Hantaan virus

Hantaan virus (HTNV) is the main cause of hemorrhagic fever with renal syndrome (HFRS) in East Asia. Hantaan virus is transmitted by the striped field mouse (Apodemus agrarius) In its natural reservoir, HTNV causes a persistent, asymptomatic 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 causes such as fever and headache, as well as the appearance of spots on the skin, hepatitis, and renal symptoms such as kidney swelling, excess protein in urine, blood in urine, decreased urine production, and kidney failure. Rarely, HTNV infection affects the pituitary gland and can cause empty sella syndrome. The case fatality rate from infection is up to 6.3%.

The genome of HTNV is about 11.9 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.

Hantaan virus 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 at the endoplasmic reticulum and bud from its surface to obtain their viral envelope. Progeny viruses are then transported by a cellular vesicle to the cell membrane, where they leave the cell by exocytosis.

HTNV was discovered in 1976 then isolated in 1978 after being extracted from striped field mice. The virus was subsequently linked to a past outbreak among soldiers in the Korean War who were stationed near the Hantan river and for that was named after the river. Hantaan virus was the first hantavirus to be discovered, and the group is named after the virus. The vast majority of HFRS cases occur in China, where Hantaan virus is responsible for up to 70% of cases. Cases of HFRS caused by Hantaan virus also occur in South Korea, Russia, and Vietnam.