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ARS Home » Research » Publications at this Location » Publication #59920
Title: LUNG AND NASAL LESIONS CAUSED BY A SWINE CHLAMYDIAL ISOLATE IN GNOTOBIOTIC PIGS

Author
item ROGERS, DOUGLAS - UNIV. NE, LINCOLN, NE
item ANDERSEN, ARTHUR
item HUNSAKER, BRECK - UNIV. NE, LINCOLN, NE

Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: The objective of this study was to determine whether a chlamydial isolate recovered from nasal swabs from swine with pneumonia could cause pneumonia and rhinitis in germ-free pigs. The isolate (R33) was grown in tissue culture. An inoculum was prepared and given intranasally and intralaryngeally to 15 3-day old germ-free piglets. All inoculated piglets sdeveloped a moderate to severe pneumonia by day 7 post-infection which lasted through day 21 post-infection. Evidence of the pneumonia was still present at day 35 post-infection. The inoculated piglets also developed a moderate enteritis and rhinitis that lasted through day 21 post-infection. No lesions were seen in the sham inoculated piglets. The results prove that chlamydia can be a primary pathogen in pneumonia in piglets and that it may also cause rhinitis and enteritis.

Technical Abstract: The objective of this study was to determine whether a chlamydial isolate recovered from nasal swabs from swine with pneumonia could cause pneumonia and rhinitis in gnotobiotic pigs. The chlamydiae were instilled into nostrils and lungs of 15 anesthetized 3-day old gnotobiotic piglets. Five age-matched gnotobiotic piglets were anesthetized and sham-infected with uninfected cell culture lysates. Two principal piglets were moribund and 2 principals were severely dyspneic prior to necropsay 7 day post-infection (DPI); whereas, remaining principals showed mild dyspnea upon exertion throughout the study. All principals developed diarrhea. All principals necropsied 7-21 DPI had extensive consolidation in cranial, middle, and accessory lung lobes; a majority had extensive consolidation in the caudal lobes. Principals necropsied 28 and 35 DPI had a lobular pattern of consolidation in all lung lobes. Histologically, lesions in lungs from principals necropsied 7, 14, and 21 DPI were characterized by broncho- interstitial pneumonia with foci of type II pneumocyte hypertrophy and hyperplasia; pneumocytes, bronchial and bronchiolar epithelial cells were markedly vacuolated. Turbinate lesions in all principals were character- ized by mild multifocal lymphoplasmacytic and occasionally neutrophilic rhinitis. Immunohistochemistry detected chlamydial antigen in bronchial and bronchiolar epithelial cells, pneumocytes, and inflammatory cells in principals necropsied 7, 14, and 21 DPI. Positive-staining was limited to alveolar macrophages in principals necropsied 28 and 35 DPI. Chlamydial antigen was detected in turbinate epithelial cells at all necropsy intervals. The results indicated that the chlamydial isolate used in this study is a pathogen in gnotobiotic pigs.