Orthohantavirus is a genus of single-stranded, enveloped, negative-sense RNA viruses in the family Hantaviridae within the order Bunyavirales.[3] Members of this genus may be called orthohantaviruses or simply hantaviruses.
Orthohantaviruses typically cause chronic asymptomatic infection in rodents.[3][4] Humans may become infected with hantaviruses through contact with rodent urine, saliva, or feces. Some strains cause potentially fatal diseases in humans, such as hantavirus hemorrhagic fever with renal syndrome (HFRS), or hantavirus pulmonary syndrome (HPS), also known as hantavirus cardiopulmonary syndrome (HCPS),[5] while others have not been associated with known human disease (e.g. Prospect Hill virus).[6] HPS (HCPS) is a "rare respiratory illness associated with the inhalation of aerosolized rodent excreta (urine and feces) contaminated by hantavirus particles."[5]
Human infections of hantaviruses have almost entirely been linked to human contact with rodent excrement; however, in 2005 and 2019, human-to-human transmission of the Andes virus was reported in South America.[7]
Orthohantaviruses are named for the greek word ortho- meaning "straight" or "true" and for the Hantan River in South Korea, where the first member species (Hantaan virus) was identified and isolated in 1976 by Ho Wang Lee.[8][9]
Hantavirus infections in humans are associated with two diseases: hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS), caused by Old World and New World hantaviruses, respectively. A common feature of the two diseases is increased vascular permeability, which causes hypotension, thrombocytopenia, and leukocytosis. The pulmonary illness is the more fatal of the two, whereas the hemorrhagic fever is much more common. Treatment for both is primarily supportive as there is no specific treatment for hantavirus infections.[10] While many hantaviruses cause either of the two diseases, some are not known to cause illness, such as the Prospect Hill orthohantavirus.[11]
Hemorrhagic fever with renal syndrome (HFRS) is caused chiefly by hantaviruses in Asia and Europe. Clinical presentation varies from subclinical to fatal, depending on the virus. After an incubation period of 2–4 weeks, the typical illness starts with non-specific symptoms such as high fever, chills, headache, backache, abdominal pains, nausea, and vomiting. After the initial period, bleeding under the skin begins, often paired with low blood pressure, followed by further internal bleeding throughout the body. Renal dysfunction leading to further health issues begins thereafter, which may cause death.[10] A more mild form of HFRS that occurs in Europe is called "nephropathia epidemica" (NE).[12] Trench nephritis during World War I is now thought to have been HFRS.