Malaria in Austria: A retrospective analysis of malaria cases diagnosed at a reference center in 2010–2020

BACKGROUND: Although malaria is not endemic to Austria, each year infections are imported by travellers, migrants and refugees. This study aims to provide an overview of malaria cases diagnosed at an Austrian institute for tropical medicine between 2010 and 2020. METHODS: A retrospective, descriptive study was conducted based on the data of malaria cases confirmed at the Institute of Specific Prophylaxis and Tropical Medicine of the Medical University of Vienna. Laboratory diagnostics included microscopy, polymerase chain reaction (PCR) and real-time quantitative PCR. RESULTS: Overall, 122 cases were identified. Annual case numbers were consistently higher from 2016 to 2020 than during the first half of the decade. Most malaria cases were diagnosed during summer and early autumn. This seasonal trend was not observed during the year 2020. With 55.1% (65/118) Plasmodium falciparum was the most common species, followed by Plasmodium vivax (19.5%, 23/118). The majority of patients were male (71.1%, 86/121) and the median age was 34.5 years (interquartile range, IQR 22.5–47.0 years). With a median age of 20.0 years (IQR 14.0–32.0 years), patients with P. vivax infections were younger than those infected with other Plasmodium species. Moreover, they were mostly male (82.6%, 19/23). CONCLUSION: From 2010 to 2020, the number of malaria cases diagnosed at the center increased. Growing international mobility and changing travel behavior could at least partly be responsible for this trend and there are indications that particularly P. vivax infections were imported by migrants and refugees.