"We still do not have a very good idea of how widespread this extensively drug-resistant tuberculosis is," said Dr. Karin Weyer, director of tuberculosis research for the South Africa Medical Research Council in Pretoria.

"We believe that there are about 6,000 cases of multi-drug resistant TB in South Africa, and when we treat these patients about 10 percent fail to get better. Extrapolating from that, we calculate that there are about 600 cases of patients with extensively drug-resistant TB in South Africa."

Last August researchers sent shudders through the World AIDS Conference when they reported an outbreak of extensively drug-resistant TB killed 52 of 53 patients who were co-infected with human immunodeficiency virus (HIV), which causes AIDS. Those cases were reported in one rural hospital in KwaZulu province in South Africa.

Since then the disease has made its way across the African nation, and it has not lost its virulence. "We have a person who came to the hospital with this co-infection and died before we even can get our laboratories to identify the organism," Weyer told United Press International at the 14th Retrovirus Conference being held in Los Angeles.

"Most of the patients who are co-infected with the extensively drug-resistant TB and HIV die within a month," she said. She also said that when the disease is spread to others -- six healthcare workers were infected -- it is spread as a virtually untreatable disease. Four of those six healthcare workers also had HIV infection, she said, and all of them died.

"Extensively drug-resistant tuberculosis represents the failure of tuberculosis control at the global level," Weyer said.

"These outbreaks of this scary form of tuberculosis and its spread underscore that the healthcare infrastructure is largely unprepared for the aerosol transmission of such a pathogen," said Dr. John Mellors, professor of medicine at the University of Pittsburgh and vice chairman of the scientific program at the retrovirus conference.

The outbreak of extensively drug-resistant tuberculosis is not limited to South Africa, said Dr. Paul Nunn, director of the Stop TB program of the World Health Organization in Geneva, Switzerland.

Nunn said nearly 9 million people in the world have tuberculosis, and the disease kills 1.6 million people a year -- roughly the same number of people who live in the nation of Botswana in southern Africa. He estimated that worldwide there are likely 16,000 deaths among those that are caused by infection with the extensively drug-resistant organism.

He said the WHO defines extensively drug-resistant tuberculosis as a form of the bacteria Mycobacterium tuberculosis that is resistant to standard oral drugs, to newer fluoroquinolones and to one of three injected drugs.

Such strains now have been reported in 28 countries, Nunn said, including the United States. However, the bulk of the resistant strains are found in China, India and Russia.

"Extensively drug-resistant TB is a wake-up call for strengthening basic tuberculosis and HIV care, prevention and control and scaling up the management of drug resistant tuberculosis," Nunn said. He estimated that a worldwide expenditure of $650 million a year will be required to control extensively drug-resistant tuberculosis.

Related Links
The science and news of Epidemics on Earth
SpaceDaily
Search SpaceDaily
Subscribe To SpaceDaily Express