Mycoplasma bovis and viral agents associated with the development of bovine respiratory disease in adult dairy cows

Abstract

The etiology and pathologic findings of bovine respiratory disease (BRD) in adult dairy cows (n = 35) from a commercial dairy herd in Southern Brazil were investigated. Pulmonary samples were examined for histopathologic patterns and specific features within these patterns, while immunohistochemical (IHC) assays were designed to

The pulmonary virome, bacteriological and histopathological findings in bovine respiratory disease from western Canada

“…We found that M. bovis infection was associated with the detection of higher numbers of viruses ( p = .002). Further, bronchiolitis obliterans, which is regarded as a chronic lesion, was associated with M. bovis infection, consistent with results of a recent study using immunohistochemistry (IHC) to analyse association of histological features with infectious agents in dairy cows (Oliveira et al, ). It is possible that chronic M. bovis infection can compromise host immunity and lead to infection with multiple viruses, or alternatively, multiple viral infections could predispose cattle to M. bovis infection.…”

“…Advances in BRD epidemiology, pathogen genomics and proteomics, characterization of the respiratory tract microbiome and the development of experimental challenge models (Fulton, ) have led to an evolution of our understanding of the relationship of pneumonic lesions with infectious pathogens originally reported in the 1970s (Jensen et al, , ). Most recently, application of advanced technologies for virus identification has resulted in further insight into the relationships between well‐recognized pathogens and BRD (Booker et al, ; Mehinagic et al, ; Oliveira et al, ). Previously, we detected 21 viruses in bovine nasal swabs and tracheal washes from western Canadian beef cattle, among which IDV, BRBV, BRSV and BCV were significantly associated with BRD (Zhang et al, ).…”

Microbial diversity involved in the etiology of a bovine respiratory disease outbreak in a dairy calf rearing unit

“…BPI-3, BoHV-1, and M. haemolytica were not detected in BALF samples these calves evaluated. In Brazilian cattle herds, BPI-3 was detected in few studies, isolated in a single animal in south of the country [38] and another study using immunohistochemical it was detected in four animals [39], but in the most BRD studies was not found [3,18,22,36]. Possibly, BPI-3 circulates with low frequency in Brazilian cattle herds.…”

“…Diagnostic techniques used in previous investigations of mixed infections in BRD cases in Brazil usually include pathological examination, serology, bacterial cultures and/or virus isolation [21,23,38,40]. However, these techniques may be appropriate for one agent but not for the other due to different sensitivity values [44].…”

“…In Brazil, BRD reports are limited to specific pathogens and do not completely describe the etiology of the disease. Most of the Brazilian studies are conducted in postmortem examinations of calves, limiting the knowledge regarding possible simultaneous infections by several etiological agents [21][22][23]. Frequently, treatment with antibiotics and supportive therapy is performed, and the etiological agents involved are rarely identified [13,24,25].…”