title: Demonstration of Listeria monocytogenes by immunohistochemistry in formalin-fixed brain tissues from natural cases of ovine and bovine encephalitis.
abstract: In the present work, evidence of Listeria monocytogenes antigens based on the avidin-biotin complex (ABC) immunoperoxidase technique was performed on formalin-fixed central nervous system tissues (CNS) from a total of 23 natural cases of encephalitis (four ovine and 19 bovine). Listeria monocytogenes serotype 4 was isolated from 10 of 17 cultured specimens. Meningoencephalitis characterized by focal necrosis, microabscesses, perivascular cuffing, and gliosis with presence of macrophages and/or neutrophils was observed at histological examination. Positive L. monocytogenes antigens were successfully identified by immunohistochemistry (IHC) in the CNS of all 23 cases. Paraffin-embedded tissues assayed were stored up for 17 years. Morbidity of the outbreaks was between 0.3-3% and 0.1-1% for ovine and bovine cases, respectively. In all the ovine cases, flocks involved were under extensive grazing conditions. In nine of the 19 bovine cases (47.3%), supplementation with corn silage was used. The ABC test can help as a practical tool for the diagnosis of natural cases of L. monocytogenes encephalitis on formalin-fixed specimens from ovine and bovine.
authors.affiliation: The Animal Health Group, Instituto Nacional de Tecnología Agropecuaria, Balcarce, Argentina. ccampero@balcarce.inta.gov.ar
authors.forename: C M
authors.initials: CM
authors.lastname: Campero
authors.forename: A C
authors.initials: AC
authors.lastname: Odeón
authors.forename: A L
authors.initials: AL
authors.lastname: Cipolla
authors.forename: D P
authors.initials: DP
authors.lastname: Moore
authors.forename: M A
authors.initials: MA
authors.lastname: Poso
authors.forename: E
authors.initials: E
authors.lastname: Odriozola
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology*; D001118:Argentina / Q000453:epidemiology; D001921:Brain / Q000382:microbiology; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000209:etiology / Q000382:microbiology; D004196:Disease Outbreaks / Q000662:veterinary*; D004660:Encephalitis / Q000453:epidemiology / Q000662:veterinary*; D005260:Female; D005557:Formaldehyde; D007150:Immunohistochemistry / Q000662:veterinary; D008089:Listeria monocytogenes / Q000276:immunology* / Q000302:isolation & purification; D008088:Listeriosis / Q000453:epidemiology / Q000662:veterinary*; D008297:Male; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology* / Q000209:etiology / Q000382:microbiology; D013048:Specimen Handling / Q000662:veterinary
chemical_list: D000942:Antigens, Bacterial; D005557:Formaldehyde