title: [Factors associated with the occurrence of influenza A virus infections in fattening swine].
abstract: In August of 1989 sera from 2115 finishing pigs out of 214 herds in the north of Schleswig- Holstein (Germany) were tested for antibodies against three strains of Influenza A viruses by using the haemagglutination inhibition test. Seroprevalences of A/Swine/Nederland/25/80 (H1N1), A/Philippines/2/82 (H3N2), and A/Port Chalmers/1/73 (H3N2) on herd level were 23.4%, 20.6% and 5.1% respectively. The mean within herd prevalences were 9.6%, 14.7% and 0.6%, respectively. Antibodies against H1N1 and H3N3 strains were simultaneously found in 7.5% of the herds and in 1.6% of the pigs. In 485 (22.9%) of the pigs and in 83 (38.3%) of the herds at least one of the strains was prevalent. In 61 (73.5%) of those herds there was no evidence of a clinical outbreak before testing. A higher risk of infection with influenza virus was associated with high pig density (> or = 200 pigs per km2) and with management factors as greater herd size (> 300 finishing pigs), slatted floors (compared to straw bedding) and all in-all out system (compared to continuous purchase).
authors.affiliation: Tierärztliche Ambulanz Schwarzenbek, Fachbereich Veterinärmedizin der Freien Universität Berlin.
authors.forename: C
authors.initials: C
authors.lastname: Ewald
authors.forename: A
authors.initials: A
authors.lastname: Heer
authors.forename: U
authors.initials: U
authors.lastname: Havenith
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D005858:Germany / Q000453:epidemiology; D009980:Influenza A virus / Q000276:immunology*; D009976:Orthomyxoviridae Infections / Q000453:epidemiology / Q000662:veterinary*; D015995:Prevalence; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology*
chemical_list: D000914:Antibodies, Viral
vernacular_title: Mit dem Vorkommen von Influenza-A-Virusinfektionen bei Mastschweinen assoziierte Faktoren.