A third of world’s tuberculosis cases remain undetected, says WHO

Although the global burden of tuberculosis is slowly falling, more intense efforts are needed to save an estimated five million lives between 2011 and 2015, a World Health Organization report says.

Efforts to plan, finance, and implement the Stop TB strategy need to be scaled up, says the report. For the strategy to be effective, diagnosis and treatment of tuberculosis need to be expanded, more care providers need to be engaged in control of the disease, and surveillance of its incidence, prevalence, and mortality needs to be strengthened.

The latest WHO data show that between 1995 and 2009 a total of 49 million people had tuberculosis, about 41 million of whom were successfully treated through the Stop TB strategy.

In 2009 there were an estimated 9.4 million cases of tuberculosis, equivalent to 137 cases per 100 000 population, down from a peak of 142 cases per 100 000 in 2004.

But the report says that a lot more needs to be done to increase the rate of detection of cases. Last year an average 63% of the estimated number of new cases of tuberculosis were diagnosed and notified to national surveillance systems, up from 56% in 2005. Although detection averaged a high of 80% in the European region, it was just 50% in the African region.

Mario Raviglione, director of the Stop TB department at WHO, told the BMJ, “We still have a gap of one third” between the number of estimated cases and the number notified.

WHO officials say that one of the best ways to increase detection is for national tuberculosis control programmes “to establish collaboration with the full range of healthcare providers.” New data for 2010 from 15 countries show that mixed public-private sector approaches can help boost case detection rates.

Most of the cases in 2009 were in Asia (55%) and Africa (30%), with fewer cases in WHO’s Eastern Mediterranean region (7%), the European region (4%), and the Americas (3%). The countries with the largest numbers of cases last year were India (two million), China (1.3 million), South Africa (490 000), Nigeria (460 000), and Indonesia (430 000).

The report says that the rate of successful treatment of new cases in the 2008 cohort (2.6 million patients) was 86% overall worldwide and 87% in the 22 countries with a high burden of the disease.

Effective control depends on “hiring, deploying, motivating and managing sufficient numbers of health workers and ensuring that they have the appropriate professional competencies at all levels of the private and public health systems,” says the report.

The report also says that there were an estimated 440 000 cases of multidrug resistant tuberculosis in 2008, of which only 30 000 cases (12%) were diagnosed. The incidence had not changed for several years, said Dr Raviglione.