Member, 12th Cohort, Field Epidemiology and Laboratory Training Program Every outbreak begins as something small. A fever in a village. A cluster of unexplained illnesses in a school. An unusual increase in diarrhoeal disease. A few patients arriving at a hospital with similar symptoms. The difference between a local health event and a public-health crisis often depends on how quickly those signals are recognized, investigated and acted upon. This is where field epidemiology matters.
On September 7, the global public-health community observes World Field Epidemiology Day, a day dedicated to recognizing the professionals who work on the front lines of disease surveillance, outbreak investigation and public-health response. The date carries historical significance: it commemorates John Snow’s pioneering investigation of the 1854 cholera outbreak in London, an investigation that helped establish the foundations of modern epidemiology but field epidemiology is not simply about remembering the past. It is about preparing for the next threat.
For countries such as Pakistan, this preparation cannot be treated as an academic exercise. We face a complex combination of infectious diseases, climate-related health emergencies, population movement, urbanization, antimicrobial resistance and recurring outbreaks. The 2022 floods, for example, displaced millions of people and were followed by major increases in malaria, dengue, cholera and other waterborne diseases in affected districts. In 2024, Pakistan also reported a resurgence of poliovirus, with cases detected in several provinces despite years of eradication efforts. These events show how quickly fragile health systems can be placed under pressure. Floods and other disasters can rapidly transform familiar health problems into emergencies. In such circumstances, having trained professionals who can move from data to action is not a luxury, it is a necessity.
A field epidemiologist is, in many ways, a disease detective. The work begins with questions: Where are the cases? Who is affected? What do they have in common? When did symptoms begin? What is the likely source? How is the disease spreading? Which intervention can stop that transmission? But the work does not end with producing a report.
The real measure of successful epidemiology is whether evidence leads to timely action.
A surveillance system is valuable only when unusual patterns are detected early. An investigation is valuable only when its findings inform intervention. Data are valuable only when decision-makers use them to protect communities.
Pakistan’s Field Epidemiology Training Program is built around precisely these capabilities, including real-time disease surveillance, outbreak detection and response, public-health emergency management and evidence-based policy decision-making.
As a member of the 12th Cohort of the Field Epidemiology and Laboratory Training Program, I have come to appreciate that field epidemiology is much more than statistics, spreadsheets or scientific terminology. It is about going into the field, listening to communities, understanding local realities, collecting reliable information and translating that information into decisions that can save lives and perhaps the most important lesson is this: the best outbreak response is often the outbreak that never becomes a crisis.
Much of the work of field epidemiologists happens long before an emergency reaches television screens or newspaper headlines. Surveillance systems are monitored, unusual signals are investigated, risks are assessed and preventive measures are recommended. In Pakistan, this can mean identifying a rise in acute watery diarrhoea after flooding, mapping malaria cases among displaced families, tracing poliovirus through environmental samples or investigating unexplained deaths when routine reporting is disrupted. It can also mean working across provincial and district boundaries when people move in search of safety, shelter or livelihoods. The public may never know about the outbreaks that were detected early and contained quietly—and that is precisely the point. Current World Field Epidemiology Day messaging similarly emphasizes that much of this work occurs behind the scenes, protecting communities before crises become visible. This invisible success deserves greater recognition.
More importantly, it deserves investment. Pakistan needs stronger surveillance systems, better laboratory capacity, reliable health data, effective coordination between institutions and, above all, a sustained investment in trained public-health professionals. Field epidemiologists should not be considered professionals who are needed only when an outbreak occurs. They should be integrated into routine public-health planning and decision-making.
We also need to strengthen the connection between epidemiology, laboratories and clinical services. A laboratory result sitting in a database cannot protect a community by itself. A clinician treating individual patients cannot always see the population-level pattern. An epidemiologist can connect these pieces, bringing together clinical information, laboratory evidence, surveillance data and field realities to identify what is happening and what needs to be done. This connection is especially important when reporting is delayed, laboratory access is limited or health facilities are overwhelmed, as occurred in many flood-affected areas.
The future will bring new challenges. Climate change is altering the geographic and seasonal patterns of infectious diseases. Pakistan’s repeated heatwaves, floods and changing rainfall patterns are creating conditions that can expand mosquito breeding and contaminate drinking-water sources. International travel and migration can accelerate the spread of pathogens. Antimicrobial resistance threatens the effectiveness of medicines that modern medicine has relied upon for decades. New infectious diseases can emerge with little warning.
We therefore cannot afford to build public-health capacity only after a crisis begins. Preparedness must come before the emergency. On this World Field Epidemiology Day, we should celebrate the epidemiologists working quietly in surveillance rooms, laboratories, hospitals, communities and outbreak investigation teams. But celebration alone is not enough.
We must ask a more difficult question: Are we investing enough in the people and systems that will protect us from the next outbreak? The answer should determine our priorities. For every disease signal detected early, every outbreak contained quickly, every unnecessary infection prevented and every public-health decision improved by evidence, field epidemiology proves its value. The goal is not merely to respond better when the next outbreak arrives. The goal is to make sure that, when it arrives, we are ready. That is the real promise of field epidemiology, and the responsibility we must embrace today.
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