China faces a “serious epidemic” of drug-resistant tuberculosis, according to the first nationwide estimate of the size of its problems.
A study in the New England Journal of Medicine published on Thursday said: “In 2007, one-third of the patients (in China) with new cases of tuberculosis and one half of the patients with previously treated tuberculosis had drug-resistant disease.”
Even more, the prevalence of multi-drug resistant (MDR) TB in new cases (5.7 percent) was nearly twice the global average, said the US study, funded by China's Ministry of Health.
Using World Health Organization figures as a basis for comparison, it said “China has the highest annual number of cases of MDR tuberculosis in the world – a quarter of the cases worldwide”.
The data came from a survey of more than 4,600 Chinese recently diagnosed or treated for TB.
The study's patients were treated at local TB clinics, not hospitals, and the survey was conducted by the National Tuberculosis Reference Laboratory of the Chinese Centers for Disease Control.
An accompanying editorial by Johns Hopkins University infectious disease specialist Richard Chaisson said the growth of drug-resistant TB presents an “enormous challenge”. Of great concern was the finding that most of the 110,000 drug-resistant cases were in people newly diagnosed, suggesting that the virulent bacteria are being transmitted from person to person and not developing solely as a result of a person prematurely stopping treatment.
TB is usually cured in six to nine months with a mixture of four antibiotics, but if that treatment is interrupted or the dose reduced, the bacteria mutate into a tougher strain that can no longer be killed by standard drugs, which will then take up to two years and thousands of dollars to treat.
“MDR tuberculosis is linked to inadequate treatment in both the public health system and the hospital system, especially tuberculosis hospitals; however, primary transmission accounts for most cases,” said the study.
China accounts for more than one million of the estimated nine million new TB infections worldwide annually. The airborne disease kills about 1.5 million people globally each year.