World TB Day, March 24, 2000 – Forging new partnerships to stop TB

Nearly 2000 years after Hippocrates described the “almost always fatal disease of the lungs” in 460 BC, tuberculosis (TB) is a global public health crisis (1). In the early 1800s, one in five Canadians had TB in their lifetime. As rates fell because of an improved standard of living, effective control of transmission by public health means and effective therapy, there were hopes for TB’s eradication (although disease remained at unacceptable levels among the Aboriginal population) (2). In Canada, approximately 2000 new cases and more than 100 deaths are reported each year (2). The number of Canadians asymptomatically infected with the tubercle bacillus (ie, skin test positive) is unknown. Of those adults who become skin test positive (ie, infected), there is approximately a 5% risk in the year after they become skin test positive and another 5% risk over the rest of their lives that they will develop TB disease of the chest, nervous system, bone, abdomen, etc. For the young child, the risk of disease, as opposed to just infection, is increased to 40% in the first year after infection when the skin test becomes positive.

The international situation has changed what now happens in Canada, at least in major urban centres. Travel to and migration from developing countries regularly brings TB to our doorstep. While the rates of tuberculosis have fallen throughout the developed world, disease in the developing world has never been brought under control. In 1997, an estimated 1.9 billion people worldwide had active TB. The World Health Organization (WHO) has warned that by 2020, nearly three billion of the world’s six billion people will be infected, unless global control efforts are strengthened (1). Annually, only five million people among the eight million new cases worldwide receive any treatment and 1.9 million die (1,3). Twenty-two countries, mostly in Africa and Asia, account for 80% of active TB cases worldwide. The HIV/AIDS pandemic has contributed to the TB burden, with 10.7 million people in Asia and Africa suffering dual infection with HIV and Mycobacterium tuberculosis (1).

Migration of the disease from endemic areas to Canada, the United States, western Europe and Australia is also a reality as thousands from developed countries visit developing countries and people flee war and poverty, seeking better opportunities in developed countries. In 1995, it was estimated that one in every 200 people was displaced as a result of war or political repression (4). Of the 100 million people killed in armed conflict this century, 90% were civilians (4). The 18% of people living in the developed world (including 5% in Canada and the United States) use more than 60% of the world’s nonrenewable resources, resulting in a very attractive lifestyle (5). Further, the developed world spends US$1,500 to US$3,000/person/year on health care while many regions, particularly those in Africa, spend scarcely US$1/person/year on health care. With the striking disparity in opportunity and consumption, there is little wonder that many are attracted to developed countries, including Canada. The risk of tuberculosis is increasingly ‘globalized’.

For treatment of TB, the WHO advocates directly observed therapy to maximize cure rates and decrease the emergence of drug-resistant strains. Only 500,000 of the five million new patients treated annually receive the necessary directly observed therapy required to prevent emergence of resistant TB. Multidrug-resistant TB (MDR-TB) is defined as resistance to the two most important anti-TB drugs, isoniazid and rifampin. MDR-TB has been found in every country in which it has been sought (except Kenya), resulting in a mean prevalence of 4.3% among all TB cases and much higher rates in certain countries (6). Select parts of Canada have rates of MDR-TB equivalent to those in the developing world. In the developing world, treatment of a case of MDR-TB ranges between US$800 and US$10,000, far beyond reasonable capability and an “expensive luxury” (5). MDR-TB has become the greatest natural threat to global survival, and, thus, the WHO has taken the unusual position of declaring MDR-TB an international emergency, the first time for such a declaration.

While the risk of acquisition of TB is apparently low during air travel, ie, only two of seven investigations of contacts of infected air travellers had demonstrated transmission (8), more recent experience with airline staff in Canada involved in the airlift of refugees from Bosnia shows that the risk is not to be ignored. TB transmission has been demonstrated on trains and cruise ships as well (8). With a successful global economy comes the necessity to address the global communicable disease risk of MDR-TB. We cannot have it both ways – a successful global economy and freedom from this deadly infectious disease – without a serious financial investment. The potential for transmission means that there is a need to maintain judicious annual screening of selected occupational groups including health care workers and the screening of travellers returning from endemic areas. Travellers, including children, may bring back home more than souvenirs.

Many Canadians have grandparents and great-grandparents who died of tuberculosis. We must make sure that the same will not be said of our grandchildren and great-grandchildren. For those born in Canada, acquisition of TB now is viewed as a failure of the medical and public health systems. For people from the developing world, even well-educated and wealthy individuals, TB still continues to carry a terrible stigma, an outward and visible sign of a heritage of poverty. The disclosure of personal histories of TB by such heroes as Nelson Mandela has helped, but an overwhelming negative association persists. Understandably, in the absence of more sensitive educational intiatives, some patients want neither to be diagnosed nor treated.

The TB plight of refugee claimants to Canada and the TB risk from immigration has awakened discussion about tuberculosis and MDR-TB. There is a compelling need for global eradication initiatives that cannot be ignored. It is not ‘their’ problem; it is all of ours or soon will be. It is we in the developed world who are ‘on another (very small) planet’, free, at the moment, from endemic TB and MDR-TB. There is much more that can be done in Canada and especially in select cities, to bring TB, once again, under control. This includes education, enhanced surveillance, improved clinical management and provision of new facilities, both outpatient and inpatient, equipped to handle the contagious patient with TB and MDR-TB. With US$1 billion dollars in aid and a dedicated network of public health professionals, New York City was able to bring resurgent TB under control and re-establish a decline in the case rate (1). The overall American rate has, however, remained unchanged among foreign-born people. Quite simply, no one in the developed world is going to win against MDR-TB until everyone in the developing world wins. Global eradication of an infectious disease, smallpox, was achieved once before (7), and the control of polio is very near (9,10). A new WHO-hosted initiative, STOP TB, is working to encourage political will and social mobilization against the disease. Canada must also take a leadership role. Guidelines for TB screening in children and youth can be found in the book, Children and Youth New to Canada – A Health Care Guide (11). We can all contribute to the global effort through the prompt diagnosis and effective treatment of our own patients while being supportive of international efforts.