Grants and residencies

Research and art

Host Ecology Determines Shifts in Pathogen Dynamics of Bats in a Changing Climate

Application summary

Bats are important to public health as they can act as vectors to several potentially harmful microorganisms. The novel coronavirus (COVID-19) identified in 2020 originated from bats and a poor understanding of safely interacting with wildlife, resulting in human illness and death. Aspects of bat ecology, e.g. seasonality, migration, and coloniality, have been associated with pathogen prevalence and infectivity in bats. Furthermore, climate change-assisted shifts in distributions of organisms creates scenarios for novel interactions, in which exchange of pathogens between potential hosts can take place. Species range expansion due to climate change is known to happen quickly on the northern side of their range. It is expected that changes will occur in Finland more quickly than at southern latitudes. The increase in detection of migratory bats in Finland should be seen as a warning as they can introduce pathogens from their overwintering areas into Finland. Human-bat interactions are common. Risk of disease spillover increases through human-bat/feces contacts. No data exist on how the ecology and behavior of the host is reflected in dynamics of pathogenic microorganisms they carry. It is suggested that pathogenic microbes, e.g. Bartonella, could be transmitted via bat ectoparasites to humans and yet, studies are lacking in how—and how many—microbes carried by bats may be a threat to humans. Furthermore, museum collections may lend additional insight into past occurrence of pathogenic microbes in bats in Finland. The aims are to understand whether i) changes in the prevalence of pathogenic microbes in bats occurred during the last 100 years, ii) there are differences in host, feces, and ectoparasite pathogen communities and the risk to humans, iii) there temporal and species-specific patterns in fecal pathogenic microbe prevalence in Northern European bats, and to iv) disseminate information on best practices for interacting with bats in human-occupied spaces.

Bats are important to public health as they can act as vectors to several potentially harmful microorganisms. The emergence of SARS-CoV-2 in 2020 highlighted the consequences of limited understanding of safe wildlife interactions. Human-bat interactions are common and contact with bats or their feces can increase spillover risk. Further, bat ecology, including seasonality, migration, and coloniality, influence pathogen prevalence, and climate-driven shifts in species distributions can create new opportunities for pathogen exchange between hosts. However, little is known about how host ecology and behavior impact the microbes carried by bats.

The aims of the project were i) to determine whether there are species-specific patterns in fecal pathogenic microbe prevalence in Northern European bats, ii) to examine population genetic structure among bat species across Finland and the Baltic region, and to iii) disseminate information on best practices for interacting with bats in human-occupied spaces.

The work combined field sampling, molecular analyses, and data synthesis. Fecal samples were collected from the northern bat (Eptesicus nilssonii), brown long-eared bat (Plecotus auritus), and Nathusius’ pipistrelle (Pipistrellus nathusii) and were screened for coronaviruses. Tissue samples from these species, collected across Finland, Latvia, Norway, and Russia, were analyzed using population genomic methods (ddRAD sequencing) to examine genetic structure across regions. The datasets produced represent an important foundation for understanding how bat population structure and ecology influence microbial dynamics across Northern Europe.


Results from this work fill a gap in knowledge on how species population structure reflects in the pathogen diversity and prevalence, and how bats and humans can better coexist.

Back to Grants listing