The threat of drug-resistant tuberculosis

By RICARDO SALUDO

Ric Saludo’s colleague Joanne Angela B. Marzan contributed this column.

Award-winning war photojournalist James Nachtwey vied for the TED Prize to fulfill a mission: to “break a story the world needs to know about.” In 2007, Nachtwey won the $100,000 TED Prize, given to an individual with “one wish to change the world.”

For the Dartmouth-educated photographer, that wish was to tell the tragedy and peril of a mutating germ that, as his website xdrtb.org explains, kills someone somewhere every 20 seconds, often within weeks of being diagnosed, with no reliable cure, and now reported in at least 55 countries, including the Philippines.

The World Health Organization (WHO) defines extensively or extreme drug-resistant tuberculosis (XDR-TB) as a form of multidrug-resistant tuberculosis (MDR-TB) resistant to the two most powerful first-line anti-TB drugs (isoniazid and rifampicin) as well as to the most powerful second-line medicines (any fluoroquinolone and any of the three injectable drugs: amikacin, capreomycin and kanamycin).

As early as 2006, WHO already “expressed concern over the emergence of virulent drug-resistant strains of tuberculosis (TB)” and called on “measures” that need to be “strengthened and implemented” to hinder the “global spread of the deadly TB strains.” But at the 2009 ministerial meeting of high M/XDR-TB burden countries, WHO Director General Margaret Chan counted 55 countries that had reported XDR-TB cases. And if the spread continues, the contagion could get as deadly as the time before antibiotics, and consumption victims just had to wait for death.

At the same conference, then-Health Secretary Francisco T. Duque raised the alarm about the higher-than-usual MDR-TB rate in the Philippines: 4 percent of new TB cases and 21 percent in re-treatment cases, against world averages of 1.7 percent and 7.7 percent, respectively.

“That approximately means 12,000 MDR-TB cases annually according to the Global TB Report of WHO,” said Duque. How many of those thousands turn into the extreme kind? By WHO’s estimate, 4.6 percent of all drug-resistant TB cases are XDR-TB patients: nearly one in every 20.

Counting 1,435 MDR-TB patients in treatment by December 2008, Sec. Duque warned three years ago: “These figures are both alarming and significant, because the prevalence rates observed in the Philippines are higher compared to the global average.” And normally effective treatments weren’t stopping the spread of MDR-TB.

Citing a national TB prevalence survey, the health chief reported: “The trend of MDR-TB cases showed that quality DOTS [Directly Observed Treatment, Short-Course] treatment helps substantially in the prevention and control of new MDR-TB cases, but the transmission continues as shown by the increase in prevalence among the new cases from 1.5 to 2.1 percent.”

Since then, health authorities and professionals had wrestled the number of new MDR-TB cases from about a thousand in 2008 and 2009 to 522 in 2010. But state funding and vigilance are needed to keep the virulence in check. Reason: the special drugs needed to fight resistant tuberculosis are expensive, so poor patients would not be able to afford them and could end up not only succumbing, but also spreading the infection to others.

While XDR-TB can be treated, even in countries with good health programs, as many as half of patients do not get well. “Successful outcomes also depend greatly on the extent of the drug resistance, the severity of the disease and whether the patient’s immune system is compromised,” stated the XDR-TB Fact Sheet.

So how many get the disease every year? By WHO’s estimate, more than half a million a year. That’s 500,000-plus sufferers able to infect others by germs in their breath or on what they wear and handle. Of that global contagion, only 3 percent get WHO-standard treatment. Indeed, in tens of thousands of those new cases, the very reason non-resistant TB became multidrug-resistant is poor treatment.

In her welcome address at the 2009 Beijing conference, WHO Director General Chan cited a 2009 WHO TB Report estimate that “more than half a million new cases of MDR-TB occurred during 2007” and that “over half of these cases were resistant to multiple drugs right from the start, and not as a direct result of substandard treatment.” That’s a quarter to a third of a million people who got infected by MDR-TB sufferers.

“This is the true alarm bell,” the former Hong Kong Director of Health warned. “This tells us that resistant strains are now circulating in the general population, spreading widely and largely silently in a growing pool of latent infection.” She added: “In most low-income countries, especially in Africa, the magnitude of the problem is unknown, as this form of TB is so difficult to diagnose.”

The high M/XDR-TB burden countries are: Armenia, Azer-baijan, Bangladesh, Belarus, Bulgaria, China, Congo, Estonia, Ethiopia, Georgia, India, Indonesia, Kazakhstan, Kyr-gyzstan, Latvia, Lithuania, Moldova, Myanmar, Nigeria, Pakistan, Philippines, Russia, South Africa, Tajikistan, Ukraine, Uzbekistan, and Vietnam.

And one thinks XDR-TB is a problem just for poor countries and communities, in fact, it could turn into a SARS-type global pandemic spreading by cough and contact with no reliable treatment to retard the contagion. “Unchecked, XDR-TB could take us back to the treatment era that predates the development of antibiotics,” warned Chan. “Preventing and managing drug-resistant TB is a global health imperative.”

(Excerpt from The CenSEI Report strategic research on drug-resistant TB and measures needed to address it. For a free copy of the Report with charts, data, video and online research, email report@censeisolutions.com.)

Joanne Angela B. Marzan is writer-analyst for the Center for Strategy, Enterprise and Intelligence, which publishes The CenSEI Report on national and global issues.