title: The bovine paranasal sinuses: Bacterial flora, epithelial expression of nitric oxide and potential role in the in-herd persistence of respiratory disease pathogens.
abstract: The bovine paranasal sinuses are a group of complex cavernous air-filled spaces, lined by respiratory epithelium, the exact function of which is unclear. While lesions affecting these sinuses are occasionally reported in cattle, their microbial flora has not been defined. Furthermore, given that the various bacterial and viral pathogens causing bovine respiratory disease (BRD) persist within herds, we speculated that the paranasal sinuses may serve as a refuge for such infectious agents. The paranasal sinuses of clinically normal cattle (n = 99) and of cattle submitted for post-mortem examination (PME: n = 34) were examined by microbial culture, PCR and serology to include bacterial and viral pathogens typically associated with BRD: Mycoplasma bovis, Histophilus somni, Mannheimia haemolytica and Pasteurella multocida, bovine respiratory syncytial virus (BRSV) and bovine parainfluenza-3 virus (BPIV-3). Overall, the paranasal sinuses were either predominantly sterile or did not contain detectable microbes (83.5%: 94.9% of clinically normal and 50.0% of cattle submitted for PME). Bacteria, including BRD causing pathogens, were identified in relatively small numbers of cattle (<10%). While serology indicated widespread exposure of both clinically normal and cattle submitted for PME to BPIV-3 and BRSV (seroprevalences of 91.6% and 84.7%, respectively), PCR identified BPIV-3 in only one animal. To further explore these findings we investigated the potential role of the antimicrobial molecule nitric oxide (NO) within paranasal sinus epithelium using immunohistochemistry. Expression of the enzyme responsible for NO synthesis, inducible nitric oxide synthase (iNOS), was detected to varying degrees in 76.5% of a sub-sample of animals suggesting production of this compound plays a similar protective role in the bovine sinus as it does in humans.
authors.affiliation: Sligo Regional Veterinary Laboratory, Department of Agriculture, Food and Marine, Doonally, Sligo, Ireland.
authors.forename: Gerard M
authors.identifier: http://orcid.org/0000-0001-9652-8819
authors.initials: GM
authors.lastname: Murray
authors.affiliation: Central Veterinary Research Laboratory, Department of Agriculture, Food and Marine, Backweston, Celbridge, County Kildare, Ireland.
authors.forename: Rónan G
authors.initials: RG
authors.lastname: O'Neill
authors.affiliation: School of Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland.
authors.forename: Alison M
authors.initials: AM
authors.lastname: Lee
authors.affiliation: Central Veterinary Research Laboratory, Department of Agriculture, Food and Marine, Backweston, Celbridge, County Kildare, Ireland.
authors.forename: Máire C
authors.initials: MC
authors.lastname: McElroy
authors.affiliation: Centre for Veterinary Epidemiology and Risk Analysis, UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland.
authors.forename: Simon J
authors.initials: SJ
authors.lastname: More
authors.affiliation: School of Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland.
authors.forename: Aisling
authors.initials: A
authors.lastname: Monagle
authors.affiliation: Animal and Bioscience Research Department, Animal & Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, County Meath, Ireland.
authors.forename: Bernadette
authors.initials: B
authors.lastname: Earley
authors.affiliation: School of Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Cassidy
mesh_terms: D000818:Animals; D001419:Bacteria / Q000235:genetics / Q000472:pathogenicity; D048090:Bovine Respiratory Disease Complex / Q000382:microbiology / Q000821:virology*; D002417:Cattle; D003430:Cross-Sectional Studies; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D008297:Male; D064307:Microbiota / Q000235:genetics; D009569:Nitric Oxide / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D029101:Parainfluenza Virus 3, Bovine / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D010256:Paranasal Sinuses / Q000378:metabolism / Q000382:microbiology*; D018112:Respiratory Syncytial Virus, Bovine / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity
chemical_list: D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II