Experts in India are raising red flags after discovering what they are calling “totally drug-resistant tuberculosis.”

In a paper published in December by the journal Clinical Infectious Diseases, Dr. Zarir Udwadia and a team of specialists identified four patients that had a lung infection essentially incurable with all available medicines.

"Short of quarantining them in hospitals with isolation facilities till they become non-infectious – which is not practical or possible – there is nothing else one can do to prevent transmission,” said Dr. Udwadia.

New reports claim at least a dozen cases have arisen in Mumbai.

"It is concerning," said Dr. Kenneth Castro of the U.S. Centers for Disease Control and Prevention. "Anytime we see something like this, we better get on top of it before it becomes a more widespread problem."

The Indian specialists blame poor treatment of patients with highly resistive strains of the infection rather than a person-to-person transmission, saying private doctors prescribed inappropriate drug plans that sparked greater resistance.

Tuberculosis kills roughly 2 million people a year, according to the World Health Organization, and India is home to a quarter of the cases worldwide.