Memory Part 3: Old or New; False or True?

March 19th, 2013

Today I went back to Nelson Cowan’s article, “What are the differences between long-term, short-term and working memory,” as he appeared to be a definitive expert on the subject. Cowan is the Curators’ Professor of Psychology at the University of Missouri and specializes in working memory research.

I’d certainly heard of long-term and short-term memory and could conceptualize those fairly easily, or so I thought. I can vividly remember a scene with each of my paternal grandparents. Grandpa Sam was angry with my first dog and kicked at her; so I kicked him. I was four or five and in trouble!

Years later, after my grandfather died, I remember Grandma Pearl dancing in her living room while watching American Bandstand. She must have been in her mid-seventies and seemed very old to me then.

These come in handy

These come in handy

Short-term memory, to me, has always been the capacity to recall something told you a brief time ago. I just got a phone call from a woman my wife Lynnette had contacted about someone who wished to volunteer at Bas Bleu, the local theatre we’ve been connected to for the last fourteen years. The staffer from the theatre said to tell the potential volunteer to go online to the Bas Bleu website and fill in a preliminary form.

I heard that message, but knew I’d be doing at least three other things before Lynnette got home, so I wrote her a note rather than trying to remember, later in the day, that I had a message to pass on to her.

An online article in psychology.about.com mentions the Ebbinghaus forgetting curve, published by a German psychologist in 1885. In one of the first scientific studies of how we do or don’t retain information, Herman Ebbinghaus, who had begun his memory work in 1879, used himself as a research subject. He utilized three-letter “nonsense syllables. All began with a consonant, followed by a vowel and another consonant. He eliminated any where the consonant was a repeat (e.g., CAC) or where an actual word or prior meaning could play a role (DOT or BOL ~Ball). That left 2,300 possible combinations.

Then he’d put the syllables in a box, pull out some at random, write them down and repeat them many times to the beat of a metronome.

His results are still thought relevant now with later research by others to support them. The forgetting curve is the most famous. The sharpest decline occurs in the first twenty minutes and the decay is significant through the first hour. The curve levels off after about one day.

Ebbinghaus noted he could concentrate and have a “fleeting grasp” of the series of three-letter syllables, but, in order to stabilize their order in his memory, he had to repeat them over and over.
A memory specialist named Elizabeth Loftus, past president of the American Psychological Society, thinks there are four reasons why we forget: our memory traces decay over time; some memories compete with others; we may never have made the particular datum into a long-term memory; or we may have suppressed or repressed the memory.

Loftus, now a Distinguished Professor of Social Ecology, Law and Cognitive Sciences at UC, Irvine, is famous (some would say infamous) for her research in “false memories,” as published in a 1997 edition of Scientific American. She had studied the “disinformation effect” since the early 1970s with studies revealing that memory may be affected by later suggestions. In one of her studies, after research subjects viewed a simulated MVA, half were told there was a yield sign at the intersection where the “accident” occurred (the initial viewing actually showed a stop sign). Those who had not been given the later suggestion that it was a yield sign were considerably more accurate in remembering the scene; the other group tended to remember a yield sign.

Loftus reviewed a number of legal cases in which suggestions had resulted in false memories and eventually was involved in the famous Jane Doe case: a published article in the medical literature had claimed an accurate “recovered memory” of childhood sexual abuse. Loftus and a colleague uncovered information strongly suggesting that the memory of abuse was false. The woman involved accused Loftus of invasion of privacy, and the University where she worked confiscated her records and conducted a year and three-quarters investigation, eventually clearing Loftus who published her findings in 2002. She then was sued by the woman, but the California Supreme Court dismissed all but one count which was eventually settled as a nuisance claim for $7,500 (the plaintiff in the case had a legal bill over $450,000).

Loftus is certainly not alone in researching false memories. She mentions a study by two other professors, Lynn Giff and Henry Roediger III, where the subjects were to knock on a table, lift a stapler, break a toothpick or similar fairly simple tasks. Later they were repeatedly asked to imagine doing some of the tasks they hadn’t actually carried out. Finally they were questioned as to which of those actions they had done.

The more times they had repeated an imaginary physical act, they more likely they were to answer that they had actually done it.

Cowan’s paper mentions that those two forms of memory differ in some fundamental ways: short-term memory exhibits temporal decay and has chunk-capacity limits. In other words, over time we lose memories we have not committed firmly to long-term memory and we are only able to focus our attention on a limited number of items at a given time.

Ah, yes, I need to go to the grocery store after I finish this post.

Ah, yes, I need to go to the grocery store after I finish this post.

If you are asked to remember a hypothetical phone number, e.g., (800) 264-7813 and repeat it often enough, you may remember it next week. But, unless it’s a number you use frequently, you’re unlikely to remember it next month. And if you are presented with the task of remembering a number with forty digits, you probably can’t memorize it at all.

Cowan notes three differing definitions of working memory: they all make sense to me, but I’ll give examples of only two. The first is using your short-term memory to solve a problem (Cowan terms this a cognitive task). So if you give me the ingredients you’d like in an omelet, I’ll start breaking the eggs. Another, that I’ve become more and more familiar with as I age is the use of attention to manage short-term memory. I watch teens and twenty-somethings multi-task with considerable amazement; if I want to remember something, I need to focus on it and if I’m in the midst of doing something that requires my attention and another item pops up (e.g., the phone message I received a few hours ago), it’s best if I write it down.

