Andes virus

Andes virus
Virus classification
(unranked):	Virus
Realm:	Riboviria
Kingdom:	Orthornavirae
Phylum:	Negarnaviricota
Class:	Ellioviricetes
Order:	Bunyavirales
Family:	Hantaviridae
Genus:	Orthohantavirus
Species:	Orthohantavirus andesense
Virus:	Andes virus
Synonyms[1][2]
Andes hantavirus Andes orthohantavirus

Andes virus (ANDV) is the most common cause of hantavirus pulmonary syndrome (HPS) in South America. Andes virus is transmitted mainly by the long-tailed pygmy rice rat (Oligoryzomys longicaudatus). In its natural reservoir, ANDV causes an asymptomatic, persistent infection and is spread through excretions, fighting, and grooming. Humans can become infected by inhaling aerosols that contain rodent saliva, urine, or feces, as well as through bites and scratches. In humans, infection leads to HPS, an illness characterized by an early phase of mild and moderate symptoms such as fever, headache, and fatigue, followed by sudden respiratory failure. The case fatality rate from infection is high, at about 40%.

The genome of ANDV is about 12.1 kilobases (kb) in length and segmented into three negative-sense, single-stranded RNA (-ssRNA) strands. The small strand encodes the viral nucleoprotein, the medium strand encodes the viral spike protein, which attaches to cell receptors for entry into cells, and the long strand encodes the viral RNA-dependent RNA polymerase (RdRp), which replicates and transcribes the genome. Genome segments are encased in nucleoproteins to form ribonucleoprotein (RNP) complexes that are surrounded by a viral envelope that contains spikes emanating from its surface.

ANDV replicates first by binding to the surface of cells with its envelope spikes. Virus particles, called virions, are then taken into the cell by endosomes, where a drop in pH causes the viral envelope to fuse with the endosome, which releases viral RNA into the host cell. RdRp then transcribes the genome for translation by host cell ribosomes and produces copies of the genome for progeny viruses. New virions are assembled near the cell membrane, where virions bud from the cell membrane and use it to obtain their viral envelope and leave the cell.

ANDV was first discovered in 1995 in Argentina and in Chile later that year. More than a hundred cases of HPS caused by Andes virus occur each year, most of them in Argentina and Chile. Apart from the long-tailed pygmy rice rat, Andes virus has also been found in various other rodent species in South America, most commonly the long-haired grass mouse (Abrothrix longipilis). Human-to-human transmission of ANDV was first reported in 1996 and continual reports since then have been made that Andes virus can spread from person to person. There is, however, insufficient evidence of such transmission.