Archive for the ‘Centers for Disease Control and Prevention (CDC)’ Category

Hantavirus syndromes part 2: the Four Corners and beyond

Wednesday, May 30th, 2012

I'm normally happy to see this sign, even in the Four Corners area

It's rare to have a "coup" in medicine, but one of mine happened just over 15 years ago. In mid-May of 1993 I was making rounds with my two staff Nephrologists and their Internal Medicine residents when I heard about a disease that had just been discovered in New Mexico. I was the "old man," the Commander of the Keesler Air Force Base medical center near Biloxi, not as current in my medical reading as my junior docs, so when I ventured a guess this would turn out to be a different Hantavirus syndrome and mentioned I have saved articles on the illness in my "War File," nobody paid much attention.

Several days later the CDC announced an unknown virus, presumed to be a Hantavirus, was causing a highly lethal pulmonary syndrome. There was an immediate scramble to borrow my War File.

El Nino had brought more rain than usual to the Four Corners area in the Fall of 1992 with a resultant growth of nuts, seeds and berries. Some of the local wild animals, including the deer mice, had markedly increased their population numbers.

The initial known victim was a young, physically fit Navajo man who had abrupt onset of breathing difficulties, was taken to a hospital and died soon afterwards.

Then it was found that his fiancé had also died, only a few days prior, with nearly identical symptoms. Another victim from the same locale and then a cluster of five others, reported independently, led to a massive effort to discover the cause. More cases turned up and 80% died.

this is how your chest x-ray should look; their's were diffusely white

Each had started with nondescript symptoms...fever, chills and muscle aches, but then they swiftly developed shortness of breath, low blood pressure and abnormal chest x-rays typical of Acute Respiratory Distress Syndrome (ARDS). That could be caused by any major injury to the lungs...trauma, severe infections, chemicals.

The short list of possible causes included Hantavirus and some of the blood samples from patients showed antibodies to several subspecies of those. No known member of the group could be be grown initially, and the causative agent was titled, Sin Nombre, "Nameless."  The new disease was named Hantavirus Pulmonary Syndrome, HPS. A laboratory test was developed to allow identification of the infecting virus from autopsy tissues and the deer mouse through its urine and droppings was thought to be the vector for the spread of the disease.

By the end of 2011, 587 cases have been reported in 34 states, with New Mexico, Colorado and Arizona leading the pack. Only 3 a year are seen in western Canada. Individuals with HPS and some outbreaks have been noted in a number of South American countries as well as Panama. Stored lung tissues from people who had died years back were examined and a Utah man who had ARDS in 1959 was found to test positive for the new virus which had eventually been grown by the Army's research lab.

Other viruses with other vector species have been reported to cause HPS. Some involve features overlapping with HFRS. An associate professor at Johns Hopkins has used satellite images to develop "risk maps" for outbreaks.

With current death rates at 35- 40%, presumably due to better handling of fluids given patients as well as discovery of milder cases, HPS is still a horrific disease.

But at least there has been no known instance of person-to-person spread.

Viral diseases old and new: Let's just begin with the flu

Sunday, March 4th, 2012

A cause for alarm and action

Two days ago I began a post on zoonoses, diseases that spread from animals to humans. As usual, my interest led me from one fairly-limited topic to more-generalized subjects and I eventually decide to write a multi-post discussion of viral diseases that either have caused massive, widespread epidemics (AKA pandemics) or could potentially lead to them.

The number of deaths they have resulted in is staggering. HIV/AIDS has killed over 25 million of us in the past 30 years; the Black Plague over a 330-year period killed 75 million and smallpox is estimated to have caused over 300 million deaths over the centuries.

But let's start with influenza, the virus that we read about year after year as a worldwide threat. In the fall my wife and I get flu shots; we got used to doing so when we were both on active duty as Air Force medical staff personnel. It was routine; I didn't pay a lot of attention to what this year's shot contained and only vaguely kept up with anything written about the flu itself.

Then so-called "bird flu" came along and  the world geared up for a terrible pandemic.Usually the kind of influenza virus found in birds doesn't infect humans. But one unusual strain, called H5N1 (I'll explain what that means later) killed a six-year-old boy in Thailand in 2003. Of the people who caught this virus, 60 % died.

Most of us have heard about the Spanish flu, a major pandemic that infected a third of everyone living in 1918-1919 and caused 20 to 40 million deaths worldwide. Yet only 3% of those whom the virus infected died from it.

The so-called Asian flu pandemic in 1956-1958 causes 2 million deaths; the Hong Kong flu in 1968-1969 killed 1 million and the yearly seasonal flu results in anywhere from 5 to 15% of us getting ill; 250,000 to 500,000 die as a result. But these flu strains actually only resulted in a death ratio of less than 0.1%.

As it turned out, there was very little person to person spread of the avian flu. If there had been the results could have been catastrophic.

But the pigs had nothing to worry about; we did!

One of the outcomes of the avian H5N1 outbreak was fortuitous. When the "Swine flu" pandemic occurred in 2009-2010, the public health establishment and the medical community were considerably better prepared. The CDC summary is worth reading as it documents the steps taken to contain the virus; actually this was a flu strain that was transmitted from person to person and wasn't present in US pig herds.

The virus itself had genes from four different influenza virus sources, two from pigs, one from birds and one from a human flu virus. The CDC widely distributed kits to labs enabling them to identify the new viral strain. They and the World Health Organization (WHO) kept tabs on the numbers of cases of the new disease and WHO announced a global pandemic in June, 2009 .