Enough for today; I just remembered I have another task to finish this evening.

 

 

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Memory Part 2: what’s old and what’s new

March 13th, 2013
Her's one way to remember things.

Her’s one way to remember things.

In my last post I wrote about what I call short-term memory and my own issues with remembering; I also mentioned typical aged-related memory problems. Now I’d like to delve into ideas for improving our own recall.

I leave myself notes on things to do and I tend to use acronyms or short phrases to remember names. For instance, I had noted a diminutive lady on the recumbent bike next to mine in our health club. She was about my age and was in the gym almost as often as I was. I finally introduced myself and found out her name and, eventually, that of her husband. She’s Allison and I quickly decided that my mental picture of her was hurrying to follow a rabbit while she was carrying an umbrella and wearing a short skirt, i.e., “Allison Wonderland.”

I tend to be be bad with remembering names, but hers is certainly fixed in my mind.

I also use acronyms. Her husband’s name is David, so together they became a court room scene with the acronym “DA.” David is the prosecuting district attorney and Allison is there because she jaywalked following the rabbit.

Another person I frequently encounter there is perhaps 15 years older than I am and his name is Jerry…I rendered that as “Jerryatric.”

But there are other ways, some of them quite old, to hit the memory bullseye

But there are other ways, some of them quite old, to hit the memory bullseye

Reading about the varied approaches to memory over many years, I became aware that prior to there being a generalized ability to read written language, people were able to memorize long segments of epic poems. I’m unsure if this was training from a young age or the use of a particular system for memorization. One possibility that has been explored came to my attention from the fictional character Hannibal Lector.

His method of memorization led me to a 1966 classic, The Art of Memory, The author, Frances Yates traces the history of systems of memory; one was the Memory Palace of Mateo Ricci, supposedly utilized by Lector, in which a well-visualized structure can be utilized to place objects.

For instance you could visualize your own home or the rooms of a building that you visit regularly. We tend to be good at remembering places we know well. The concept of the “Memory Palace” is just a metaphor, one that can be as complex or simple as you like, perhaps being a visual map of the places you saw walking to school or driving to work. Whatever the place that you choose, you then have to have it well-visualized because you’re going to “drop” memories at a particular corner or on an object you see in your house every day.

I thought this wouldn’t work for me, but I just memorized a shopping list of ten items (bacon, eggs, wine, batteries, bubble gum, milk, envelopes, spinach, coffee, tomato) using the technique of mind pegging, the basic start to this concept for remembering a number of items.

When I decided to utilize this method on my list I pictured myself sitting at my kitchen table planning an omelet (bacon and eggs) while drinking a glass of wine. Then the lights went out.

I had to put new batteries into my flashlight and used it to look for additional items in my refrigerator to add to my creation, only to first find I had stashed bubble gum (I’ve done similar things before) next to the milk.

I still wanted to write down ingredients for my omelet, so I looked for paper and found the most accessible source was in a drawer where I keep envelopes. I made a list adding spinach while I drank a cup of coffee and then finished my recipe with a tomato.

It really worked! I may have to try a similar approach the next time i really do plan to go shopping.

Let’s skip to what’s current advice and research in the field.

The March 12, 2013 edition of The Wall Street Journal  had an article titled, “The New Power of Memory.” It referred to a recent publication in the journal Cerebral Cortex  by Daniel Schacter, the Chair of the Department of Psychology at Harvard, and colleagues.The WSJ article had an illustration that tied in with my exercise in using a visual link to a list of objects. In this case someone was planning a party for a friend. If they relied on hunches and assumptions about their pal (this step was called “access the past”), then continued in this manner with guesswork in piecing together the image of their friend’s personality and imagining their mindset, the end result was a dud, a failure.

If, on the other hand, they remembered specifics about their buddy’s past likes and dislikes, as well as incidents that revealed their personality, then used those to imagine their likely mindset, the end result was a hit.

Dr. Schacter was quoted as saying, “using past experiences to anticipate future happenings” lets people weigh approaches to a coming situation without needing to try out the actual behavior.

In other words, if you hone your recall skills until they are sharper, you may be able to avoid a party that’s a dud or even prevent a business decision that’s a catastrophe.

I’ll have to use this approach more often.

 

 

 

 

 

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Memory issues Part 1: Is it Alzheimer disease or something else?

March 9th, 2013

'Alzheimer's disease', under 'Alzheimer's'A while back I read an article in the Wall Street Journal with the intriguing  title, “Detective Work: The False Alzheimer’s Diagnosis.” The story was that of a man who developed problems in the memory and movement arena, was treated for Parkinson’s and eventually found to have normal pressure hydrocephalus (NPH), a buildup of the cerebrospinal fluid (CSF) that surrounds and helps protect the brain and spinal cord.

Hydrocephalus, sometimes called “water on the brain,” can occur at any age, but is more commonly seen in infants and seniors. When it is present in the very young, often due to a birth defect in which the spinal column doesn’t close properly, it puts pressure on the brain and skull usually resulting in an abnormally large head and a bulging of the fontanel, the soft area on the top of the baby’s head. It’s treated, in many cases, by insertion of a shunt, a tube placed in one of the brain’s ventricles (these are a communicating set of cavities filled with CSF). The tube has a one-way valve and is tunneled under the skin of the patient and usually empties into the abdomen.

