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Originally published November, 1997

Commentary

Wanted: A practical approach to TB diagnostics

Richard T. Root

Contrary to what many in the industrialized world believe, tuberculosis has not been eradicated. It has not even been kept under control. In fact, according to the World Health Organization (WHO), TB killed more people in 1995 than at any other time in history. In this decade alone, it is estimated that at least 30 million people will die from this disease.

In the near term, most of those victims will be from Third World countries, completely out of sight of the inhabitants of developed nations and of the majority of IVD Technology readers. But that situation is changing rapidly—and not for the better. Despite our best efforts to cleanse our countries of TB—and although an effective, low-cost treatment exists—TB is a raging epidemic on this planet. In 1993, for the first time in history, WHO declared a global health emergency because of the continued spread of TB.

One of the reasons that current conditions justify the WHO declaration is that many nations with strong economies—those in the best position to combat the disease—believe they are no longer at risk. But this is a mistaken and deadly bit of self-deception. In 1992, Nobel laureate Joshua Lederberg, PhD, said that with regard to infectious diseases, "the world really is just one village." And documented cases indicate that multidrug-resistant TB is spreading through our village at a very rapid pace. On an airline flight, remnants of a cough laden with TB bacteria drifted through the cabin, infecting passengers. In Maine, a single shipyard worker infected over 400 others with multidrug-resistant TB, most by as little as a few seconds' conversation.

For most of us, the chances of infection through such rare occurrences seem slight. But consider the fact that one-third of all humanity is already infected. And this infected population is moving around the globe as never before. In 1990, the American Medical Association estimates, nearly one-third of the 26,000 TB victims in the United States were foreign-born. The United States screens legal immigrants for active tuberculosis, but not visitors; and during 1993 there were 21.4 million nonimmigrant—and thus unscreened—arrivals in the United States. Suddenly, the chances do not seem so slight.

Tuberculosis is very good at finding the chinks in our health-care armor, and we have plenty of them, beginning with our methods for diagnosing the disease. Current work in our industry seems focused on supplying an advanced, genetic-based diagnostic for use in developed countries. Such tests cost between $8 and $20 apiece, and may require complex, automated, and very expensive instruments. So intent are companies on this goal that they have abandoned development of simple, low-cost diagnostics, fearing that these would harm present and anticipated sales of instruments and consumables.

But the high cost of genetic tests guarantees that they will never be used among the vast populations that desperately need a TB diagnostic. Indeed, cost is the major impediment to acceptance even in the United States. What is critically needed is a simple method with a very low total cost, and it is doubtful that any gene-amplifying IVD will meet these conditions in time to make a difference. It would be a pleasure, and a surprise, to hear of a company planning to sell such a test to Third World countries for a dollar or less.

We in the IVD business need to take a very hard and realistic look at this situation, because we can make a difference. WHO is engaged in an initiative to control the spread of TB. To succeed, it does not need new antibiotics, but it does need an inexpensive and rapid sputum-based IVD that can replace the acid-fast stain technique of diagnosis. Such a product would be a major contribution to the initiative.

The history of mankind's battle with TB is filled with great labors and momentous sacrifices. In 1945, for instance, George Merck returned the patents for streptomycin to Rutgers University because this antibiotic was becoming so important in fighting TB. He did so at the request of Nobel laureate Selman Waksman, who had urged that the production of streptomycin be opened to competition in order to lower the cost of treatment. In agreeing to do as Waksman asked, Merck & Co. gave up millions in profits, but maintained its resolve to do battle against TB.

But now we face the possibility of losing the battle merely for lack of resolve. We in the IVD industry need to resolve to provide the needed diagnostic at the requisite cost. And we should provide it to the entire world—not only to those who can pay for it now.

True, our corporations exist to make profits, but this sometimes requires them to take a risk—such as producing a product for a very low-paying market—in the hope of opening new opportunities. In this case, the risk seems far greater than it is. One of the payoffs of success will almost certainly be that the economic status of the affected countries will be vastly improved. The 1996 WHO report states that the Thai economy may lose $7 billion by 2015 due solely to TB. India is already losing an estimated $372 million each year. And the American Lung Association has testified that controlling TB could result in a $24-billion annual increase in economic output from developing countries. That represents new purchasing power for the people in those countries, much of which will be directed toward health care—including other diagnostics. With 98% of TB victims living in developing countries, it would be difficult to identify another market with equivalent growth potential.

Sooner or later, the world's leading economic and technological nations will be forced to do battle against the maladies that victimize the rest of humanity—if for no other reason than to protect themselves. In this case, sooner is unquestionably better, and IVD manufacturers can play a key role in leading the way.

Even if they can do nothing else, IVD manufacturers should educate themselves about the current crisis and battle to control TB. A good starting point is the list of Web sites about tuberculosis found at http://www.cpmc.columbia.edu/tbcpp/extres.html. The WHO site listed there is particularly worthy of attention.

Richard T. Root is senior project leader and head of the antibody technology laboratory at Bard Diagnostic Sciences, Inc. (Redmond, WA), and a member of the IVD Technology editorial advisory board.

For further reading

"Cost Resistance Slows Adoption of Nucleic Acid TB Tests," IVD Technol, 3(5):21—22, 1997.

Garret L, The Coming Plague: Newly Emerging Diseases in a World Out of Balance, New York, Farrar, Straus and Giroux, 1994.

Groups at Risk: The WHO Report on the Tuberculosis Epidemic 1996, New York, World Health Organization, 1996.

Kenyon TA, Valway SE, Ihle WW, et al., "Transmission of Multidrug-Resistant Mycobacterium Tuberculosis during a Long Airplane Flight," N Engl J Med, 334 (15):933—938, 1996.

Ryan F, The Forgotten Plague: How the Battle against Tuberculosis Was Won—and Lost, Boston, Brown, Little & Co., 1992.