M. tuberculosis has been killing human beings for millennia. Signs of the effects of tuberculosis (TB) have been discovered in the remains of Egyptian mummies dating to almost 3,500 years ago.

Measured on this scale, the period of time during which we have had any effective medical knowledge of TB is quite short. In 1720 it was first suggested that "wonderfully minute living creatures" might be the cause of the disease. Developments in the second half of the 19th century included the first elucidation of the benefits of the fresh air sanitarium cure. And, in 1882, the bacterium was seen and identified by the aided human eye for the first time. But the most important breakthrough came in 1944 when streptomycin successfully, and very quickly, cured a critically ill patient. Scientists believed the ancient nemesis of humankind would be vanquished at last.

Alas, this was not the case. We should applaud the power of science for so advancing in less than 300 years our knowledge and treatment of a disease that has been an insidious killer for at least ten times that long. But we should be humbled, and moved to action, by the fact that nearly 60 years after a cure was discovered, TB continues to kill 2 million people every year, and remains the primary cause of death from a single infectious agent among adults in the developing world.

During the last five decades, the cure for TB has been available in theory. But rates of infection held stable or increased in impoverished regions of the world where poor living conditions remained the norm and/or the regimen of TB-treating drugs were not supplied or properly administered.

Now, with the advent of HIV, our primordial foe has returned as firmly entrenched as ever, and even more deadly. HIV and TB work together with a grim efficiency. It is estimated that among people infected with M. tuberculosis, only one in ten people with healthy immune systems will develop TB over the course of their lifetimes. Among M. tuberculosis-infected individuals with HIV, that number changes to one in ten per year, while one in every two or three such patients whose HIV has developed into AIDS will suffer from TB each year.

In other words, there is a direct correlation between HIV prevalence and incidence of TB infection. The increased incidence of TB in turn exacerbates death rates in HIV-infected patients, among whom TB is the single most common coinfection. The highest rates of TB/HIV coinfection can be found in sub-Saharan Africa, with large and growing epidemics in Asia (already home to the highest total number of TB-infected people) and Eastern Europe.

Given the ways these two diseases work in synergy, it is imperative that we devise strategies that allow us to fight them simultaneously. The World Health Organization (WHO) encourages voluntary counseling and testing programs to screen for both HIV and TB and, thus, to link individuals to treatment or prevention of both diseases. In short, healthcare programs combating HIV should cooperate with programs combating TB.

One method of TB treatment has become a shining example of effective medical and social interventions in resource-limited settings over the past ten years. Under the auspices of the WHO's Stop-TB Program, the Directly Observed Treatment, Short Course (DOTS) strategy has, by improving adherence, proven a means of ensuring successful therapy -- where medication and infrastructure permit.

Therein, however, lies the current dilemma in redressing the plight of the TB pandemic. When seen from clinical and public health perspectives, there has not been the full global commitment to providing said medication and infrastructure, both of which are also critical to addressing HIV and HIV-related morbidity and mortality. And while the curability of TB should in and of itself prompt us to necessary global action, the often-intimate relation of TB treatment to reduced HIV infection and complications is all the more reason to act.

Thinking more radically, the world community could make the most difference in fighting TB, HIV, and the other so-called "diseases of poverty," by addressing their root causes. They are endemic in nations with inadequate nutrition, underdeveloped medical infrastructure, insufficient housing, and the host of problems that both encourage the spread of these diseases and make them more lethal. Interventions addressing these problems of global development can be effective against both epidemics and improve overall quality of life.

Finally, at the individual level, members of the International Association of Physicians in AIDS Care (IAPAC), and all healthcare workers, must commit to understanding and implementing the practices by which HIV and TB can be simultaneously fought in daily interactions with their patients. Many thousands of years ago, TB began its prolonged attack on humanity with the illness of a single person. And it is at this grassroots point of contact -- supported by increased global policy and regional programmatic commitment to fighting HIV, TB, and the conditions that engender their devastation -- that these diseases might finally be brought to heel.

José M. Zuniga is President of the International Association of Physicians in AIDS Care, and Editor-in-Chief of the IAPAC Monthly.