The other age group in which hydrocephalus is seen more commonly is the over 60 age group. But it can certainly happen to younger adults as well.

One morning in 1990, when I was forty-nine, my wife noted I was having considerable difficulty with a particular kind of memory; the ability to recall something that was just told me was impaired. I turned out to have a benign mass in the center of my head (the technical term is a colloid cyst of the third ventricle) and had it removed by a neurosurgeon. Although the pathologist said it was benign, its location in that crucial area could have resulted in major brain damage or even sudden death.

If that were to happen today, it could be removed via endoscopic neurosurgery (an endoscope is a tube, usually flexible, for visualizing the insides of a hollow organ; it typically has one or more channels to enable passage of forceps or scissors). That procedure takes 45 minutes to an hour, is done via a one-inch incision and the patient goes home in one or two days.But, as you can see by clicking this link and then the photos in the article, colloid cysts have fairly large draining veins and they need to be most carefully attended to.

An MRI can guide the neurosurgeon's path

An MRI can guide the neurosurgeon’s path

In my case, prior to the advent of the neurosurgical endoscope, the mass was removed the typical old-fashioned way by making several round holes in my skull and then the cyst itself. One of the veins leaked and I had a major seizure in the recovery room. That left me with a good-sized scar; on an MRI it’s more of a cavity in the front part of my brain.

The scar impaired my short-term memory. I’ve managed to compensate, writing reminders and keeping a calendar, but I developed an interest in Alzheimer Disease and related memory issues, many of which are age-related and some of which are reversible.

The article on “False Alzheimers,” notes that >100 medical conditions can present with memory loss, confusion and personality changes. Medications, or drug-drug interactions should be high on the list of things to rule out. An April 2012 article on autopsy studies of over 900 patients thought to have Alzheimer disease found over a sixth had been misdiagnosed.

The prevailing opinion is that NPH is the cause of five or six percent of all patient felt to have dementia. Adult-onset hydrocephalus is different in many respects from that which happens in the very young. It results from a gradual blockage of the conduits that normally drain CSF. It’s not uncommon for the person with NPH to think that their symptoms are typical for the aging process.

But difficulties in focusing your eyes, an unusual series of headaches, personality changes, seizures, leg weakness and/or sudden falls should be investigated; it’s wise to see your physician if  any of these occur, especially if there are associated memory problems.

Then there are, as Dr. Daniel Schacter, the former Chair of Harvard’s Psychology  Department calls them, “The Seven Sins of Memory ,” age-related memory issues that we all will likely encounter as we grow older. Being absent-minded, blocking the retrieval of a piece of information (It’s on the tip of my tongue), or not remembering a complex chemical formula you learned for a college freshman course fifty years ago all can be totally normal. His book on the subject book revolves around the theory that “the seven sins of memory” are similar to the proverbial “seven deadly sins,” and that if you try to avoid committing these sins, it will help to improve your ability to remember. Schacter, on the other hand, argues that these features of human memory are not necessarily bad, and that they actually serve a useful purpose in memory.

My comment over the years has been, “Whenever I put a fact in the front of my mind, one falls out the back.”

So don’t assume the worst if you forget something; on the other hand, don’t ignore memory problems if they are persistent.

 

 

 

 

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Marijuana controversies: Part 2, state laws, health issues and DUI

March 6th, 2013

When I was a Veterans Administration Research and Education fellow (1970-1972) working inTorrance, CA, at Harbor General Hospital, I volunteered at the Long Beach Free Clinic once or twice a week to keep up my clinical skills. One evening I made an emergency “house call” across the street from the clinic at the headquarters of the “Peace and Freedom Party.” I didn’t know anything about that group, but as I attended to the ill member of the Party, I realized that many of those in the rooms I passed through were smoking pot.

It was clearly an illegal drug then, even in California, but my role there was that of a physician, not a policeman, so I just took care of my patient, eventually calling an ambulance to take him to a local hospital.

Fast forward to the 21st century.

Should this be legal for adults? Voters in Washington state and Colorado said, "yes."

Should this be legal for adults? Voters in Washington state and Colorado said, “yes.”

Now a Colorado state amendment has legalized the drug as of December 10, 2012 with 55% of voters approving use, possession, cultivation and distribution by anyone 21 and older. A group called “Sensible Colorado” has outlined the development of Colorado laws regarding pot. As of March 1, 2013  a state task force on recreational marijuana has recommended special sales and excise taxes on it as well as rulings barring smoking it in bars, restaurant and social clubs. The group also said the plant should only be grown indoors, but could be sold to those visiting from out of state and given away, an ounce, at a time to adults.

In late February the Colorado House Judiciary Committee unanimously passed a Marijuana DUI bill, setting a 5 nanograms (ng) per milliliter of blood as the THC level as which a person could be ticketed for driving while impaired.

In past legislation, the 5 ng limit was considered a “per se” limit, which meant that if a driver’s blood level is 5 ng per milliliter of whole blood, the driver is assumed to not be in a fit state to drive safely. Similarly a driver’s blood alcohol content (BAC) of .08 per milliliter is sufficient to issue a DUI ticket.

HB 1114 states that in a marijuana DUI prosecution , a jury may “infer” that a defendant was under the influence with a 5 ng level, but that defendant has the opportunity to prove that he/she was not impaired.

