About 1 in 3 South Koreans have latent tuberculosis as of last year, a lawmaker said Wednesday.

Rep. Nam In-soon of the ruling Democratic Party cited the annual Korea National Health and Nutrition Examination Survey in 2016 conducted by the Korea Centers for Disease Control and Prevention, which showed that 33.2 percent of 2,051 participants tested positive for latent TB infection.

LTBI is a condition in which TB bacteria are present in the body but are dormant.

That is the highest incidence rate among the 34-member Organization for Economic Cooperation and Development as of last year.

People aged 40 and above were found to be more affected than younger generations.

Around 46.1 percent of people in their 40s tested positive for LTBI, while the incidence rate for the 50-59 and 60-69 age groups were at 48.7 percent and 45.0 percent, respectively.

The LTBI incidence rate was the lowest among those aged between 10-29, standing at 6.5 percent and 10.9 percent, respectively.

The contagious disease, which mainly occurs in developing countries, is caused by the Mycobacterium tuberculosis bacteria. It spreads through coughing and sneezing.

Its symptoms include excessive weight loss, high fever and night sweats, and it could be fatal if not treated properly.

In 2015, as many as 80 out of every 100,000 individuals here were TB positive, the highest according to OECD statistics. The OECD average rate stood at 11.4 patients per 100,000 people in the same year.

The mortality rate of the infection also stand the highest among OECD member states, at 5.2 deaths out of 100,000 people, according to the group’s 2016 statistics.

The Ministry of Health and Welfare aims to lower the rate of new TB patients to close to the OECD average by 2025, employing more medical staff and public health facilities across the country to fight the disease.

By Bak Se-hwan (sh@heraldcorp.com)i