The facultative human oral pathogen Prevotella histicola in equine cheek tooth apical/ periapical infection: a case report

Background Prevotella histicola is a facultative oral pathogen that under certain conditions causes pathologies such as caries and periodontitis in humans. Prevotella spp. also colonize the oral cavity of horses and can cause disease, but P. histicola has not yet been identified. Case presentation A 12-year-old Tinker mare was referred to the clinic for persistent, malodorous purulent nasal discharge and quidding. Conservative antibiotic (penicillin), antiphlogistic (meloxicam), and mucolytic (dembrexine-hydrochloride) treatment prior to referral was unsuccessful and symptoms worsened. Oral examination, radiography, sino-/ rhinoscopy, and standing computed tomography revealed severe apical/ periapical infection of the upper cheek tooth 209 with accompanying unilateral sinonasal inflammation and conchal necrosis. The tooth exhibited extensive subocclusal mesial infundibular cemental hypoplasia and caries, and an occlusal fissure fracture. After mechanical debridement and thermoplastic resin filling of the spacious subocclusal carious infundibular lesion, the tooth was extracted intraorally. The sinusitis and conchal necrosis were treated transendoscopically. Selective bacteriological swab cultures of affected tooth roots and subsequent matrix-assisted laser desorption ionization-time of flight mass spectrometry showed an infection with the obligate anaerobic, Gram-negative bacterium P. histicola. Surgical intervention and adapted antibiotic therapy led to normal healing without complications. Conclusions This study provides the first documented case of dental infection in a horse caused by P. histicola at once indicating necessity of more sufficient microbiological diagnostics and targeted antibiotic treatment in equine dental practice. This finding is also conducive to understand species-specific Prevotella diversity and cross-species distribution.

First discovery of Stegodon (Proboscidea) in Malaysia

A cheek tooth of Stegodon, an extinct genus of Proboscidea, had been discovered in a cave in Gopeng, Perak. The discovery represents the first fossil of Stegodon ever found in Malaysia. Embedded in lithified cave infillings are the associated dental remains from at least three or four other different taxa of fossil mammals commonly found among Southeast Asian Pleistocene-Holocene faunas. The finding provides a unique chance for investigations into the evolution dynamics of Stegodon in this part of Southeast Asia and the species diversity of Proboscidea in prehistoric Peninsular Malaysia. Fossil mammal assemblages from different phases of Pleistocene-Holocene period collected from karstic caves in Peninsular Malaysia, when considered with similar assemblages from other parts of Southeast Asia, have the potential to contribute to our understanding of prehistoric faunal migrations and species compositional changes among the biogeographic (sub)divisions in Southeast Asia. This may ultimately lead to a better knowledge of the possible paleoenvironmental and paleoclimatic fluctuations that influenced patterns of migration and adaptive responses of mammalian faunas in Quaternary Southeast Asia.

Listriodon skull from the late middle Miocene of Nebisuyu (Çanakkale – MN 8) Turkey

The late middle Miocene (MN 8) sediments at Nebisuyu, in the southwestern extremity of the Gelibolu Peninsula, Turkey, yielded remains of a large individual of Listriodon splendens: a skull lacking the premaxillae but containing both cheek tooth rows, and a detached left maxilla fragment containing a canine. The material evidently represents a male individual on the basis of the large dimensions of the canine, an inference borne out by the presence of a horn-like protuberance on the thickened frontal bones. The dentition is typical of the large “subspecies” Listriodon splendens major Roman, 1907. The presence of an ossicone suggests that head-to-head combat was an aspect of the behaviour of Listriodon, just as it is in several extant suid taxa. The Nebisuyu discovery extends the geographic distribution of the subspecies well to the east of its previously known range.