BALI, Indonesia (Reuters) - Cases of multi-drug resistant tuberculosis are underdiagnosed around the world and even among those who have been diagnosed, only a fraction are being treated, a Global Fund official said on Monday.

A patient with tuberculosis sits on a bed in "Tuberculosis Village," a separate health facility at a clinic run by the medical charity Medecins Sans Frontieres (Doctors Without Borders), in the town of Nasir in southeastern Sudan, June 20, 2009. REUTERS/Finbarr O'Reilly

“The Global Fund is funding about 25,000 to 30,000 patients but the estimated total number of cases is 500,000,” Michel Kazatchkine, executive director of the Global Fund’s effort to fight HIV/AIDS, TB and malaria, told an HIV/AIDS conference.

“So we are very far off. It is a dangerous epidemic that is spreading,” he told the conference in Bali. “There is an underdiagnosis of MDR-TB.”

The Asia-Pacific region has the highest number of multi-drug resistant TB (MDR-TB), but only one percent of the cases are being treated, he added.

Most cases of TB can be cured with a drug regimen of 6 to 8 months. Multi-drug resistant TB emerges when there is improper use of antibiotics in fighting regular TB, such as failure to complete the whole course of treatment.

People with HIV/AIDS are especially susceptible to falling ill with TB because their immune systems are compromised. An estimated one-third of people living with HIV are co-infected with TB, and TB continues to be the leading cause of death among people living with HIV.

The emergence of multi-drug resistant TB and extensively drug-resistant TB in recent years poses a significant public health threat, especially for countries with high HIV prevalence. Multi-drug resistant TB is resistant to two of the most powerful TB drugs, isoniazid and rifampicin.

Kazatchkine said treatment for someone with multi-drug resistant TB costs US$7,000 a year, about 100 times the cost of treating regular TB.

“The best way to prevent resistant TB is to get people to take the whole course of standard TB drugs,” he said. He stressed, however, there was still an urgency to allocate more money to treat people with multi-drug resistant TB.

“If we can do it for H1N1, we can do it for TB. These epidemics have been at (pandemic) level 6 plus plus plus plus for years,” he said.