Hunt for ticks carrying deadly virus yields few leads

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Hunt for ticks carrying deadly virus yields few leads

Published: 30 Aug. 2025, 16:32

Audio report: written by reporters, read by AI

A researcher from the Korea Disease Control and Prevention Agency collects ticks outside the home of an elderly woman who died from a flea-borne infection. [KOREA DISEASE CONTROL AND PREVENTION AGENCY]

Multiple government agencies are carrying out a joint epidemiological investigation following the death of an elderly woman in June from severe fever with thrombocytopenia syndrome, a rare but deadly tick-borne disease.

The 69-year-old woman had been working in her vegetable garden in Boeun County, North Chungcheong, when she was bitten by a tick. Days later, she developed a fever and was rushed to the hospital in Cheongju.

Despite intensive care, including cardiopulmonary resuscitation and the use of a ventilator, she died on June 11 of multiple organ failure.

The tragedy did not end there. Seven medical workers who had performed CPR in the intensive care unit became infected themselves, raising alarm among public health officials. While secondary infections are occasionally reported, never before in Korea had so many occurred at once.

Authorities have responded by launching a two-week investigation involving six agencies — the Korea Disease Control and Prevention Agency, the National Institute of Wildlife Disease Control, the Animal and Plant Quarantine Agency, the North Chungcheong provincial government and local authorities in Boeun County.

Teams scoured the woman’s garden, her home, surrounding neighborhoods, and nearby hillsides for ticks. Stray cats were captured, and even the family dog was tested. Using drones, investigators drove out wild water deer, then dispatched hunters to capture three of them for blood samples. One carcass yielded ticks. Four feral cats were also tested. In total, about 1,000 ticks were collected.

A dog that belonged to the elderly woman who died of a flea-borne infection is inspected for ticks. Testing showed that none of the fleas on the animal carried the fatal infection that killed its owner. [KOREA DISEASE CONTROL AND PREVENTION AGENCY]

Yet the effort yielded no trace of the virus. No blood samples nor any of the ticks tested positive for SFTS. “It was like searching for a needle in a haystack,” one official admitted.

SFTS is transmitted by the haemaphysalis longicornis tick — known locally as the “small grass tick” — a brown, wingless parasite just 2 to 3 millimeters long that moves in clusters and is found throughout the country. Investigators suspect the infected ticks may have dispersed after biting the woman.

Her village, a typical farming community, had never before recorded a case of SFTS, underscoring what health experts have long warned: the disease can surface anywhere in South Korea.

The woman developed symptoms — fever, nausea and fatigue — six days after the tick bite. She was admitted to a local hospital on June 4 and transferred to a larger medical center as her condition worsened. The secondary infections among hospital staff were detected between June 17 and 20.

Because its symptoms resemble the common cold, SFTS often goes unrecognized. Patients may dismiss it as seasonal illness and attempt to recover at home. The incubation period ranges from five to 14 days, and health officials advise anyone experiencing high fever, vomiting, diarrhea or loss of appetite after outdoor activity to seek immediate medical care.

“Such ticks are most abundant in dense grass and brush,” said Kim Jong-hee, an official at the Korea Disease Control and Prevention Agency. “It’s dangerous to lie down, leave clothes on the ground, or relieve oneself in such areas. People should use mats, shake out and wash clothing, shower promptly, and carefully check their bodies after outdoor activity.”

SFTS remains one of the most lethal infectious diseases in the country. Korea’s cumulative fatality rate stands at 18.5 percent, with the death rate of occurrences in some years reaching nearly 50 percent. There is no vaccine and no effective treatment.

This article was originally written in Korean and translated by a bilingual reporter with the help of generative AI tools. It was then edited by a native English-speaking editor. All AI-assisted translations are reviewed and refined by our newsroom.
BY SHIN SUNG-SIK [[email protected]]