We conducted some research over the course of the past year that we are currently working on publishing regarding travelers’ health issues and Tick-borne Encephalitis (TBE). TBE is one amongst many diseases that can be contracted by tourists who originate in an areas without the disease, but travel to an area where the disease is endemic. In some instances, such as TBE or Yellow Fever, vaccines exist that can protect travelers. In others, however, perhaps only prophylactics are available, such as Malaria. Determining how many travelers from outside of a country travel to the country and then put themselves at risk is quite difficult, with risk varying based on the characteristics of the disease.
In order to address this question, public health practitioners can use traditional methods such as surveys and data mining, but in many instances this has not been particularly accurate. It is difficult to diagnose the diseases after the travelers return to their home countries, for doctors there may not be familiar with the symptoms and the travelers themselves may not supply all relevant facts. This is what researchers suspect occurs with TBE. Many travelers visit endemic regions, which span from central Europe through the Eurasian sub-continent, and then visit specific areas of highest risk for exposure. In the case of TBE, this is the outdoor areas where ticks live. Getting bit by the tick species Ixodes ricinus means you are potentially exposed to the potentially serious TBE virus. European health agencies, especially Austria, have taken great steps to vaccinate their populations against TBE through rigorous annual programs. For travelers, however, these programs are little known.
Assessing how many travelers from a country where TBE is not endemic might travel to an endemic country and then further travel to endemic (natural) areas is a complicated problem. Recent research in commercial and academic settings has been working to track tourist movements using information uploaded to social networking sites. We took their lead in the methodologies and applied them to a different problem: travelers’ health. Using pictures and associated data from the photo-sharing website Flickr, we identified travelers coming to Austria who originated from countries where TBE is not endemic AND traveled to high-risk areas in Austria (natural areas). Our hats go off to the smart researchers who developed the methodologies that we adapted.
As for results, it’s best displayed graphically. Using the open-source GIS program GRASS, we displayed the distribution of the travelers identified above. Below you can see a few mashups, beginning with all travelers in Vienna coming from non-endemic TBE countries. The gold dots are locations of photographs taken by any non-endemic country traveler, while the red dots represent pictures taken in high-risk areas.
And here are the pictures taken in the at-risk areas, which are the ones we were interested in.
We also have the data for other portions of Austria, including Salzburg as below. This is a mashup of pictures taken by at-risk users in and around Salzburg.
And finally, here is a snapshot of the Central Austria region, displaying photograph locations in at-risk areas.
There are lots of methodological issues to work through in applying such a procedure to public health analysis, so the technique is not for sure. Nevertheless, it’s important to incorporate and assess the value of new data sources to older problems.