If she succeeds, Sarita Shah, principal investigator at the Albert Einstein College of Medicine of Yeshiva University, United States, may be able to help those in most parts of the developing world, including India, fight drug-resistant tuberculosis.
The National Institutes of Health has awarded scientists at the college a five-year, $3.9 million grant to study how extensively such tuberculosis is transmitted in rural South Africa, which has a high rate of the disease. Her findings could alter public health approaches for controlling the XDR-TB epidemic in the developing world.
According to a 2007 study -- the first-ever -- by researchers from the Hinduja Hospital in Mumbai, XDR-TB has struck root in India as well.
Shah, assistant professor of medicine and of epidemiology and public health, said that most cases of XDR-TB are thought to arise when people infected with susceptible strains of TB do not take their medications correctly or are prescribed the wrong medications.
She said these medication failures encourage the growth of drug-resistant strains of TB bacteria, a phenomenon known as amplified resistance. XDR-TB can also arise when someone who never had TB, or who had TB that was cured, is directly infected with a drug-resistant strain of TB.
"Person-to-person transmission of XDR-TB was believed to be rare," Shah said. "But increasing evidence suggests that it's much more common than previously thought. We estimate that two-thirds to three-quarters of XDR-TB cases arise this way," she added.
Shah will interview and analyse the medical records of 400 patients with XDR-TB to determine how many new cases develop due to person-to-person transmission compared with new cases of amplified resistance.
The study will take place in Tugela Ferry in the KwaZulu-Natal district in South Africa, which has very high rates of XDR-TB.