Andes virus

The genome of Andes virus is about 12.1 thousand nucleotides in length and segmented into three negative-sense, single-stranded RNA (-ssRNA) strands. The segments form into circles via non-covalent bonding of the ends of the genome. The small segment, about 1.87 kilobases (kb) in length, encodes the viral nucleoprotein and a non-structural protein that inhibits interferon production. The medium segment, about 3.67 kb in length, encodes a glycoprotein precursor that is cleaved into the two spike proteins Gn and Gc during virion assembly. The large segment, about 6.56 kb in length, encodes the viral RNA-dependent RNA polymerase (RdRp), which is responsible for transcribing and replicating the genome. The ends of each segment contain untranslated terminal regions (UTRs) that are involved in the replication and transcription of the genome. ==Structure==

Virions are mostly spherical or pleomorphic in shape and range from 80 to 160 nm in diameter. They contain a lipid envelope covered in spike proteins made of the two viral glycoproteins, Gn and Gc. The spike proteins extend about 10 nm out from the surface and are tetrameric, consisting of four copies each of Gn and Gc with helical symmetry, in which Gn forms the stalk of the spike and Gc the head. Spikes are arranged on the surface in a lattice pattern. Inside the envelope are the three genome segments, which are encased in nucleoproteins to form a ribonucleoprotein (RNP) complex. Attached to each RNP complex is a copy of RdRp. ==Life cycle==

ANDV primarily infects endothelial cells and macrophages. For replication of the genome, a complementary positive-sense strand is produced by RdRp. Copies of the genome are made from this complementery strand. Progeny RNA strands are then encapsidated by nucleoproteins. ==Evolution==

The most common way that hantaviruses evolve is through mutations of individual nucleotides being inserted, deleted, or substituted. Because Andes virus has a segmented genome, it is possible for recombination and reassortment of segments to occur, whereby segments from different lineages mix in a single host cell and produce hybrid progeny. ==Ecology==

Andes virus is carried mainly by the long-tailed pygmy rice rat (Oligoryzomys longicaudatus), Apart from the long-tailed pygmy rice rat, Andes virus is relatively common in the long-haired grass mouse. Seroprevalence of ANDV in its hosts is found throughout South America, but is highest in Patagonia. Transmission to humans occurs mainly through the inhalation of aerosols that contain mouse salivas, urine, or feces. It can reportedly spread through saliva, airborne droplets from coughing or sneezing, breastmilk, from mother to child across the placenta, and through the digestive tract. Person-to-person transmission reportedly occurs mainly within families or when engaging in close activities with an infected person during the prodromal disease phase. A 2021 systematic review, however, found these claims not to be supported by sufficient evidence and cited flawed methodology in research on Andes virus outbreaks. ==Disease==

Andes virus infection usually causes hantavirus pulmonary syndrome (HPS), also called hantavirus cardiopulmonary syndrome (HCPS). Symptoms occur within 1–8 weeks after exposure to the virus and come in three phases: prodromal, cardiopulmonary, and recovery. Prodromal (early) symptoms last for a few days and include fever, muscle pain, headache, coughing, nausea, vomiting, chills, and dizziness. The cardiopulmonary phase lasts for several days and is characterized by fluid buildup in the lungs, low oxygen levels in the blood, elevated or irregular heart rate, low blood pressure, cardiogenic shock, and respiratory failure. ANDV infection is diagnosed based on observation of symptoms and testing for hantavirus nucleic acid, proteins, or hantavirus-specific antibodies. Treatment is supportive in nature and includes supplementing oxygen during the cardiopulmonary phase. No vaccines exist for Andes virus infection, so the main way to prevent infection is to avoid or minimize contact with rodents. ==Classification==

Andes virus is classified into the species Orthohantavirus andesense in the genus Orthohantavirus, which is in the family Hantaviridae, the family that all hantaviruses belong to. Other member viruses of Orthohantavirus andesense include the Castelo dos Sonhos virus, Lechiguanas virus, and Orán virus. The Chile-9717869 isolate of Andes virus is the exemplar virus of the species. This taxonomy is shown hereafter: • Family: Hantaviridae • Genus: Orthohantavirus • Species Orthohantavirus andesense • Andes virus • Castelo dos Sonhos virus • Lechiguanas virus • Orán virus ==History==

Andes virus was first discovered in Argentina in 1995 Andes virus was accepted as a species by the International Committee on Taxonomy of Viruses in 1999 and has undergone a series of changes to its species name, first changing to Andes hantavirus, then Andes orthohantavirus, and most recently to the current Orthohantavirus andesense. ==References==