The 5 ng limit is based on the amount of active THC (delta 9 THC) in whole blood,  This form of THC functions for a short period of time following ingestion, typically from two to four hours. Latent THC, the kind that remains in the blood after active THC has dissipated, can remain in the blood for days after ingestion, according to a toxicology expert who testified in the Colorado hearings on the subject.

In early December, 2012 the state of Washington also legalized recreational marijuana for adults over 21. An article in the Huffington Post online said that there would be state licensing for those who grow pot, process it or sell it in a retail setting. Although smoking it in public is still illegal, much like drinking in public places, the Seattle Police Department told its officers not to issue citations for those who do so…pending further notice. Instead police officers will advise people to smoke pot at home. Washington’s Initiative 502, much like Colorado’s Amendment 64, allows the state to regulate and tax the drug’s sale and sets limits for DUI.

The website of the Office of National Drug Control Policy says the Justice Department is reviewing these state initiatives and has no further comment at present. Federal law currently doesn’t permit even medical marijuana, much less recreational pot use.

Gallup polls, as reported in a December 10, 2012 online review, show nearly two-thirds of Americans surveyed (64%) believe the federal government should not take active steps to enforce its policy on marijuana in states that have legalized its use.  Amazingly forty percent of those who oppose the legalization of pot still think this should be a state by state decision, decided by voters. Overall 48% of those surveyed were in favor of the drug being legal and 50% were against it. This is a marked change from the 1969 poll where only 12% wanted it to be legal or even 2005  when about one-third favored legalization.

As I would have expected, the survey results varied by age. Sixty percent of those under 30 are pro-marijuana; those in the 30 to 64 age range are equally divided into pro- and anti-pot camps and sixty percent of those 65 and old are against the new state laws.

A number of studies conclude that heroin, cocaine, alcohol and cigarettes are more dangerous to those who use them than marijuana. That by no means implies there aren’t potential major issues with smoking pot. One of the physicians who commented on the New England Journal of Medicine discussion on medical marijuana had a mid-twenties patient with a 10-year history of smoking marijuana frequently and now needed a tracheotomy for cancer of the larynx. An online review of the medical dangers of marijuana focused on negative effects on the immune system, potential for carcinogenesis, and effects on memory and brain function, but some of its conclusions have been denied by other scientists.
DUI is DUI, but maybe we need to develop a better test.

DUI is DUI, but maybe we need to develop a better test.

A High Intensity Drug  Trafficking Areas (HIDTA) website comments that 9% of Washington eighth grade students, a fifth of 10th graders and over a quarter of seniors in high school are current marijuana users. Teen drivers are involved in motor vehicle accidents (MVAs) disproportionally and  data strongly suggest that marijuana users who drive have significantly increased rates of increased rates of MVAs. The combination of teens smoking pot and then driving is scary.

Are we at a tipping point concerning marijuana? It seems like that may be true.

If so, what will the next few years show about the risks of recreational pot use?

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Marijuana controversies: Part 1, background and medical use

March 1st, 2013
Now physicians can prescribe marijuana in some states

Now physicians can prescribe marijuana in some states

Last evening I glanced at the table of contents of the New England Journal of Medicine and was somewhat surprised to find there was an article online on medical marijuana.It discussed a hypothetical patient with metastatic breast cancer who had considerable pain issues and had asked her primary care physician if she could use pot to relieve her pain, nausea and fatigue. There were pro and con discussants with a psychiatrist from the Mayo Clinic in favor of “thoughtful prescription of medicinal marijuana,”  but wanting those to occur within established doctor-patient relationships.

That latter comment made sense to me; if medical marijuana (AKA Cannabis) is recommended by a physician, it should be by a doctor who knows that particular patient well, not someone who writes Rx’s for dozens of people a day in a “pain mill.”

On the other side of the issue were a Clinical Professor of Psychiatry at Georgetown University (a former White House Drug Czar) teamed with the Chief of the Pain Management Services at a Florida University. They noted that most of the research efforts have focused on specific chemicals from the marijuana plant and that there is limited, but high-quality, data supporting relief of some kinds of pain by smoking pot, but not the type of pain the patient being discussed had. They mentioned two prescription “cannabinoids” that are currently FDA-approved as oral agents specifically for the treatment of nausea/vomiting secondary to chemotherapy.

There have been over a hundred comments to date in the online discussion of the article. One was from a Colorado anesthesiologist/acute pain specialist who commented that patients who use marijuana on a daily basis may become cross-tolerant to opiate drugs, therefore requiring much higher and more dangerous doses of them to have a desired effect in pain control.

A major issue remains the 1970 classification of marijuana as a Controlled Substance Schedule 1 drug, therefore, putting it into the company of heroin, LSD and mescaline, chemicals that have a high potential for abuse and a lack of any medical value.

To date eighteen states have legalized physicians to prescribe the drug, but Federal policy lags far behind and, in theory, docs who write Rx’s for marijuana could face legal action. In Israel, on the other hand, over 10,000 patients use marijuana under government license  according to a July, 2012 NPR article.

