Another health care worker at a pediatric unit at a general hospital has been diagnosed with tuberculosis, just days after the nation’s second case was reported at a different hospital, raising concerns over the current preventive measures against the infectious disease.

According to the Korea Centers for Disease Control and Prevention, the 23-year-old nurse was reported to the authorities after she was diagnosed with TB through a regular health examination last month. The health care worker, who is currently being treated in isolation, had been working at Korea University Ansan Hospital’s intensive care unit for newborns.

Following her diagnosis, a total of 51 babies and 57 health care workers are being tested for TB, the KCDC said.

Since last month, two other nurses in Seoul -- one at Ewha Womans University Medical Center and the other at Samsung Medical Center -- were diagnosed with TB also through regular health check-ups provided by their employers. Notably, both of the health care workers also worked at pediatric units at the medical institutions, one at the intensive care unit for infants and the other unit for children patients with blood cancers.

At Ewha, 166 babies and 60 health care workers were tested following the nurse’s diagnosis last month. Among them, two infants and five health care workers were diagnosed with latent TB -- a condition in which the TB bacteria is in the body but inactive and causing no symptoms. Without treatment, about 5 to 10 percent of latent TB patients are known to develop TB at some point in their lives.

According to the World Health Organization, over 95 percent of TB cases and deaths worldwide are in developing countries. South Korea currently has the highest incidence rate of TB among nations in the Organization for Economic Cooperation and Development, partly due to the lack of epidemiological research of the disease since the 1950-53 Korean War. It is known that roughly one third of the entire Korean population currently has latent TB.

“When we introduced our national health insurance system in 1989, many state-run health centers were replaced by private clinics that focused on treatments rather than epidemiological research on infectious diseases, including TB,” Health Minister Chung Chin-youb said earlier this year.

As of 2014, Korea’s TB incidence rate marked 86 per 100,000 persons, about 28 times higher than one in the U.S. -- where the incidence rate of the disease is the lowest among the OECD -- which is 3.1 per 100,000 persons. Last year alone, 32,181 Koreans were newly diagnosed with the disease, while 2,305 died of the disease in 2014.

“Many latent TB patients aren’t aware of the disease because they are asymptomatic,” said a doctor at a general hospital who wanted to remain anonymous. “Some TB and latent TB patients find out about their disease while applying for a visa in a foreign country, as many countries require foreign visitors to submit their TB test results along with their visa application.”

South Korea has recently seen a number of TB cases at facilities with a large number of people, such as schools and postpartum centers. Last year, TB cases were reported in 974 schools, 332 military bases and 91 day care centers and postpartum care facilities -- where many newborns are placed in a same room together.

To tackle the issue, the Health Ministry announced in March that all Koreans would be required to be tested for latent TB at least twice in their lifetime, at age 15 and 40, starting next year. TB treatments became free for all patients in Korea last month. Earlier this month, the ministry also said employees who work at facilities with a large number of people, such as health care workers and school teachers, are going to be required to be tested for TB regularly. Yet it’s the workers’ employers, not the government, that are responsible for financing the cost of the tests, which costs about 50,000 won ($44.91) per person. The Health Ministry did not allocate any budget for the specific project.

Rep. Kim Seung-hee of the ruling Saenuri Party told Health Minister Chung last week that the ministry should finance the cost of the TB test for health care professionals, day care workers and school teachers. Minister Chung said the government will try to allocate a budget for the tests next year.

It was during former President Lee Myung-bak‘s administration (2008-2013) that South Korea increased its budget for TB prevention dramatically, from 14.9 billion won in 2010 to 44.5 billion won in 2011. The former president in fact suffered from TB back in 1965, when he was a university student, and was treated for a severe lung condition in 2009, according to his autobiography. This year’s budget for TB prevention is 3.92 billion won.

By Claire Lee(dyc@heraldcorp.com)