Spontaneous listeriosis in grey mouse lemurs (Microcebus murinus), but not in Goodman's mouse lemurs (Microcebus lehilahytsara) of the same colony.

Listeriosis is a zoonotic infection with the gram positive, facultative intracellular bacterium Listeria (L.) monocytogenes. Infections mainly occur in ruminants, but also in other species, including humans. Case fatality rate usually is high. The incidence of listeriosis in captive non-human primates is very low. We report the first spontaneous, fatal, and likely food-born outbreak of listeriosis in a population of captive grey mouse lemurs (Microcebus murinus). Conspicuously, none of the closely related Goodman's mouse lemurs (Microcebus lehilahytsara) in the same facility were affected.

Population- and Individual-Level Dynamics of the Intestinal Microbiota of a Small Primate.

UNLABELLED: Longitudinal sampling for intestinal microbiota in wild animals is difficult, leading to a lack of information on bacterial dynamics occurring in nature. We studied how the composition of microbiota communities changed temporally in free-ranging small primates, rufous mouse lemurs (Microcebus rufus). We marked and recaptured mouse lemurs during their mating season in Ranomafana National Park in southeastern mountainous rainforests of Madagascar for 2 years and determined the fecal microbiota compositions of these mouse lemurs with MiSeq sequencing. We collected 160 fecal samples from 71 animals and had two or more samples from 39 individuals. We found small, but statistically significant, effects of site and age on microbiota richness and diversity and effects of sex, year, and site on microbiota composition, while the within-year temporal trends were less clear. Within-host microbiota showed pervasive variation in intestinal bacterial community composition, especially during the second study year. We hypothesize that the biological properties of mouse lemurs, including their small body size and fast metabolism, may contribute to the temporal intraindividual-level variation, something that should be testable with more-extensive sampling regimes. IMPORTANCE: While microbiome research has blossomed in recent years, there is a lack of longitudinal studies on microbiome dynamics on free-ranging hosts. To fill this gap, we followed mouse lemurs, which are small heterothermic primates, for 2 years. Most studied animals have shown microbiota to be stable over the life span of host individuals, but some previous research also found ample within-host variation in microbiota composition. Our study used a larger sample size than previous studies and a study setting well suited to track within-host variation in free-ranging mammals. Despite the overall microbiota stability at the population level, the microbiota of individual mouse lemurs can show large-scale changes in composition in time periods as short as 2 days, suggesting caution in inferring individual-level patterns from population-level data.

Root sepsis associated with insect-dwelling Sebaldella termitidis in a lesser dwarf lemur (Cheirogaleus medius).

Sebaldella termitidis is a rare fastidious microorganism of the Leptotrichiaceae family. A variety of closely related species are associated with severe and even life-threatening disease in humans and animals, such as Streptobacillus moniliformis, the etiological organism of rat-bite fever as well as members of Leptotrichia spp. and Sneathia sanguinegens, which have been reported from cases of septicaemia. In contrast, since its description some 50 years ago, S. ermitidis has so far never been reported as a vertebrate pathogen, nor has it been found aside from its natural termite host. A lesser dwarf lemur was presented with unilateral facial inflammation originating from rotten maxillary teeth and septic root abscess. Surgical intervention and root extraction significantly improved the clinical cause in that a pus-filled cavity underneath the right eye could be drained, sampled and flushed. Bacteria displaying substantial characteristics of S. termitidis were cultured from the sampled pus. Morphological features observed included strictly anaerobic regular Gram-negative rods. Significant shared biochemical properties included negative reactions for cytochrome oxidase, catalase, urease, nitrate reduction and indole production. Furthermore, 16S rRNA gene sequencing revealed 99.9 % sequence homology to the S. termitidis type strain NCTC 11300(T), from which it, nevertheless, differed with respect to rep and rep- and RAPD-PCR profiles. An affiliation of the lemur isolate described in this study with the type strain of S. termitidis as well as a clear discrimination from other members of the Leptotrichiaceae could also be confirmed by matrix-assisted laser desorption/ionization time-of flight mass spectrometry and Fourier transform-infrared spectroscopy. This is the first evidence for clinical disease caused by S. termitidis in a vertebrate species indicating a broader host spectrum of this rarely encountered microorganism.