I found an online article titled “How Marijuana Works.” This comes from one of the HowStuffWorks websites, not a medical publication, but seems fairly well balanced. It mentions that cultivation of marijuana is not at all new, with written reports in China dating back over 2,000 years. The plant apparently came from India where it can grow to heights over 13 feet. It contains an enormous number of chemicals, over 400 of them with 60 falling into the cannabinoid group. The National Cancer Institute’s webpage on Cannabis and Cannabinoids define these as chemicals that activate specific receptors found throughout the body to produce drug-like effects.

So what’s a receptor? I read a superb analogy in Discover magazine with science writer Gary Taubes comparing them to miniature locks on the surface of cells, locks that can only be opened with the correct chemical key.

Cells, including those involved in immunity and the central nervous system, have receptors that bind with substances such as hormones, antigens, drugs, or neurotransmitters (brain chemicals that communicate information from nerve cells). Two different kinds of receptors, termed CB1 and CB2, bind with cannabinoids. The CB1 receptor, when triggered, causes the drug high; THC (the full chemical name is delta-9-tetrahydrocannabinol) is primarily the cannabinoid that leads to this effect. A March, 2012 study from the Mount Sinai School of Medicine focused on the CB2 receptor after research showed that a medication that triggered only CB2 might prove a significant adjunctive treatment to standard anti HIV therapy in late-stage disease.

Other articles in the medical literature discuss the use of marijuana versus cannabinoids in glaucoma therapy. Smoking marijuana lowers intraocular pressure in roughly two-thirds of glaucoma patients. One issue, however, is smoking marijuana is smoking and in end-of-life care probably poses acceptable risks, but done in other situations it may cause a host of problems. Other means of administration include drinking raw cannabis juice, the use of inhalers or administering only specific active cannabinnoids.

In my state, Colorado, there’s an organization, headed by an attorney and calling itself Sensible Colorado, that has advocated for medial marijuana. One of their websites outlines the “History of Colorado’s Medical Marijuana Laws.” Over thirteen years ago our voters passed Amendment 20 to the state constitution, legalizing limited amounts of marijuana for patients and their primary caregivers.

Checking for high intraocular pressure, a precursor of glaucoma

Checking for high intraocular pressure, a precursor of glaucoma

The statute listed the diseases for which a person could be prescribed marijuana/cannabinoids. The first group included cancer, HIV/AIDS and Glaucoma. As I read background articles I could see some reason behind those choices. I’m less impressed with data on most of the other reasons to give the drug  to patients.

In 2000, Colorado voters support the legalization of medical marijuana. In our city and around the state there followed a proliferation of “pot shops,” without a great deal of unified regulation. Some cities were stricter in their approach toward the sale of marijuana than others.

All this may have been overcome by events; I’ll write about the recent changes in the law in my next post.

 

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I meant cholera, not typhoid

February 27th, 2013

I just re-read my last post. Somehow, I substituted typhoid for cholera in one section (the Haitian outbreak).

Sorry

 

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Cholera: Part two, the nearby 21st century epidemic

February 26th, 2013

Until 2010 I hadn’t thought much about cholera in the modern era. I had considered it a disease from the past  and associated it with Dr. John Snow, the father of modern

Algae can carry cholera bugs a long ways

epidemiology , the study of the patterns, causes and effects of health and disease in defined populations (Hippocrates, the famous Greek physician is considered the ancient father of the field).

I was clearly wrong in doing so.

I had previously read parts of the science writer Laurie Garrett’s first two books, The Coming Plague: Newly Emerging Diseases in a World Out of Balance published in 1994 and Betrayal of Trust: the Collapse of Global Public Health which followed in 2000. Her first book touches on cholera in Africa and then has a section on the seventh Global Pandemic starting in 1961 in Indonesia’s Celebes Islands.

Now I read Chapter 16 of The Coming Plague in detail. It mentioned that Rita Colwell, PhD, an  environmental microbiologist, was convinced in the 1970s and 1980s that bacteria and viruses could be carried in algae, the world’s  oldest living life form. Algae are responsible for “red tides”  (AKA Harmful Algal Blooms or HABs), episodes when those ocean plants massively increase in number then produce toxins making shellfish dangerous to eat and killing off fish.

Colwell found that the bacterium responsible for cholera could survive encysted in algae and float long distances in their “plant capsules.” The El Tor strain of the bug was responsible for the 1991 epidemic in Peru. The CDC’s publication Morbidity and Mortality Weekly Report, AKA MMWR, mentioned that outbreak in its February 15, 1991 edition. MMWR noted this was the first appearance of cholera in South America in the 20th century and recommended exclusive use of boiled water for drinking, careful cleaning of fruits and vegetables, and avoidance of raw or inadequately cooked fish or other seafood. It stated the risk to U.S. travelers was low.

In the next eleven months cholera claimed over 330,000 victims in the Western Hemisphere, killing just over 1%. Lima, the Peruvian capital, had stopped chlorinating its water and Peruvians often ate ceviche, uncooked fish and shellfish mixed with lime juice. By the Fall of 1993, 8,000 deaths and over 900,000 cases of cholera were reported in Latin America. The El Tor strain of the cholera bacterium had become endemic in the region.

A 1994 article in the Journal of Clinical Microbiology documented the next chapter in the modern history of cholera. A new strain struck in December of 1992, first in the Indian city of Madras and then spreading to Calcutta, Bangladesh and Thailand. Even those who had previously been through a siege of cholera were not immune to the O139 strain as the Bengal cholera Vibrio was termed.

