title: Neuropathogenesis of naturally occurring encephalitis caused by Listeria monocytogenes in ruminants.
abstract: Listeriosis is a serious food-borne disease with increasing frequency in humans and ruminants. Despite the facts that in both hosts, listeriosis can occur as rhombencephalitis and ruminants are a reservoir of Listeria monocytogenes (LM) strains pathogenic for humans, little work has been done on the pathogenesis in ruminants. This study investigates the neuropathogenesis of listeric encephalitis in over 200 natural cases in cattle, sheep and goats by analyzing anatomical distribution, severity, bacterial load and temporal evolution of the lesions. Our results suggest that LM gains access to the brainstem of all three species via axonal migration not only along the trigeminal nerve, but also along other nerves. The ensuing encephalitis does not remain restricted to the brainstem. Rather, LM spreads further from the brainstem into rostral brain regions likely by intracerebral axonal migration. Significant differences in severity of the lesions and bacterial load were found between cattle and small ruminants, which may be caused by species-specific properties of antibacterial immune responses. As histopathological lesions of human rhombencephalitis caused by LM strongly resemble those of ruminants, the disease likely has a similar pathogenesis in both hosts.
authors.affiliation: Department of Clinical Research and Veterinary Public Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland. anna.oevermann@itn.unibe.ch
authors.forename: Anna
authors.initials: A
authors.lastname: Oevermann
authors.forename: Stefano
authors.initials: S
authors.lastname: Di Palma
authors.forename: Marcus G
authors.initials: MG
authors.lastname: Doherr
authors.forename: Carlos
authors.initials: C
authors.lastname: Abril
authors.forename: Andreas
authors.initials: A
authors.lastname: Zurbriggen
authors.forename: Marc
authors.initials: M
authors.lastname: Vandevelde
mesh_terms: D000818:Animals; D001369:Axons / Q000473:pathology / Q000502:physiology; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D001933:Brain Stem / Q000473:pathology / Q000503:physiopathology; D002417:Cattle; D002418:Cattle Diseases / Q000473:pathology* / Q000503:physiopathology; D003391:Cranial Nerves / Q000473:pathology / Q000503:physiopathology; D018450:Disease Progression; D004660:Encephalitis / Q000473:pathology / Q000503:physiopathology / Q000662:veterinary*; D005260:Female; D015511:Goat Diseases / Q000473:pathology* / Q000503:physiopathology; D006041:Goats; D008089:Listeria monocytogenes; D008088:Listeriosis / Q000473:pathology / Q000503:physiopathology / Q000662:veterinary*; D008297:Male; D012720:Severity of Illness Index; D012756:Sheep; D012757:Sheep Diseases / Q000473:pathology* / Q000503:physiopathology; D014276:Trigeminal Nerve / Q000473:pathology / Q000503:physiopathology