Swine Influenza Virus and Association with the Porcine Respiratory Disease Complex in Pig Farms in Southern Brazil

Schmidt, Candice; Cibulski, Samuel Paulo; Andrade, Caroline Pinto de; Teixeira, Thaís Fumaco; Varela, Ana Paula Muterle; Scheffer, Camila Mengue; Franco, Ana Cláudia; Almeida, Laura Lopes de; Roehe, Paulo Michel

doi:10.1111/zph.12223

Cited by 26 publications

(24 citation statements)

References 31 publications

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“…However, studies also exist in which SIV is detected from pigs suffering from respiratory symptoms or slaughtered finishing pigs with lung lesions, but other pathogens are more frequently observed [6,8,39]. Typically for SIV, the virus is often detected in combination with other pathogens [6,38]. In our present study, SIV was not found in the nasal swabs or lung samples and none of the case herds were therefore classified to suffer from an acute respiratory infection caused by SIV.…”

Section: Discussionmentioning

confidence: 50%

“…In a recent study in Brazil, nearly 70% of the nasal swab samples taken from piglets expressing signs of respiratory disease were PCR-positive for SIV. Furthermore, SIV was the most common finding in the virological evaluations of diseased animals showing lung lesions [38]. However, studies also exist in which SIV is detected from pigs suffering from respiratory symptoms or slaughtered finishing pigs with lung lesions, but other pathogens are more frequently observed [6,8,39].…”

Section: Discussionmentioning

confidence: 99%

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Etiology of acute respiratory disease in fattening pigs in Finland

et al. 2017

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BackgroundThe objective of our study was to clinically and etiologically investigate acute outbreaks of respiratory disease in Finland. Our study also aimed to evaluate the clinical use of various methods in diagnosing respiratory infections under field conditions and to describe the antimicrobial resistance profile of the main bacterial pathogen(s) found during the study.MethodsA total of 20 case herds having finishing pigs showing acute respiratory symptoms and eight control herds showing no clinical signs suggesting of respiratory problems were enrolled in the study. Researchers visited each herd twice, examining and bleeding 20 pigs per herd. In addition, nasal swab samples were taken from 20 pigs and three pigs per case herd were necropsied during the first visit. Serology was used to detect Actinobacillus pleuropneumoniae (APP), swine influenza virus (SIV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine respiratory coronavirus (PRCV) and Mycoplasma hyopneumoniae antibodies. Polymerase chain reaction (PCR) was used to investigate the presence of porcine circovirus type 2 (PCV2) in serum and SIV in the nasal and lung samples. Pathology and bacteriology, including antimicrobial resistance determination, were performed on lung samples obtained from the field necropsies.ResultsAccording to the pathology and bacteriology of the lung samples, APP and Ascaris suum were the main causes of respiratory outbreaks in 14 and three herds respectively, while the clinical signs in three other herds had a miscellaneous etiology. SIV, APP and PCV2 caused concurrent infections in certain herds but they were detected serologically or with PCR also in control herds, suggesting possible subclinical infections. APP was isolated from 16 (80%) case herds. Marked resistance was observed against tetracycline for APP, some resistance was detected against trimethoprim/sulfamethoxazole, ampicillin and penicillin, and no resistance against florfenicol, enrofloxacin, tulathromycin or tiamulin was found. Serology, even from paired serum samples, gave inconclusive results for acute APP infection diagnosis.ConclusionsAPP was the most common cause for acute respiratory outbreaks in our study. SIV, A. suum, PCV2 and certain opportunistic bacteria were also detected during the outbreaks; however, viral pathogens appeared less important than bacteria. Necropsies supplemented with microbiology were the most efficient diagnostic methods in characterizing the studied outbreaks.

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Section: Discussionmentioning

confidence: 50%

Section: Discussionmentioning

confidence: 99%

Etiology of acute respiratory disease in fattening pigs in Finland

et al. 2017

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“…The clinical outcomes of SIV‐infected pigs are known to become much more severe when the pigs are co‐infected with other pathogens, such as porcine reproductive and respiratory syndrome virus, Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae (Yazawa et al., ). In fact, SIVs are thought to be one of the pathogens responsible for the so‐called porcine respiratory disease complex (Schmidt et al., ), which causes significant economic losses to the pig industry. Thus, the control of SIV infection is important for pig farming.…”

Section: Introductionmentioning

confidence: 99%

Distribution of gene segments of the pandemic A(H1N1) 2009 virus lineage in pig populations

