Building on what I’ve written in prior chapters, this very short chapter serves to concretize an important principle of infectious diseases: solving the puzzle of what is making someone sick.
In the early days of a burgeoning pandemic, epidemic, or outbreak the key task is to identify the inciting pathogen. What type of pathogen is it? A virus, fungi, bacteria, prion, parasite, etc.? What species is it? What does it resemble? All these questions are aiming to understand the identity of the pathogen. While this might sound very obvious and simple, knowing the identity of a pathogen gives humans a very powerful tool. It illuminates what I call “biological dark matter” — all the unidentified pathogens that lurk behind infectious syndromes of all severities that are not completely identified (more on this in a later chapter).
Every sniffle, every UTI, every sore throat, every pneumonia, every gastroenteritis, every ear infection starts out as biological dark matter that may or may not yield a final specific diagnosis (often because diagnostic tests might not be deemed necessary).
However, when one grasps the entity’s identity and is able to categorize it, a whole host of related knowledge one has accumulated can then be applied to it. For example, if one knows that some clinical syndrome is due to an infecting bacterial species that will lead to general treatment and diagnostic principles such as the use of certain types of antibiotics, certain types of culture media, and anticipating certain types of transmission. Similarly, if something is known to be caused by a virus it will lead to unique considerations specific to viruses.
This reasoning can be extended, for example, to knowing a virus is of a specific viral family or if a bacterial species is of a certain type (e.g., gram stain positive or gram negative). What comes along with each iterative step of identification is a whole slew of information that can be applied to the problem based on what has been learned in the past regarding entities of this type. If the unidentified pathogen is subsumed by an already known concept, all that prior knowledge can now be applied to the new instance of it.
Knowing, to any degree of specificity, what kind of thing the culprit organism is conveys explanatory power which can then be wielded for therapeutic, prognostic, or other purposes.
A little digression
I am someone who shamelessly loves the Ghostbusters and am always at the ready to equate infectious disease physicians to the Ghostbusters or the Men in Black (”We're your first, last and only line of defense against the worst scum of the universe”; “'Cause we see things that you need not see and we be places that you need not be”).
But I sometimes think a better analogy is to a science-based “exorcist”. After all, infection is a type of possession or infestation in which the host’s normal physiology can be severely altered by the invader It then becomes the infectious disease physician’s task to identify the invader and develop a plan to remove its influence on the host by killing it with medications and modulating the host’s immune response to it.
Maybe I’m making too much of this and it’s just the indelible 9 years of Catholic school I attended as an atheist child who was intrigued by the mythology of the dark side.
But, an aspect of all the exorcist demonic possession movies I have watched is the power that the exorcist (infectious disease physician) gains by learning the demon’s name (the identity of the pathogen).
In the movie The Rite, it is explained that:
“It is the job of an exorcist...
...to determine the number of
possessing demons and their names...
...something the demons protect
with great ferocity.
And when the exorcist has a name...
...he can then begin to
assert control over the entity...”
Like the German fairytale character Rumpilztilksen, the evildoer hides its name lest it lose the power it possesses. Once the name is known, it seems like child’s play to rid the person of the demon. Quoting again from the movie, The Rite, when the priest discovers the demon’s name he states:
“I know you, Ba'al.
And I command you, retire therefore.
Depart from this place. Leave!
Surrender now.”
To complete the analogy: in the case of, for example, severe septic shock, once the inciting cause is discovered the clinician can start a specific treatment plan and gain some control back (“Well I guess we're gonna have to take control”). While this may or may not be ultimately successful in rescuing the patient by ridding them of the infection, at a minimum, explanatory power is obtained.
***
Having the capacity to determine the etiology of the unknown unknown making someone, a city, a country, or the world sick is a critical aspect of pandemic preparedness and response. You have to know the demon’s name. However, to be able to do this adeptly in an emergency situation requires aiming for specific microbiologic diagnoses (and not ceasing investigation at the level of, for example, “pneumonia” or “viral syndrome”) to be the norm during day-to-day medical care, the topic for the next chapter.