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| Asian Longhorned Tick - Credit CDC |
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SFTS or Severe Fever with Thrombocytopenia Syndrome - a tickborne Phlebovirus - was first discovered in China in 2009, but since been found in both Japan and Korea, and is believed be carried and transmitted by the Asian Longhorned tick (along with Amblyomma testudinarium & Ixodes nipponensis).
Phleboviruses are part of the very large family Bunyaviridae, and SFTS is is genetically similar to Heartland Virus (see MMWR: Heartland Virus Disease — United States, 2012–2013).While SFTS has never been detected in the United States, in 2017 the CDC reported our first detection of the Asian Longhorned tick. Their most recent update states:
As of August 1, 2019, longhorned ticks have been found in Arkansas, Connecticut, Delaware, Kentucky, Maryland, North Carolina, New Jersey, New York, Pennsylvania, Tennessee, Virginia, and West Virginia.
In 2014, Taiwan's Epidemiology Bulletin published a Risk Assessment of Severe Fever with Thrombocytopenia Syndrome in Taiwan, that found that `Overall there is a low public health risk related to SFTSV human infection in Taiwan.'
Earlier this year the CDC's EID Journal reported on retrospective evidence of SFTS virus (SFTSV) infection in Vietnam (see Endemic Severe Fever with Thrombocytopenia Syndrome, Vietnam), a finding which raises new questions over the geographic range of SFTS.
All of which brings us to a (translated) announcement today from Taiwan's CDC, on their first diagnosed case of (what appears to be) locally acquired SFTS, after which I'll have a postscript:
The first case of fever in China with thrombocytopenia syndrome (SFTS) confirmed the case, and urged the public to pay attention to protective measures in the forest activities to prevent locust bites.
Release date: 2019-11-19
The Department of Disease Control announced the first case of Severe Fever with Thrombocytopenia Syndrome (SFTS). It is a 70-year-old male in the north who has not recently gone abroad but is often active in mountainous areas, October 24-11. On the 2nd of the month, due to repeated fever and vomiting symptoms, he went to the clinic for medical treatment. Later, due to rash and consciousness change, he was sent to hospital on November 3 and admitted to hospital. After the hospital was diagnosed, he was suspected of dengue fever. On November 6th, he was admitted to the hospital. Although the results of the dengue test were negative, the epidemiological testers carefully investigated and conducted in-depth tests. The test was judged to be SFTS virus positive on the evening of November 13, and the expert meeting held yesterday (18) confirmed the virus sequence and the date. Korean epidemic strains are similar.
The Department of Diseases said that the SFTS combined with Pseudomonas aeruginosa bacteremia and coagulation abnormalities continued to be isolated from the intensive care unit and received blood transfusion and antibiotics. The total number of people living with contacts and medical contacts was 68. Continuous monitoring until November 27.
After receiving the notification, the health unit will start various prevention and treatment work, including environmental investigations, chemical mosquito control of the mosquitoes and health tracking and health education of the contacts in the case and surrounding areas. The epidemic prevention personnel did not collect cockroaches near the case. Due to the history of mountain activities before the onset of the case, the possibility of being bitten was high. Further investigations into the possible field activities of the case will be conducted to clarify the source of the infection.
SFTS is a sputum virus infection. It was first discovered in mainland China in 2009. In recent years, there have been confirmed cases and deaths in mainland China, Japan and South Korea. The fatality rate is about 5% to 15%, and the epidemic is mostly from May to October. It mainly occurs in mountainous and hilly areas and spreads through the bite of the long-term bloody sputum of the main SFTS. The incubation period of SFTS is about 7 to 14 days. After humans are bitten by mites with SFTS virus, there will be redness, rash, blisters or ecchymoses in the bite. Most people with fever have fever, nausea, vomiting and loss of appetite, platelets and white blood cells.
Reduced cases; a small number of patients may have multiple organ failure, or even death. Although SFTS has no specific antiviral drugs, it can reduce the mortality rate through active supportive therapy. In addition, direct contact with blood or body fluids with high viral concentrations in acute patients may also lead to infection, but there are very few actual cases, indicating that long-horned blood stasis is still the main route of infection.
