A worker collects ticks on an Olle trail in western Jeju last week. The government said no ticks carrying a deadly virus were found. [NEWSIS]

Concern is growing over a potentially fatal virus as more people with symptoms similar to those of three tick-bite victims who died were reported over the weekend.

According to the Jeju Provincial Government, an 81-year-old woman surnamed Heo, a Seogwipo resident, has been hospitalized at Jeju National University Hospital since Wednesday with symptoms of SFTS, or severe fever with thrombocytopenia syndrome, transmitted through a tick bite.

Jeju health authorities said she has been suffered from high fever, diarrhea and vomiting since May 20 after planting lettuce and beans at a garden about two weeks ago. On Thursday, authorities sent Heo’s blood sample to the National Institute of Health for analysis. They said results are expected next week.

“We found a mark made by an insect bite, but we are not sure that it was a tick,” said a spokesman for Jeju health authorities. “We have to wait until the test result comes out to find out if she is infected.”

On May 16, a Seogwipo resident surnamed Kang, 72, died. Jeju health authorities said last week Kang had been bitten by a species of tick associated with the virus (haemaphysalis longicornis), and a blood test confirmed she had SFTS.

In South Jeolla, a 60-year-old woman surnamed Kang has been hospitalized at Chonnam National University Hospital in Hwasun with SFTS symptoms after she gathered herbs on a mountain near her house in Naju, about two weeks ago. She has been suffering from diarrhea and vomiting since May 17.

“She has symptoms of thrombocytopenia syndrome,” said a Chonnam hospital spokesman. “But the good news is that she is getting better.”

The Korea Centers for Disease Control and Prevention (KCDC) said yesterday it will begin an investigation today to determine if Kang has SFTS.

Two more patients with symptoms of SFTS have been reported.

The Gangwon Provincial Government said yesterday a woman in her 50s and a man in his 70s have been hospitalized at Kangwon National University Hospital since Wednesday with symptoms of thrombocytopenia. The female patient told the hospital she had gathered wild herbs on a mountain May 10, and the male patient said he believes he was bitten on his leg while working at his farm.

As of yesterday, a total of three people - one each from Gangwon, Jeju and Busan - with SFTS have died. Patients suspected of suffering from SFTS have been reported in Gangwon, Daegu, North Jeolla, Busan, North and South Chungcheong and Gwangju. The KCDC recently concluded that the patients in Daegu and North Jeolla are not infected.

By Choi Kyung-ho, Kwon Sang-soo [sakwon80@joongang.co.kr]