Preventive Medicine Column
Dr. David L. Katz
Lincoln told us that a house divided against itself cannot long stand. If this is true of the houses in which the body politic gathers, it is no less true of the gathering housed by our very bodies.
Last week, I spoke at a plenary session of the Council of State and Territorial Epidemiologists annual meeting in Pasadena, California. I shared the session podium with a former Yale colleague, and now Dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston, Dr. Peter Hotez.
Dr. Hotez’ work focuses on what he calls neglected diseases. These are infectious disease scourges, mostly parasites, affecting the 1 billion or so people on the planet still prone to starvation while the rest of us succumb to obesity. This is the population barely hanging on to the bottom stave of the socioeconomic barrel.
Dr. Hotez’ talk, complete with a video showing such things as advanced elephantiasis (technically, lymphatic filariasis), was extremely compelling. His work is vitally important, facilitating the widespread use of antiparasitic drugs in areas of greatest need around the globe.
Before even leaving for California, however, I had already started this column, inspired by the book I am now finishing, An Epidemic of Absence. The author, Moises Velaszquez-Manoff, convinces me that much of the modern burden of autoimmune and inflammation-related disease in developed and developing countries owes something, and perhaps much, to the wholesale eradication of organisms once resident within us. This is provocative stuff for me, given the prevalence of such diseases in my clinical practice in Connecticut, and the frequency with which these conditions- think MS, Lupus, inflammatory bowel disease- resist conventional therapies.
We have long known that resident bacteria outnumber our own cells by an order of magnitude. Velasquez-Manoff explores much further reaches of our inner menagerie, showing associations between the eradication of parasites and microbes and the onset of specific modern ills in distinct populations. Exposure to malaria is clearly not a good thing, but it may- for some of us at least- prevent multiple sclerosis. Intestinal worms may have the potential to prevent, and perhaps treat, inflammatory bowel disease. The bacterium Helicobacter pylori may reduce the risk of certain cancers, even if increasing the risk of others. And in this and many other cases, risks and benefits may vary with the timing and circumstances of exposure.
Velaszquez-Manoff’s account, relevant to everything from rheumatoid arthritis to obesity, is logical, beautifully reasoned, clearly articulated, and meticulously researched. Dr. Hotez is better qualified than I to find subtle flaws in the case, and I encouraged him to read the book. I hope he does so, and look forward to his impressions.
For now, as a practicing physician reading this book, my abiding fascination was plagued by frustrations. We don’t yet know what organisms are best for whom, when, or in what doses and combinations. Much work remains.
And these frustrations were acutely compounded by Dr. Hotez’ impassioned reality check. There may, indeed, be an epidemic of absence for those of us in the privileged majority; but Dr. Hotez devotes his considerable expertise to the plight of the 1-billion person minority still mired in epidemics of the old-fashioned kind. It’s a whole lot easier to contemplate the downside to killing intestinal worms when intestinal worms aren’t busy killing you.
The notion that parasites are ravaging populations- and clearly, they are- is hard to reconcile with the already impressive and fast accumulating evidence that the aftermath of eradicating parasites is ravaging other populations. If Dr. Hotez is right, must the argument of Velaszquez-Manoff be wrong? If Velaszquez-Manoff’s argument is valid, are Dr. Hotez and colleagues doing inadvertent harm along with obvious good?
The great challenge before us now- inspiring, and potentially confusing for the foreseeable future- is to deal harshly with the true enemies within, while allowing for the potential presence of friends. I believe Velaszquez-Manoff is right, and it is past time to commune with the unity on which our health depends. It turns out that while unity is intrinsic to community, the converse may be just as true. We unbalance populations both without, and within, at our peril. But I am certain that Dr. Hotez is right, and the parasites ruining lives must be hunted down.
We are aiming at the power of a balance we are just beginning to understand, a unity we have just begun to recognize. Much, therefore, will depend on the balanced application of our powers, and the wisdom within which we house them.
Dr. David L. Katz; www.davidkatzmd.com