We are the Germiest Place in the World

One of my least favorite types of popular infectious disease news story has to deal with variations on the question of "what is the germiest (fill in the blank)?" The latest version of this question has people swabbing airplane surfaces and, not too surprisingly, the tray table was found to harbor the most bacteria.

What studies like these overlook are a lot of important points such as:

• We live in a bacteria-laden world and we ourselves are teeming with bacteria
• There is a distinction to be drawn between potentially harmful bacteria and the much more numerous harmless bacteria in the environment (in fact the actual study points out that no fecal coliforms were noted)
• How "germy" a place really doesn't have much of an impact unless you're dragging a open wound (or the equivalent) through it -- this has a minimal to zero health impact

That tray tables--the place where people rest their hands, their utensils, their napkins, and deposit their sneezes and coughs--have a lot of bacteria is, somewhat paradoxically, the result of the fact that that are of the plane is the one with the most contact with...us.

Plague and Cholera: A Portrait of A Genius

When people speak of the influence of Louis Pasteur they often delimit it to the actual breakthroughs which he directly presided over. Though enormous in its scope, limiting Pasteur's achievements to just these does not do him justice. Not only did Pasteur discover a great many things (germ theory of disease, rabies vaccination, anthrax vaccination, pasteurization, the falsehood of spontaneous generation) his discoveries provided a green light for others to follow in his path--indeed he overtly cultivated a band of Pasteurians who pushed the field further and to whom we all owe a debt of gratitude.

Of the Pasteurians, one in particular deserves special mention and consideration: Alexandre Yersin, the subject of a recent fictionalized biography entitled Plague and Cholera written by Patrick Deville. 

Fictionalized biographies are tricky as the author must balance presenting a plot while staying somewhat bounded by actual events in the subject's life and I believe Deville accomplishes this expertly.

Yersin is chiefly remembered today for his discovery of the plague bacillus, which today bears his name. This story of Yersin's discovery, in spite of the odds tilted in favor of Kitasato a rival from the Koch Institute, was one I was familiar with but I had little knowledge of Yersin's life outside this episode and upon learning of it my admiration for his genius has grown.

Yersin was a true polymath who excelled and made advancements not just in microbiology but in botany, agriculture, geography, and many other fields. He basically had to be dragged from his hobbies in order to solve infectious disease problems, which he did in a manner that makes it look easy before returning to his hobbies. He is portrayed as a solitary, independent-minded man--a theme of many of the lives of innovators and geniuses--whose fascination with the world was never-ending. 

My favorite quote from the book is a great description of the Pasteurians and those who study and treat infectious diseases to this day:

"They are daredevils, too, adventurers, because in that day and age there is as much danger in getting close to infectious diseases as in taking off in an aircraft made of wood. A crowd of loners."

Never awarded a Nobel Prize, Yersin's life serves as an exemplar of a genius at work at the relentless pursuit of understanding. I highly recommend Plague and Cholera. 

Prions, not Zombies, are the Real Brain Eaters

Of all the etiologies of infectious diseases, one of the coolest has to be the prion. Prions are the smallest infectious agents and broke all the paradigm when they were definitively linked to diseases. It was almost heresy to postulate that a proteinaceous infectious particle--devoid of nucleic acid--could cause disease. But today's heresy is tomorrow's Nobel Prize, as Carleton Gajdusek and  Stanley Prusiner showed.

Prions cause disease in a unique way. Though they are definitely transmissible prion diseases they are, in essence, misfolded proteins that cause a cascade of protein misfolding leading to neurologic dysfunction. In some instances, the initial misfolding is the result of a sporadic genetic mutation and in others it is because of introduction of a misfolded protein causing the cascade. It is an impressive process.

Eventually prions, first linked to scrapie in sheep, were linked to human diseases known as the Creutzfeldt-Jakob Diseases (CJD), the most famous of which is new variant CJD (vCJD)--the human form of mad cow disease--as well as the human cannibalism-linked kuru. The story of vCJD is well documented. In short it has to do with changes in industrial farming practices allowing scrapie in sheep to get into cows and then into humans. The human outbreak, which captured headlines in the 1990s, is essentially over as farming practices have changed so as to eliminate exposure to the prion. 

Prions may have slipped from the headlines but research on them continued nonetheless and this week it was announced that a novel prion (alpha-synuclein) was linked to another neurologic disease: Multiple System Atrophy (MSA). Not surprisingly, this discovery came from Dr. Prusiner's lab. 

The biggest implication of this finding is further evidence supporting the hypothesis that other neurodegenerative diseases may have a prion component to their cause. Such an understanding may open up new avenues for treatment and screening for these dreaded diseases. 

Chickenpox Party in the Royals Dugout

If I ever walk through a baseball dugout, my biggest worry would be stepping in or touching chewing tobacco spit however the Kansas City Royals have much more to worry about after 2 players contracted chickenpox. It is assumed that the 2 infected players were not vaccinated and somehow escaped natural infection (possibly due to both Alex Rios and Kelvin Herrera being from the tropics where the virus spreads poorly).

Chickenpox, once a horrible rite of passage, has now been relegated to a rarity given the prowess the varicella vaccine. This vaccine that has nearly vanquished a disease that just over two decades ago infected 4 million, hospitalized over 10,000, and killed 150 Americans yearly. Now those numbers are 95% lower. Additionally because the same virus that causes chickenpox can years later reactivate and cause shingles the benefit of the vaccine will be far reaching as shingles and its horrible after-effect of post-herpetic neuralgia require billions of dollars of medical treatment costs annually.

Chickenpox is a very contagious disease and for those susceptible because they are too young to be vaccinated, not vaccinated for medical reasons, or not vaccinated for deliberate non-medical reasons can, for certain individuals, be a serious disease. As such, I oppose chickenpox parties for obvious reasons though maybe those anti-vaccine parents who fondly recall their beloved experiences with chickenpox might try to book the Royals dugout to give their poor children that same experience.

Alexandra Levitt's Deadly Outbreaks: An Expert Tour of Epidemiology (including aerosolized pig brains)

Reading the tales of infectious disease outbreak investigations is, to me, the equivalent of opening up Sherlock Holmes' case book and seeing a master unravel a case. The delight I get in reading books like that keeps me coming back to read each new infectious disease book with wide eyes, trying to glean whatever I can from the particular outbreak being described. 

Such was my reaction to Deadly Outbreaks: How Medical Detectives Save Lives Threatened by Killer Pandemics, Exotic Viruses, and Drug-Resistant Parasites by the CDC's Alexandra Levitt. The book is a compendium of important outbreak investigations over the past few decades that are illustrative of the power of epidemiology in elucidating causes, avoiding blind alleys, and changing policy.

Some of the included topics are: the original Legionnaire's Disease outbreak, the Four Corners Hantavirus outbreak, a multi-drug resistant malaria scare in Cambodian refugee populations, and the fascinating non-infectious pig-brain inhalation neurologic autoimmune syndrome. Being in the field of infectious disease, an added bonus for me was to read about people I know and interact with doing the investigative work.

I highly recommend the book for a concrete glimpse of what epidemiology is and how big its impact can be. Plus, who wouldn't want to read about aerosolized pig brains?