An earthquake can be both a disaster in itself and the seed for an epidemic.

The Western Hemisphere would have another cholera epidemic eight years later. In the January 10, 2010 a major earthquake in Haiti occurred. Although its magnitude on the logarithmic Richter scale was “just” 7.0, while the offshore earthquake in Japan in 2011 was an 8.9 (an 8.0 quake is 10 times as intense as a 7.0 and a 9.0 is 100 times as powerful), the depth of the Haiti quake was ~half that of the 2011 tremor in Japan and it struck a major Haitian city. The damage was immense and the local infrastructure was severely disrupted with healthcare, water and sanitation being affected.

A recent New England Journal of Medicine article (Feb 14, 2013) reviewed the surveillance efforts during the subsequent two years. Prior to the earthquake, less than two thirds of Haiti’s population of 9.8 million had access to even the lowest category of an improved water source; less than an eighth drank treated water from a pipe system and only a sixth lived with adequate sanitation. The 1991 Peruvian cholera didn’t reach Haiti so there was little or no prior immunity to the El Tor Vibrio strain.

The results were predictable, a major outbreak of cholera, but the government and international medical assistance markedly ameliorated the epidemic. Through October 20, 2012 over 600,000 cases of cholera were reported and 7,436 deaths resulted. The case fatality rate was initially high in some locales (4.6%), but within three months of the start of the epidemic it fall to the World Health Organizations target of <1.0%.

In comparison there were 2.8 million cases of cholera globally in 2011 with 91,000 deaths (3.25%). The CDC notes that twenty-three cases occurred in the U.S.; 22 were associated with travel to Haiti, one with consumption of food products from that country.

The treatment of cholera is relatively simple: the WHO says rehydration with oral rehydration salts is enough in almost all cases. Intravenous administration of fluids can be life-saving in especially serious cases.

But how about preventing the disease?  A Perspective column in the same journal edition (NEJM Feb 13, 2013) is titled “The Cure for Cholera–Improving Access to Safe Water and Sanitation.” The three authors, all with dual MD, MPH degrees, note that the malady is still a major source of illness and mortality in the developing world with WHO estimating 3 to 5 million cases and 100,000 to 200,000 deaths a year.

In the treatment arena, they note that antibiotics should be given to those with even moderate dehydration, that all patients should receive zinc, which can decrease the duration of diarrhea, and a newer variant of the two-dose vaccine should get wider usage.

Safe drinking water and modern sewage disposal is still a major issue for many in 2013: two and a half billion live without adequate toilet facilities and nearly 40% in the least developed regions of the world don’t have bacteria-free water to drink.

More than a billion of the poor and marginalized need help. But estimates of $50 billion needed per year are daunting in these tough economic times.

 

 


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Cholera: Part 1 background and history

February 24th, 2013

An 1882 monument to victims of cholera

Cholera is an infectious illness, found only in humans, caused by a bacteria in contaminated water, leading to severe diarrhea and dehydration and capable of killing its victims in a matter of hours if untreated. When I read about the disease for the second time in decades (the first time was after a 21st-century epidemic in Haiti), I was amazed at how quickly a victim can lose 10% or more of their body weight in severe cases; e.g., eight quarts between my normal bedtime and when I usually wake up. Many people who ingest the bacteria don’t develop any symptoms, but if they do and lack modern re-hydration therapy, their chance of dying is 40-60%.

In all likelihood it is an ancient disease with writings from the lifespan of Buddha  (563-583 BCE) and from the time of Hippocrates (460-377 BCE) revealing diseases that presumably were  cholera. It has, over the last several hundred years, been a major killer of mankind, causing millions of deaths in the 19th century.   Those numbers place it among the deadliest of infectious illnesses, in the company of smallpox, the Spanish flu, bubonic plague, AIDS and malaria.

A CBC News article online with the title “Cholera’s Seven Pandemics,” starts with a major outbreak in India near the Ganges River delta. Between 1817 and 1823 there were 10,000 deaths among the British soldiers stationed in that country, estimates of hundreds of thousands of fatal cases among native Indians and 100,000 dying in Java in the year 1820. The second pandemic began in 1829, again in India, and spread to Russia, Finland, Poland, England, Ireland, Canada, the U.S. and Latin America, before another outbreak in England and Wales that killed 52,000 over two years. The sixth pandemic killed more than 800,000 people in India alone and, over the next 24 years swept over parts of Europe, Russia, northern Africa and the Middle East.

The National Library of Medicine’s website entry on cholera associates it with crowding, poor sanitation, famine and war. India has remained a source as the disease is endemic (ever present) there. People get cholera by eating or drinking either contaminated food or water; the medical term is the fecal-oral route.

In the summer of 1854 London was the epicenter of a deadly outbreak. Dr. John Snow, a famous British physician born March 15th, 1813, had been noted as a pioneer in anesthesiology, using chloroform to assist in Queen Victoria’s delivery of her eighth child in 1853.

Then, as documented in the book, The Ghost Map by Steven Johnson, Snow turned his investigative talents and keen mind to cholera, becoming in the process the modern father of epidemiology.

London’s population had grown immensely and its sewage system was antiquated. In addition to basements filled with excrement, cesspools and drainage into water sources were rampant. A major concept of disease causation was the miasma theory. The term means “bad air” and the assumption was illness was caused by the presence in the air of a miasma, a ill-smelling vapour containing suspended particles of decaying matter .

