title: Maternally-derived antibodies do not prevent transmission of swine influenza A virus between pigs.
abstract: A transmission experiment involving 5-week-old specific-pathogen-free (SPF) piglets, with (MDA(+)) or without maternally-derived antibodies (MDA(-)), was carried out to evaluate the impact of passive immunity on the transmission of a swine influenza A virus (swIAV). In each group (MDA(+)/MDA(-)), 2 seeders were placed with 4 piglets in direct contact and 5 in indirect contact (3 replicates per group). Serological kinetics (ELISA) and individual viral shedding (RT-PCR) were monitored for 28 days after infection. MDA waning was estimated using a nonlinear mixed-effects model and survival analysis. Differential transmission rates were estimated depending on the piglets' initial serological status and contact structure (direct contact with pen-mates or indirect airborne contact). The time to MDA waning was 71.3 [52.8-92.1] days on average. The airborne transmission rate was 1.41 [0.64-2.63] per day. The compared shedding pattern between groups showed that MDA(+) piglets had mainly a reduced susceptibility to infection compared to MDA(-) piglets. The resulting reproduction number estimated in MDA(+) piglets (5.8 [1.4-18.9]), although 3 times lower than in MDA(-) piglets (14.8 [6.4-27.1]), was significantly higher than 1. Such an efficient and extended spread of swIAV at the population scale in the presence of MDAs could contribute to swIAV persistence on farms, given the fact that the period when transmission is expected to be impacted by the presence of MDAs can last up to 10 weeks.
authors.affiliation: Swine Epidemiology and Welfare Research Unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440, Ploufragan, France. charlie.cador@anses.fr.|Université Bretagne Loire, Rennes, France. charlie.cador@anses.fr.
authors.forename: Charlie
authors.identifier: 0000-0002-9386-8313
authors.initials: C
authors.lastname: Cador
authors.affiliation: Swine Virology Immunology Research Unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440, Ploufragan, France.|Université Bretagne Loire, Rennes, France.
authors.forename: Séverine
authors.initials: S
authors.lastname: Hervé
authors.affiliation: Swine Epidemiology and Welfare Research Unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440, Ploufragan, France.|Université Bretagne Loire, Rennes, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Andraud
authors.affiliation: Swine Virology Immunology Research Unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440, Ploufragan, France.|Université Bretagne Loire, Rennes, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Gorin
authors.affiliation: SPF Pig Production and Experimental Unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440, Ploufragan, France.|Université Bretagne Loire, Rennes, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Paboeuf
authors.affiliation: Swine Virology Immunology Research Unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440, Ploufragan, France.|Université Bretagne Loire, Rennes, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Barbier
authors.affiliation: Swine Virology Immunology Research Unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440, Ploufragan, France.|Université Bretagne Loire, Rennes, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Quéguiner
authors.affiliation: Swine Virology Immunology Research Unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440, Ploufragan, France.|Université Bretagne Loire, Rennes, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Deblanc
authors.affiliation: Swine Virology Immunology Research Unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440, Ploufragan, France.|Université Bretagne Loire, Rennes, France.
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Simon
authors.affiliation: Swine Epidemiology and Welfare Research Unit, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), BP 53, 22440, Ploufragan, France.|Université Bretagne Loire, Rennes, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Rose
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology; D005260:Female; D007112:Immunity, Maternally-Acquired / Q000276:immunology*; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D007252:Influenza Vaccines / Q000276:immunology / Q000627:therapeutic use; D008297:Male; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000635:transmission / Q000662:veterinary* / Q000821:virology; D011247:Pregnancy; D013552:Swine; D013553:Swine Diseases / Q000276:immunology / Q000635:transmission / Q000821:virology*
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines