleotides, a single open reading frame of about 7.1 kilobases, and a 3′ untranslated region of around 148 nucleotides. This open reading frame encodes a polyprotein that is cleaved into structural proteins (VP0, VP3, VP1) and non‑structural proteins involved in replication. Like other picornaviruses, Salivirus A enters host cells via receptor-mediated endocytosis, uses an internal ribosome entry site for translation of its RNA, and replicates in the cytoplasm before progeny virions are released by cell lysis. The virus has been detected in faecal samples from humans and chimpanzees; however, it has not been cultured, and much of its biology is inferred from sequence analysis. Two genetic types have been described, but only the species Salivirus A has been formally recognised.
Epidemiology and Research Findings
Salivirus A was identified in stool surveillance studies in Asia and Africa. Reports from case–control studies show similar detection frequencies in patients with acute gastroenteritis and in healthy controls. For example, salivirus RNA was found in 3.5 % of diarrhoeal cases and 2.8 % of controls, a difference that was not statistically significant. Viral RNA has also been detected in chimpanzee faeces, suggesting a wider host range. While some early reports considered salivirus a candidate gastroenteritis agent, subsequent analyses and meta‑analyses have concluded that there is no clear association with human disease. The virus appears to be transmitted by the faecal–oral route, similar to other picornaviruses, but its ecological reservoirs remain to be elucidated.
Salivirus A is a picornavirus that is frequently found in human and primate faeces but has not been associated with clinical illness. Understanding its distribution and genetic diversity helps clarify the landscape of enteric viruses and may provide insights into virus evolution in the Picornaviridae family.
Related Terms: Picornaviridae, Cosavirus A, Saffold Virus, Aichi Virus, Salivirus B