The present study investigated the effects of vaccinating sows and piglets or piglets alone against on the prevalence of in nasal swabs, on the humoral and cellular immune responses, and on the production parameters of piglets at 3 Korean farms with a clinical history of polyserositis caused by Piglets born to vaccinated or non-vaccinated sows were subdivided into 3 groups: vaccinated sows and vaccinated pigs (VS-VP), non-vaccinated sows and vaccinated pigs (NVS-VP), and non-vaccinated sows and non-vaccinated pigs (NVS-NVP). group had significantly higher levels (< 0.05) of des truies et des porcelets ou des porcelets uniquement sur la prvalence ddans des couvillons nasaux, sur les rponses immunitaires humorale et cellulaire, et sur les paramtres de production des porcelets dans trois fermes corennes avec une histoire de cas cliniques de polysrosites causs par partir de lcouvillon nasal tait significativement plus faible (< 0,05) chez les animaux vaccins (groupes VS-VP et NVS-VP) que chez les animaux non-vaccins (groupe NVS-NVP) 35 et 60 jours dage sur les trois fermes. Sur les 3 fermes, les performances de croissance globales (de 7 60 jours dage) des porcelets vaccins taient significativement meilleures (< 0,05) que celles des porcelets non-vaccins. Sur les trois fermes, les porcelets du groupe VS-VP avaient des niveaux significativement plus levs (< 0,05) danticorps IgG spcifiques contre de prolifration lymphocytaire, et de cellules secrtant de linterfron- que les porcelets dans les groupes NVS-VP et NVS-NVP aux jours 1, 7, 21, 35, et 60 aprs la naissance. (Traduit par Docteur Serge Messier) Introduction Polyserositis is general Pelitinib inflammation of serous membranes such as pleura, pericardium, and peritoneum (1). Its consequences are economic losses due to expensive antibiotic treatment and animal death. In Korea, polyserositis is one of the most common necropsy findings in growth-retarded and culled pigs, especially those 3- to 5-weeks-old (2). Although polyserositis is caused by several pathogens (1), is the most common etiologic agent in Korea (2). This organism is one of the earliest and most prevalent to be found in the nasal swabs of pigs at 1 wk of age (3). Sows are reservoirs in infected herds. Piglets are colonized during the suckling period because sows shed both pathogenic and nonpathogenic strains during this period (4). Prevention of colonization by early weaning alone is unlikely to be successful because newborn piglets become infected soon after birth (3). The ideal method to prevent infection is vaccination of sows and piglets combined with prophylactic antibiotic treatment of newborn piglets. Whether the efficacy of vaccination in piglets is affected by maternally derived antibodies (MDAs) from the vaccinated dam that are present in the piglets at the time of vaccination is controversial (5C8). One objective of the present study was to develop an effective program of vaccination and prophylactic antibiotic treatment to control infection in pigs between farrowing and the nursery period. Another CX3CL1 objective was to determine whether passively transferred MDAs interfere with Pelitinib the humoral and cellular immune responses in piglets after vaccination. Materials and methods Farms The clinical field trial was conducted on 3 farms. Farms A, B, and C have 200-sow, 250-sow, and 400-sow herds, respectively. Farms A and C have 1-site production systems. Farm B has a 2-site production system, with nursery and finishing units. At all 3 farms the pigs were weaned into a nursery barn (housing pigs from weaning until approximately 10 wk of age) at an average age of 21 d, with approximately 2 farrowing-house litters to a nursery pen. The pigs were moved to the finishing barns at approximately 10 wk of age. Pigs at all 3 Pelitinib farms were seropositive for porcine reproductive and respiratory syndrome virus (PRRSV); none of the farms vaccinated pigs against PRRSV. All 3 farms had consistently suffered losses due to polyserositis caused by in several recent months. The organism was consistently isolated from lesions of pericarditis and peritonitis in pigs submitted from all 3 farms. Serotypes 2 and 4 were identified at farm A. Serotypes 4 and 5 were identified at farms B and C, respectively. For farms A and C, clinical signs first appeared at approximately 21 to 35 d of age, and peak mortality (7% to 10%) occurred at approximately 42 to 56 d of age. For farm B, clinical signs first appeared at approximately 21 to 28 d of age, and peak mortality (6% to 8%) occurred at approximately 35 to 49 d.