How Does Public Health Surveillance Work?


By Barry C. Fox, M.D.University of Wisconsin

You might be wondering, are there organizations looking out for global health issues that might affect the U.S., helping to protect us against outbreaks and epidemics? During wartime, natural disasters, or outbreaks, public health surveillance is critical to providing evidence for sound decision-making. It provides a formal system of collecting, analyzing, interpreting, and disseminating data.

Image of people being scanned to determine their health status.
An example of successful public health surveillance is the SARS epidemic in China. (Image: r.classen/Shutterstock)

How the SARS Epidemic Was Stopped in Its Tracks

In 2002, a severe pneumonia epidemic broke out in China, spread to Hong Kong in 2003, and later to Singapore and Canada. It was called severe acute respiratory syndrome, hence the name SARS. It was identified as a new coronavirus. More than 8000 people in 26 countries were affected, with over 700 deaths. The WHO spearheaded efforts to control the human health epidemic.

China, after initially hiding the disease events, also mobilized its trained health workers, who started collecting data. Collection and sharing of data between countries with outbreaks revealed there was an incubation period of the virus of about 10 days. It was decided that quarantine measures would be useful to gain control of this epidemic, and it was stopped in its tracks in July of 2003.

This is a transcript from the video series An Introduction to Infectious Diseases. Watch it now, on Wondrium.

WHO and the GeoSentinel Surveillance Network

Image of a glass building with “World Health Organization” written on it.
WHO collects data from all over the world and even welcomes informal calls delivering information. (Image: Skorzewiak/Shutterstock)

The WHO also monitors trends, disseminates information and hosts the Global Health Observatory. This is a data repository for such health-related topics as world health statistics, specific disease statistics, and environmental risks. Formal reports are actually generated. Data from informal sources are welcome. Suspicious informal reporting allows for a potential earlier response to health threats. 

There are other systems and organizations that are tasked with monitoring health in the U.S. and all over the world. The GeoSentinel Surveillance Network has been monitoring health around the world for over a decade. This network has 57 medical clinics through each continent, which continually collect information on ill travelers, immigrants, or refugees who have gone to their clinics. The clinics fax information to a central data site, where this is all aggregated. 

Finally, both the CDC’s National Center for Emerging and Zoonotic Infectious Diseases and the International Society for Infectious Diseases are heavily involved in preventing diseases and deaths due to infectious diseases. 

They also publish the current outbreak list and ProMED Digest, which lists all domestic and foreign infectious disease events and outbreaks. The Animal and Plant Health Inspection Service coordinates efforts to monitor plants and animals coming into the United States to ensure they don’t carry any diseases that can be transmitted.

Learn more about how you can protect yourself from germs.

Social Media during the Information Age 

We have seen examples of how social media has helped in various disaster situations. Videos are taken by bystanders who bear witness to the devastating circumstances of war and post them on YouTube for the world to see. 

For example, using YouTube videos that provided real-time information in Syria, clinicians were able to firmly conclude that sarin nerve gas had been used based on the signs affecting the victims. 

Image of an earthquake-stricken city in Haiti.
Social media helped in the aftermath of the 2010 earthquake in Ushahidi, Haiti. (Image: G Allen Penton/Shutterstock)

Pictures are sent on TwitPic to show the reality of desperate situations; in fact, donations to the Red Cross for Haiti relief poured in over text messages pledging $10 each, adding up to over $30 million. Also, after Haiti’s earthquake in 2010, Ushahidi—an open-source web platform—used information that was crowd-sourced to link healthcare providers who needed supplies with people who had the supplies.

Closer to home, during flu outbreaks, some health departments have tweeted and texted to campus students where they should go to get vaccines. It looks like social media will have an expanding role in the future that may be extremely helpful for monitoring public health all over the world, even to the point of confirming diagnoses.

Learn more about the powerful effect of vaccines on public health.

Collaboration Is Crucial for Public Health Surveillance

There’s an app called Outbreaks Near Me that gives real-time updates on outbreaks in specific locations. This app is part of HealthMap, an online information source for monitoring disease outbreaks. It was developed by a team at Boston Children’s Hospital in 2006, and it uses informal sources for real-time surveillance of emerging public health threats. 

It collects and aggregates informal data from sources such as online news and eyewitness reports, as well as official reports. From there, it can provide a comprehensive view of current infectious disease risks both locally and globally. In this way, it facilitates early detection of a public health threat and a quick response. 

Lastly, we should not forget the One Health Initiative, which is the collaborative effort among human, animal, and environmental health professionals. You can see why it would be important to collaborate and share information from all three sources to identify potential dangers and to coordinate response efforts. We know that many of the emerging infectious diseases are zoonotic, and many emerge because of the artificial alterations in the environment. It’s a fact that we are inextricably linked to the health of all three of these health groups.

Common Questions about How Public Health Surveillance Works

Q: How did China contain the SARS epidemic in 2003?

Sending trained health workers to collect data and collaborating with other countries with the same outbreak helped public health surveillance. It was decided to utilize quarantine protocols which ended up being effective.

Q: How does the GeoSentinel Surveillance network gather data?

Their public health surveillance consists of 57 clinics in various continents collaborating on the data they gather on sick travelers, refugees, etc.

Q: What role did the social media play in helping people after an earthquake devastated lives in Haiti in 2010?

After Haiti’s earthquake in 2010, Ushahidi—an open-source web platform—used information that was crowd-sourced to link healthcare providers who needed supplies with people who had the supplies.

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