Snow, on the other hand, felt cholera was caused by something ingested, most likely by drinking water contaminated by waste products.

In a painstaking and extremely clever investigation, Snow had, in a prior cholera outbreak in 1849 which was responsible for a dozen deaths in flats in a slum area, shown that two separate  sets of milieu had markedly differing death rates. All environmental parameters were essentially identical in the two groups with one exception; where they obtained their water. The group who suffered a much higher rate of illness got theirs from a company whose river source was in the same area where many sewers emptied.

Vibrio cholerae, the cholera bacteria

Five years later a much larger cholera epidemic provided an opportunity to more closely examine the water sources of the victims. One particular pump, seemingly providing clear water, proved to be the culprit. The Broad Street pump’s output was examined by a Snow’s colleague, a skilled microscopist Dr. Arthur Hassall, and found to contain what Hassall believed to be decomposed organic matter with oval-shaped tiny life-forms felt to be feeding on that organic substance. Snow was not aware then of the 1854 work of an Italian scientist, Filippo Pacini, who had examined the intestines of patients dying from cholera in Florence and found a comma-shaped bacillus he termed a Vibrio.

The proponents of the miasma theory did not yield easily, but Snow’s map of the location of deaths from cholera eventually let his hypothesis of a water-borne illness prevail.  Then an assistant curate (church figure in charge of a parish) named Henry Whitehead who had read Snow’s papers on the epidemic eventually found the index (first) case, a baby Lewis. As a result, the Broad Street pump was excavated and a direct connection to a cesspool was found.

The juxtaposition of Snow’s scientific data and Whitehead’s work as a beloved neighborhood figure led to the local Vestry Committee’s report endorsing the water-as-culprit theory.

The city subsequently launched a major project to carry waste and surface water away from Central London.

 

 

 

 

Five years later, he

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Vaccination/Immunization: Part 3 Adults and the disease risks some of us take

February 16th, 2013

You need protection against viruses and bacteria that lurk out there

After reading a number of articles, I decided that Lynnette and I  are up to date on all our vaccinations, but many adult are not; the CDC on Feb 1, 2013, published an online review titled “Noninfluenza Vaccination Coverage Among Adults–United States 2011” that reveals a sad picture. The first two sentence sums it up, “Vaccinations are recommended throughout life to prevent vaccine-preventable diseases and their sequelae. Adult vaccination coverage, however, remains low for most routinely recommended vaccines and well below Healthy People 2020 targets.”

I had only a vague idea what does Healthy People 2020 referred to, so I found the definition on a CDC website. 

In December of 2010 the Department of Health and Human Services (HHS) launched a multi-faceted ten-year program with four major goals for our American population: 1). Attain high-quality, longer lives free of preventable disease, disability, injury, and premature death. 2). Achieve health equality, eliminate disparities, and improve the health of all groups. 3). Create social and physical environments that promote good health for all. 4). Promote quality of life, healthy development, and healthy behaviors across all life stages.

It’s obviously a huge undertaking and HHS came up with 1,200 objectives (sic) organized into “topic areas” (42 of those) each covering something felt to be very important in our public health. That’s too big of a chunk for me to even think of writing about today.

So in this post I’ll focus on vaccinations for adults.

Every year an Advisory Committee on Immunization Practices is given the charge of reviewing and updating the recommendations for childhood vaccinations and also those for adults. The Annals of Internal Medicine published the adult schedule and comments on its changes January 29, 2013.

Let’s go back to the non-influenza vaccination article; the discussion was on immunizations to protect us against tetanus, diphtheria and pertussis/whooping cough combined as Tdap; pneumococcal pneumonia, hepatitis A, hepatitis B, herpes zoster (AKA shingles), and the human papillomavirus (HPV).

The Tdap numbers were startling to me. Only 55.4 of adults over 65% are protected and <65% of adults from ages 19 to 64, but  fatality rates for tetanus are over 13%. Far too many people are taking chances with a terrible, but preventable disease. The American Geriatrics Society is urging all of us over age 65 to have the Tdap shot, to protect ourselves and our grandkids (from pertussis in the latter case).

I’ve written on pertussis, but to recap we’re seeing more cases in the U.S. (22,550 were  reported in 2010 and many more, especially among the elderly, are never reported). There have been epidemics of pertussis in 2012-2013. If you think you’re still immune to whooping cough  because you had the childhood vaccination five-shot series, you should know that an person’s immunity wanes from 98% protection to 70% after five years have elapsed.

There hasn’t been a case of diphtheria in this country since 2003, but lots of us travel to countries where that disease is endemic (regularly found) and the case-fatality rate for respiratory diphtheria is 5-10%.

The pneumoccocal vaccination rate for those in this country who are 19 to 64 and considered at high risk for this kind of infection (e.g., anyone whose immune system isn’t at its best) is only a tad over 20%, while the 2011 figures for those of us over 65 are much higher, at 62.3% in 2011. Even in the older age group the data showed Caucasians have gotten this immunization much more commonly then Asians, Hispanics or blacks, all of whom had vaccination rates <50%.

I’ve had the herpes zoster shot, but I’m in the 15.8% (20111 figures) who’ve done so. I never wanted to have shingles after knowing two people who had prolonged excruciating pain from this disease.

