Bats as Reservoir Hosts of Human Bacterial Pathogen, Bartonella mayotimonensis

The 1,100 species of bats (1) constitute ≈20% of known mammalian species and are outnumbered only by animals in the order Rodentia. Bats play a vital role in natural ecosystems in arthropod suppression, seed dispersal, and pollination. Modern-day economies also benefit from these voracious predators of crop and forest pests (2). However, bats have been implicated as reservoir hosts for viral human pathogens, such as paramyxoviruses (3) and rabies virus and related lyssaviruses (4). Compelling evidence also indicates that bats carry asymptomatically some of the most deadly viruses, including Marburg (5) and Ebola (6) viruses. Whether bats carry clinically significant bacterial pathogens is unknown. The development of next-generation sequencing techniques has revolutionized biological science. It is now possible—and cost-friendly—to gain access to massive amounts of qualitative and quantitative sequencing data in a short time without a priori knowledge of the sequence (7). Most bacteria do not grow on laboratory media, and next-generation sequencing technologies have proven useful for studying bacterial species diversity and dynamics, even in complex systems like the gut (8). Our initial objective in 2010 and 2011 was to conduct a quantitative metagenomic analysis of the fecal bacterial flora of the Daubenton’s bat (Myotis daubentonii) in Finland. Unexpectedly, we found that the fecal material contained DNA of several hemothrophic and ectoparasite-transmitted bacterial genera, such as Bartonella. This DNA may originate either from bleeding into the intestine or from the insect prey of the bats that includes the abundant bloodfeeding bat ectoparasites. Therefore, the study further focused on detecting and isolating Bartonella spp. from peripheral blood and ectoparasites of several bat species in Finland in 2012.