Call it the cough heard round the world. The World Health Organization's Feb. 26 report on how super strains of tuberculosis are on the loose has shaken physicians and policy makers everywhere to the marrow. And rightly so. The study, based on a massive survey of 90,000 patients worldwide, is eloquent testimony to the ravages of a modern killer: multi drug resistant tuberculosis, known as MDR TB in the chilly shorthand of public health, and its even deadlier next of kin, extensively drug resistant tuberculosis, or XTR-TB, which is practically untreatable.  

It's no surprise that poor countries, rife with malnutrition, claustrophobic slums, and especially AIDS are super TB's closest ally. Precisely because HIV strafes the human immune system, patients are sitting ducks for infection. That's why almost everywhere that AIDS is prevalent,  tuberculosis is soaring. Worst hit are the fragments of the old Soviet Union (led by Baku, the capital of Azerbaijan, where one in four new tb patients have the super variety) and Africa, with the highest rate of TB in the world and the worst public health statistics (only six nations on the continent managed to report to Geneva).  At this rate the Economic Forum at Davos might have to be scrapped in favor of the sanatorium that once crowned that Magic Mountain.

There is one bright spot in the developing world's deathlock with TB: Brazil. That may sound odd. Nearly a quarter of the 185 million Brazilians live below the poverty line, where contagions rage, and some 620,000 have AIDS, a third of all cases in Latin America. But unlike almost every other developing nation, Brazil has not seen the overall TB infection rate spike - much less a runaway outbreak of MDR-TB - among the most vulnerable population. The reason is as simple as it is controversial: free meds for HIV and AIDS patients. In 1996, the Brazilian congress passed a law requiring the government to hand out antiretrovirals to anyone with HIV free of charge. Drug companies were disgruntled, not least because Brazil browbeat them into slashing prices for the three-way cocktail of antiretrovirals, the state of the art medicine used to combat the virus. The same policy encouraged nearly two dozen other developing countries to take on the biggest pharmaceutical corporations as well.

No one ever claimed Brazil was a health spa, of course. After a brief lull, mosquito-borne dengue fever has come raging back, including the killer hemorrhagic variety. An outbreak of micobacteriosis, which causes a nasty hospital infection, leaves lasting surgery scars and can withstand all but the most drastic disinfectants, is on the loose. And while in theory anyone may be treated at the country's public hospitals, chronic underfunding has apparently forced brain surgeons in Rio de Janeiro to resort to common power tools, like home drills, in the operating rooms.

Still, it's hard to argue with success. A team of international scientists recently crunched the numbers and found that Brazilians living with AIDS who reguarly took the three-way cocktail of antiretrovirals had 80 percent lower TB infection rates than did patients who were not treated. (The study reviewed data from 1995 to 2001, but researchers say that the trend holds to this day.) The bottom line is that systematic use of  cutting edge HIV/AIDS medicine may be one of the best ways to keep this millennial scourge at bay. That may not be the best news for Big Pharma's shareholders. But it ought to give public health authorites a shot in the arm.