HPV is the most common sexually-transmitted viral disease in the United States. The CDC says, “Almost every sexually active person will acquire HPV at some point in their lives.” In doing so they increase their risk of certain cancers; in a major CDC study that covered everyone in the U.S. from 2004-2008 there were over 33,000 HPV-associated cancer cases per year.

There are a host of reasons people don’t get vaccinated. The CDC has an article online that covers the topic of common misconceptions about the need to continue vaccination. Some people think that infectious diseases were being prevented by improvements in sanitation/hygiene even before immunizations were developed. Or they may believe that a majority of us have already been vaccinated so they don’t need to (the herd immunity concept) or that certain “lots” of a particular vaccine are dangerous. Some think we’ve gotten rid of all the diseases that vaccines can prevent, so they reject having themselves get the shots.

Especially if “out there.” in your case, means most of the world

Unfortunately, none of these concepts are valid and many of us travel to parts of the world that have much worse immunization statistics than America does. So, if we’re not vaccinated before our trips, we run the risk of bringing home a disease and spreading it to others.

 There are some significant changes coming in the vaccination arena, but I’ll save those for another time, including a few words on Hepatitis A and B. For now I’d suggest asking your physician is she/he thinks you’re current in all the immunizations you need; that’s especially true if you are planning a major trip somewhere outside the country.

 

 

 

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Vaccination/immunization: Part 2 Smallpox: history

February 13th, 2013

We don’t see these signs anymore.

Vaccines have a humble beginning. Smallpox was the first infection that people tried to prevent using a method called variolation, developed in China and India, in which dried material from a smallpox scab was ground up and then administered to a well individual, blowing the powder into their nose and hopefully giving them a mild case of smallpox and long-term immunity to the disease.

It originated from the observation that people who survived a previous smallpox infection somehow become resistant to getting the infection again. It was thought that by artificially infecting an unaffected person, the process could protect the individual from the dire malady.

Smallpox is an ancient disease; a great online article by Stefan Riedel, an MD, PhD from the Baylor University Medical Center, traces its history over an estimated 12,000 years, with Egyptian mummies from 3,000 to 3,500 years ago showing typical facial scars.

The Antonine Plague, which lasted from CE 165 to 180, most likely was smallpox (though possibly measles). It killed 2,000 per day in the Roman Empire with total deaths estimated at nearly seven million. Many scholars feel it significantly contributed to the downfall of the empire.

Ancient Chinese documents show that variolation was practiced in the Song dynasty in China (CE 960 to 1279). Legend has it that the Song emperor had lost his eldest son to smallpox, so he traveled deep into the forest of a high mountain and sought help from a reclusive nun. The woman was known as a holy healer, and she passed on the technique of variolation to save the ancient Chinese royal family.

Two to three percent of individuals receiving variolation ended up dying from smallpox. The only reason this practice continued was because the chance of dying from smallpox caught “naturally” from another infected person was much higher with some epidemics killing 30% or more of victims.

In 1717, Lady Mary Mortley Montagu, was in Constantinople as the wife of the British ambassador. She herself had suffered from smallpox and also lost a brother to the disease. She found that the Turks had another approach to gaining smallpox immunity, inoculation. The word is derived from the Latin inoculare, meaning “to graft.” Inoculation referred to the subcutaneous instillation of smallpox virus into non-immune individuals. The inoculator usually used a lancet wet with fresh matter taken from a ripe pustule of a person who suffered from smallpox. The material was then introduced into the arms or legs of the non-immune person.

Lady Montagu had two of her own children inoculated, one while in the Ottoman Empire and the other upon returning to England. A number of prisoners and later some abandoned children were subjected to the procedure; both Lady Montagu and the Princess of Wales were involved in this “research project,” which next had those inoculated deliberately exposed to smallpox. None of them got the disease.

After this success, members of the British royal family were inoculated and the practice spread widely in Europe, reaching America with Reverend Cotton Mather being a strong supporter.

During one of Boston’s succession of smallpox epidemics, after hearing from Cotton Mather of a publication in  the Transactions of the Royal Society, Dr Zabdiel Boylston, in spite of strenuous protests from the general public and from other physicians, inoculated his own son and two family servants. Eventually he performed the procedure on 247 ranging in age from nine months to sixty-seven years; other physicians inoculated 39, and of the 286 only six died  (2%) and three may have already had smallpox, while 14% of the 5,759 who had not been inoculated and caught the disease perished.

Thanks to Edward Jenner

The next step came from Dr. Edward Jenner, who had speculated about the protective effects of cowpox during his “apprenticeship” with George Harwicke. He had heard a woman who was a dairymaid and had a pock-free complexion say, “I shall never have smallpox because I have had cowpox.” Over ten years later, in 1796, he used material from a cowpox-infected woman to inoculate an eight-year-old boy. The child recovered from cowpox, but when deliberately inoculated later with smallpox did not develop any signs or symptoms of the much more serious disease.

Since the Latin word for cow is vacca, Jenner dubbed the process vaccination and after being rejected for publication by the Royal Society, sponsored his own booklet to promote the method of smallpox prevention.

The rest, as they say, is history and Jenner became famous; in 1802 he received a large sum of money from Parliament and a still larger one in 1807. He continued his research in several areas of medicine and science and was appointed Physician Extraordinary to the King.

Vaccination became an established medical procedure.

 

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