Asian Longhorned Tick - Credit CDC
#17,786
Although SFTS or Severe Fever with Thrombocytopenia Syndrome - a tick borne Phlebovirus - was first discovered in China in 2009 - it was subsequently found in Japan, South Korea and Vietnam - and in 2019 was detected for the first time in Taiwan.
Phleboviruses are part of the very large family Bunyaviridae, and SFTS is genetically similar to Heartland Virus (see MMWR: Heartland Virus Disease — United States, 2012–2013). Also known as the Dabie bandavirus, SFTS believed be carried and transmitted by the Asian Longhorned tick (along with Amblyomma testudinarium & Ixodes nipponensis).
As of April 13, 2023, longhorned ticks have been found in Arkansas, Connecticut, Delaware, Georgia, Indiana, Kentucky, Maryland, Massachusetts, Missouri, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Virginia, and West Virginia.
According to Clinical Update of Severe Fever with Thrombocytopenia Syndrome, published in 2021 in the journal Viruses, states:
The mortality rate of patients with SFTS remains high because the disease can quickly lead to death through multiple organ failure. In particular, an average fatality rate of approximately 20% has been reported for SFTS patients, and no treatment strategy has been established. Therefore, effective antiviral agents and vaccines are required.
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.
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).
Since this infection is likely under diagnosed, and the tick vector and virus appear to be spreading, SFTS is viewed as an emerging public health threat (see 2018 WHO List Of Blueprint Priority Diseases). The Taiwan CDC website carries this epidemic risk assessment:
Epidemic and risk assessment of fever with thrombocytopenia syndrome
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging acute infectious disease. The virus was first isolated and discovered in Henan Province, Mainland China in 2009. The disease is mainly endemic in Mainland China, Japan and South Korea.Since China is adjacent to endemic countries, there are also various types of Ixodes ticks that can serve as vectors for SFTS virus (severe fever with thrombocytopenia syndrome virus, SFTSV) in China. In the past, microscopic ticks have been detected in domestic cattle, sheep and their ectoparasitized Rhipicephalus ticks. SFTSV was detected, and anti-SFTSV antibodies were detected in sheep. In addition, the Department of Disease Control and Prevention detected one locally confirmed case on November 4, 2019 and May 10, 2022 respectively. Sequence analysis showed that both cases belonged to Group B, and their virus strains were relatively similar to the strains prevalent in South Korea and Japan. Based on the above, in order to understand domestic epidemic risks and develop reference basis for prevention and control measures, it is urgent to assess the impact and possible impact of SFTS on my country.This article refers to the international risk assessment framework and collects information on the risk of infection among Chinese people, domestic epidemic potential, disease severity, and prevention and control strategies for assessment. The results show that the risk of imported human cases and community epidemic of SFTS is low, but it does not rule out the possibility of imported infected animals or vectors carried by migratory birds from entering my country. In addition, the fatality rate of SFTS is about 6-30%, which can pose a threat to the health of Chinese people. Comprehensive research has determined that the risk of SFTS in the domestic epidemic is moderate.In order to protect the health of the Chinese people, the Department of Disease Control has listed it as the fourth category of notifiable infectious diseases on April 15, 2020 and continues to actively monitor it. It will strengthen the monitoring of economic animals, wild animals and vectors in high-risk areas, and through health education propaganda Lead the public and medical institutions to increase their awareness and alertness of SFTS prevention and control, and implement measures such as protection and isolation when in contact with blood and body fluids and intubation to avoid contact infection, thereby reducing the risk and impact of the domestic epidemic.
All of which brings us to a new study, published this week in the Journal Viruses, which finds an unexpectedly high prevalence rate of SFTS in both stray and domesticated dogs and cats in Taiwan.
Due to its length, I've only posted some excerpts, so follow the link to read it in its entirety.
