Febrile thrombocytopenia syndrome (SFTS) carried by 'killer ticks'Professor Kang Joon-koo, College of Veterinary Medicine, Seoul National University

What is SFTS?

Have you heard of the little tick, also known as the "killer tick"? The reason for this nickname is that the tick is a carrier of the virus, and its main symptoms are high fever and diarrhea, followed by a sharp drop in platelets and white blood cells, which eventually leads to death. The name of the disease is febrile thrombocytopenia syndrome, which is abbreviated as SFTS.

Ticks have coexisted with humans for a long time, but in recent years, they have become a problem because the population of wild animals such as elk and wild boar, which are host animals, has increased due to the government-run wildlife protection project, and the average annual temperature has increased due to global warming, creating a favorable environment for ticks to live.

Fortunately, tick bites do not necessarily mean that you will develop febrile thrombocytopenia syndrome. For SFTS to occur, a person must be bitten by a tick that carries the virus, and the tick must carry enough of the virus to infect a human. According to the statistics we came from, only about 1 in 100 ticks were infected with the virus. While it is true that ticks should be taken care of as a precaution, the probability of contracting SFTS is somewhat smaller, about 1 in 40,000 if you calculate it mathematically.

Are there any people who are vulnerable to SFTS?

There is no need to worry too much, but there are other susceptible groups of ticks that carry febrile thrombocytopenia syndrome. Statistically, people over 60 years of age and, interestingly, Asians are more likely to get it. This may be due to the fact that older people around the world are more likely to be engaged in agriculture, and that small ticks that carry SFTS are rare in the West, but relatively abundant in the East.

In addition, if you have one or more underlying diseases, you are more likely to be infected with febrile thrombocytopenia syndrome virus. If you have a chronic illness such as diabetes, you can easily get it even if you are not over 60 years old.

What is surprising is that in 2017, there was a case in which a dog in Japan was infected with SFTS. Direct transmission between animals and humans has not been documented, but it is possible that ticks carrying SFTS have sucked blood in animals, and in humans and then in humans. This is not impossible, because ticks can live up to three months without prey.

There is only a difference in quantity, but ticks are also present in Seoul. They are usually found in grasslands, sometimes as many as 300 at the end of the grass. When the host passes over the grass, it sticks right away, so special care must be taken.

How can I prevent SFTS?

To date, there is no vaccine or treatment for febrile thrombocytopenia syndrome. Therefore, it is important to prevent the tick from attaching itself to it in advance. You don't need to be extra careful in the case of a park that is managed by people, but if you're going to play in a country paddy field or pasture, it's a good idea to spray the tick repellent on the most vulnerable areas.

Tick repellents are quasi-drugs and are available without a prescription at supermarkets and pharmacies. All of the medicines on the market in Korea are guaranteed to be safe for the skin, and there are a variety of drugs from artificial synthetic chemical drugs to natural drugs, so you can choose the medicine that suits you appropriately.