As governments across the world continue to grapple with the ongoing Covid-19 pandemic, China — where cases of the deadly infection were first reported — is now facing a new health threat. A disease called Severe Fever with Thrombocytopenia Syndrome (SFTS), caused by a tick-borne virus, has killed seven and infected at least 60, setting off alarm bells among health officials in the country.
A large number of the cases reported were concentrated in East China’s Jiangsu and Anhui provinces, local media reported. While more than 37 people were diagnosed with SFTS in Jiangsu in the early months of 2020, 23 were later found to be infected in Anhui.
While the disease is transferred to humans through tick bites, Chinese virologists have warned that human-to-human transmission of the virus cannot be ruled out. Unlike SARS-CoV-2 however, this is not the first time the SFTS virus has infected people. The recent spate of cases merely marks a re-emergence of the disease.
What is the SFTS virus?
Severe fever with thrombocytopenia syndrome virus (SFTSV) belongs to the Bunyavirus family and is transmitted to humans through tick bites. The virus was first identified by a team of researchers in China over a decade ago. The first few cases were reported in rural areas of Hubei and Henan provinces in 2009.
The team of researchers identified the virus by examining blood samples obtained from a cluster of people exhibiting similar symptoms. According to a report by Nature, the virus killed at least 30 per cent of those infected. The current case fatality rate rests between approximately 16 and 30 per cent, according to the China Information System for Disease Control and Prevention.
Due to the rate at which it spreads and its high fatality rate, SFTS has been listed among the top 10 priority diseases blue print by the World Health Organisation (WHO).
Virologists believe an Asian tick called Haemaphysalis longicornis is the primary vector, or carrier, of the virus. The disease is known to spread between March and November. Researchers have found that the total number of infections generally peaks between April and July.
Farmers, hunters and pet owners are particularly vulnerable to the disease as they regularly come in contact with animals that may carry the Haemaphysalis longicornis tick. Scientists have found that the virus is often transmitted to humans from animals like goats, cattle, deer and sheep. Despite being infected by the virus, animals generally do not show any symptoms associated with SFTSV.
What are the symptoms of the SFTFS virus?
According to a study conducted by a team of Chinese researchers in 2011, the incubation period is anywhere between seven and 13 days after the onset of the illness. Patients suffering from the disease usually experience a whole range of symptoms, including, fever, fatigue, chill, headache, lymphadenopathy, anorexia, nausea, myalgia, diarrhea, vomiting, abdominal pain, gingival hemorrhage, conjunctival congestion, and so on.
Some of the early warning signs of the disease include severe fever, thrombocytopenia or low platelet count and leukocytopenia, which is low white blood cell count. The risk factors observed in more serious cases include multi-organ failure, hemorrhagic manifestation and the appearance of central nervous system (CNS) symptoms.
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Have cases of SFTS been recorded outside China?
The virus eventually travelled to other East Asian nations, including Japan and South Korea. Since the virus was first discovered, the total number of cases has risen significantly.
While in 2013, as many as 36 cases were reported in South Korea, the number rose sharply to 270 by 2017. Meanwhile, China registered 71 cases in 2010 and 2,600 in 2016. The number of infections reported in Japan increased by 50 per cent between 2016 and 2017, a Nature report stated.
When the number of cases began to rise in all three countries, public health officials began educating local doctors and ordinary citizens about the health risks posed by tick bites. As more people became aware of the virus and the disease it causes, the fatality rate of the infection began to drop significantly, scientists found.
How is SFTS treated?
While a vaccine to treat the disease is yet to be successfully developed, the antiviral drug Ribavirin is known to be effective in treating the illness.
In order to avoid contracting the illness, various government authorities, including China’s Centers for Disease Control and Prevention (CDC), urges the general public to avoid wearing shorts while walking through tall grass, the woods, and any other environment where ticks are likely to thrive.
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