Coinfection of Swiss cattle with bovine parainfluenza virus 3 and Mycoplasma bovis at acute and chronic stages of bovine respiratory disease complex

• Published in: Journal of veterinary diagnostic investigation Vol. 31; no. 5; pp. 674 - 680
• Main Authors: Mehinagic, Kemal, Pilo, Paola, Vidondo, Beatriz, Stokar-Regenscheit, Nadine
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.09.2019
• Subjects: Acute Disease; Animals; Bovine Respiratory Disease Complex; Bronchopneumonia - veterinary; Cattle; Cattle Diseases - diagnosis; Cattle Diseases - microbiology; Cattle Diseases - virology; Chronic Disease - veterinary; Coinfection; Full Scientific Reports; Mycoplasma bovis; Mycoplasma Infections - veterinary; Parainfluenza Virus 3, Bovine; Respiratory Syncytial Virus Infections - veterinary; Respiratory Syncytial Virus, Bovine; Respirovirus Infections - veterinary; Retrospective Studies; bovine respiratory disease complex; Mycoplasma bovis; bronchopneumonia
• ISSN: 1040-6387; 1943-4936
• DOI: 10.1177/1040638719861686

Viral agents such as bovine respiratory syncytial virus (BRSV) and bovine parainfluenza virus 3 (BPIV-3) are considered primary infectious agents in bovine respiratory disease complex (BRDC). Information regarding the pathogenesis of BRDC is scarce, especially at an advanced chronicity stage, in addition to ongoing coinfection with other primary agents such as Mycoplasma bovis. Based on a retrospective review of histology slides from 104 autopsy cases, we classified cases according to type of pneumonia and chronicity. We performed immunohistochemistry (IHC) for BRSV, BPIV-3, and M. bovis as well as real-time PCR (rtPCR) for M. bovis on lung tissue of all 104 cases and correlated results with the morphologic type of pneumonia. Histomorphologically, 79 cases were classified as bronchopneumonia, 16 as bronchointerstitial pneumonia, and 9 as interstitial pneumonia. In 89 cases, at least 1 of the investigated agents was detected by IHC; 44 of these cases had a coinfection. BPIV-3 was the predominant agent present, as a single infection in 39 cases, and in coinfection with M. bovis in 39 cases. Comparing the detection methods for M. bovis, rtPCR was more specific and sensitive than IHC. The combination of both methods provided a good visual tool for assessing severity and distribution of M. bovis antigen within the tissue. Unlike BRSV, BPIV-3 and M. bovis persisted in chronic BRDC, suggesting ongoing impairment of defense mechanisms in the lung.