SFTSV is a Phlebovirus in the family of Bunyaviridae

Bunyaviridae

Bunyaviridae is a family of negative-stranded RNA viruses. Though generally found in arthropods or rodents, certain viruses in this family occasionally infect humans. Some of them also infect plants....

. It appears to be more closely related to the Uukuniemi virus serogroup than to the Sandfly fever group. It may be the prototype of a new serogroup within the Phlebovirus genus as it is only distantly related to both the existing serogroups.

The clinical condition it causes is known as severe fever with thrombocytopenia syndrome (SFTS). SFTS is an emerging infectious disease recently described in northeast and central China. SFTS has a fatality rate of 12% and as high as 30% in some areas. The major clinical symptoms of SFTS are fever, vomiting, diarrhea, multiple organ failure, thrombocytopenia (low platelet count), leucopenia (low white blood cell count) and elevated liver enzyme levels.

History

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

Life cycle

The life cycle of the SFTSV is not yet known, but seems most likely to involve arthropod vectors and mammaliam hosts, including cat

Cat

The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...

s, mice

Mouse

A mouse is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse . It is also a popular pet. In some places, certain kinds of field mice are also common. This rodent is eaten by large birds such as hawks and eagles...

, hedgehog

Hedgehog

A hedgehog is any of the spiny mammals of the subfamily Erinaceinae and the order Erinaceomorpha. There are 17 species of hedgehog in five genera, found through parts of Europe, Asia, Africa, and New Zealand . There are no hedgehogs native to Australia, and no living species native to the Americas...

s, weasel

Weasel

Weasels are mammals forming the genus Mustela of the Mustelidae family. They are small, active predators, long and slender with short legs....

s, possum

Possum

A possum is any of about 70 small to medium-sized arboreal marsupial species native to Australia, New Guinea, and Sulawesi .Possums are quadrupedal diprotodont marsupials with long tails...

s and yak

Yak

The yak, Bos grunniens or Bos mutus, is a long-haired bovine found throughout the Himalayan region of south Central Asia, the Tibetan Plateau and as far north as Mongolia and Russia. In addition to a large domestic population, there is a small, vulnerable wild yak population...

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

Tick

Ticks are small arachnids in the order Ixodida, along with mites, constitute the subclass Acarina. Ticks are ectoparasites , living by hematophagy on the blood of mammals, birds, and sometimes reptiles and amphibians...

, Haemaphysalis longicornis

Haemaphysalis longicornis

Haemaphysalis longicornis is a species of tick. Lyme spirochetes and spotted fever group rickettsiae have been detected in H. longicornis, as have Ehrlichia chaffeensis and Anaplasma bovis....

. The transmission route of SFTSV is unknown, but person to person transmission either plays no role, or at least is not an important route of transmission of SFTSV.

Epidemiology

This virus has been found in the Chinese provinces of Anhui

Anhui

Anhui is a province in the People's Republic of China. Located in eastern China across the basins of the Yangtze River and the Huai River, it borders Jiangsu to the east, Zhejiang to the southeast, Jiangxi to the south, Hubei to the southwest, Henan to the northwest, and Shandong for a tiny...

, Henan

Henan

Henan , is a province of the People's Republic of China, located in the central part of the country. Its one-character abbreviation is "豫" , named after Yuzhou , a Han Dynasty state that included parts of Henan...

, Hubei

Hubei

' Hupeh) is a province in Central China. The name of the province means "north of the lake", referring to its position north of Lake Dongting...

, Jiangsu

Jiangsu

' is a province of the People's Republic of China, located along the east coast of the country. The name comes from jiang, short for the city of Jiangning , and su, for the city of Suzhou. The abbreviation for this province is "苏" , the second character of its name...

, Liaoning

Liaoning

' is a province of the People's Republic of China, located in the northeast of the country. Its one-character abbreviation is "辽" , a name taken from the Liao River that flows through the province. "Níng" means "peace"...

 and Shandong

Shandong

' is a Province located on the eastern coast of the People's Republic of China. Shandong has played a major role in Chinese history from the beginning of Chinese civilization along the lower reaches of the Yellow River and served as a pivotal cultural and religious site for Taoism, Chinese...

. SFTS occurs in rural areas, from March to November, and a majority of cases are found from April to July.