Okuya

Matsuu

Kawabata

et al. 2018

Transbound Emerg Dis

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Swine influenza viruses (SIVs) are important not only for pig farming, but also for public health. In fact, pandemic A(H1N1) 2009 viruses [A(H1N1)pdm09] were derived from SIVs. Therefore, timely characterization of locally circulating SIVs is necessary for understanding the global status of SIVs. To genetically characterize SIVs circulating in Japanese pig populations, we isolated 24 SIVs of three subtypes (17 H1N1, four H1N2 and three H3N2 strains) from 14 pig farms in Japan from 2013 to 2016. Genetic analyses revealed that the haemagglutinin (HA) and neuraminidase (NA) genes of the 17 H1N1 and the HA gene of one H1N2, A/swine/Aichi/02/2016 (H1N2), SIVs belonged to the A(H1N1)pdm09 lineage. More importantly, all of the remaining six gene segments (i.e., PB1, PB1, PA, NP, M and NS) of the 24 SIVs, regardless of the HA and NA subtype, were also classified as belonging to the A(H1N1)pdm09 lineage. These results indicate that gene segments of A(H1N1)pdm09 lineage are widely distributed in SIVs circulating in Japanese pig populations In addition, the NA gene of A/swine/Aichi/02/2016 (H1N2) shared less than 88.5% nucleotide identity with that of the closest relative A/swine/Miyagi/5/2003 (H1N2), which was isolated in Japan in 2003. These results indicate the sustained circulation of classical H1N2-derived SIVs with remarkable diversity in the NA genes in Japanese pig populations. These findings highlight the necessity of both intensive biosecurity systems and active SIV surveillance in pig populations worldwide for both animal and public health.

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“…To adopt appropriate measures, such as vaccination or hygiene management, and to minimize the economic loss of PRDC, it is necessary to quickly, accurately and comprehensively detect multiple pathogens present in varying proportions in each herd. Serological tests [13], pathogen isolation [22] and PCR-based tests [1,11] are currently available to diagnose PRDC in laboratories. Most tests are based on a one assay-one pathogen approach, and they are not enough for diagnosis of PRDC in terms of comprehensiveness and rapidity.…”

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confidence: 99%

Development of a one-run real-time PCR detection system for pathogens associated with porcine respiratory diseases

et al. 2020

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The etiology of Porcine respiratory disease complex is complicated by infections with multiple pathogens, and multiple infections increase the difficulty in identifying the causal pathogen. In this present study, we developed a detection system of microbes from porcine respiratory by using TaqMan real-time PCR (referred to as Dempo-PCR) to screen a broad range of pathogens associated with porcine respiratory diseases in a single run. We selected 17 porcine respiratory pathogens (Actinobacillus pleuropneumoniae, Boldetella bronchiseptica, Haemophilus parasuis, Pasteurella multocida, Pasteurella multocida toxin, Streptococcus suis, Mycoplasma hyopneumoniae, Mycoplasma hyorhinis, Mycoplasma hyosynovie, porcine circovirus 2, pseudorabies virus, porcine cytomegalovirus, swine influenza A virus, porcine reproductive and respiratory virus US strain, EU strain, porcine respiratory coronavirus and porcine hemagglutinating encephalomyelitis virus) as detection targets and designed novel specific primer-probe sets for seven of them. In sensitivity test by using standard curves from synthesized DNA, all primer-probe sets showed high sensitivity. However, porcine reproductive and respiratory virus is known to have a high frequency of genetic mutations, and the primer and probe sequences will need to be checked at a considerable frequency when performing Dempo-PCR from field samples. A total of 30 lung samples from swine showing respiratory symptoms on six farms were tested by the Dempo-PCR to validate the assay's clinical performance. As the results, 12 pathogens (5 virus and 7 bacteria) were detected and porcine reproductive and respiratory virus US strain, Mycoplasma hyorhinis, Haemophilus parasuis, and porcine cytomegalovirus were detected at high frequency. These results suggest that Dempo-PCR assay can be applied as a screening system with wide detection targets.

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Swine Influenza Virus and Association with the Porcine Respiratory Disease Complex in Pig Farms in Southern Brazil

Cited by 26 publications

References 31 publications

Etiology of acute respiratory disease in fattening pigs in Finland

Etiology of acute respiratory disease in fattening pigs in Finland

Distribution of gene segments of the pandemic A(H1N1) 2009 virus lineage in pig populations

Development of a one-run real-time PCR detection system for pathogens associated with porcine respiratory diseases

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