The World Health Organisation warned Monday that more new tuberculosis cases are slipping through the detection net, as countries fail to keep up with rapid progress made in earlier years.
"After some years of good trends for tuberculosis control, 2006 documents a slowing of progress -- the rate at which new cases were detected increased only slightly compared to recent years," WHO director-general Margaret Chan told journalists.
"This slowdown in progress comes at a time when numbers are still way too high," she added.
The WHO estimates that only 61 percent of all TB cases worldwide are registered.
In 2006, some 9.2 million new cases of TB were detected against 9.1 million in 2005, said the WHO in its annual report on TB control.
The WHO estimates that, including non-detected cases, there were 14.4 million cases of the disease worldwide in 2006.
Between 2001 and 2005, detection rates were increasing by six percent a year, but in 2006, this rate was halved to three percent.
"This is not a good sign because our target is to detect all cases that exist. There is 39 percent that we are unable to find, but which we think is there," said Mario Raviglione, who is director of the WHO's Stop TB department.
The slowdown was attributed to the fact that some national programmes that were making steady progress during the last five years have not been able to continue at the same pace in 2006, said the WHO.
In addition, in many African countries, there has not been any increase in the detection of TB cases through national programmes.
Others are slipping out of the detection net as they are treated by private care providers, and by NGOs or community groups, added the WHO.
"We've entered a new era. To make progress, firstly public programmes must be further strengthened. Secondly we need to fully tap the potential of other service providers," said Chan.
The health organisation also drew attention to the significant number of HIV-infected people with TB. In 2006, some 700,000 new cases of HIV-infected people with TB were detected.
"The report clearly demonstrates how closely linked TB and HIV are," said Peter Piot, who is executive director of UNAIDS.
In 2006, 200,000 TB deaths were recorded among people who were infected with HIV, while an estimated 1.5 million people without HIV also succumbed to tuberculosis.
"It's the single most important cause of death for people living with HIV," said Piot.
The report singled out Rwanda, Malawi and Kenya as posting the highest HIV testing rates among African states.
"The report tells us that we are far from providing universal access to high-quality prevention, diagnostic, treatment and care services for HIV and TB," said Piot.
Just last month, the WHO warned that drug-resistant strains of tuberculosis have been recorded at their highest rates ever around the globe amid shortages in funding needed to combat the disease.
Nearly a half million new cases of multi-drug resistant tuberculosis occur each year worldwide, or around five percent of the nine million new cases in total, the WHO said then.