title: A longitudinal study of Salmonella enterica infections in high-and low-seroprevalence finishing swine herds in The Netherlands.
abstract: The purpose of this investigation was to study the incidence and course of Salmonella infections in finishing pig herds in order to asses the stability of a given Salmonella herd status. Five low- and 7 high-seroprevalence herds were followed for seven sampling rounds. Each round, blood and faecal samples were tested in an indirect ELISA and by bacteriological culturing, respectively. In high-seroprevalence herds a positive Salmonella status was an indication of a long-term problem and the status was relatively stable over time. The herds experiencing clinical salmonellosis were not necessarily the herds with the highest seroprevalence. It is possible to deliver sero-negative finishers to the slaughterhouse, even though these pigs were seropositive as growers. In three out of five low-prevalence herds, major infection incidents occurred, indicating that changes in the Salmonella status should be anticipated. Low-prevalence herds can remain negative over a longer period of time as a result feeding a complete liquid feed containing fermented by-products.
authors.affiliation: Pig Health Department, Deventer, The Netherlands. p.vd.wolf@gdvdieren.nl
authors.forename: P J
authors.initials: PJ
authors.lastname: van der Wolf
authors.forename: D M
authors.initials: DM
authors.lastname: Lo Fo Wong
authors.forename: W B
authors.initials: WB
authors.lastname: Wolbers
authors.forename: A R
authors.initials: AR
authors.lastname: Elbers
authors.forename: H M
authors.initials: HM
authors.lastname: van der Heijden
authors.forename: F W
authors.initials: FW
authors.lastname: van Schie
authors.forename: W A
authors.initials: WA
authors.lastname: Hunneman
authors.forename: P
authors.initials: P
authors.lastname: Willeberg
authors.forename: M J
authors.initials: MJ
authors.lastname: Tielen
mesh_terms: D000821:Animal Feed; D000818:Animals; D004196:Disease Outbreaks / Q000662:veterinary*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005243:Feces / Q000382:microbiology; D005285:Fermentation; D015994:Incidence; D009426:Netherlands / Q000453:epidemiology; D015995:Prevalence; D012481:Salmonella Infections, Animal / Q000453:epidemiology* / Q000473:pathology; D019779:Salmonella enterica / Q000472:pathogenicity*; D012698:Serologic Tests; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000382:microbiology* / Q000473:pathology