Archive for September, 2013

Lyme Disease Redux

Monday, September 23rd, 2013

Yesterday's edition of The New York Times had an article by an experienced academic physician that called for a new Lyme disease vaccine, Dr. Stanley A. Plotkin, a professor of pediatrics at the University of Pennsylvania said new CDC data had been released showing a ten-fold greater incidence of the disease than was previously thought. He explored the history of the vaccine put on the market in 1998 by a major US pharmaceutical company, then called SmithKlineBeecham (now it's become GlaxoSmithKline).

I looked for that news release from the CDC and found their old numbers in an August, 2013 online site (30,000 cases a year reported by state and DC health departments) had been superseded by new preliminary figures coming from three different databases. So instead of the numbers we've thought represented human cases, 96% of which occur in thirteen states in the Northeast and upper Midwest, we have 300,000 cases a year, still heavily concentrated in those regions.

The white-footed mouse is the main reservoir for Lyme disease.

The white-footed mouse is the main reservoir for Lyme disease.

In 2011 Richard Ostfeld, a senior disease ecologist working at the Cary Institute in New York published an excellent book, Lyme Disease: The Ecology of a Complex System, aimed at a mixed readership of scientists and nonscientists. I've mentioned this before but should reiterate his finding that white-footed mice were a highly significant reservoir (host animal) for the bacteria that is then transmitted to humans by, in this country, one particular insect-like species, the black-legged tick.It's actually an arachnid, cousin to spiders and scorpions. There are other host species and a variety of predators, weather/climate conditions and habitat factors also play a role.

His work predicted a surge in cases of Lyme disease in the spring of 2012, based on an acorn crop boom-and-bust cycle. The town of Whitman, MA, published an online summary of this prediction quoting the Cary Institute's press release. In brief that mouse species' population soars in a year with an abundant acorn crop and falls markedly when acorns are scarce. The organism that causes Lyme disease is a bacterial species called Borrelia burgdoferi, The white-footed mouse is a superb host for that bug; the mouse doesn't get sick; the bacteria multiplies and there is an abundant supply of B. burgdorferi waiting to spread to other animals. Those mice are also frequently bitten by the tick in question, especially around their ears.

In the seasons of acorn abundance the mouse population soars and the ticks, which need a blood meal three times in their life span (once in the larval storage, once as a nymph and once as an adult), have plenty of mice to feed on.

But then comes a lean crop year for the acorns and the B. burgdorferi infected ticks have to find other blood sources for their next meal. Any mammal will do, but humans are certainly among those available. If we are camping or hiking through an area where the tiny tick nymphs or abound, we may never notice the bite. We may not even be wearing any  bug spray or perhaps have more skin exposed than is safest. The nymphs are cold-blooded, so the countryside has to warm up from Winter's blasts before they are ready to feed. If it's a milder cold season (and with global warming that may be the case), the nymphs may be out looking for a meal as early as April.

Forest ecologists from the Cary Institute noted 2010's crop of acorns was very heavy;  mouse population numbers rose appropriately. Then, in the fall of 2011, their research site had a marked acorn scarcity. Mouse numbers plummeted leading to a prediction from the group of at least 20% more human cases of Lyme disease.

Let's return to Dr. Plotkin's article in the New York Times. Eight years ago he almost lost an adult son to a cardiac complication of a Lyme infection. Alec D. Plotkin was walking his dog on an August day in Pennsylvania when he abruptly lost consciousness and collapsed. In 2011 his father (Dr. Plotkin) published an article, "Correcting a Public health Fiasco: The Need for a New Vaccine against Lyme Disease," in the Journal Clinical Infectious Diseases. At that time the yearly US case estimate was (reported cases only) roughly 20,000, but as Dr. Plotkin noted, "the extent of underreporting is unknown." He mentioned that the state of Connecticut's statistics would imply that 1% of its entire population could develop the ailment over a ten-year stretch and that nine of sixteen countries in Europe, where Lyme disease is caused by a different variant of B. burgdorferi, had data showing an increased case incidence over time.

But you may or may not have the pathognomonic rash.

But you may or may not have the pathognomonic rash.

On Septmeber 19, The New York Times published the obit of Dr. Stephen E. Malawista, who, as chief of rheumatology at Yale School of Medicine had, with his postdoctoral student, Allen C. Steere, defined Lyme disease. In the fall of 1975 two women from Lyme, CT and Old Lyme had developed joint swelling, peculiar rashes and neurological complaints undiagnosable by their local physicians. Each went to Yale seeking answers.

Researchers there noted that the clinical picture, which was originally felt to be juvenile rheumatoid arthritis, had occurred in clusters and at a rate 100 times that expected for JRA. It also was clustered in warm-weather months. Dr. Malawista suggested the name Lyme arthritis and he and his team made the eventual linkage with tick bites. In 1982 Dr. Willy Burgdorfer found the bacterium responsible and Yale scientists wnet to work to develop a vaccine.

It was finally licensed in 1998, but a series of events, detailed by Dr. Plotkin in his medical article, led to it being removed from the market four years later. In brief: the CDC's Advisorty Committee on Immunization Practices (ACIP) gave greater emphasis to protective clothing, tick repellants and, in the event of an infection, consistent early diagnosis and antibiotic treatment, than to the vaccine, even for those at high risk. Then it was only tested in adults and more in the group who got the vaccine than in the control group experienced some transient joint soreness...but not actual arthritis (typically red,hot, swollen, painful joints. The marketing of the drug was inappropriately directed at a lay, not a medical audience. A class action suit was brought against Glaxo, the drug company which produced the vaccine and, in spite of later studies showing no increase in Lyme-related joint disease, was settled by Glaxo for $1 million in 2003. Only the lawyers involved got any money.

