SFTS transmitted person-to-person

The state-run disease control authority said in a recent study that two doctors and two nurses were infected by the fatal tick-borne SFTS virus while treating a patient, which marks the first case in Korea in which the virus was transmitted person-to-person.

Animal hosts are mostly infected with the SFTS virus, or severe fever with thrombocytopenia syndrome (low platelet count), though humans have been known to contract it if bitten by a tick.

The recent discovery also goes against the public notion that the virus only infects people bitten by an SFTS-carrying haemaphysalis longicornis tick, a native species.

About 1 to 3 percent of these domestic ticks, active from April to November, are believed to carry the SFTS virus. According to the Korea Centers for Disease Control and Prevention (KCDCP), the doctors and nurses were treating a woman, 68, who had been bitten by a tick in September.

She was initially treated at a local hospital but was taken to a university hospital after her symptoms became more severe. The patient later died despite efforts by the four medical staff members to help her.

When one of the doctors later developed a fever and thrombopenia, or extremely low platelet levels, he was found to have been infected by the SFTS virus.

He made a full recovery after a week, while the three others also tested positive for the virus but merely exhibited cold symptoms.

But despite what appears to be person-to-person transmission, the disease control authority claims SFTS is not spread among people in typical conditions.

“It appears the infected doctors and nurses had close contact with the patient’s bodily fluids while performing cardiopulmonary resuscitation over about 30 minutes,” KCDCP Director Yang Byeong-guk said. “The virus is not easily transmitted in usual conditions or when family members interact with the patients in their daily lives.

“People need not panic,” he added, “because the contagion occurred under exceptional circumstance.”

The case has been submitted to the United States Centers for Disease Control and Prevention for publication.

Last year alone, 50 people were infected by the fatal tick-borne virus and 15 of them, most of them elderly, died. “Young people typically only suffer cold symptoms,” Yang said.

The SFTS virus was first reported in China in 2012.

In 2013, when SFTS was first recorded in Korea, 37 people contracted the virus and 17 died. The virus has a six- to 14-day latent period. Major clinical symptoms can include vomiting, diarrhea and multiple organ failure.

BY KIM BONG-MOON [bongmoon@joongang.co.kr]