Associations between Pleurisy and the Main Bacterial Pathogens of the Porcine Respiratory Diseases Complex (PRDC)

Abstract

Porcine Respiratory Diseases Complex (PRDC) is a multifactorial disease that involves several bacterial pathogens, including Mycoplasma hyopneumoniae (M. hyopneumoniae), Actinobacillus pleuropneumoniae (A. pleuropneumoniae), Pasteurella multocida (P. multocida), Glaesserella parasuis (G. parasuis), and Streptococcus suis (S. suis). In pigs, the infection may cause lesions such pleurisy, which can lead to carcass condemnation. Hence, 1015 carcasses were selected from three different commercial pig farms, where the respiratory conditions were evaluated using slaughterhouse pleurisy evaluation system (SPES) and classified into five groups. In total, 106 pleural and lung fragments were collected for qPCR testing to identify the five abovementioned pathogens. A moderate correlation between the severity of the lesions and the presence of P. multocida (R = 0.38) and A. pleuropneumoniae (R = 0.28) was observed. Concerning the lung samples, the severity of the lesions was moderately correlated with the presence of P. multocida (R = 0.43) and M. hyopneumoniae (R = 0.35). Moreover, there was a strong correlation between the presence of P. multocida and M.hyopneumoniae in the pleura (R = 0.82). Finally, this approach may be a useful tool to identify and quantify causative agents of PRDC using qPCR, providing a comprehensive evaluation of its relevance, strength, and potential application in the field as a surveillance tool for veterinarians.

Establishment and Application of a Quadruplex Real-Time Reverse-Transcription Polymerase Chain Reaction Assay for Differentiation of Porcine Reproductive and Respiratory Syndrome Virus, Porcine Circovirus Type 2, Porcine Circovirus Type 3, and Streptococcus suis

“…Recent advancements in disease control on large-scale swine farms have identified key pathogens contributing to PRDC in pig populations, including PRRSV, PCV2, PCV3, SS , and swine pneumonia-like Mycoplasma [ 17 ]. Co-infections with various PRDC pathogens at varied concentrations are prevalent in clinical settings for fattening pigs [ 3 , 4 ]. The compromised immunity resulting from PRDC pathogen infections in fattening pigs renders them susceptible to additional pathogens, resulting in heightened economic losses [ 18 ].…”

“…The compromised immunity resulting from PRDC pathogen infections in fattening pigs renders them susceptible to additional pathogens, resulting in heightened economic losses [ 18 ]. Furthermore, secondary infections from pathogens such as Actinobacillus pleuropneumoniae, S. suis, G. parasuis, and Pasteurella multocida are associated with PRDC [ 3 , 8 , 19 ]. Conventional diagnostic methods for PRDC-related viruses involve virus isolation in cell culture, antigen detection through direct fluorescent antibody staining, enzyme immunoassays, and bacterial isolation [ 3 , 20 ].…”

“…Furthermore, secondary infections from pathogens such as Actinobacillus pleuropneumoniae, S. suis, G. parasuis, and Pasteurella multocida are associated with PRDC [ 3 , 8 , 19 ]. Conventional diagnostic methods for PRDC-related viruses involve virus isolation in cell culture, antigen detection through direct fluorescent antibody staining, enzyme immunoassays, and bacterial isolation [ 3 , 20 ]. Despite being cost-effective, these methods are time-consuming, necessitating independent testing for each pathogen [ 21 , 22 ].…”

“…Porcine respiratory disease complex (PRDC) is a significant challenge in the swine industry worldwide [ 1 ]. Four common and important respiratory pathogens in swine production include Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), Porcine Circovirus Type 2 (PCV2), Porcine Circovirus Type 3 (PCV3) and Streptococcus suis ( SS ) [ 2 , 3 , 4 ]. Pathogens like PRRSV and PCV2 can cause severe respiratory diseases, suppress the host’s immune function, and create opportunities for secondary pathogens like Streptococcus and Actinobacillus pleuropneumonia to invade [ 5 , 6 ].…”

Streptococcus suis Research Update: Serotype Prevalence and Antimicrobial Resistance Distribution in Swine Isolates Recovered in Spain from 2020 to 2022

“…As happens with respiratory illnesses in humans and other species, these conditions often arise due to the interplay of both primary and opportunistic infectious agents. One primary concern in pig farming arises from the Porcine Respiratory Disease Complex (PRDC), a term coined to characterize the viral and bacterial pneumonia processes that frequently manifest in growing and finishing pigs [ 1 ]. Some of the most relevant agents include the Porcine Circovirus type 2 (PCV2), the Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), the Swine Influenza Virus (SIV), Mycoplasma hyopneumoniae , Actinobacillus pleuropneumoniae , Glaesserella parasuis , Pasteurella multocida , and Streptococcus suis [ 2 ].…”