"The World Health Organisation Regional Committee for Africa, comprising health ministers from 46 member states, has declared tuberculosis an emergency in the African region," WHO said after four days of talks in Mozambique.

"The declaration is a response to an epidemic that has quadrupled the annual number of new TB cases in 18 African countries since 1990 and continues to rise across the continent, killing more than half a million people every year," it said.

HIV-positive vulnreable

Tuberculosis is a leading cause of death among people who are HIV-positive, accounting for about 11% of AIDS deaths worldwide. It poses a major challenge in managing treatment for people with HIV, WHO experts say.

Declaration of a tuberculosis emergency should unlock more money from the Group of Eight (G8) industrialised nations, the United States and the Global Fund from where developing countries draw much of their cash for fighting AIDS and other diseases, the WHO says.

HIV weakens the immune system, making sufferers more susceptible to infectious diseases like TB and pneumonia.

Someone who is HIV-positive and infected with TB is 5-7 times more likely to develop active TB than someone infected with TB but not infected with HIV, the WHO said.