Washington: An Indian woman with a rare deadly form of tuberculosis has created a health scare in three US states where authorities are tracking down hundreds of people who may have been in her contact during her visit.

The woman, who arrived in Chicago from India on April 4 and travelled by car to visit relatives in Illinois, Tennessee and Missouri, is now being treated at the National Institutes of Health (NIH) Clinical Center in Bethesda, Maryland. She is suffering from an extremely rare drug-resistant form of the disease, known as XDR-TB, which is immune to most Tuberculosis drugs, The New York time reported.

The unidentified woman is in an isolation room designed for patients with dangerous respiratory infections, according to the National Institutes of Health and the Centers for Disease Control and Prevention (CDC). The CDC today described her condition as stable.

Health officials in Illinois were working with the CDC to find people with whom the woman may have had prolonged direct contact, in close quarters. Health officials say the risk to the public is low. TB is nowhere near as contagious as the flu or measles. But people who had long periods of close contact with the patient, like the relatives with whom she stayed, are at risk.

For people who were on the flight with the woman, the odds of catching TB are low but not zero. The CDC said that it will obtain the flight manifest for the woman's trip from India and notify passengers who may have been exposed.

Based on her medical history and molecular testing, she was diagnosed with XDR TB, it reported. She was initially placed in respiratory isolation at a suburban Chicago hospital and later transported by air ambulance to the NIH Clinical Center.

Globally, nine million people contracted TB in 2013, and one and a half million died from it, according to the World Health Organization. Nearly a quarter of all the cases occurred in India, which has the world's largest epidemic.