Tuberculosis is a disease of the poor that thrives in crowded, unsanitary settings. Although it is still found in the United States in prisons and homeless shelters, by the 1980’s it had largely disappeared from the general population in the industrialized countries of the North. But now it has struck with ferocious force in the developing nations. Worldwide, TB takes the lives of two million people a year. In Sub-Saharan Africa, the combination of the human immunodeficiency virus, which causes AIDS, and TB results in a death-dealing co-infection. This is because H.I.V. weakens a person’s immune system in a way that makes those infected especially vulnerable to development of active TB disease. Ninety percent of healthy hosts wall off the tuberculosis bacillus and never develop the disease, but 40 percent of co-infected patients may develop it immediately after exposure.
During the recent AIDS conference in Bangkok, Nelson Mandela, former president of South Africa, who himself contracted tuberculosis during his 27 years in prison, urged that greater attention be paid to this insufficiently recognized aspect of the AIDS pandemic. He noted that the battle against AIDS cannot be won unless a simultaneous battle is fought against tuberculosis, which has become the single largest killer of people with H.I.V. African women in the age range 15 to 24 are twice as likely to be H.I.V.-positive as men in the same age group, and as a consequence they fall victim at disproportionately higher rates to the tuberculosis that is ravaging their countries.
Lack of access to treatment in the developing world remains a major roadblock in efforts to control the disease. For those who do have access, the most successful form of treatment is considered to be what is called directly observed therapy, short course, or DOTS. As its name suggests, this approach to treatment requires that a health or community worker or a family member ensure by direct observation that the patient takes the prescribed daily medication, at least for the first two months of a six-month period. The cost can be as little as $10 for the entire treatment. DOTS has proven effective in African countries like Sudan, as well as in the Middle East and in Peru and Nicaragua. Though rates of success vary according to the region, an average of 82 percent have been cured. But only 25 percent of the world’s poorest populations are covered by DOTSa sign that much more needs to be done in the area of access.
Because it extends over a long period of time, however, DOTS is arduous. Yet if they are not under close supervision, patients who begin to feel better are often tempted to stopin part or entirely. Such interruptions can lead to drug resistence and relapse, and the consequent further spread of drug-resistant strains. Multi-drug-resistant TB, or MDR, has in fact become a major obstacle to efforts to eradicate TB. This is true not only of Africa. Russia too has been hit hard. Nearly half of all TB cases are resistant to at least one of the first-line drugs used in DOTS. Treating people with MDR, moreover, takes far longeralmost two yearsand is much more expensive.
To meet such challenges, the development of new drugs is urgently needed. Those presently in use were developed decades ago. Relatively little research and development, however, is being conducted by profit-oriented pharmaceutical companies, because they foresee little financial gain from developing newer drugs for populations with minimal purchasing power. As noted in a report by the Nobel Peace Prize-winning humanitarian aid group Doctors Without Borders in March 2004, the pharmaceutical industry’s lack of interest in developing these drugs has brought the search to a virtual standstill. Other obstacles include the lack of drug dose combinations suitable for children, and better diagnostic methods. Early diagnosis is key to effecting a cure.
One positive step in the struggle against the rising incidence of TB has been taken by a public-private partnership, the nonprofit Global Alliance for TB Drug Development, established in 2000. It is backed by the World Health Organization and other international institutions and receives funding from the Bill & Melinda Gates Foundation and the Rockefeller Foundation, as well as from a few donor governments like the Netherlands and the United States. But as with AIDS itself, greater political commitment and more funding are needed from all the wealthy nationsa commitment that would not only promote active sponsorship of the development of new drugs, but also wider access for those lacking even the older therapies.
AIDS is not curable; tuberculosis is. It should shock the conscience to realize that far too little is being done to cure and prevent tuberculosis, especially in those countries where it works in such deadly tandem with the virus that leads to AIDS.
