Purpose
Transmission of infectious diseases through international travel is increasing, especially in travelers from developed to developing countries. Still, actual incidence of typical travel diseases is not known, especially if we take into account asymptomatic as well as symptomatic infections.
Methods
In this study, we took medical history and analyzed blood samples of 81 individuals from Germany before and after traveling to regions endemic for Vector-Borne diseases (VBD) and Food- and Water Borne Diseases (FWD). Additionally, we tested for two infections unrelated to travel. Blood was drawn before and after travelling to South and Southeast Asia. IgG, IgM, and if possible IgA antibody titers were measured using ELISA kits for Dengue virus (DENV), Chikungunya virus (CHIKV), Zika virus (ZIKV), Hepatitis E virus (HEV), Camphylobacter jejuni (C.jejuni), and for Cytomegalovirus and Helicobacter pylori.
Results
No symptoms were reported. Still, we found one anti-ZIKV and two anti-DENV IgG seroconversions. For CHIKV, we found three individuals who were IgG-positive before travel and negative afterwards. Regarding FWD, we found five IgG seroconversions for C.jejuni and zero for HEV. We also found one IgG seroconversion for CMV, and zero for H.pylori. Calculated incidences were between zero and 1.2% for VBDs and between zero and 6.5% for FWDs.
Conclusion
Serological analyses pre and post traveling are a useful tool to detect asymptomatic travel diseases, and to objectively determine the risk of infection in endemic areas. This, even though the results for CHIKV may hint to a low selectivity of the test kits we used.