Tuesday, March 31, 2009

National Immunization Conference

This week I am in Dallas for the National Immunization Conference. And I must say it is very good! I promise to post on some of the sessions I attended.

As an aside, why must all events held in Texas be somehow cowboy themed?

Tuesday, March 17, 2009

We Want To Talk To You

Sometimes when we call people to investigative communicable disease reports, they get angry with us. They want to know how we got their info when it is supposed to be private. HIPPA does protect the privacy of your health records; however, it contains a stipulation which allows public health access to your information in regards to a public health investigation. One guy recently yelled at my investigator about invading his privacy. This was a guy with salmonella. He said, “Why are you bothering me? You people need to be doing something about the peanut butter!!”

Yes. He’s right. We do need to be doing something about the peanut butter. And we are. The thing is, how do you think we found out the peanut butter was a problem? We figured out through patient interviews. When we call and interview someone with salmonella, we ask them to name all of the foods they ate in the few days before onset of their symptoms. We find out every restaurant, and as much as possible about what else they ate, what exactly it was, and where it came from. That way we can identify patterns. If we have ten cases of salmonella reported to our health department within a short time span, and they all said they ate at the IHOP, we are going to go over to the IHOP and see if there is a problem. If CDC identifies a national outbreak through their lab surveillance system, then multiple jurisdictions get together on a conference call and compare notes to figure out what the likely culprit was. Once we’ve pegged down a possibility, we will conduct a case-control study to further confirm that’s what it is. Meanwhile, CDC alerts the FDA so they can start product tracing. All of this – ALL OF IT – is dependent on sick patients telling us what they ate.

Personal health information is private. But not at the expense of the public’s health. More about the balance between private and public interests later.

Friday, March 13, 2009

Don't Eat It If You See Human Blood

A good one today... A doctor's office called wanting advice on how to handle a blood-borne exposure. They had a patient visit them who claimed that she had gone out for a burger at lunchtime and was concerned about possible disease exposure. After she bit into the burger, she realized that there was "something on it that looked and tasted like human blood." She claimed to have spit it out and did not finish the burger.

"Is she sure it wasn't ketchup?"

"We asked her that too. Nope. She says it was blood."

"Did she tell the manager?"

"We didn't ask. Do we need to test her for blood-borne pathogens?"

We get calls about blood-borne exposures on occasion. These typically come from EMS, fire fighters, police officers. In the course of duty they get splashed with blood. Sometimes in their eyes or mouth. Or both. Generally speaking, the risk of contracting HIV or hepatitis B or C this way is pretty unlikely, but anything is possible. In those cases we recommend baseline testing. If possible, we would like to test the person who belonged to the blood but we are not always able to. If we feel the exposure was particularly risky, we will consult with the patient's doctor about post-exposure prophylaxis. Baseline testing is done, with a follow-up test at 6 months. Sometimes they will follow-up at 3 months also, but it really takes until 6 to be sure. This may not prevent anything, but at least gives them records to file for worker's comp.

There is a huge fear factor for a lot of people when it comes to human blood.

Back to our hamburger woman. While I am skeptical about the story, it wouldn't hurt to do baseline testing. My investigator brought up a good point: Perhaps the burger is just a cover story. Perhaps the woman shot up with a friend the night before and thinks she caught something.

I have a tendency to assume people are telling the truth. In this job, you find out pretty quickly that sometimes people lie.

Either way, if your burger has something that looks like human blood on it, send it back to the kitchen.

Tuesday, March 10, 2009

Recession and Infectious Disease?

MSNBC published a story yesterday about the potential rise in infectious diseases as a result of the economic downturn. They site leishmaniasis, Chagas, dengue, and other bug-borne illnesses as likely candidates for re/emergence in the US. Pro-MED mail sent out a report of a woman in Washington who inadvertently gave herself and her children botulism from improperly canned green beans. The editors of that report also hypothesized that we may see more of this as people turn to home canning to save money. This is not to imply that home canning is necessarily dangerous, but it is important to know what you are doing.

Meanwhile public health funding continues to decline.

Microbes and Genetics

This morning on the way in to the office, I caught a story on NPR about the role of genetics in susceptibility to infectious diseases.

What factors in the host make the host more susceptible to particular germs than others? This question is often asked of me. I once investigated an elementary school outbreak of coxsackie virus. The school nurse called me: She had more than 100 vomiting kids. Could I help? I grabbed an intern (new on the job), and called the sanitarian to meet me out there. Upon arrival, we were confronted with a hallway lined with little kids puking in trash cans.

Here's the thing about a bunch of kids puking: It is really, really difficult to figure out who is actually sick and who is sick because of the sight/smell/sound of everyone else throwing up. The school nurses call it WGA. They have "what's going around." We focused on those who first succumbed.

They were mostly first graders. The little epidemiologists had already determined this was all a result of the hot dogs they had eaten in the cafeteria the day before. I remember school cafeteria hot dogs. I get why they were pegged. Nonetheless, the intern and I set about conducting our own interviews. We tried to focus on the teachers. Who among them were sick? What did they eat? Was it different from the well teachers? We interviewed some of the kids too. Next time you talk to a first grader, ask her what she ate for lunch the day before. Recall bias is a challenge! Despite the children's insistence that the hot dogs were the problem, statistically in our case control study we did not find that to be the case. No particular food stuck out as the likely culprit.

This outbreak appeared to be point-source -- in other words, they were probably all infected at the same time by the same source. All of the children and teachers who got sick did so within a couple of hours of each other. Interestingly, once they all recovered there were not any more cases.

The sanitarians had better luck. They identified a cafeteria worker who had been sick for a few days before all this, and came to work with active diarrhea. Was she our index case? Schools are required to save a tray of all the foods served for at least a week just in case something like this happens. We took the tray and sent it to the lab. The lab found a high coliform count (in other words, fecal contamination).

In the end we hypothesized that the sick cafeteria worker had contaminated hands (wash your hands people!!) and spread her germs all over the cafeteria. It didn't matter what the kids ate; the contamination was probably not contained to one food item.

Of all the kids, only one went to the doctor, so despite the puking drama, the kids were not that sick. But the one kid who went to the doctor actually went to the emergency room. He was diagnosed with viral myocarditis, an infection of his heart, as a result of coxsackie virus.

We don't know for sure that the other children has coxsackie virus. The samples that were taken were unfortunately tested for bacterial infections only and all came back negative. But outbreaks like this are certainly not unheard of. But if the outbreak was due to coxsackie, why is it that some of the children experienced mild gastrointestinal symptoms, but this one child was hospitalized because the virus entered his heart? Perhaps the answer is that some people are genetically more susceptible to certain infectious diseases than others.

Welcome to the Epidemiologist!

"You have such crazy stories. You should write them down."

I can't tell you how many times colleagues have told me this.

I am the Chief Epidemiologist of a large public health department. My jurisdiction encompasses a population of about three-quarters of a million people -- larger than some states. I oversee infectious disease investigations, disaster epi, and occasionally am involved in some chronic disease surveillance.

So this is my blog, my collection of stories about the life of a disease detective. Hope you enjoy.