In a rural, impoverished area of South Africa, a scary outbreak is occurring primarily among AIDS patients -- a type of tuberculosis that is extremely drug resistant.
Of 53 patients who had this form of the lung infection in a research study, 52 died.
Two of the people who died were health-care workers.
A doctor on staff suspects it may have killed other hospital workers who sought TB treatment at private clinics after becoming infected.
"It does mean that these people are virtually untreatable," said Dr. Tony Moll, the AIDS treatment director at the Church of Scotland Hospital in Tugela Ferry, South Africa.
Moll spoke to ABC News by phone.
"That's why we had the high death rate. There was nothing we could do in terms of offering medication."
The discovery was made when Moll and several other researchers collected sputum, or lung secretions, from 1,540 patients who had visited the hospital between January 2005 and March 2006. Thirty-five percent of them, or 536 patients, had tuberculosis.
Of those, 221 had multi-antibiotic resistant TB, and of that group, 53 had the extremely drug-resistant form of TB.
The findings were presented Thursday at the 16th annual International AIDS Conference in Toronto.
Most of the group with extremely drug resistant TB also had HIV.
The two infections often strike a person at the same time, because tuberculosis is often an opportunistic infection or lies dormant until a person's immune system is weakened.
Tuberculosis is caused by the bacteria Mycobacterium tuberculosis, and is spread through the air.
It is one of the many types of bacteria that have developed resistance to antibiotic treatment.
Giving HIV drugs, known as antiretroviral therapy, helped patients deal with the co-infection.
Moll noticed, however, that there always seemed to be patients who, in spite of receiving the treatment and other medical care, still died from TB. This led to the sputum research.
The emergence of a potent TB strain is a major setback for HIV treatment and an additional cause for concern about the spread of antibiotic-resistant bacterial infections around the world.
"Not only does this have serious implications on our patients, it also has serious implication on this staff," said Moll, who has implemented tighter infection-control policies in the hospital.
"It also undermines a new hope that we had in antiretroviral therapy and what it could do for us and our community."
While this is not the first time extremely drug resistant TB has been reported, the finding makes Tugela Ferry the de facto epicenter of the infection.
Health officials admit there is a lack of information about TB infections in poor and rural areas of the world, and the true impact is not understood.
The discovery is alarming enough that the World Health Organization is quickly convening with South African health officials to investigate the matter, according to a source quoted in The New York Times.