Even Captain America Needs a Robust Microbiome

Captain America and Agent Carter exchanging microbiomes

I can't count how many times people ask me about what the "germiest" place in a home, car, or gym is. What I think such a question overlooks are several basic facts about the planet:

1. We live in a world dominated, in terms of biomass, by microbes.
2. Our own bodies, soon after birth, are colonized with so much bacteria that eventually bacterial cells come to outnumber human cells.
3. The majority of bacteria do not do us harm or damage our bodies.
4. Our native bacterial species, our microbiome, is essential for life. Not only do bacteria perform vital functions for us, such as vitamin K synthesis, they also crowd out and serve as a barrier for potentially harmful bacteria. 

Given these facts one should view any desire for ultra-sterility in daily life (obviously sterility is needed in operating rooms and hygiene when preparing food) as misguided and potentially harmful. However this realization came to be fully appreciated rather recently in light of growing interest in the microbiome and the consequences of its disruption as well as the hygiene hypothesis. 

So, it wasn't surprising to see Marvel's Agent Carter, a Captain America-related television series set in the 1940s, warn of the danger of acquiring a bacterial infection from a public phone. Though a public phone--when you can find one--is likely laden with bacteria, unless one has abrasions and lacerations on the face, it poses no more risk than playing a game in an arcade. 

So if a baby's pacifier falls on the floor, don't rush to have it autoclaved (of course if it falls in horse manure, that's a different issue); if you have an abrasion, put a Band-Aid on it; and don't abuse antimicrobial hand-sanitzers. 

A robust microbiome is important for everyone, even Captain America.

Vaccines: Nectar for Human Flourishing

With all the media attention, and now political attention, on the measles outbreak and the anti-vaccine movement, I composed a few thoughts on these issues:

• All schools have a right to set conditions of enrollment and, moreover, no school should want to be labeled a nidus for the spread of vaccine preventable infectious disease and have high rates of absenteeism because of illness
• With respect to the public government schools, the government acts as their  administrator and, given that role it has assumed, can set the rules for enrollment
• Vaccination requirements for schools should be considered a student safety issue, akin to healthcare worker vaccination requirements
• Certain vaccinations are much more important for a child in the US to have than others (e.g. Japanese Encephalitis is less important than measles)
• Until eradicated from the globe, vaccines against a highly communicable infectious diseases such as measles (whose indigenous transmission has been eliminated from the Americas), are crucial at keeping the disease from re-establishing itself in the US
• Certain infectious diseases pose such a risk that to refrain from vaccinating a child is tantamount to neglect (this list will be fluid and be context dependent)

Hopefully, the current measles outbreak (not to mention pertussis) will bring these issues to light and expose the motives and goals of the anti-vaccine movement which can only be described as a return to the primitive in which life was nasty, brutish, and short. 

It's Remarkable What a Little Chlamydia Will Do

In the film The Other Woman, the character played by Kate Upton uses the potential of having chlamydia as a way to excuse herself from having sex with the villain who then promptly takes the antibiotic azithromycin (Z-Pak) and offers it to his wife because something "nasty" is going around. 

With 1.4 million cases reported in 2013 (an 2-fold underestimation) it is clear that people in real life are as astute as even the villain in the movie. Chlamydia is a ubiquitous disease and is the reigning champion as the most commonly reported sexually transmitted infection in the US. It is present in about 2% of those aged 14-39 years of age. Untreated it can lead to pelvic inflammatory disease and infertility; neonates can contract chlamydial eye infections. Guidance recommends screening sexually active females under the age of 25 yearly, men who have sex men, pregnant females, and other high risk groups.

Judging by those statistics, it is clear that the transmission dynamics of this microbe seem incredibly suited to widespread dissemination through the population. The chief factor is the high rate of people without symptoms (90% of men and up to 70-95% of women) who can serve as vectors for spread of chlamydia. Also, infections of the pharynx and rectum (a Z-Pak may be less effective with rectal chlamydia) can play roles as hidden reservoirs of infection. A recent Canadian study revealed up to 13.5% of woman had rectal chlamydia, some irrespective of anal intercourse of presence of the organism at other sites.

The salient point is that infections that are asymptomatic but yet contagious will always be a challenge to control.

The movie also has another infectious disease reference--this time to pork tapeworms causing brain infections (cysticercosis), a major cause of seizures worldwide. However, the script got it wrong. Eating undercooked pork gives one an intestinal tapeworm, not the brain manifestations. If, however, one eats the tapeworm eggs found in the feces of someone with an intestinal tapeworm, they can get cysts in the brain.

Pork tapeworms and chlamydia in the same post: almost like an infectious disease version of 6 Degrees of Kevin Bacon (no pun intended).

Understanding the Revolutionary Germ Theory

When the germ theory of infectious disease is discussed today, it is almost second nature and obvious. Indeed when a new syndrome appears, everyone assumes it will turn out to be the result of an infection with some sort of microbe. 

However just like gravity, the heliocentric solar system, and evolution by means of natural selection, the germ theory of disease had a rocky start and was opposed by virtually everyone at its inception.

What I've always wanted to read was a history of the development of this theory that presents each of the major steps forward in an easily integratabtle format. While many people have some idea of the role of those such as Pasteur, Koch, Lister, Semmelweis, and others, many do not understand how their findings integrate and their relative chronology. Dr. Robert Gaynes ably fills this gap with his book Germ Theory: Medical Pioneers in Infectious Disease. 

The book provides vignettes of all the major figures who had a hand in the path to the germ theory. Dr. Gaynes expertly shows how each discovery built on the prior and led to the next, essential for truly grasping how science advances in any of its branches.

I think the next step in furthering this line of inquiry is to draw attention to the deductive and inductive methods used by these brilliant minds. Such an analysis would highlight important cognitive principles and habits useful in all realms of human endeavor (an aspiration of mine).

Understanding of how an earlier revolution in medicine (the germ theory) occurred is crucial to understanding how the next--which will encompass data analytics, systems biology, synthetic biology, and nanotechnology--will occur.

If a Scorpion Hugged an Armadillo, would it contract Leprosy?

Of all the infectious diseases in history, one that has gotten an unwarranted bad rap is leprosy, or Hansen's Disease. This disease, which is mentioned in the bible, has become synonymous with contagion--but it's not really a very contagious disease at all. 

Hansen's Disease, caused by infection with Mycobacterium leprae (and also M.lepromatosis), is a chronic disease that effects the respiratory system nerves, skin, and mucus membranes. It is by no means incurable as it is amenable to treatment with antibiotics. It is spread from person-to-person via the respiratory route. It's natural host is the armadillo. In 2009, a little over 200 new cases were reported in the US.

What most people don't realize however, is that 95% of humans are unable to be infected because of a specific genetic resistance conferred via their immune systems.  This means that far from being highly contagious, leprosy's transmissibility between humans is seriously hobbled. 

All of these facts have been known for sometime but it didn't stop the creation of leper colonies (e.g. Molokai in Hawaii) or other unjustified control measures in the not too far past. These misconceptions persist to this day and have penetrated deeply into popular culture. Case in point: the television program Scorpion. On a recent episode, one character states to another that he hugs as if he's at a leper colony. Such a comment is based on an extremely erroneous notion of leprosy's contagiousness.

What this brief mention on a tv program illustrates is the need to educate people on the difference between highly contagious infectious diseases and those that are less contagious. Such a point was something that I sought to make, over and over, with Ebola lest unjustified control measures be instituted as they were with leprosy.