Cross-border surveillance differences: tick-borne encephalitis and Lyme borreliosis in the Czech Republic and Poland, 1999-2008

A neat investigation of a simple approach to evaluate how surveillance systems measure disease burden in different countries. We just compared reporting of two tick-borne diseases on the border between Poland and Czech Republic. We found a very high "gradient", which in some years amounted to a 10-fold higher incidence on the Czech side of the border. Since the border cannot be a barrier for ticks, wild animals or human movement, to explain such difference in disease risk, the only explanation could be a difference in access to testing and overall surveillance sensitivity.