Severe fever with thrombocytopenia syndrome

Severe Fever with Thrombocytopenia Syndrome (SFTS) is a life-threatening infectious disease caused by the SFTS virus (SFTSV), which belongs to the Phenuiviridae family, genus Banyangvirus. First identified in China in 2009, SFTS has since been reported in several East Asian countries, including Japan, South Korea, and Vietnam. The disease is characterized by high fever, thrombocytopenia (a reduced number of platelets in the blood), gastrointestinal symptoms, and can lead to severe complications such as multi-organ failure.

Transmission

SFTS is primarily transmitted through bites from infected ticks, particularly the Haemaphysalis longicornis species. Human-to-human transmission can occur through contact with the blood or bodily fluids of an infected person. Health care workers are at risk when proper protective measures are not taken.

Symptoms

The incubation period of SFTS ranges from 6 to 14 days post-exposure. Initial symptoms include severe fever, fatigue, chills, headache, lymphadenopathy (swelling of the lymph nodes), and muscle pain. As the disease progresses, patients may develop thrombocytopenia, leukopenia (a decrease in the number of white blood cells), and elevated liver enzymes, indicating liver damage. Severe cases can result in hemorrhagic manifestations, encephalitis, and multi-organ failure.

Diagnosis

Diagnosis of SFTS is based on clinical symptoms, epidemiological history, and laboratory tests. Specific laboratory tests include polymerase chain reaction (PCR) to detect SFTSV RNA, enzyme-linked immunosorbent assay (ELISA) for IgM and IgG antibodies, and isolation of the virus in cell cultures. Early diagnosis and treatment are crucial for improving patient outcomes.

Treatment

There is no specific antiviral treatment for SFTS. Management of the disease is supportive and includes maintaining fluid balance, correcting electrolyte imbalances, and treating any secondary infections. In severe cases, intensive care support may be required. Research is ongoing to develop specific antiviral therapies and vaccines against SFTSV.

Prevention

Preventive measures focus on avoiding tick bites, especially in areas where SFTS is endemic. This includes wearing protective clothing, using insect repellents, and avoiding bushy or wooded areas where ticks are commonly found. Public health measures include educating the public about the risks of tick bites and the importance of tick control in animals.

Epidemiology

Since its discovery, SFTS has been reported in several countries in East Asia, with the number of cases and geographical distribution increasing. The case fatality rate varies but can be as high as 30% in some reports. The disease predominantly affects middle-aged and elderly individuals who live in rural areas and have a history of tick exposure.