Ad Hoc Commentary – the first case of Ebola in USA



“…On 24 September the patient began developing symptoms of Ebola, which can include high fever, vomiting, diarrhea and in serious cases internal and external bleeding…”
“…On 26 September the patient sought treatment for the first time, but was not admitted to a hospital…”
“…On 28 September the patient was admitted to Texas Health Presbyterian Hospital in Dallas and placed in isolation…”
“…On 30 September the CDC received specimens from the infected individual, tested them and determined that they were positive for Ebola…”

The most important people to talk to on Ebola today are not medical doctors, clinicians, microbiologists and not politicians. The right people to consult are epidemiologists. They study the patterns of disease and its transmission. A good book on this subject is Modeling Infectious Diseases in Humans and Animals by Matt Keeling and Pejman Rohani (Princeton University Press 2007).

Even if you don’t have the time, you should at the very least read sample Chapter 1 at
“…The models and diseases of this book are focused toward the study of directly transmitted, micro-parasitic infectious diseases [Figure 1.1]…”
“…This fundamental classification (as susceptible, exposed, infectious, or recovered) solely depends on the host’s ability to transmit the pathogen. This has two implications. First, the disease status of the host is irrelevant—it is not important whether the individual is showing symptoms; an individual who feels perfectly healthy can be excreting large amounts of pathogen (Figure 1.2). Second, the boundaries between exposed and infectious (and infectious and recovered) are somewhat fuzzy because the ability to transmit does not simply switch on and off…”

If you are a pictures person, then download the pdf version from the website and look at Figure 1.2. In general, for directly transmitted, micro-parasitic infectious diseases (like influenza, measles, and HIV) the symptomatic period is not necessarily correlated with any particular infectiousness state.

It is therefore curious that Ebola is said to be non-infectious during the incubation period. Does this mean Ebola has the ability to simply switch on and off its infectiousness ability? That seems highly unlikely. Isn’t Ebola just a filovirus like HIV? What if someone with Ebola had sexual relationships during the late incubation period? Would he/she infect his/her partner? Perhaps the fear alone will keep people less promiscuous during this time.

In all likelihood, the CDC will take good care of the first case of Ebola in USA. That would likely lead to over-confidence and complacency. Remember, Ebola likely follows Reed Frost dynamics and will likely come in waves:
“…The plague, just like the Black Death, probably follows Reed Frost dynamics. In that case, we should have a reprieve soon, say in Oct 2014, and it will probably come back in a stronger wave in spring 2015. The key is that it will come in waves. For all of you out there, please do not underestimate this pestilence. Stay safe…”

Good luck in the markets.