Epidemiology of Severe Fever with Thrombocytopenia Syndrome in Dogs and Cats in Taiwan
by Chih-Ying Kuan 1,Shan-Chia Ou 1, Chao-Chin Chang 1,Pei-Ling Kao 2,Ruei-Sheng Tsai 1,Porjai Rattanapanadda 3,Tsai-Lu Lin 4,Ken Maeda 5,Tsun-Li Cheng 6,Ya-Jane Lee 7,Shih-Te Chuang 8ORCID,Shiun-Long Lin 8,Hsien-Yueh Liu 9,Fong-Yuan Lin 9,Jen-Wei Lin 9,Wei-Li Hsu 1,10, andChi-Chung Chou 8,
Abstract
Severe Fever with Thrombocytopenia Syndrome (SFTS), caused by the SFTS Virus (SFTSV), is a global health threat. SFTSV in Taiwan has only been reported in ruminants and wild animals. Thus, we aimed to investigate the infection statuses of dogs and cats, the animals with closer human interactions.Overall, the SFTSV RNA prevalence was 23% (170/735), with dogs showing a 25.9% (111/429) prevalence and cats at 19.3% (59/306) prevalence. Noticeably, the prevalence in stray animals (39.8% 77/193) was significantly higher than in domesticated ones (17.2%, 93/542). Among the four categories analyzed, the highest SFTSV prevalence was found in the stray dogs at 53.9% (120/193), significantly higher than the 24.2% prevalence noted in stray cats. In contrast, domesticated animals exhibited similar prevalence rates, with 17.1% for dogs and 17.2% for cats.It is noteworthy that in the domesticated animal groups, a significantly elevated prevalence (45%, 9/20) was observed among cats exhibiting thrombocytopenia compared to those platelet counts in the reference range (4.8%, 1/21). The high infection rate in stray animals, especially stray dogs, indicated that exposure to various outdoor environments influences the prevalence of infections.
Given the higher human interaction with dogs and cats, there is a need for proactive measures to reduce the risk associated with the infection of SFTSV in both animals and humans.
(SNIP)
Both dogs and cats are companion animals that often share the same living quarters as humans, and they have the potential to transmit SFTSV to both humans and other animals. In Korea, SFTSV has been reported to transmit from infected dogs to the owners via tick infestation [31], as well as from tick bites to an 8-year-old girl [32]. Via intramuscular inoculation, SFTSV infection was proven capable of inducing clinical symptoms in dogs; thus, SFTSV transmission could occur via contact with affected dogs. [19].Moreover, in Japan, SFTSV was transmitted from cats to veterinary personnel through nosocomial infection [10,12] and sick cats biting their owners [11]. Cats exhibit a higher susceptibility to SFTSV compared to dogs, with a case fatality rate of 62.5% [33]. In contrast, dogs have shown varying SFTSV mortality rates, ranging from 0 [34,35,36] to 43% [37]. Consequently, understanding the epidemiological characteristics of SFTSV in companion animals is crucial for public health.Until now, there has been no comprehensive national report on the seroprevalence of SFTSV in small animals, specifically dogs and cats in Taiwan. To address this gap, the present study aimed to assess the prevalence of SFTSV-specific RNA among companion animals in Taiwan. Additionally, this study explored various factors that could potentially contribute to viral transmission. These factors encompassed geographic distribution and variations in habitat environments, specifically focusing on domesticated and stray animal populations.
In conclusion, this study effectively addressed the knowledge gap pertaining to the prevalence of SFTSV in small animals in Taiwan. The presence of SFTSV RNA was observed in both companion and stray dogs and cats. Notably, the prevalence of RNA was higher in stray animals, particularly those with thrombocytopenia. Given the significant mortality associated with SFTSV, special attention should be paid to animals (particularly cats) displaying thrombocytopenia in clinical settings.
Like Lassa Fever, CCHF, Nipah, and even the recently discovered Langya virus, SFTS is one of those relatively obscure zoonotic diseases that - while currently lacking pandemic potential - could easily become a bigger public health threat over time.
