North Korea is facing a surge of multidrug-resistant tuberculosis, or MDRTB, an aid group has warned.

At least 5,000 cases of TB that can't be treated with conventional antibiotics are reported in North Korea each year, according to Stephen Linton, chairman of the South Korea-based Eugene Bell Foundation.

The true number could be far higher, since North Korea lacks the advanced testing methods needed to detect drug-resistant strains of the disease and foreign doctors' access to the country is restricted.

North Korea has long been plagued by TB, which spreads rapidly in cold, damp, crowded conditions and especially among people who are malnourished. Now its epidemic could prove a risk to its neighbors, as the powerful new strains incubated in the North threaten to spread to South Korea and China.

The Eugene Bell Foundation has been working to combat TB in North Korea for several years and in March sent more than $600,000 of medicines. They only have the resources to treat around 500 patients each year, however, a fraction of the total number.

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Treating MDRTB requires an intensive, long-term course of second-line drugs, at a cost of some $2,000 per patient per year.

For most North Koreans, the program is out of reach. The country suffers from chronic shortages of medicine due to poverty and Western sanctions.

The sanctions ban the import of "dual-use" items, or products that can be used for military as well as civilian purposes. Some of the chemicals used to test the quality of pharmaceuticals, which allows private businesses to put medicines on the North Korean market, fall under this category.

Tuberculosis and cataract blindness have been known to strike young children and the elderly in the remote, far-north provinces of North Korea. Pyongyang, on the other hand, is home to an affluent class that can generally afford medicines; a handful of Chinese- and European-led companies have entered the pharmaceuticals market, including PyongSu, which has a Belgian manager.

The TB epidemic has prompted unprecedented cooperation between North Korea and the outside world. In 2010 the North Korean health ministry worked with American scientists to set up the first laboratory equipped to test for MDRTB, while the same US non-profit that helped bring about that collaboration recently announced plans to build a training center to educate North Korean doctors tuberculosis treatment and prevention.

But not all is a crisis. In 2010, a former World Health Organization director famously announced that North Korea's health-care system, which remains free for all on paper, was the envy of the developing world. Amnesty International, on the other hand, painted a grimmer picture that year, describing doctors who performed amputations without anesthesia and by candlelight.

In another indicator of poor health, the WHO reported last year that 1 in 10 North Korean babies were born early. The complications from preterm birth led to the deaths of some 2700 babies that year in the country. But North Korea isn't at rock bottom in this respect: for the first factor, it ranked 80 out of 184 countries.

Geoffrey Cain contributed to this report from Seoul, South Korea.