Pasteurella multocida polyserositis in growing-finishing pigs.

Pasteurella multocida is the main secondary bacterium isolated from cases of swine pneumonia. Although highly pathogenic strains of P. multocida have been associated with primary septic lesions and polyserositis in pigs, studies on this pathological presentation in naturally occurring cases are limited. The aim of this work was to characterize the clinical, pathological and molecular findings in cases of P. multocida polyserositis in growing-finishing pigs in a commercial farm in Brazil. The mean age of 17 investigated pigs was 120 days. Clinically, the disease was acute (11/17), with clinical signs of dyspnoea and apathy. Sudden death occurred in some animals (6/17). The main gross findings included fibrinous serositis affecting the abdominal and thoracic cavities (17/17), fibrinous pericarditis (15/17), marked cranioventral pulmonary consolidation (17/17) and splenic infarcts (3/17). P. multocida was isolated in all cases from systemic sites, including the pericardial sac and abdominal exudate. Molecular typing of genus and species was performed on four isolates, and all were characterized as P. multocida type A. Another five isolates were positive for the pathogenicity marker gene pfhA by polymerase chain reaction. This study reinforces the role of P. multocida as a cause of polyserositis in growing-finishing pigs.

Causes of death in growing-finishing pigs in two technified farms in southern Brazil / Causas de morte em suínos de crescimento e terminação em duas granjas tecnificadas no Sul do Brasil

The aim of this study was to investigate the main causes of death in growing-finishing pigs in southern Brazil. During a one-year period (from 2018 to 2019), two industrial pig herds (18 and 20 thousand pigs each farm) in southern Brazil were monitored along the four seasons of the year (12 days per season on each farm), in order to perform necropsies of all pigs that died in that period. The two farms had an average monthly mortality rate ranging from 0.94 to 3.93% in the evaluated months. At necropsy, tissues were collected, fixed in 10% formalin solution and processed routinely for histopathological examination. When necessary, samples were sent for bacterial culture and PCR to identify etiologic agents. A total of 601 necropsies were performed, with 94.9% of conclusive diagnoses. Infectious diseases corresponded to 64.4% of conclusive diagnosis and non-infectious diseases to 35.6%. The most prevalent causes of death were: pneumonia (33%), gastric ulcers (15.4%), circovirosis (9.9%), systemic bacterial embolism (5.4%), polyserositis (4.4%), dilated cardiomyopathy and torsion of abdominal organs (4.3% each), and bacterial pericarditis (3.4%). Regarding pneumonias (199/601), the main agents identified in these cases were Pasteurella multocida, Influenza A virus and Mycoplasma hyopneumoniae, mainly in associations.(AU)

O objetivo do presente trabalho foi investigar as principais causas de morte de suínos em fase de crescimento e terminação no Sul do Brasil. Durante o período de um ano (entre 2018 e 2019), duas granjas tecnificadas de suínos no Sul do Brasil foram acompanhadas nas quatro estações (12 dias por estação em cada granja), para realização de necropsias dos suínos que morreram nesse período. As duas propriedades apresentavam mortalidade mensal média entre 0,94 e 3,93% nos meses avaliados. Na necropsia, amostras de órgãos foram colhidas, fixadas em formol 10% e processadas rotineiramente para o exame histopatológico. Quando necessário, amostras foram enviadas para o cultivo bacteriano e PCR para identificação de agentes etiológicos. Foram realizadas um total de 601 necropsias, com 94,9% de diagnósticos conclusivos. As doenças infecciosas corresponderam a 64,4% dos diagnósticos conclusivos e as não infecciosas a 35,6%. As principais causas de morte foram: pneumonias (33%), úlcera gástrica (15,4%), circovirose (9,9%), embolia bacteriana sistêmica (5,4%), polisserosite (4,4%), cardiomiopatia dilatada e torção de órgãos abdominais (4,3% cada) e pericardite bacteriana (3,4%). Com relação às pneumonias (199/601), os principais agentes associadas as lesões foram Pasteurella multocida, vírus da Influenza A e Mycoplasma hyopneumoniae, principalmente associados entre si.(AU)