CDC is home to little-known army of disease detectives

The Epidemic Intelligence Service (EIS) is a small, largely unknown training program for young epidemiologists within the Centers for Disease Control and Prevention (CDC). Mark Pendergrast’s new book, Inside the Outbreaks, looks behind the scenes of the EIS, at medical mysteries around the world. I talked to Pendergrast yesterday.

When it was formed in 1951, the EIS was considered a medical equivalent of the CIA. Was there the same secrecy? And how would you describe the modern EIS?

I don’t think it’s changed materially. It was not exactly secret, but they flew under the radar of everyone. Alexander Langmuir, who created the EIS, very deliberately named it with military terms. The CIA had come into being only a few years before. In the context of the Cold War there was a great deal of paranoia—we thought the Communists might poison the water supply. Nobody thought there was a future in public health in the early ‘50s. We had these new miracle drugs—antibiotics--and everyone thought infectious diseases would be conquered. Langmuir got funding for the EIS because it was mainly going to look out for bioterrorism. Fifty years later, there was a real and frightening bioterrorism incident with anthrax, which the EIS investigated.

The EIS is a two-year service program, and officers are on call 24 hours a day. What types of backgrounds do they have?

At first they were almost all white male doctors and veterinarians, and many joined to avoid the draft. Today over half are women; about 20 percent are minorities; and 10 to 15 percent are from foreign countries. About half are doctors. Many have Ph.D.s or masters in public health. There are some anthropologists, sociologists and lawyers.

You say in the book that epidemiology is a science of probability, not proof. What does that mean?

Often you act on incomplete information. If people are dying, and it’s clear it’s something in the air, you act on what you know—despite the fact that you don’t have proof. Quite frequently, the epidemiologist will figure it out before the lab does. You’re trying to figure out how many people in the population have a condition, and what characteristics they share. At the classic church supper, you ask everyone what they ate. If everyone who got sick had the potato salad, there’s a good probability it’s the potato salad.

What are the EIS’s biggest remaining unsolved mysteries?

• A disease called sarcoidosis, which causes tiny lumps in various organs of the body, usually starting in the lungs. They still don’t know what causes it. They suspect it may be a spore from a fungus or mold.
• Brainerd diarrhea, a terrible form of diarrhea that won’t go away and can last for months. Nobody knows what causes it. It’s been traced to milk and water, but the laboratory can’t find anything.
• The EIS spent years trying to look at what appeared to be Leukemia clusters. The EIS officer, Clark Heath, thought it was probably a virus. That may well be, but nobody has figured it out.
• The same is true with a lot of environmental toxins. It’s very difficult to prove something that takes 20 to 30 years to affect you. In one rare case, Henry Falk was able to implicate vinyl chloride gas (the primary component of PVC) in a rare form of liver cancer.

There are EIS counterparts in other countries, but EIS offers still investigate around the world?

Yes, but they can only go where someone invites them. That’s true in a state, too—they have to be invited by a state public health department. As states’ departments are getting more sophisticated, EIS officers are getting sent out less. Politics gets into a lot of this. But this is one government program that people should support—for humanitarian reasons but also because it saves money. The classic case is smallpox. There is no more smallpox today, so we don’t have to spend millions of dollars vaccinating or treating people.

In the past, EIS officers have taken on polio and cholera, but today they are looking at some very different types of public health threats, including smoking, obesity and gun violence. How do they determine what’s an epidemic?

An epidemic is an unusual number of cases of a particular health problem that’s growing over time. To tell whether there’s an epidemic, you have to know what the normal rate of something is, so that’s why you have surveillance. We’ve completely gotten rid of polio in this country, so if you have one case of polio, that’s an epidemic. Typically you see an epidemic curve—a bell curve. You can see a bell curve of obesity, but it’s not going down; it’s going up. You can compare it to other places in the world and see we’re having an epidemic. Same with gun violence.

What’s a pseudoepidemic, and what are some examples?

It’s when there’s not really an epidemic happening but people think there is. One example was at an elementary school in Alabama in 1973, where a bunch of students began to itch terribly and developed horrible rashes. There were headaches, coughing , nausea and loss of consciousness. Some were hospitalized overnight. But there was nothing physically the matter with them. They were giving rashes to themselves by itching. It was a case of mass hysteria.

Images: Mark Pendergrast

This post was originally published on Smartplanet.com