Porcine Respiratory Pathogens in Swine Farms Environment in Mexico

Abstract

Respiratory pathogens are the main health problem in the swine industry worldwide. These pathogens are transmitted by direct contact between animals or by aerosols and however are not well known yet, if the environment works as its reservoir, inoculum and/or dispersion medium. The objective of this study was to determine the presence of respiratory pathogens in environmental samples from swine farms in Aguascalientes, Mexico, through of PCR and RT-PCR techniques. The bacteria Actinobacillus pleuropneumoniae and Pasteurella multocida were found viable in samples from water, food, soil and air. Streptococcus suis was found in a viable state in water samples. Haemophilus parasuis, Porcine Reproductive and Respiratory Syndrome virus and Swine Influenza virus (H1N1 and H3N2) were detected in drinking water samples. Mycoplasma hyopneumoniae and Porcine Circovirus type 2 (PCV2) were not detected in environmental samples. These results suggest that the environment of the farms acts as a reservoir, inoculum and/or vehicle of dispersion for these pathogens except for M. hyopneumoniae and PCV2.

Detection of Actinobacillus pleuropneumoniae ApxIV toxin antibody in serum and oral fluid specimens from pigs inoculated under experimental conditions

“…As distinct from the inoculation protocol used in this and other experimental studies, A. pleuropneumoniae infections in the field are believed to occur by direct contact between pigs or via aerosol exposure (11, 17 ). However, recent research has shown that the environment (drinking water, feed, soil) is also heavily seeded with A. pleuropneumoniae ( 32 ), suggesting that field infections may involve repeated low-dose exposures ( 55 ). Thus, differences among experimental results may reflect variability in the exposure route and dose under experimental conditions ( 24 , 25 , 54 , 55 ) and differences between experimental results and field observations may result from the fact that experimental exposures do not reflect the mode of A. pleuropneumoniae transmission (dose, route, frequency) in the field ( 20 ).…”

“…Transmission of A. pleuropneumoniae among swine is commonly ascribed to exposure to contaminated respiratory secretions, and/or aerosols ( 11 , 55 ). More recent publications have described environmental contamination of commercial swine production systems with A. pleuropneumoniae , which raises the possibility of indirect routes of transmission ( 32 ).…”

Actinobacillus pleuropneumoniae and the development of an ELISA for the detection of ApxIV antibody in swine oral fluids

“…47 As distinct from experimental inoculation, APP infections in the field are believed to occur by direct contact between pigs or via aerosol exposure. 11,17 However, recent research has shown that the environment (drinking water, feed, soil) is also heavily seeded with APP, 32 suggesting that field infections may involve repeated low-dose exposures. 56 Thus, differences among experimental results may reflect variability in the exposure route and dose under experimental conditions 24,25,55,56 and differences between experimental results and field observations may result from the fact that experimental exposures do not reflect the mode of APP transmission (dose, route, frequency) in the field.…”

“…11,56 More recent publications have described environmental contamination of commercial swine production systems with APP, which raises the possibility of indirect routes of transmission. 32 Two APP biotypes have been identified on the basis of the nicotinamide adenine dinucleotide (NAD or V-factor) requirement for growth: biotype I (NAD-dependent) and biotype II (NAD-independent). 44 APP is further divided into 15 serovars on the basis of capsular polysaccharide antigen composition.…”

“…48 The economic impact of APP on the swine industry is a consequence of chronic infections that reduce productivity, i.e., lower feed conversion rates or feed intake; infections that result in acute death, particularly in late finishers; lesions at slaughter; and the costs attributable to prevention, control, and/or elimination of APP. 32,52 The prevention and control of the APP in commercial production settings is based on the detection of APP infections via serological monitoring. Several APP serum antibody assays have been described and most are available for use in the diagnostic setting, including the complement fixation (CF) test, a variety of enzyme-linked immunosorbent assays (ELISA), and a fluorescent microsphere immunoassay.…”