Dengue in Travellers Is Still Underestimated

BACKGROUND: Dengue fever (DF), one of the main emerging virus diseases, also increases in German travellers, due to the increasing number of travellers to tropical regions. METHODS: We determined antibodies against DF virus in a group (n = 149) of long-distance travellers in order to evaluate the risk of acquiring DF. Serum samples were collected at the travel vaccination centre in Frankfurt/Main and DF seroprevalence in serum samples was determined using different antibody assays with particular attention to flavivirus cross-reactivity. So, antibodies against tick-borne encephalitis and previous flavivirus vaccination of the travellers were checked. RESULTS: Depending on the test system, 8.7-19.5% of the screened travellers were found to be DF virus IgG antibody positive, significantly more than in previous investigations. Remarkably, younger adults and women are more often affected. CONCLUSIONS: These data imply that the risk for travellers to acquire DF has been underestimated. Nevertheless, dengue haemorrhagic fever and dengue shock syndrome are still rare in travellers, but those with a history of dengue should be advised to protect themselves well from mosquitoes when travelling to endemic areas.