By then the vaccine was off the market.

It's clearly time for it to come back, perhaps in a new version, perhaps developed by a different company, but, in any case a human Lyme disease vaccine is needed.

 

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Posted in black-legged tick, Borrelia burgdorferi, CDC, Dr. Richard S. Ostfeld, Dr. Stanley A. Plotkin, Dr. Stephen E. Malawista, FDA, Lyme Disease, Lyme disease vaccine, white-footed mouse | No Comments »

Ditch fad diets; use common sense instead

Monday, September 16th, 2013

When I returned home on September ninth from a twenty-eight-day trip, I found stacks of mail, magazines and newspapers plus about 650 emails to wade through. Most got short shrift and the old papers were pitched. But then I found four editions of JAMA and started reading selected articles. Over the years I've deplored the menagerie of fad diets that have been described, advertised and exploited for profit.

You don't have to weigh and measure each time you eat a pea

You don't have to weigh and measure each time you eat a pea

So coming upon a Viewpoint piece in the Aug 21, 2013 edition, I read with intense interest  "A Call for an end to the Diet Debates." The pair of PhDs who authored the two-page discussion, Sherry L. Pagoto and Bradley M. Appelhans, are both academics, serving on the faculty of major medical schools. They commented on the host of studies and four recent meta-analyses that have reviewed the results of a variety of diets varying the amount of protein, carbohydrates and fats one is allowed.

Their conclusion is they don't differ in their results in any significant way and that sticking to a diet and adding exercise is what counts.

There's a second comment that was striking: in spite of markedly increased percentages of US adults being overweight or obese, the chances of their getting any counseling on the issue when they see their primary care physician have fallen. Researchers from the Penn State College of Medicine published an article in February of this year titled "A silent response to the obesity epidemic: decline in US physician weight counseling." The National Center for Biotechnology, a National Library of Medicine section, published a short version of this study comparing outpatient visits in 1995-1996 to those in 2007-2008 (the most recent data available from an ongoing national ambulatory medical care survey).

What I think this means is that we still don't pay physicians enough for preventive medicine interventions; we pay much more for procedures, what I think of as "Catch-up Medicine."

Over the past forty-seven years, ever since I graduated from medical school in 1966, I've seen a host of fad diets come and go. The Rice Diet, invented at Duke where I served as an intern and resident, is still around, but was originally utilized as a very-low-protein approach for patents with severe kidney disease. Since then we've seen high protein, low protein, several that focus on carbohydrates, and, this year, in a blog from a Phoenix newspaper, an entertaining look at "5 Fad Diets to Avoid in 2013."

Those include: a gluten-free diet (reasonable only for those who actually have been diagnosed, preferably by an experienced physician, as having gluten intolerance); the Dukan Diet (I'll supply a link to the WebMD review of this French approach), essentially a high-protein and limited calorie approach that may work short-term, but doesn't supply a balanced diet for the years to come; the alkaline diet (here's another review from WebMD) which claims to alter your blood pH, which is nonsense, but basically is a fresh fruit and vegetable plus hydration approach which in itself isn't unreasonable for those who don't have kidney disease or severe diabetes. But the components of this diet can easily be purchased in your supermarket and therefore don't need to be obtained through a website; the HCG diet, dangerously restrictive in calories and supplying a hormone that ought to be used only by a physician's prescription, usually for fertility issues (here's a Mayo Clinic review that says the diet dangerous); and finally, the beef tapeworm diet where some go over our southern border and actually pay to be infected with a parasitic disease. I don't feel the need to even comment on the logic of that approach.

So what does make sense to me is, as always, eating less and doing more.

Of course that's not as easy as it sounds. Some of my previous posts have alluded to the ways I've made this work for me, but you may or may not find them to fit your own lifestyle.

Use a good scale, but it doesn't have to be this fancy.

Use a good scale, but it doesn't have to be this fancy.

So I'd suggest the following: 1). Don't fall for the expensive fad diet ploy; eat in whatever pattern suits you (three meals a day is my habitual approach, but I sometimes eat two with a medium-sized brunch in anticipation of an evening event that includes food in abundance), but avoid snacking and late evening binges; 2) Eat balanced meals with more fruits and vegetables and less (or no) red meat than is typical for many Americans; 3). Find a form of exercise that you're comfortable with and do it almost every day (We walk an hour a day and I spend another hour or often two in the gym six days a week; that may not work for you, especially if you have a full-time job.); 4). Don't beat yourself up when you fall off your eating and exercise (figurative) bike, but get back on it ASAP. 5). Weigh yourself daily on a good scale, at the same time of day, wearing nothing (or as little as possible) and keep a record of your weight. 6). Don't expect to lose twenty-five pounds in a few weeks. If you did that, my bet is you'd gain it all back in a year. Aim for a pound a week.

I took my eating plan, which I first decided on in 1996 or 1997, and really started using in early 2009, and wrote down all of the ideas and some recipes my wife added; I ended up with a 50,000 word book that I may eventually try to polish enough to publish. There are a number of specifics that I've added to the six basics concepts in the paragraph above, but I'll mention those at another time.

I still occasionally struggle with one aspect of my eating plan; late-night reading can be a prelude to minor binging. And events with food are another potential minefield. But I've managed to get back to my diet whenever I'm above what I consider to be my acceptable range.

So I have four by six inch cards that tell me: "Don"t snack at events."

I'll bring one along tonight when I go to a writers' meeting; there will be two speakers, but someone is bound to have lots of snacks for the group.

I don't plan to eat them.

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Posted in exercise, fad diets, lifestyle changes, sensible weight loss | No Comments »