ABSTRACT
Protozoa are well-known inhabitants of the mammalian gut and so of the gut microbiome. While there has been extensive study of a number of species of gut protozoa in laboratory animals, particularly rodents, the biology of the gut protozoa of wild rodents is much less well-known. Here we have systematically searched the published literature to describe the gut protozoa of wild rodents, in total finding records of 44 genera of protozoa infecting 228 rodent host species. We then undertook meta-analyses that estimated the overall prevalence of gut protozoa in wild rodents to be 24%, with significant variation in prevalence among some host species. We investigated how host traits may affect protozoa prevalence, finding that for some host lifestyles some protozoa differed in their prevalence. This synthesis of existing data on wild rodent gut protozoa provides a better understanding of the biology of these common gut inhabitants and suggests directions for their future study.
Subject(s)
Animals, Wild , Rodentia , Animals , Rodentia/parasitology , Animals, Wild/parasitology , Rodent Diseases/parasitology , Rodent Diseases/epidemiology , Gastrointestinal Tract/parasitology , Gastrointestinal Tract/microbiology , Protozoan Infections, Animal/parasitology , Protozoan Infections, Animal/epidemiology , Prevalence , Gastrointestinal MicrobiomeABSTRACT
Members of the bacterial genus Rickettsia were originally identified as causative agents of vector-borne diseases in mammals. However, many Rickettsia species are arthropod symbionts and close relatives of 'Candidatus Megaira', which are symbiotic associates of microeukaryotes. Here, we clarify the evolutionary relationships between these organisms by assembling 26 genomes of Rickettsia species from understudied groups, including the Torix group, and two genomes of 'Ca. Megaira' from various insects and microeukaryotes. Our analyses of the new genomes, in comparison with previously described ones, indicate that the accessory genome diversity and broad host range of Torix Rickettsia are comparable to those of all other Rickettsia combined. Therefore, the Torix clade may play unrecognized roles in invertebrate biology and physiology. We argue this clade should be given its own genus status, for which we propose the name 'Candidatus Tisiphia'.