Dirofilaria immitis and D. repens in Europe: a systematic literature review on vectors, host range, and the spatial distribution in the 20th and 21st century

BackgroundDirofilaria immitis and D. repens are mosquito-borne nematodes with dogs as primary hosts, but other mammalian species including humans can be also infected. In the last century, circulation of both pathogens was predominantly restricted to Southern Europe. However, different studies indicated a potential establishment in Central, Eastern and Western parts of Europe as an increasing threat to animal and human health. MethodsWe conducted a systematic literature review of publications reporting D. immitis and D. repens screening in mosquitoes and mammalian vertebrates in Europe. These data were used to analyse the range of vectors and hosts and for a comparison of the spatial distribution between the 20th and 21st century. ResultsBoth nematodes appear to have a high overlap of Aedes, Anopheles and Culex vector species, which are abundant in Europe. Most D. immitis infections were reported in dogs, while D. repens predominated in humans. Dirofilaria immitis infections were detected in a wider range of wild and zoo animals. Compared to the last century, many more countries especially in Central Europe were affected by Dirofilaria spp. circulation, illustrating a significant spread over the last 20 years. ConclusionOur findings suggest that D. immitis and D. repens are a growing health concern for animals and humans in Europe. Continuous globalisation and climate warming will probably lead to a further spread and increased circulation in the future. All data are made available open access, which will enable further analysis in the future.