''Dabie bandavirus'', also called SFTS virus, is a tick-borne virus in the genus '' Bandavirus'' in the family ''

Phenuiviridae ''Phenuiviridae'' is a family of negative-strand RNA viruses in the order '' Bunyavirales''. Ruminants, camels, humans, and mosquitoes serve as natural hosts. Member genus ''Phlebovirus'' is the only genus of the family that has viruses that cau ...

'', order ''

Bunyavirales ''Bunyavirales'' is an order of segmented negative-strand RNA viruses with mainly tripartite genomes. Member viruses infect arthropods, plants, protozoans, and vertebrates. It is the only order in the class ''Ellioviricetes''. The name ''Bunyavir ...

''. The clinical condition it caused is known as

severe fever with thrombocytopenia syndrome Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne infection. Signs and symptoms include fever, vomiting, diarrhea, loss of consciousness and heamorrhage. It is an emerging infectious disease caused by ''Dabie bandavirus'' also k ...

(SFTS). SFTS is an emerging infectious disease that was first described in northeast and central China 2009 and now has also been discovered in Japan, South Korea, Vietnam and Taiwan in 2015. SFTS has a fatality rate of 12% and as high as over 30% in some areas. The major clinical symptoms of SFTS are fever, vomiting, diarrhea, multiple organ failure, thrombocytopenia (low platelet count), leukopenia (low white blood cell count) and elevated liver enzyme levels. Another outbreak occurred in East China in the early half of 2020.

History

In 2009, Xue-jie Yu and colleagues isolated the SFTS virus (SFTSV) from SFTS patients’ blood.

Genome

The genome has been sequenced. There are three segments—large (L), medium (M) and small (S). Five proteins have been identified—an RNA dependent RNA polymerase (RdRp), a glycoprotein N (Gn), a glycoprotein C (Gc), a nuclear protein (NP) and a non structural protein (NSs). The L segment encodes the RNA polymerase with 2084 amino acid residues. The M segment encodes one open reading frame encoding 1073 amino acid precursors of glycoproteins (Gn and Gc). The S segment has 1746 nucleotides of ambisense RNA encoding two proteins, the N and NSs proteins. These lie in opposite orientations and are separated by a 54 nucleotide intergenic region.

Evolution

Five genotypes (A–E) have been identified. Strains from China could be grouped into all five genotypes while isolates from

South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...

lay in three (types A, D and E) and those from Japan only in one (type E). The virus appears to have originated in the

Dabie Mountains The Dabie Mountains () are a major mountain range located in central China. Running northwest-to-southeast, they form the main watershed between the Huai and Yangtze rivers. The range also marks the boundary between Hubei Province and its neighb ...

in central China between 1918 and 1995. Among bunyaviruses, it appears to be more closely related to the

Uukuniemi virus ''Phlebovirus'' is one of twenty genera of the family ''Phenuiviridae'' in the order ''Bunyavirales''. The genus contains 66 species. It derives its name from Phlebotominae, the vectors of member species '' Naples phlebovirus'', which is said to ...

serogroup than to the Sandfly fever group. It is a member of the Bhanja virus serocomplex.

Life cycle

SFTSV is a tick-borne virus; it is not clear whether it can be transmitted by other blood-sucking arthropods. It can infect many mammalian hosts, including

cat The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...

mice A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...

hedgehog A hedgehog is a spiny mammal of the subfamily Erinaceinae, in the eulipotyphlan family Erinaceidae. There are seventeen species of hedgehog in five genera found throughout parts of Europe, Asia, and Africa, and in New Zealand by introduct ...

weasel Weasels are mammals of the genus ''Mustela'' of the family Mustelidae. The genus ''Mustela'' includes the least weasels, polecats, stoats, ferrets and European mink. Members of this genus are small, active predators, with long and slender ...

brushtail possum The brushtail possums are the members of the genus ''Trichosurus'' in the Phalangeridae, a family of marsupials. They are native to Australia (including Tasmania) and some small nearby islands. Unique among marsupials, they have shifted the hypax ...

s and

yak The domestic yak (''Bos grunniens''), also known as the Tartary ox, grunting ox or hairy cattle, is a species of long-haired domesticated cattle found throughout the Himalayan region of the Indian subcontinent, the Tibetan Plateau, Kachin St ...

s. Humans appear to be accidental hosts, and play no essential role in the life cycle of SFTSV. SFTSV has been detected from the ixodid

tick Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...

, ''

Haemaphysalis longicornis ''Haemaphysalis longicornis'', the Asian longhorned tick, longhorned tick, bush tick, Asian tick, or cattle tick, is a parasitic arachnid belonging to the tick family Ixodidae. The Asian longhorned tick is a known livestock pest, especially in N ...

'', ''

Ixodes nipponensis ''Ixodes'' is a genus of hard-bodied ticks (family Ixodidae). It includes important disease vectors of animals and humans (tick-borne disease), and some species (notably ''Ixodes holocyclus'') inject toxins that can cause paralysis. Some ti ...

'', ''

Amblyomma testudinarium ''Amblyomma testudinarium'' is a hard-bodied tick of the genus ''Amblyomma''. It is found in Indonesia, India, Japan, Thailand, Sri Lanka and Vietnam. Adults parasitize various larger mammals such as buffalo and cattle, whereas nymphs and larvae ...

'' and ''

Rhipicephalus microplus The Asian blue tick (''Rhipicephalus'' (''Boophilus'') ''microplus'', ''Rhipicephalus microplus'', or ''Boophilus microplus'') is an economically important tick that parasitises a variety of livestock species especially cattle, on which it is th ...

''. In addition to tick bite, SFTSV can be transmitted from person to person through contact with blood or mucus of an infected person.

Epidemiology

This virus has been found in the Chinese provinces of

Anhui Anhui , (; formerly romanized as Anhwei) is a landlocked province of the People's Republic of China, part of the East China region. Its provincial capital and largest city is Hefei. The province is located across the basins of the Yangtze River ...

Henan Henan (; or ; ; alternatively Honan) is a landlocked province of China, in the central part of the country. Henan is often referred to as Zhongyuan or Zhongzhou (), which literally means "central plain" or "midland", although the name is al ...

Hubei Hubei (; ; alternately Hupeh) is a landlocked province of the People's Republic of China, and is part of the Central China region. The name of the province means "north of the lake", referring to its position north of Dongting Lake. The pr ...

Jiangsu Jiangsu (; ; pinyin: Jiāngsū, alternatively romanized as Kiangsu or Chiangsu) is an eastern coastal province of the People's Republic of China. It is one of the leading provinces in finance, education, technology, and tourism, with its c ...

, Liaoning and Shandong. SFTS occurs in rural areas, from March to November, and a majority of cases are found from April to July. The virus has also been found in South Korea, Japan, Vietnam and Taiwan.

References

{{Taxonbar, from=Q5313087, from2=Q24809104, from3=Q57756649 Arthropod-borne viral fevers and viral haemorrhagic fevers Hematology Insect-borne diseases Phleboviruses Zoonoses