How to track virus outbreaks: An overview of disease surveillance

Modern outbreak tracking works like a sophisticated early warning system. Think of it as a vast network of sensors where healthcare providers, laboratories, and public health agencies act as detection points, constantly monitoring for unusual patterns of illness.

The process typically involves four key components:

Case detection and reporting

At the frontline of outbreak detection are healthcare providers who report unusual symptoms or disease patterns to public health authorities. In the United States, the CDC’s National Notifiable Diseases Surveillance System (NNDSS) receives around 2.7 million disease reports annually from state health departments [2]. 

Similarly, the European Centre for Disease Prevention and Control (ECDC) maintains TESSy (The European Surveillance System), which collects data from 30 EU/EEA countries on 52 communicable diseases and health issues [3]. These surveillance systems create a comprehensive network that can quickly identify potential outbreaks.

Laboratory confirmation

Virus identification happens at different laboratory levels, depending on the pathogen’s nature and risk level. Most common viral infections, like influenza or respiratory syncytial virus (RSV), can be confirmed in regular clinical laboratories. 

However, some viruses require specialized facilities. For instance, Biosafety Level 4 (BSL-4) laboratories are needed for deadly viruses like Ebola or Crimean-Congo hemorrhagic fever (CCHF). 

The United States has 13 operational BSL-4 labs, while Europe has 14 [4]. Many developing nations lack such facilities, creating challenges in rapid pathogen identification during outbreaks.

Contact tracing

Contact tracing works like detective work in disease control. When someone tests positive for a virus, public health workers interview them to identify everyone they’ve been in close contact with during their infectious period.

These contacts are then notified, tested, and may be asked to quarantine. For example, during a 2014 Ebola outbreak in Nigeria, contact tracers monitored 894 contacts, making 18,500 face-to-face visits. Their efforts helped contain the outbreak to just 19 cases in a city of 21 million people [5].

Data analysis and sharing

The real power of modern outbreak surveillance lies in how we analyze and share data. Public health agencies use sophisticated software to detect unusual disease patterns. For instance, if several hospitals in one region report a spike in similar symptoms, the system raises an alert. This data is then shared through international networks, allowing rapid response to emerging threats.

The World Health Organization, WHO, has a Global Outbreak Alert and Response Network (GOARN) that exemplifies this global cooperation. It connects many experts and resources worldwide. 

When an outbreak occurs, GOARN can deploy response teams within 24 hours, bringing together local health authorities, laboratories, and emergency response units. This coordinated approach has helped contain numerous outbreaks before they could become global health emergencies [6].

Staying ahead of infectious disease outbreaks is like trying to complete a puzzle while the pieces are constantly changing shape. Public health agencies and the field of epidemiology face several challenges.

Political barriers

Some countries delay or underreport outbreaks fearing economic impacts. During past outbreaks, delayed reporting has led to preventable spread across borders and lost opportunities for early containment.

Resource limitations

Many regions lack basic diagnostic equipment and trained personnel. This creates surveillance blind spots where outbreaks can grow undetected until they become major health emergencies.

Emerging pathogens

New viruses can appear with unfamiliar symptoms, making them harder to identify. Think of it like meeting someone who speaks a language you’ve never heard before; it takes time to understand what they’re trying to tell you.

When SARS-CoV-2 emerged in late 2019, doctors faced this challenge exactly—a new virus causing symptoms that looked like many other common respiratory infections. By the time scientists had begun to understand its unique characteristics, it had already spread to 114 countries in just three months [7]. This rapid spread taught us a crucial lesson: our surveillance systems need to be ready to detect and decode these new viral “languages” quickly.

Climate change impact

Our warming planet is redrawing the maps of where viruses can thrive. Dengue fever, long considered a tropical disease, is now knocking on Europe’s door. 

In the past decade alone, Europe has witnessed a startling 7.2-fold increase in dengue cases between 2010 and 2021 [8]. Places like France, Spain, and Italy, countries that never had to worry about dengue before, are now reporting local transmission. The mosquitoes that carry dengue are finding these previously too-cold regions increasingly hospitable. 

Scientists predict that if our planet continues to warm at current rates, parts of southern Europe might become year-round homes for these mosquitoes by 2050 [9].

