Well, this is a bad way to start the year.
Over the past 48 hours, news has broken in India of the existence of at least 12 patients infected with tuberculosis that has become resistant to all the drugs used against the disease. Physicians in Mumbai are calling the strain TDR, for Totally Drug-Resistant. In other words, it is untreatable as far as they know.
News of some of the cases was published Dec. 21 in an ahead-of-print letter to the journal Clinical Infectious Diseases, which just about everyone missed, including me. (But not, thankfully, the hyper-alertglobal-health blogger Crawford Kilian, to whom I hat-tip.) That letter describes the discovery and treatment of four cases of TDR-TB since last October. On Saturday, the Times of India disclosed that there are actually 12 known cases just in one hospital, the P. D. Hinduja National Hospital and Medical Research Centre; in the article, Hinduja’s Dr. Amita Athawale admits, “The cases we clinically isolate are just the tip of the iceberg.” And as a followup, the Hindustan Times reported yesterday that most hospitals in the city — by extension, most Indian cities — don’t have the facilities to identify the TDR strain, making it more likely that unrecognized cases can go on to infect others.
Why this is bad news: TB is already one of the world’s worst killers, up there with malaria and HIV/AIDS, accounting for 9.4 million cases and 1.7 million deaths in 2009, according to the WHO. At the best of times, TB treatment is difficult, requiring at least 6 months of pill combinations that have unpleasant side effects and must be taken long after the patient begins to feel well.
Because of the mismatch between treatment and symptoms, people often don’t take their full course of drugs — and from that (and some other factors I’ll talk about in a minute) we get multi-drug resistant and extensively drug-resistant, MDR and XDR, TB. MDR is resistant to the first-choice drugs, requiring that patients instead be treated with a larger cocktail of “second-line” agents, which are less effective, have more side effects, and take much longer to effect a cure, sometimes 2 years or more. XDR is resistant to the three first-line drugs and several of the nine or so drugs usually recognized as being second choice.
As of last spring, according to the WHO, there were about 440,000 cases of MDR-TB per year, accounting for 150,000 deaths, and 25,000 cases of XDR. At the time, the WHO predicted there would be 2 million MDR or XDR cases in the word by 2012.
That was before TDR-TB.
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