Molecular Survey of Protist Enteroparasites in Bats (Order Chiroptera) from Portugal

Bats constitute 20% of all mammal species, playing a vital role in ecosystem health as pollinators, seed dispersers, and regulators of insect populations. However, these animals can also be reservoirs for infectious agents, including viruses, bacteria, and enteroparasites such as Cryptosporidium spp., Giardia duodenalis, and Balantioides coli, raising questions about their role in the epidemiology of these agents. Our study analyses bat faecal samples from Portugal with the aim of assessing the prevalence, distribution and diversity of enteroparasitic protozoa.

We conducted a retrospective study that included 380 bat faecal samples collected between 2014 and 2018 in northern and central Portugal.

In our study, a Cryptosporidium spp. prevalence of 3.2% was identified, with genetic diversity observed and strains grouped with known bat genotypes. Giardia duodenalis was detected in 0.5% of the samples, exhibiting distinct genetic characteristics that may suggest a potential new assembly group encompassing bats and rodents. Finally, B. coli was detected in 0.26% of samples, representing the first observation of this ciliate in bats, with the identified genetic variant belonging to genotype B.

Our results provide valuable molecular epidemiological insights that underscore the importance of bats in the epidemiology of these enteroparasites. Furthermore, this is the first report of Cryptosporidium spp. and G. duodenalis in bat faeces samples from Portugal, and the first study worldwide to show that bats can shed B. coli in their faeces.