Disease Detectives

In 2020, the world shut down as the infectious coronavirus spread. Families quarantined. Schools went virtual. Communities masked and gloved up.

But before the pandemic hit the United States, Michael Callahan was at ground zero in Asia, trying to understand this new virus. Callahan is an epidemiologist — or, as many in the field describe themselves, a disease detective. Epidemiologists study the causes and spread of diseases. As an epidemiologist, Callahan asks questions like, “What caused the coronavirus? How is the virus transmitted? Who is most at risk? And how can we prevent the virus from spreading?”

Callahan specializes in field epidemiology, which means he works directly with communities experiencing public health crises. Often covered from head to toe in a biocontainment suit, Callahan responds to disease disasters. He controls the outbreak, investigates the causes, and works with communities to put disease prevention strategies in place. For example, Callahan flew to Japan in February 2020 to safely evacuate four passengers from the Diamond Princess, a cruise ship suffering a coronavirus outbreak.

Callahan decided to pursue a career in epidemiology after working in a refugee camp in Africa, where he witnessed the uncontrollable spread of diseases. “I realized that it wasn’t the earthquake or tsunami that’s killing everybody, but it’s the malaria, the dengue, and waterborne diseases that come afterward. Infectious disease is a slow-rolling disaster. And it goes on forever,” Callahan shared.

After returning from Africa, Callahan earned a master’s degree in International Public Health and attended medical school at the University of Alabama. Over the last 20 years, he has worked in Ebola clinics in Africa and fought the SARS virus in Hong Kong. He has researched how to rapidly develop vaccines to fight diseases and worked for the Department of Defense to predict emerging diseases. At the height of coronavirus outbreaks, Callahan suited up and treated COVID patients at Massachusetts General Hospital.

Fighting Disease On Many Fronts

But, not all epidemiologists travel the globe and put themselves in disease disaster zones. Scientists in the field of epidemiology often specialize and concentrate their learning and efforts on a specific issue. More than half of epidemiologists work with government agencies, like the Center for Disease Control (CDC). About 15% work in hospitals to keep patients and doctors safe, and 11% work as researchers or teachers at universities.

For instance, medical epidemiologists study outbreaks of diseases and search for cures. They look for remedies in medicines and treatments and research how lifestyle changes affect diseases. Medical epidemiologists could analyze what types of drugs or diets prevent heart disease best.

Another kind of epidemiologist, pharmacoepidemiologist, spends a lot of time in laboratories. These researchers study how diseases react to medicines and calculate the possibility of harmful side effects of drugs. Then, they communicate these findings to hospitals, government agencies, and pharmaceutical companies.

Infection control epidemiologists work in hospitals and clinics. To help hospitals and doctors' offices control outbreaks, these epidemiologists create preparedness plans. In addition, they educate health care workers, investigate outbreaks of infection, and promote hygiene practices like hand washing to reduce infections and the spread of diseases.

Academic research epidemiologists work at universities to investigate the causes and effects of infectious diseases. They collect samples of blood and body fluids to study how viruses affect the human body. They also interview infected people to learn how lifestyle and people’s choices change how diseases spread.

Veterinary epidemiologists study how diseases spread in animals. They diagnose the cause of diseases in animals and devise solutions to stop it from spreading. They also protect humans from illnesses by limiting the spread of disease transmitted to humans through eating livestock like cows, chickens, and pigs.

The Skills of Disease Detectives

Whether epidemiologists work at the scene of an outbreak, for the government, or in a laboratory, they share some common characteristics. Like all detectives, epidemiologists must be strong observers. This means they notice details and gather lots of information. They also demonstrate critical thinking, analyzing data, spotting trends, and developing theories about the causes and spread of diseases. To present their findings to doctors, government officials, and the public, epidemiologists must communicate clearly. Finally, epidemiologists are problem solvers, coming up with solutions to health crises and the spread of disease.

Do you have what it takes to be a disease detective?