Submitted to: Canadian Journal of Veterinary Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/18/2007
Publication Date: 7/15/2008
Citation: Hermann, J.R., Brockmeier, S., Zimmerman, J.J. 2008. Detection of respiratory pathogens in aerosols from acutely infected pigs. Canadian Journal of Veterinary Research. 72(4):367-370. Interpretive Summary: It is important to determine the method by which respiratory pathogens are transmitted among pigs to stop the spread of disease. The ability to quantitate the amount of a respiratory pathogen that is excreted through respiration and aerosolization would help us predict the infectious cycle of these organisms. Research was conducted to determine the amount of common respiratory viruses and bacteria of pigs that were excreted through exhalations. Although all viruses and bacteria were detected on nasal swabs taken from infected pigs, only the bacteria Mycoplasma hyopneumoniae and Bordetella bronchiseptica were detected in the expired air from infected pigs. The quantity of virus was apparently below the threshold of detection for current sampling techniques.
Technical Abstract: Infectious agents that cause respiratory disease in pigs include porcine reproductive respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV2), swine influenza virus (SIV), porcine respiratory corona virus (PRCV), Mycoplasma hyopneumoniae, and Bordetella bronchiseptica. The objective of this research was to characterize the excretion of these pathogens in respiratory exhalations from acutely infected pigs. Pigs were infected under experimental conditions with a single pathogen (PRRSV, PCV2, SIV, PRCV, M. hyopneumoniae, or B. bronchiseptica). Thereafter, samples were collected from the upper respiratory tract and from respiratory exhalations. All pathogens were detected in the upper respiratory tracts of infected pigs, but only M. hyopneumoniae and B. bronchiseptica were detected in expired air from individual, acutely infected pigs. These findings indicate that, if acutely infected pigs aerosolize PRRSV, PCV-2, SIV, and/or PRCV, the quantity is below the detection threshold of current sampling and/or assay systems at the individual pig level.