Field Investigation
A number of people are sick and no one knows why. The local
government invites CDC to come and investigate. CDC sends a
team of disease detectives to try and discover the cause of
the disease outbreak.
What is causing the outbreak? People could be sick from food they ate, water they drank, or something in their environment. Maybe they were bitten by an insect or animal. The disease detectives are specially trained and equipped to solve this mystery.
This specimen collection tent is equipped with many of the tools the disease detectives will need to uncover clues about what is making people sick. Here you see a disease detective about to take blood from a patient.
Click on an area in the photo to learn more about how disease detectives work.
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Spot MapThe disease detective drew this chart to show where each sick person lives. Knowing this may give clues to what is causing the outbreak. This type of chart is called a spot-map. Line listings and histograms are other ways detectives piece the clues together. |
Line Listing
As detectives learn about who is sick, they
add key pieces of information about each person to a line listing.
Each row or line represents one sick person. In the line listing
below, the information collected for each person includes the
day they reported being sick, the day they first felt sick
(date of onset), and their symptoms, age, and sex.
How old are most of the people who are sick? Are they young or old? Male or female? Do you see a pattern? The line listing is a good tool for detectives to learn more about who is getting sick. If they see a pattern such as mostly teenagers being sick, for instance, they would try to figure out why the disease is affecting that age group.
Histogram
A histogram shows how many people got sick and
when they got sick. Each square in the histogram below represents
a sick person. What was the day when the most people were sick?
This is when the outbreak peaked.
Knowing when an outbreak started, when it ended, and when it peaked helps the disease detective narrow down the kinds of diseases that could have caused the outbreak.
Spot Map
Spots are placed on a map to show where
each sick person lives or works. The spots could also be
used to show where key events have happened, such as where
each sick person ate lunch. The location of the spots may
give detectives clues to the cause of an outbreak. When
the spots are clustered in one area, that may mean that
something about that area is causing the outbreak.
What clues do you see in the spot map?
Disease Detective
A disease detective is a person who is trained
at CDC to figure out the who, when, where, and what of
disease outbreaks. These detectives use their knowledge
and skills in medicine, statistics, and epidemiology.
During a field investigation, disease detectives must be sure to take care of themselves. Wearing protective goggles keeps debris and harmful bacteria out of their eyes and a wide-brimmed hat protects them from the sun.
Camera
This disease detective uses the camera to
take pictures of the surroundings. There may be a clue
to the cause of the outbreak right under his nose!
Special packages and labels are used to safely store and ship the specimens that are collected from patients. Take a closer look. What do you think is in that container?
Computer
This disease detective collects information
to figure out the cause of the outbreak. Tools like the
portable computer and calculator help the detective sift
through the information.
See the insect repellent and sun screen? Why are they important here?
Cooler
What do you think is in the detectives
cooler? Its probably not what you think.
The cooler contains dry ice to keep specimens cold, if needed.
Safe drinking water is often a problem in the places where a disease detective travels. This detective brought his own fresh drinking water in the green jug.