MEDICINE

Global emergency

Tuberculosis is once again causing alarm

PATRICIA CHISHOLM May 24 1993
MEDICINE

Global emergency

Tuberculosis is once again causing alarm

PATRICIA CHISHOLM May 24 1993

Global emergency

MEDICINE

Tuberculosis is once again causing alarm

At first, Janice Preston thought there was nothing more to her cough and fever than a bad cold. But after several visits to her family doctor and a course of antibiotics, Preston’s bug persisted. “I was losing weight, I kept coughing and I just didn’t feel well,” the Saskatoon resident recalls about the period from January to April in 1988. Finally, her doctor tested her for a disease that most people, including many physicians, had imagined belonged to the past—tuberculosis. Preston, like almost 2,000 Canadians that year, tested positive for tubercle bacillus, the bacterium that causes the disease commonly known as TB. Far from being under control, tuberculosis kills three million people worldwide every year. Fortunately, it usually responds to drugs, and after 2M> years of treatment, including surgery to remove part of her diseased left lung, Preston now is well. But recovery was arduous. “I had X-rays every month and the hole in my lung was not getting any smaller,” says the 52-year-old former clothing store manager. “I just wanted it to go away—I was so scared about what it could do.”

An ancient plague that was in decline in most developed countries until the mid1980s, TB has returned with a vengeance. In Europe, the incidence has jumped by 33 per cent during the past five years. Health authorities have reported a 12-per-cent increase in the United States between 1986 and 1991.

Between one-third and one-half of the world’s population carry the bacillus and 95 per cent of people who eventually develop TB and die from it live in the Third World. Last month, the World Health Organization declared that tuberculosis had become a global emergency, and warned that without better control at least 30 million people would die of it over the next 10 years.

In Canada, the rate of increase has been far less spectacular. Still, worried public health officials say that after an overall eight-year decline that began in 1980— when there were 2,751 new cases—the downward trend has ended. After bottoming out at 1,947 in 1988, the number of new cases had risen to 2,012 in 1991. The prospects are more ominous. Health officials estimate that the 35,000 Canadians now infected with HIV, the virus that causes AIDS, could be at significantly greater risk of developing TB. ‘This is not a time to be complacent,” says Dr. Donna Holton, of Health and Welfare Canada’s Laboratory Centre for Disease Control. “We are not doing well enough on TB control.”

Caused by a tough germ that usually requires a minimum of six months of treatment with more than one drug, TB is a relatively difficult disease to catch. Ordinarily, a person can become infected only after prolonged close contact—on average about six

months—with someone who already has the disease. Bacteria are spread when a victim coughs or sneezes. Even then, only about 10 per cent of those who carry the bacillus will go on to develop infectious tuberculosis, generally when their immune systems have been weakened by other illnesses, stress or age. Almost 50 per cent of new cases each year occur among people born in parts of the world where TB remains rampant, such as Asia, Africa and Central and South America.

Early this year, immigration laws were amended to ensure that refugee claimants underwent a medical examination, including a chest X-ray, within 60 days of arrival. (Other immigrants to Canada must have

£ had a medical before leaving home.) g But some public health experts ar5 gue that a lot can happen in 60 days “ and refugees should be tested when

they enter Canada for undetected TB.

In fact, two cases of infectious TB, both immigrant students, were found in January at Glen Forest Secondary School in Mississauga, Ont., a community of 460,000 west of Toronto. Public health officials then tested more than half of the school’s 1,200 students, and 23 students and two teachers tested positive. Dr. Peter Cole, who ordered the testing, said that tighter immigration procedures would go a long way towards controlling the disease in schools. Noted Cole: “Immigration does not even screen kids under 11. But younger kids are more vulnerable than older students.”

Other groups are also proving to be at higher risk than the general population. Twenty per cent of new TB cases are found among native people, although they represent only three per cent of the general population. Overcrowding, poverty and too few doctors have condemned Canada’s natives to one of the highest rates of TB in the country. Most other cases occur among elderly Canadians who may have carried the bacillus for many years and succumbed to the disease as they aged.

There are no publicly available figures on drug-resistant TB cases in Canada, but most medical experts believe that the number is rising. Dr. Monica Avendaño, associate director of respiratory medicine at West Park Hospital in Toronto, the only in-patient TB facility in Ontario, says that drug-resistant cases now constitute between 15 and 20 per cent of the patients she sees, up from less than five per cent 10 years ago. Said Avendaño, whose facility’s 29 beds are nearly always full: “I don’t want to alarm people, because we have the tools to control TB, but we need a much higher element of public awareness. TB was barely mentioned in medical schools for a while and now it is back.” Of all the new weapons available to fight this old killer, vigilance may prove to be the most crucial.

PATRICIA CHISHOLM