Influenza A virus infection of healthy piglets in an abattoir in Brazil: animal-human interface and risk for interspecies transmission

• Published in: Memórias do Instituto Oswaldo Cruz Vol. 108; no. 5; pp. 548 - 553
• Main Authors: Amorim, Ariane Ribeiro, Fornells, Luz Alba Maria Garcete, Reis, Felicidade da Costa, Rezende, Daiana Jacinto, Mendes, Gabriella da Silva, Couceiro, José Nelson dos Santos Silva, Santos, Norma Suely de Oliveira
• Format: Journal Article
• Language: English
• Published: Brazil Instituto Oswaldo Cruz, Ministério da Saúde 01-08-2013; Fundação Oswaldo Cruz (FIOCRUZ)
• Subjects: Abattoirs; Animals; Asymptomatic Diseases - epidemiology; Brazil - epidemiology; Influenza A virus; Influenza A virus - genetics; Influenza A virus - isolation & purification; influenza virus; interspecies transmission; Male; Occupational Exposure; Orthomyxoviridae Infections - diagnosis; Orthomyxoviridae Infections - epidemiology; Orthomyxoviridae Infections - transmission; Orthomyxoviridae Infections - veterinary; PARASITOLOGY; pork industry; Reverse Transcriptase Polymerase Chain Reaction; Risk Factors; Sus scrofa; Swine; Swine Diseases - diagnosis; Swine Diseases - epidemiology; Swine Diseases - transmission; Swine Diseases - virology; TROPICAL MEDICINE; zoonosis; Brazil; influenza virus; pork industry; interspecies transmission; zoonosis
• ISSN: 0074-0276; 1678-8060; 1678-8060; 0074-0276
• DOI: 10.1590/0074-0276108052013003

Asymptomatic influenza virus infections in pigs are frequent and the lack of measures for controlling viral spread facilitates the circulation of different virus strains between pigs. The goal of this study was to demonstrate the circulation of influenza A virus strains among asymptomatic piglets in an abattoir in Brazil and discuss the potential public health impacts. Tracheal samples (n = 330) were collected from asymptomatic animals by a veterinarian that also performed visual lung tissue examinations. No slaughtered animals presented with any noticeable macroscopic signs of influenza infection following examination of lung tissues. Samples were then analysed by reverse transcription-polymerase chain reaction that resulted in the identification of 30 (9%) influenza A positive samples. The presence of asymptomatic pig infections suggested that these animals could facilitate virus dissemination and act as a source of infection for the herd, thereby enabling the emergence of influenza outbreaks associated with significant economic losses. Furthermore, the continuous exposure of the farm and abattoir workers to the virus increases the risk for interspecies transmission. Monitoring measures of swine influenza virus infections and vaccination and monitoring of employees for influenza infection should also be considered. In addition regulatory agencies should consider the public health ramifications regarding the potential zoonotic viral transmission between humans and pigs.