Modern technology is revolutionizing how we track and respond to outbreaks. Artificial intelligence algorithms scan multiple data sources in real time, detecting early signs of unusual disease activity. Digital disease surveillance tools can now process massive amounts of data from various sources, including health records, social media, and environmental monitoring.

Equipping point-of-care facilities with sophisticated yet user-friendly diagnostic tools and comprehensive infectious disease databases could transform outbreak detection, particularly at major travel hubs. Access to such resources would enable healthcare workers to quickly identify potential threats and take appropriate action before infectious diseases spread widely.

As our world becomes more interconnected, the way we track virus outbreaks must keep evolving. From drawing simple maps to track local cases to today’s AI-powered surveillance systems, we’ve come a long way in our ability to detect and respond to outbreaks. 

Yet each new virus teaches us something new. Whether it’s dengue appearing in unexpected places or novel pathogens emerging from previously unknown sources, our surveillance systems must stay one step ahead. 

By combining traditional detective work with modern technology and global cooperation, we’re better equipped than ever to spot outbreaks early and respond quickly. The key to our success lies in the tools we build and our willingness to share information and work together across borders in our shared mission to protect global health.

GIDEON is one of the most well-known and comprehensive global databases for infectious diseases. Data is refreshed daily, and the GIDEON API allows medical professionals and researchers access to a continuous stream of data. Whether your research involves quantifying data, learning about specific microbes, or testing out differential diagnosis tools– GIDEON has you covered with a program that has met standards for accessibility excellence.

Learn more about Infectious Disease on the GIDEON platform.

[1] International Air Transport Association, Press release 68, “Airlines Set to Earn 2.7% Net Profit Margin on Record Revenues in 2024”, Dec. 2023. [Online]. Available: https://www.iata.org/en/pressroom/2023-releases/2023-12-06-01/. Accessed: Jan. 15, 2024.

[2] Centers for Disease Control and Prevention, “National Notifiable Diseases Surveillance System (NNDSS),” Atlanta, GA, USA, Tech. Rep. CDC-NNDSS-2023-01, Dec. 2023. [Online]. Available: https://www.cdc.gov/nndss/. Accessed: Jan. 10, 2024.

[3] European Centre for Disease Prevention and Control, “European Surveillance System (“TESSy”) – ECDC.” Sep. 2010. [Online]. Available: https://www.edps.europa.eu/data-protection/our-work/publications/opinions-prior-check/european-surveillance-system-tessy-ecdc_en.  Accessed: Jan. 15, 2025.

[4] World Health Organization, “WHO Consultative Meeting on High/Maximum Containment (Biosafety Level 4) Laboratories Networking: Meeting Report,” Geneva, Switzerland, WHO/WHE/CPI/2018.40, Feb. 2018. [Online]. Available: https://www.who.int/publications/i/item/WHO-WHE-CPI-2018.40. Accessed: Jan. 11, 2024.

[5] O. O. Oleribe et al., “Nigerian response to the 2014 Ebola viral disease outbreak: lessons and implications for future epidemic outbreaks,” Pan African Medical Journal, vol. 22, no. 1, pp. 13-18, Jan. 2015, https://doi.org/10.11694/pamj.supp.2015.22.1.6490.

[6] World Health Organization, “Global Outbreak Alert and Response Network (GOARN): Strategy 2022-2026,” Geneva, Switzerland, WHO/WHE/2023.2, Feb. 2023. [Online]. Available: https://apps.who.int/iris/handle/10665/366066. Accessed: Jan. 12, 2025.

[7] F. Wu et al., “A new coronavirus associated with human respiratory disease in China,” Nature, vol. 579, no. 7798, pp. 265-269, Mar. 2020, https://doi.org/10.1038/s41586-020-2008-3.

[8] J. C. Semenza et al., “Observed and projected drivers of emerging infectious diseases in Europe,” Nature Communications, vol. 13, no. 5774, pp. 1-12, Oct. 2022, https://doi.org/10.1111/nyas.13132.

[9] J. Liu-Helmersson et al., “Climate change and Aedes vectors: 21st century projections for dengue transmission in Europe,” EBioMedicine, vol. 7, pp. 267-277, May 2016, https://doi.org/10.1016/j.ebiom.2016.03.046.