Research Progress of Fever with Thrombocytopenia Syndrome

Abstract

Severe fever with thrombocytopenia syndrome (SFTS) is a new infectious disease first discovered in Ta-pieh Mountains in central China in 2009. It is caused by a novel bunyavirus infection (SFTSV). Since the first discovery of SFTSV, there have been case reports and epidemiological studies on SFTS in several East Asian countries, such as South Korea, Japan, Vietnam and so on. With the rising incidence of SFTS and the rapid spread of the novel bunyavirus around the world, it is clear that the virus has a pandemic potential and may pose a threat to global public health in the future. Early studies have suggested that ticks are an important medium for the transmission of SFTSV to humans; in recent years, it has been reported that there is also human-to-human transmission. In endemic areas, potential hosts include a variety of livestock and wildlife. When people are infected with SFTV, the main clinical manifestations are high fever, thrombocytopenia, leukocytopenia, gastrointestinal symptoms, liver and kidney function damage, and even MODS, with a mortality rate of about 10-30%. This article reviews the latest progress of novel bunyavirus, including virus transmission vector, virus genotypic diversity and epidemiology, pathogenesis, clinical manifestation and treatment.

Keywords: Clinical manifestation; Epidemiology; Pathogenesis; Route of Transmission; The novel bunyavirus; Treatment.

Fig. 1

Tick life cycle

Fig. 2

The mechanism of SFTSV pathogenesis. SFTSV transmission to humans commonly occurs from virus-carrying-tick-bite. The SFTSV then invades the lymph node nearest to the tick-bite wound, targeting immune cells such as B-cells, impairing host immune response from invading pathogen.It also leads to a decrease in white blood cells.After further replication, the virus goes to the systemic circulation, in response to viremia, other immune cells are over-stimulated causing cytokine storm and severe inflflammatory response syndrome(SIRS). SIRS causes damage to the vascular endothelium, which allows platelets to adhere and aggregate.Thrombocytopenia is a hallmark of SFTSV infection.Body response disorder and stress response caused by cytokine storm lead to multi-organ dysfunction, reflflected by the elevation of liver, kidney, and heart serum markers. Severe cases often die from MODS