The key finding
A 2025 multi-country survey has produced the most detailed map yet of sand fly distribution in Central Europe, documenting six species across Germany, Austria, Hungary, and Slovakia. Phlebotomus mascittii, the most cold-tolerant species, was found in all surveyed countries except Czechia, with peak activity in July. Environmental analysis identified 15 land cover types associated with sand fly presence, but urban locations were occupied most frequently—a pattern confirmed by statistical models showing significantly higher sand fly presence in forested and urban landscapes compared to rural areas. While no Leishmania DNA was detected in the surveyed sand flies or rodents, researchers found DNA from two distinct Trypanosoma lineages in several specimens, indicating these insects feed on both birds and ruminants.
What the study looked like
Researchers combined a comprehensive literature review with new entomological field surveys across five Central European countries: Germany, Austria, Czechia, Slovakia, and Hungary. The team trapped sand flies in various habitats and also screened local rodents for sand fly-borne pathogens. Laboratory analysis included extracting nucleic acids from specimens, conducting COI barcoding (a genetic identification technique), analyzing blood meal contents to determine what the insects had fed on, and performing phylogenetic studies to understand evolutionary relationships. The environmental component used unsupervised machine learning to identify land cover patterns associated with sand fly presence, analyzing data from the Corine land cover classification system. This approach allowed researchers to move beyond anecdotal reports and create a data-driven picture of where these insects actually live in Central Europe today.
Why researchers think this happened
The northward expansion of sand flies into Central Europe likely reflects ongoing climate change, as warmer temperatures allow previously Mediterranean species to establish populations further north. Phlebotomus mascittii’s success across multiple countries stems from its greater cold tolerance compared to other sand fly species. The unexpected prominence of urban habitats may relate to the “urban heat island” effect—cities retain warmth that extends the viable season for these insects—and the availability of both vertebrate hosts (pets, urban wildlife, humans) and suitable microhabitats in parks, gardens, and building crevices. The detection of Trypanosoma DNA rather than Leishmania suggests Central European sand fly populations may carry different pathogen profiles than their Mediterranean relatives, possibly due to differences in available vertebrate hosts. The identification of four distinct Ph. mascittii ecological clusters—broadly grouped into Upper Rhine Valley and Carpathian Basin populations—suggests these populations may be adapting to local conditions and could represent separate colonization events from southern source populations.
How to read this carefully
This study provides distribution data but cannot establish whether these sand fly populations pose an immediate disease transmission risk to humans. The absence of Leishmania DNA in surveyed specimens is reassuring but doesn’t guarantee it won’t appear as populations grow and climate continues changing. The sample represents a snapshot in time across selected locations rather than exhaustive coverage of all five countries—Czechia, notably, yielded no Ph. mascittii despite the species’ presence in neighboring nations, which may reflect sampling limitations rather than true absence. The Trypanosoma findings indicate feeding on wildlife but don’t confirm these lineages can infect humans. Urban prevalence may partially reflect sampling bias, as researchers often set traps where human populations live. Finally, sand fly presence doesn’t automatically mean disease transmission; that requires competent vectors, infected hosts, and suitable conditions for parasite development within the insect.
What this means for everyday life
If you live in Central Europe, particularly in urban areas of Germany, Austria, Hungary, or Slovakia, you might now share your environment with sand flies during summer months, especially July. These tiny insects are establishing themselves further north than historical records indicated, favoring cities and forests over open countryside. While this study found no evidence of Leishmania parasites in local populations yet, the insects are present and feeding on local animals, which represents a change in the regional ecosystem. For travelers, veterinarians, and public health officials, this means sand fly-borne diseases are no longer exclusively Mediterranean concerns. It might be worth considering that Central European physicians may increasingly encounter patients with sand fly bites, and veterinarians should remain alert for leishmaniasis in pets with travel history. The urban concentration suggests keeping window screens closed during July evenings and being aware that city parks—not just wilderness—can harbor these insects.