title: Evaluation of farm management practices as risk factors for clinical listeriosis and fecal shedding of Listeria monocytogenes in ruminants.
abstract: OBJECTIVE
  To assess seasonal variation in prevalence of Listeria monocytogenes on ruminant farms and identify management practices associated with ruminant listeriosis and fecal shedding of L. monocytogenes.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  2056 samples of feces, feed, soil, and water from 24 case farms with listeriosis and 28 control farms without listeriosis.
  
  
  METHODS
  Samples were collected and evaluated via bacterial culture for L. monocytogenes. Univariate associations between farm management practices and listeriosis and fecal shedding of L. monocytogenes were assessed. Multivariate models were developed to identify farm management practices associated with listeriosis and fecal shedding of L. monocytogenes.
  
  
  RESULTS
  The prevalence of L. monocytogenes on cattle, goat, and sheep farms was seasonal, especially in fecal samples, with peak prevalence in winter. Although the prevalence of L. monocytogenes in feedstuffs from small-ruminant farms also peaked during winter, the bacterium was detected at a constant rate in cattle farm feedstuffs throughout the year. Farm management practices, animal health and hygiene, and feedstuff quality and storage were associated with ruminant listeriosis and fecal shedding of L. monocytogenes.
  
  
  CONCLUSIONS
  Results suggest that the prevalence of L. monocytogenes on ruminant farms is seasonal, management practices are associated with ruminant listeriosis and fecal shedding of L. monocytogenes, and the epidemiologic features of listeriosis differ in cattle versus small ruminants. Awareness of risk factors may be used to develop control measures to reduce animal disease and introduction of L. monocytogenes into the human food chain.
authors.affiliation: Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853, USA.
authors.forename: Kendra K
authors.initials: KK
authors.lastname: Nightingale
authors.forename: Esther D
authors.initials: ED
authors.lastname: Fortes
authors.forename: Alphina J
authors.initials: AJ
authors.lastname: Ho
authors.forename: Ynte H
authors.initials: YH
authors.lastname: Schukken
authors.forename: Yrjo T
authors.initials: YT
authors.lastname: Grohn
authors.forename: Martin
authors.initials: M
authors.lastname: Wiedmann
mesh_terms: D000822:Animal Husbandry / Q000379:methods* / Q000592:standards; D000818:Animals; D016022:Case-Control Studies; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000635:transmission; D005243:Feces / Q000382:microbiology*; D015511:Goat Diseases / Q000453:epidemiology / Q000635:transmission; D006041:Goats; D008089:Listeria monocytogenes / Q000302:isolation & purification*; D008088:Listeriosis / Q000453:epidemiology / Q000635:transmission / Q000662:veterinary*; D012307:Risk Factors; D012418:Ruminants / Q000382:microbiology*; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology / Q000635:transmission; D012988:Soil Microbiology; D014871:Water Microbiology