Many of us have read news stories, books, or journal articles chronicling the exploits of disease hunters on the search for the origin of a new outbreak in some exotic corner of the world. While those stories indisputably form a core part of pandemic preparedness, there are many aspects of the field that depend on the essential work of physicians in Anytown, USA.
There are countless examples of infectious disease emergencies being recognized in locations not traditionally considered disease hotspots. These events have had a wide level of significance ranging from the recognition of a new influenza pandemic (2009 H1N1, San Diego) to contained outbreaks (monkeypox, 2003, Indiana), to widespread outbreaks (hepatitis A, 2003, Beaver County, Pennsylvania), to national panic-inciting events (Ebola, 2014, Dallas). Astute clinicians, wherever they may practice, are lynchpins in the preparedness apparatus that provide key situational awareness of the infectious disease landscape and magnify the power to detect outbreaks before they reach uncontainable size.
In my analysis, there are three key messages that physicians should keep in mind and each is an action item that should activate a mental context for physicians, so it can be thought of as a standing order.
Be Diagnostically Curious
It happens more often than not that a physician will use the throw-away wastebasket diagnosis of “viral syndrome” to explain any constellation of signs and symptoms that defies basic clinical and laboratory diagnosis. Almost all upper respiratory tract infections and gastrointestinal infections are labeled as such. However, leaving these usually minor illnesses without a specific microbiologic diagnosis may have important consequences. This is one of the themes in a recent report my colleagues and I at the Johns Hopkins Center for Health Security released on the Characteristics of Pandemic Pathogens.
Many high-consequence infectious diseases present with a spectrum of severity with mild cases outnumbering severe cases — both US MERS (Middle East Respiratory Syndrome) cases were minor — and giving a non-specific diagnosis to a patient may constitute a missed opportunity to discover the first forays of a new microbe into humans or the arrival of a travel-related infection to a new geographic region. That about half of septic shock cases — by definition a life-threatening condition resulting from infection — go without a specific microbial diagnosis is alarming, as is the fact the most cases of acute HIV infection are not diagnosed despite the majority of those infected presenting for medical care.
The infectious disease diagnostics available to the physician have increased tremendously over the past decade with point-of-care molecular tests — some of which test for multiple different pathogens — now available. Additionally, genetic sequencing is now readily available and can test for dozens and dozens of microorganisms of multiple different classes (virus, fungi, and bacteria).
Curiosity might have killed the cat, but in this context, it could be life-saving.
Know That It Could Happen Here
It is easy for a physician to fall into the trap of taking the dictum “common things are common” too literally and closing off their mind to the possibility that unusual infections can present anywhere. The sheer volume of intercontinental travel — let alone domestic travel — means that basically any person in the world can get anywhere in the world within a day. As incubation periods now dwarf travel times anywhere on the planet, it has become increasingly likely that disease importations can occur with sickness occurring only after arrival — indeed this is the pattern followed by the man who died of Ebola in Dallas.
Thinking about zebras is something I spend a lot of time doing — it’s even the name of my blog — and, though many people mischaracterize this approach to diagnosis, it is not a manner of thinking that discounts common infections but an approach that is active-minded. For example, never fail to ask a patient about travel history, animal exposure, sick contacts, hobbies, and unusual food consumption.
Diagnoses DO Change Treatment
Another objection to taking this aggressive approach to diagnosing infectious disease syndromes is that “it doesn’t change treatment.” Specific diagnoses do change treatment even when they are not linked directly to a specific medication for treatment. While we lack specific antivirals for non-influenza respiratory infections, physicians have a horrible habit of prescribing antibiotics for them. Empowering physicians to have diagnostic confidence regarding the etiology of an infection may go a long way in improving antibiotic stewardship and diminish the myriad negative impacts of inappropriate antibiotic prescriptions. It is also likely that as more specific diagnoses are made, and the true burden of illness determined, the more likely new antivirals are to be developed.
A specific diagnosis provides prognostic information that can forestall a patient returning for another visit when symptoms have not abated as they will have a better idea of the course of illness. For patients hospitalized, there may be important infection control implications for those with certain pathogens (e.g., respiratory viruses merit droplet precautions).
Pandemic preparedness might seem like a nebulous field strewn with data scientists, swashbuckling virus hunters, and sophisticated laboratory equipment, but it is so much more. The foundation for pandemic preparedness has always been the astute clinician who, in 2018, has the tools to greatly enhance our resiliency.
Dr. Adalja, board-certified in internal medicine, emergency medicine, infectious disease, and critical care medicine, is a senior scholar at the Johns Hopkins Center for Health Security. His personal blog is www.trackingzebra.com and his Twitter handle is @AmeshAA.