The Department of Diseases and Diseases pointed out that there were no confirmed cases of SFTS in China in the past, and no records of long-horned blood stasis were published. However, because there are still secondary vectors in China, such as tiny fan-heads, and neighboring countries such as China, Japan, and South Korea, Therefore, long-term monitoring has been deployed in advance.
Since 2013, the SFTS test has been carried out for the cases of dengue fever, tsukistan and Japanese encephalitis. Since 2018, the SFTS has been simultaneously tested for tsutsugamushi notifications. Except for the first exception announced today, the rest are negative.
In response to the emergence of the first confirmed case in the country, the CDC has set up an epidemic team and invited insect media experts to assist in the investigation and analysis of the epidemic risk around the case activities. In addition, it will strengthen the notification of the doctors, monitor the epidemic and facilitate the prevention and treatment. Announced that SFTS is a legal infectious disease to enhance the vigilance of the public and medical institutions.(Continue . . . )
According to international epidemiological surveillance data, more than 5,300 confirmed SFTS were diagnosed in China from 2011 to 16 years. Most of the cases were from rural areas such as Henan, Hubei, Shandong, Anhui, Zhejiang, Jiangsu and Liaoning, and more than 90% of cases were 40 to 40. 80 years old. In Japan (2019), as of November 10, there were 96 cases, of which 5 died, and the fatality rate was 5.2%. The number of cases was higher than the total number of years from 2013 to 18, and the cases were distributed in the west and the south, with 11 cases in Shankou County. Second, there were 9 cases in Tokushima Prefecture, and the median age of cases in the country since 2013 was 75 years. South Korea has accumulated 223 cases as of November 9 this year, which is higher than the total number of years from 2014 to 16 years. The case distribution is more than 42 cases in Gyeonggi Province, followed by 30 cases in Gangwon Province.
Current evidence suggests that SFTS is primarily a tick-transmitted disease, although we've also seen scattered reports suggesting that human-to-human, or nosocomial transmission, may have occurred.
A recent report in the CMI Journal found that contact with blood or respiratory secretions of an infected patient was linked to infection in HCWs.
Nosocomial person-to-person transmission of severe fever with thrombocytopenia syndrome.
Jung IY1, Choi W2, Kim J3, Wang E2, Park SW2, Lee WJ2, Choi JY4, Kim HY1, Uh Y3, Kim YK5.
(Continue . . . )
Results
Among 25 HCWs who had direct contact with the index patient, five HCWs were confirmed to have SFTS. All five HCWs had contact to blood or bloody respiratory secretions of the index patient without adequate use of personal protective equipment (PPE). No HCW with contact before haemorrhagic manifestations of the index patient contracted SFTS. Overall, the transmission rate was higher for HCWs who had contact after the index patient had haemorrhagic manifestations (33.3%, five of 15 HCWs, vs. 0%, zero of ten HCWs, p 0.041).
Conclusions
In HCWs who are inadequately protected, person-to-person transmission of SFTSV may be associated with contact with blood or bloody respiratory secretions. Therefore, universal precaution and full PPE is highly recommended for protection against SFTSV when there are signs of bleeding.
This patient has also been diagnosed with a co-infection of Pseudomonas aeruginosa bacteremia, which is an opportunistic bloodstream infection generally affecting those with impaired immune function. It too can be transmitted to others, although healthy people are generally immune.
Hence the decision to monitor 68 contacts, including medical personnel, until November 28th.One of the big lessons of the past five years has been that vectorborne diseases can sometimes be transmitted to others in unknown or unexpected ways (see EID Journal: Zika Virus Infection in Patient with No Known Risk Factors, Utah, USA, 2016 and ECDC CDTR: Autochthonous Sexual Transmission Of Dengue Fever - Spain, 2019).
Which is why, when it comes to infectious diseases, we never like to say `never'.
