We spend a lot of time on bird flu here because, as I have explained, it is a useful lens through which to look at the void in public health leadership as well as preparedness issues of the system that allegedly protects us from bird flu and much else. We don’t spend all this time on bird flu because we believe it is the most important public health problem in the world. It could become so, but it isn’t now. Our view is that if it ever does, we should be ready for it, and it takes leadership for that to happen. But there are other gigantic problems, too, and we want to highlight one of them because it also bears on pandemic flu preparedness. In this case it’s another potential public health time bomb, extreme drug resistant tuberculosis (XDR TB).
Tuberculosis was once one of the world’s scourges, dubbed by Osler, The Captain of the Men of Death (after Bunyan). One hundred years ago it was one of the leading causes of death, if not the leading cause. When I was born there were no drugs to treat it and it was routine for health care workers to convert to a positive TB test during the course of their schooling and training. The first antibiotic active against TB was streptomycin in 1946. Then came the cheap and effective mainstays para-aminosalycilic acid (PAS) and isoniazid (INH) in the late 40s and early 50s. Since then other drugs like rifampicin and pyrizinimide in combination have produced 98% cure rates and now many people in developed countries think of the disease as a historical curiosity (although it remains prevalent in some groups and is still a serious problem). In some cases resistance to these first line drugs has developed, but there have been back-up drugs available as a second line of defense.
If the TB organism is resistant to both first line drugs it is called Multiply Drug Resistant TB (MDR TB). Now it is back in a form that is almost untreatable except by very expensive drugs with bad side effects. The new bug is resistant to most of the drugs we’ve been treating it with. XDR TB is resistant to both the first line drugs and at least three of the six classes of second line drugs. Described in South Africa in September (by a close friend of mine, it turns out), there are also cases in South Korea and the former Soviet Republics, the rest of the world has been waiting for the other shoe to drop. A report from Toronto indicates it might already have dropped.
A Toronto hospital is treating several cases of extensively drug resistant tuberculosis, with one of the patients being held in isolation under court order, the doctor overseeing the treatment said Monday.
Public health experts fear the dangerous strain of tuberculosis, which is susceptible to very few of the antibiotics normally used to treat TB, is a global health crisis in the making.
Dr. Monica Avendano, the physician in charge of the tuberculosis service at West Park Healthcare Centre, said since 2004 her unit has treated five or six patients with XDR TB, as it is called. All the patients were either infected abroad or infected by a family member who picked up the highly resistant strain elsewhere, she said.
“Currently I am treating three,” said Avendano. “All of them have a previous history of tuberculosis that was not well managed.” (Helen Branswell, Canadian Press)
The key element here, as Branswell notes in her (as usual) excellent article, is “not well managed.” The patients probably caught the disease from others who were under treated with conventional drugs allowing a resistant strain to emerge. Authorities have not released personal information on the patients except to say two were young women who got the XDR version after visiting sick grandmothers in another country. These are not the first cases in North America or even in Canada (see summary at ProMed). Countries that have significant XDR TB also have scant or deteriorated public health infrastructures. TB is a public health problem as much or more than a clinical one.
Meanwhile, a nasty XDR TB is spreading to a neighborhood near you:
When the World Health Organization announced last September that a new and deadly strain of XDR TB had been detected in Tugela Ferry, a town in the South African province of KwaZulu-Natal, it noted that 53 people had been found to have been infected with the strain. Of those, 52 had died; most lived less than a month after testing positive for the strain.
By November, the number of infected there had swelled to at least 300 known cases, though it is assumed those cases may represent a tip of the iceberg.
Bird flu? Very bad XDR TB? What next? Well, don’t throw up your hands. These are different diseases but in one respect what we need to cope with them is the same: a resilient and robust public heath infrastructure. Infrastructure is the part of the system you don’t see, but it’s the part the visible system depends on. What’s in infrastructure? Substance abuse programs, surveillance, maternal and child health, vaccination and immunization, injury control, mental health services and much more. Not the stuff you read about here or that makes the headlines, but bread and butter public health. Many of these programs are directly applicable to the XDR TB and bird flu problems: substance abuse (HIV/AIDS is a risk factor for XDR TB), mental health services (homelessness is a risk factor for TB), surveillance (keeping track of TB and influenza and ?), maternal child health (pregnant women and babies at special risk from flu), etc. Not to mention the TB/communicable diseases bureau itself. Hardly anything that goes on in a health department doesn’t touch in some way on our ability to respond to XDR TB or bird flu or whatever comes up next. A strong public health infrastructure is the Swiss Army Knife of Preparedness.
And when it doesn’t work, you get cases of TB that are “not well managed.”