The high (≈33%) prevalence of Bartonella
spp. in bat populations in southern Guatemala might suggest persistent infection of long-lived bats with Bartonella
spp., similar to their infection with some viruses (13
). Depending on the bat species, Bartonella
spp. exhibit high, low, or no infectivity, which may explain the variation in Bartonella
spp. prevalence between study sites because the assemblage of bat species differed at each site. Additional studies are needed to illustrate the distribution of Bartonella
spp. among the bat fauna in Guatemala and throughout the region.
Further characterization is necessary to verify whether the Bartonella
strains representing a variety of distinct phylogroups represent novel Bartonella
species. Unlike the discovery in bats in Kenya (12
), host specificity of Bartonella
spp. was not found in bats in Guatemala. Such lack of specificity may be partly associated with the arthropod vectors that parasitize bats, although we were unable to attempt isolation of agents from the bat ectoparasites. Future studies of bat ectoparasites would enable testing of hypotheses about whether any arthropods may be vectors in the Bartonella
spp. transmission cycle and whether ectoparasite specificity contributes to the lack of host specificity observed in this study.
The tendency of some bat species to share roosts, reach large population densities, and roost crowded together creates the potential for dynamic intraspecies and interspecies transmission of infections (14
). In accordance with this hypothesis, our finding that co-infection with multiple Bartonella
strains in a single bat species, and even in an individual bat, indicate that active interspecies transmission of Bartonella
spp. likely occurs among bats in Guatemala. The specificity of ectoparasite arthropod vectors among the bat fauna remains unclear and may contribute to interspecies transmission of Bartonella
spp. among bats.
The long life spans of bats (average 10–20 years) may have made them major reservoirs that contribute to the maintenance and transmission of Bartonella
spp. to other animals and humans. The bite of the common vampire bat has been long recognized to transmit rabies virus to humans throughout Latin America (2
). These bats typically feed on the blood of mammals, including domestic animals and humans (15
). Predation of vampire bats on humans is a major problem in Latin America (2
). If Bartonella
spp. can be transmitted to humans through the bite of bats, the need for further studies with vampire bats is imperative. Bartonella
spp.–specific DNA has been detected in ectoparasites collected from bats (3
). Presumably, if Bartonella
spp. are transmitted through a bat ectoparasite vector, some, if not all, bat-associated Bartonella
spp. could be transmitted to humans because bats are frequent hosts to a wide variety of ectoparasites, including bat flies, fleas, soft ticks, and mites. However, transmission potential might vary with the degree of synanthropic roosting or foraging behavior within the bat community.
Because an increasing number of Bartonella spp. are being associated with human illness, the need to identify the animal reservoirs of these novel Bartonella spp. and to understand their disease ecology is also increasing. Our study of Bartonella spp. in bats has enlarged our scope of this zoonotic potential as we search for the reservoirs that harbor novel and known Bartonella spp.