John Rogers, executive director of the Eugene Bell Foundation (right) distributes medication to patients in Ryokpo, the Democratic People's Republic of Korea.? Photo By Eugene Bell Foundation Via AP

Despite poor relations between the governments of the United States and the Democratic People's Republic of Korea, a US charity is ramping up efforts against an epidemic of multidrug-resistant tuberculosis in the DPRK, where it says it is making inroads in fighting the deadly disease.

The Eugene Bell Foundation travels to the DPRK twice a year, bringing high-end equipment and drugs to treat TB patients. The foundation returns this month on a whirlwind, three-week mission to help hundreds of patients.

Pyongyang currently faces stiff US criticism for detaining three US citizens. But the foundation, located in Washington, says it has a good working relationship with Pyongyang and its doctors. It started out providing food aid in the 1990s, but has since mostly helped the nation's health system.

"It's a collaboration, and it works. Our goals are aligned," said John Rogers, executive director of the foundation, which was set up by the son of a Southern Presbyterian missionary family with long experience in Korea.

TB is a contagious, bacterial disease that usually attacks the lungs. The World Health Organization estimates that there were about 100,000 new cases of TB in 2012 among DPRK's 25 million people.

Since 2010, a $48 million program supported by the Global Fund to Fight AIDS, Tuberculosis and Malaria has increased availability in the DPRK of regular treatments for TB. But multidrug-resistant strains, which are more difficult and costly to treat, are widespread, said Dr Seung Kwon-june, Eugene Bell's medical director.

There's been no nationwide survey of the problem, but based on experience at a dozen of these facilities in the southern half of the DPRK, Seung predicts such strains could be up to three times more common than the WHO has estimated.