Seoul virus

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

Seoul virus (SEOV) is one of the main causes of hemorrhagic fever with renal syndrome (HFRS). Seoul virus is transmitted by the brown rat (Rattus norvegicus) and the black rat (Rattus rattus). In its natural reservoirs, SEOV 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 HFRS, an illness characterized by general symptoms such as fever and headache, as well as the appearance of spots on the skin and renal symptoms such as kidney swelling, excess protein in urine, blood in urine, decreased urine production, and kidney failure. The case fatality rate from infection is 1–2%.

The genome of SEOV is about 12 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.

SEOV 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.

SEOV was first discovered in a brown rat 1980 in Seoul, South Korea. Within a few years of its discovery, it was found in numerous countries and has since been found in Africa, Asia, Europe, and the Americas due to the global distribution of its natural reservoirs. Most cases of SEOV infection occur in China and South Korea. Globally, SEOV accounts for about a quarter of all HFRS cases. SEOV has been found in pet rats, but is not a major public health concern. For laboratory rats, various measures such as culling and screening for SEOV are performed to prevent SEOV infection.