Asian Longhorned Tick - Credit CDC
#16,805
SFTS or Severe Fever with Thrombocytopenia Syndrome - a tickborne Phlebovirus - was first discovered in China in 2009, but since been found in Japan, South Korea, and Taiwan, 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 genetically similar to Heartland Virus (see EID Journal: Seroprevalence Of Heartland Virus Antibodies In Northwestern Missouri).).
According to Clinical Update of Severe Fever with Thrombocytopenia Syndrome, published in 2021 in the journal Viruses, SFTS has a high case fatality rate; . . . an average fatality rate of approximately 20% has been reported for SFTS patients, and no treatment strategy has been established.
While primarily transmitted by the bite of a tick, there is evidence that the virus can also be transmitted from from animals-to-humans (see EID Journal Direct Transmission of SFTS from Domestic Cat to Veterinary Personnel), and from human-to-human (see Nosocomial person-to-person transmission of severe fever with thrombocytopenia syndrome) presumably through close contact with infected body fluids.But there have also been reports suggestive of potential aerosol transmission of the virus (see Aerosol transmission of severe fever with thrombocytopenia syndrome virus during resuscitation).
Nosocomial outbreak of severe fever with thrombocytopenia syndrome among healthcare workers in a single hospital in Daegu, Korea(Continue . . . )
SohyunBae1*Hyun-HaChang1*Shin-WooKim1YoonjungKim1EunByeolWang2 Chi KyeongKim2 EunjiChoi2 BohyunLim3 SookkyungPark3 HwajinChae4 HyeyoungJeon4
https://doi.org/10.1016/j.ijid.2022.03.048Get rights and content
Under a Creative Commons license
Open access
Abstract
Background
In August 2020, 17 healthcare workers (HCWs) were simultaneously diagnosed with severe fever with thrombocytopenia syndrome (SFTS) at a university hospital in Daegu, Republic of Korea.
Methods
An epidemiologic investigation using questionnaires was conducted for all suspected HCWs who had viral infection symptoms or who had the possibility of exposure to the index patient.
Results
A total of 17 HCWs infected with the SFTS virus (SFTSV) (28.8%) were identified among the 59 HCWs who had contact with the patient. Operating a bag valve mask during cardiopulmonary resuscitation (CPR) (OR 7.50, 95% CI 1.75–41.07), cardiac massage during CPR (OR 12.00, 95% CI 1.76–241.94), exposure to the patient's body fluids (OR 7.43, 95% CI 1.91–34.69), and shorter individual hospital work experience periods (OR 6.79, 95% CI 1.70–32.10) were significantly associated with SFTS infection in the univariate analysis. However, exposure to body fluids was found to be the only statistically significant risk factor when multivariate analysis was conducted (OR 6.27. 95% CI 1.23–42.81, p = 0.036).
Conclusions
This finding illustrates the importance of wearing appropriate personal protective equipment in treatment areas and when conducting any medical procedures, including CPR for patients with SFTS, and any procedure that involves potential exposure to body fluids.
Although it is impossible to say with absolute certainty that these nosocomial infections were due to airborne transmission of the virus, the authors consider it likely. And even though this outbreak occurred during the first year of COVID, they cite a inconsistent PPE compliance as a contributing factor.
In this study, 52.9% of the infected HCWs showed GGO pneumonia on the periphery of their lungs according to chest CT imagery. Therefore, it is thought that airborne transmission during administration of CPR was the primary cause of this outbreak. Comparing the CCTV data and questionnaire responses, 3 HCWs responded that they had worn a mask during CPR, but it was found that CCTV showed that they did not actually wear their masks properly (2 in the SFTS group, and 1 in the non-SFTS group).
Additionally, 7 HCWs responded to the survey saying that they did not wear their mask properly but in actuality, it turned out that they had worn their masks properly according to CCTV data. These differences found between the questionnaire survey results and the actual CCTV investigation results are believed to be a potential barrier to revealing accurate risk factors for infection.
It is almost impossible to clearly distinguish between contact and airborne transmission, and both are thought to have played an important role in this infection outbreak. In this study, as in another previous study (Yoo et al., 2019), the exposure of the patient's body fluids was also found to be a significant risk factor.
In this study, environmental culture tests were not performed, so the degree of environmental contamination around the index patient during and after CPR is not known. According to Ryu et al. (2018), 21% (14 of 67) of swab samples reported positive SFTSV cultures from the surfaces of stethoscopes, furniture, or other fomites around patients. This highlights the importance of environmental disinfection.
As of September 27, 2021, longhorned ticks have been found in Arkansas, Connecticut, Delaware, Georgia, Kentucky, Maryland, Missouri, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia, and West Virginia.
In 2019 the CDC released a list of the 56 zoonotic diseases of greatest concern to the United States, and CCHF came in at number 15 (see below). While SFTS didn't make that list, Monkeypox came in at #29, and a `generic' coronavirus came in at #6.
A reminder that, just because a pathogen it isn't a direct threat to us today, doesn't mean we can afford to ignore it.
