Gastrointestinal complaints were the most common health problem reported by people who went abroad and took part in a study on travel-related illnesses.
The study was based on data from a mobile application developed by researchers at the University of Zurich (UZH) in collaboration with the World Health Organization (WHO).
“Travelers are an excellent reflection of what is happening around the world. They also often play a role in the introduction of pathogens into different parts of the world. This real-time bottom-up approach is much faster than top-down reporting systems. Mobile technologies offer a revolutionary solution for the way we track travel-related diseases,” says study leader Patricia Schlagenhauf of the Epidemiology, Biostatistics, and Prevention Institute at UZH.
Scientists say early detection of outbreaks and reporting of travel-related illnesses are crucial to implementing effective public health measures. Top-down systems rely on healthcare professionals, laboratories and official health authorities to report mandatory infections.
Bottom-up reporting by travelers ensures timely detection of disease clusters, enables rapid investigation and intervention, and can provide insight into environmental exposures, regional risk factors and potential disease hotspots.
Tracking travel-related infections
The Illness Tracking in Travelers (ITIT) app allows people to report daily symptoms by type, intensity and impact by completing a short questionnaire. This information is then linked to location data and information about climate and air quality.
The research team analyzed data collected through the app between April 2022 and July 2023. The analysis included 470 trips recorded by 609 people on all continents. The findings were published in the magazine BMJ Open.
Participants had an average age of 37 years, but ranged from 18 to 79 years old, and an average travel time of 26 days with a range of 2 to 281 days. Most people traveled for leisure or tourism, followed by visiting friends and family, and business trips.
A total of 404 travelers who downloaded the app and completed the demographic survey also completed at least one daily survey. Of the 470 registered trips, people on 163 trips reported having complaints for at least one day. Gastrointestinal problems were reported on 87 trips.
The most common health concerns were gastrointestinal symptoms, which were reported in 19 percent of trips and most commonly among travelers to Asia, where the risk of foodborne pathogens can be high. These complaints occurred less often in people who went to Africa. Significantly more women than men reported symptoms of diarrhea. It’s possible that women were more sensitive to diarrhea, or that they were more conscientious about recording information in the app.
Travel time, higher humidity and atmospheric ammonia were associated with the presence of gastrointestinal symptoms. Diarrhea, headache and nausea symptoms with the greatest impact on daily activities.
A possible bias could be that people who were more health conscious and willing to participate in citizen science were included in the dataset.
The free ITIT app is available in 14 languages. Researchers invite more people to use the app. Larger data sets would allow them to perform automated analyzes using artificial intelligence. The updated app will also monitor lingering illnesses after travel.
(To sign up for a free subscription to Food Safety News, click here.)