The Parable of the Clinician and the Epidemiologist
The brown river usually flows lazily through the middle of town. But today it is a torrent carrying human bodies. Some, still alive, are gasping for air and thrashing the water.
Approaching the river to enjoy lunch on its banks, two doctors, horrified by what they see, begin to haul people out of the water. There are no signs of violence, but the victims' eyes are glazed, their weak pulses racing.
The doctors cannot keep up with the flow of bodies. They save a few and watch helplessly as the others drift beyond them.
Suddenly, one of the doctors lowers an old man to the ground and starts to run. "What are you doing?" yells the other doctor. "For God's sake, help me save these people!"
Without stopping, she yells back over her shoulder, "I'm going upstream to find out why they're falling in."
This is the epigraph of Mark Pendergrast's Inside the Outbreaks, a history of the Epidemic Intelligence Service, a part of the US Centers for Disease Control. It summarizes, I think, the sort of thing EIS doctors do and the resentment they sometimes feel from doctors who are trying to stem an Ebola epidemic in the Congo or a flu outbreak in Hong Kong.
Epidemiology is inherently interesting. Every incident is a sort of medical detective story, as recognized by Berton Roueche in his now-famous book, The Medical Detectives, a book that was published in 1980 but is still relevant enough to have provided the plots for numerous House episodes. I used to look for Roueche's "Annals of Modern Medicine" columns in the New Yorker knowing they would be entertaining as well as puzzling and sometimes shocking. They usually told of an at least marginally heroic doctor who was able to figure out why two patients had turned up in the local hospital having turned blue, or why a man had grown three breasts, or why another man had the hiccups - for 27 years.
Books like this usually describe less than a dozen cases in depth but Pendergrast's book is a history of the EIS and so he tries to give the reader a feeling for the constant motion of these doctors (and later nurses, veterinarians, nutritionists, etc.) as they respond to one case after another. An entire family is in the hospital near death. Navajos in the Four Corners Area are succumbing to an unidentifiable respiratory problem. A little girl rapidly goes into multiple organ collapse for no apparent reason. Staff and patients in an African hospital are contracting a horrifying disease that is killing more than 90% of those who have it.
Sometimes the doctors are successful, as they were with the Four Corners problem. Working with the medicine men of the Navajo tribe, who say that legend connects this problem with very wet springs and the many small animals that come down out of the mountains to eat the abundant food produced, they were able to identify a hantavirus spread by the urine of mice. You don't have to have mice running around your house to acquire this - the urine dries and much later the dust kicked up by cleaning house spreads the virus.
Pathologists recognize a virus akin to Marburg and Lassa Fever and trace it to the area of the Ebola River after which it is named. They are able to trace a patient's meal of fast food hamburgers contaminated with E coli. After years of detailed record keeping they connect Reyes Syndrome with aspirin given to children.
Sometimes they are unsuccessful. They are unable to explain why patients and staff at St Elizabeth's hospital in DC are stricken with an unusually deadly respiratory illness. Or why the same illness fells a number of people in Pontiac, Michigan, some years later. In that case they were ultimately successful in identifying a virus that was killing veterans at an American Legion convention in Philadelphia, the same virus they had found at St Elizabeth's and in Pontiac years before. They named the condition Legionnaires Disease and there are still many cases each year in the US.
The book is an institutional history so there are a lot of names and a good deal of information about funding and reorganization as well as the stories of men and women rushing in the middle of the night to some small American city or an almost inaccessible African village. But the dozens of one-page stories about what the doctors of the EIS actually do - stories we don't usually read about in the news - gives the reader a good idea of the hard work and ingenuity of these people who work so hard to help keep us all a little safer.
2012 No 78