title: A cross-sectional study of swine influenza in intensive and extensive farms in the northeastern region of the state of São Paulo, Brazil.
abstract: Swine influenza (SI) is a seasonal infectious disease highly important to the world pig industry. Loss of daily weight gain, increased costs for the prevention and treatment of secondary infections are the main economic losses associated with the presence of this disease. However, some epidemiological features of SI remain quite unclear. This study focused on assessing the prevalence of swine influenza virus (SIV) infection in intensive and extensive pig herds and associating risk factors. A set of 601 blood samples of five intensive farrow-to-finish farms and 361 blood samples from 56 extensive farms were analyzed using an indirect ELISA kit CIVTEST SUIS INFLUENZA®, Hipra (Amer, Spain), in order to detect anti-SIV antibodies. In total, 24.13 % of samples from intensive herds were positive, while no positive samples were detected in extensive rearing herds. Sow and weaning piglets had the highest prevalence values. In the intensive rearing system, occurrence of reproductive disorders and exposure to recently introduced animals were positively associated with the disease occurrence in swine herds. The findings highlight the importance of sows in the epidemiology of the disease and bring information about risk factors involved in the occurrence of swine influenza in intensive herds.
authors.affiliation: Faculty of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Via de Acesso prof. Paulo Donato Castellane s/n, 14884-900, Jaboticabal, São Paulo, Brazil.
authors.forename: Henrique Meiroz de Souza
authors.initials: HM
authors.lastname: Almeida
authors.affiliation: Faculty of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Via de Acesso prof. Paulo Donato Castellane s/n, 14884-900, Jaboticabal, São Paulo, Brazil.
authors.forename: Gabriel Yuri
authors.initials: GY
authors.lastname: Storino
authors.affiliation: Faculty of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Via de Acesso prof. Paulo Donato Castellane s/n, 14884-900, Jaboticabal, São Paulo, Brazil.
authors.forename: Daniele Araújo
authors.initials: DA
authors.lastname: Pereira
authors.affiliation: Faculty of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Via de Acesso prof. Paulo Donato Castellane s/n, 14884-900, Jaboticabal, São Paulo, Brazil.
authors.forename: Igor Renan Honorato
authors.initials: IR
authors.lastname: Gatto
authors.affiliation: Faculty of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Via de Acesso prof. Paulo Donato Castellane s/n, 14884-900, Jaboticabal, São Paulo, Brazil.
authors.forename: Luis Antonio
authors.initials: LA
authors.lastname: Mathias
authors.affiliation: Faculty of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Via de Acesso prof. Paulo Donato Castellane s/n, 14884-900, Jaboticabal, São Paulo, Brazil.
authors.forename: Hélio José
authors.initials: HJ
authors.lastname: Montassier
authors.affiliation: Faculty of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Via de Acesso prof. Paulo Donato Castellane s/n, 14884-900, Jaboticabal, São Paulo, Brazil. luis.guilherme@fcav.unesp.br.
authors.forename: Luís Guilherme
authors.initials: LG
authors.lastname: de Oliveira
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000914:Antibodies, Viral / Q000097:blood; D001938:Brazil / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D000072480:Farms; D005260:Female; D053118:Influenza A Virus, H1N1 Subtype; D009976:Orthomyxoviridae Infections / Q000453:epidemiology*; D015995:Prevalence; D012307:Risk Factors; D013030:Spain; D013552:Swine / Q000821:virology; D013553:Swine Diseases / Q000453:epidemiology / Q000821:virology*; D014886:Weaning
chemical_list: D000914:Antibodies, Viral
keywords: ELISA; Epidemiology; Orthmyxoviridae; Pigs; Porcine respiratory disease complex; SIV