Clinico-laboratory profile of dengue patients returning from tropical areas to Poland during 2010-15

Background & objectives: Dengue is a mosquito-borne viral disease, incidences of which have increased rapidly in the past decade. About 400 million new infections are recorded annually worldwide, and 40% of the human population lives in the areas at risk of dengue transmission. In this study, the clinical and laboratory profile of dengue diagnosed patients returning to Poland from tropical areas has been analyzed. Methods: This is a retrospective study of 65 patients based on clinical symptoms and serological tests conducted in the Department of Tropical Parasitology of Institute of Maritime and Tropical Medicine (IMTM) in Gdynia, Poland during 2010-15. The diagnosis of dengue virus (DENY) infection was based on the detection of specific immunoglobulin M (IgM) and IgA antibodies performed by specific ELISA assays. The samples were considered as positive, if the absorbance was >10% above the cut-off value. Results: Among 65 persons with dengue selected for the analysis, 59 patients were admitted to the hospital because of clinical symptoms of the disease; the six persons initially asymptomatic were hospitalized due to routine control treatment returning from tropical regions. Patients reported various destinations, purpose and duration of their travels. All of them had returned from dengue endemic regions and were positive for IgM antibodies against DENY. Common clinical symptoms observed were fever (ranging from 38 to 40 degrees C in 43% of patients), weakness, headache and rash. Laboratory tests revealed elevated levels of transaminase activity, leukopenia and thrombocytopenia in 35.3, 24.6 and 20% of patients, respectively. Interpretation & conclusion: The number of Polish travelers to subtropics and tropics increases every year. As cases of fever and other symptoms appear to be increasingly in Polish people returning from tropical regions of Asia, America and Africa, their screening and management should be taken seriously. The study also suggests that the disease might be more widespread than it was known previously.