Dengue antibodies in Polish travellers returning from the tropics. Evaluation of serological tests

Dengue is a viral disease caused by an RNA virus of the genus Flavivirus, family Flaviviridae, occurring as four serotypes (DEN-1, -2, -3, -4). It is transmitted to humans by the Aedes mosquitoes, mainly A. aegypti. The occurrence of dengue is strictly related with their preferred breeding areas. Dengue endemic regions are inhabited by some 2.5 billion people. 50-100 million cases of dengue fever and up to 1 million cases of dengue haemorrhagic fever are noted worldwide in more than 100 countries every year. The aim of the reported examinations was to diagnose dengue virus infections in returning travellers. In the years 2006-2009 serological tests were performed in 753 persons. In the diagnostics we used ELISA to find IgM and/or IgG class of antibodies against dengue virus, rapid immunochromatographic (cassette) test, NS1 viral antigen detection by ELISA, and virus RNA detection by RT-PCR method. IgM or IgG class antibodies, and both classes simultaneously, were detected in 19.8% of the examined cases. The greatest number of infections came from India and the Far East, next from South and Central America, and the smallest number from Africa. Sixteen patients with diagnosed dengue, including three cases of dengue haemorrhagic fever, were hospitalized.