Disease Detectives: Tracking an Infectious Disease Like COVID-19
By Deborah Barkin Fromer
Faculty Member, School of Health Sciences, American Military University
Disease detectives are people whose work is invisible, until they contact you or there is an outbreak or unusual newsworthy condition causing illness, suffering and/or deaths. In my years as a health department epidemiologist, I have interviewed countless cases of reportable illnesses. These mandatory reportable diseases can be found on the Centers for Disease Control and Prevention (CDC) list of Nationally Notifiable Diseases.
How an Infectious Disease Is Reported
By law, when a person has symptoms and/or tests positive to one of these reportable illnesses, the lab sends the result electronically to the state health department. The provider can also contact the health department to report it.
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The epidemiologist receives the report, and the next step is a follow-up with the provider who filed the report and the patient to complete a disease-specific investigation form. Examples of information that I typically collect about the patient’s case might include:
- Dates of the onset of the patient’s symptoms
- The location of the patient’s school or workplace and attendance dates
- The patient’s vaccination status if applicable
- Travel history
- A detailed food history
- Recreational sources (lakes, rivers or pools)
- Drinking water sources
- Animal, reptile and pet exposures
- Human contacts
Data is collected and inputted from patients using these CDC information protocol forms, which are designed to be shared and analyzed rapidly. This information helps epidemiologists to understand transmission patterns, clinical features and risk factors. That same information helps us to locate the source or cause of each specific illness and reduce its spread, as well as give us a better understanding of the process and practices that may contribute to contamination and transmission.
Challenges to Obtaining a Patient’s Information
Some of the challenges to gathering information include having incorrect or no contact information or the patient not returning phone calls. In some cases, investigation forms can be sent by snail mail if needed.
People are hard to reach when they are ill. Once they are better, patients do not always take the time to return calls. I have done many investigations where I suspected people were traveling in their car.
Another challenge is trust. People are not always told that the health department will follow up with an investigation and do not trust that their information will remain private.
A big problem is memory. I cannot remember what I ate yesterday, so asking someone what and where they ate in the last seven days is daunting.
Some investigation protocols are very specific. For instance, patients not only might be asked if they had eaten lettuce in the last seven days, but are asked to identify the type of lettuce such as romaine or iceberg and whether it was packaged in a bag. The same type of information goes for tomatoes such as cherry, beefsteak or Roma.
People also forget the date the symptoms started and may not know if they had a temperature above normal. But most remember if they attended school or work while they were ill or just prior to experiencing a disease’s symptoms.
Travel is easier since most folks have a record of plane flights or hotel bookings. Credit card receipts are great for tracking restaurant and food purchases.
People can also misinterpret questions asked during a phone interview. I once asked a woman diagnosed with salmonellosis when her gastrointestinal symptoms started. She said that she was leaving the grocery store on the way to her car and…..whoops, they started. I said I just needed the date, and we both had a chuckle.
Another time, I interviewed a young mother as her newborn was hospitalized for pertussis (whooping cough). I asked if anyone who was coughing had been around the baby. She said her 14-year-old brother had been near the baby, so I reviewed my database for cases at his school and found other cases.
The brother later tested positive for pertussis. The young mother and family were all given antibiotics/immunizations where necessary, as well as an education on the seriousness of this illness to an infant who was not yet vaccinated.
Interviewing COVID-19 and Other Critically Ill Patients
There are challenges to interviewing someone critically ill, such as a patient with COVID-19. Speaking with the medical provider or close family member, along with information gathered in the hospital medical record, is very helpful.
If a patient is hospitalized, pre-existing medical conditions can be found in the medical chart. But who that patient had been in contact with prior to infection is a challenge to uncover. Those who were not hospitalized may be hard to trace or convince to return your calls and answer questions.
The CDC has a COVID-19 report form that is used to collect information about each Patient Under Investigation (PUI). But COVID-19 infection sources aren’t easy to track, due to this disease’s scale and complexity.
Multiple state/local health departments may be involved in a single investigation. People travel – that’s how diseases like COVID-19 spread. Much is still unknown about coronavirus transmission, but dedicated people are working on solving the problem.
About the Author
Deborah Barkin Fromer received a B.S. in biology at the Sage Colleges in Albany, New York and was certified with the American Society of Clinical Pathologists as a medical technologist in 1976. She worked in the clinical laboratory as a medical technologist specializing in microbiology. In the 1990s, Ms. Fromer became interested in public health, returned to graduate school and completed a Master of Public Health (MPH) degree at Wichita State University in Wichita, Kansas.
Ms. Fromer spent several years at the University of Kansas School of Medicine as a researcher in obstetrics and gynecology, and several years as a researcher and teaching associate in preventive medicine and public health. She has taught online epidemiology and public health courses since 2001.
From 2007-2015, Ms. Fromer was an epidemiologist at the Sedgwick County Health Department in Wichita, Kansas. Her work involved electronic surveillance of reportable disease and medical conditions, investigating outbreaks and illness, solving mysteries, and keeping people in the community educated and healthy.