A vaccine was developed with unusual speed and a preliminary target group of higher-risk individuals was identified; this consisted of 159 million people in the US. Vaccine safety was tested in various groups and the vaccine itself was administered starting in early October; by late December 2009 enough had been produced to allow vaccination of anyone wishing it.

The final results were impressive; less than two-thirds of a million people caught the virus and the death rate was 0.03%

 

 

Adults, obese and otherwise

Sunday, February 12th, 2012

PIck well and cut back your waste/waist

In my last post I explained the concept and the math behind the body mass index (BMI) approach to evaluating if your weight was normal or not (your BMI is very  well in synch with the most scientific methods of determining body fat percentages). Now I want to expand on that a bit  with some recent statistics and some thoughts on how we can lose weight if we need to. Unfortunately, some of us have lots of extra pounds we should shed if we want to have our best shot at leading long, healthy lives.

The Feb 1, 2012 issue of JAMA had a number of interesting articles on obesity. I've previously mentioned several on childhood and adolescent obesity; today I'd like to zero in on two whose focus is American adults.

Four CDC staffers, led by Katherine Flegal, PhD, published the most recent statistics from a recurring national survey with the daunting acronym NHANES. This national health and nutrition survey (the E stands for examination) started in 1971, but from 1999 on has been released results in two-year cycles. The current article from the National Center for Health Statistics, looking at the 2009-2010 NHANES data had a little good news and lots of bad news.

After 1980, until the turn of the 21st century, the prevalence (scientific term for percentage) of obesity in our population kept zooming up. Now it appears to have leveled off. I guess that's something we should be happy about, except now over 35% of adults in this country are obese. Men and women have about equally high rates of obesity and men have caught up to women in this regard over the last twelve years. Some subsets, by sex and racial groups, are even more likely to be obese or very obese.

The worst news from this article was that no group--men, women, non-Hispanic whites, Hispanics or non-Hispanic blacks--had a decrease in the prevalence of obesity in this most recent data set.

So which exercise and diet should we try?

getting enough exercise is difficult when your joints hurt

Many adults report "No Leisure-Time Physical activity." Overall, more of us are exercising, but the data vary from state to state. Those who have arthritis, fifty million in the US, need special attention or are even more likely to get no exercise. The CDC has worked with the Arthritis Foundation to develop ideas for this huge group. Going back to my review of articles on youngsters, I think for the rest of us, we could begin with simple steps, parking at the far end of the parking lot and substituting some walking for part of our screen time as two examples.

Harvard Medical School's free online HEALTHbeat publication had a review of pros and cons of various diets in its Feb 7, 2012 edition. The bottom line still is if you want to lose weight, you must cut down on your calories. The Mediterranean-style emphasis on fruits and vegetables, unrefined carbohydrates, nuts, seeds and fish may be the most effective in reducing cardiovascular and diabetic risks.

My New Year's Resolution is to keep my weight under 150 pounds. I have to work at it as I like to eat, but most of the time I've stayed away from splurges.

How about you?

 

JAMA

 

 

Meth Madness: Part 2

Sunday, January 1st, 2012

Users of both genders and all ages abuse this drug

I want to be perfectly clear: methamphetamine use is a terrible plague in our society.  Although overall numbers are down over the past decade, we're still talking about a million plus people in the United States, many of whom are young and heterosexual. But, of course, that's not the only population group with members who abuse the drug; The CDC factsheet on its risk for HIV/AIDS stresses it can contribute to sexual risk behaviors, regardless of the sexual orientation of the user. I spoke recently to a long-term friend who is gay.  I asked him about its use in the gay community and he replied, "Everyone I ever knew about who used meth is dead."

There's a brain chemical called dopamine that affects how we experience pleasurable activities. Lab experiments show this highly addictive and illegal drug can lead to considerably greater dopamine being released than either eating or having sex.

A user experiences a high, a "rush" much more intense than from any normal activity. But there's a problem; it doesn't last more than eight to 24 hours. And it's not as intense in succeeding uses. So that leads to a pattern of addiction, the need for not only repeated  drug use, but more and more of the substance.

Chronic, repeated meth exposure, whether by oral ingestion, 'snorting", smoking or injection, clearly leads to damage in the brain, the teeth and the skin.

An online review by the  National Institute on Drug Abuse, part of the National Institutes of Health, says imaging studies (e.g., MRIs) done on meth addicts show alterations in parts of the brain involved in motor skills, verbal learning, emotion and memory.

I went back to the PBS special, "How Meth Destroys the Body" and was stuck by the graphic photos of "meth mouth." A common sign of abuse of this drug is severe tooth decay. The cause is uncertain, but meth does lead to shrinkage of a user's blood vessels and the mouth requires an adequate blood supply to stay healthy. The addicts often binge on high-sugar foods and drinks; their mouths lack sufficient saliva to maintain optimal healthy oral tissue and, on a high, meth users often grind their teeth and, of course, forget to brush or floss.

Between the tooth decay, the increased physical activity frequently experienced and the failure to eat adequately, meth users lose weight and look older.

the model of meth's structure looks benign; it's not, though!

They also lose interest in any activities other than those related to obtaining and snorting or injecting the drug. Men may become impotent; women may lose their interest in sex.

So why don't we require simply prescriptions for the cold and allergy pills that contain psudoephedrine, the chemical I mentioned in my last post that is used in the production of methamphetamine? I read an article in the 20 December 2011 edition of the Annals of Internal Medicine which told of the widespread abuse of controlled substances in the United States. It wasn't describing illegal drugs, just ones that normally do require a doctor's prescription. Many of these can now be purchased on the Internet.

That series of photos of meth users mouths and "before" and "after" photos of addicts may be one place to start.