Mycoplasma bovis pneumonia in cattle.
ABSTRACT Mycoplasma bovis is an important and emerging cause of respiratory disease and arthritis in feedlot cattle and young dairy and veal calves, and has a variety of other disease manifestations in cattle. M. bovis is certainly capable of causing acute respiratory disease in cattle, yet the attributable fraction has been difficult to estimate. In contrast, M. bovis is more accepted as a cause of chronic bronchopneumonia with caseous and perhaps coagulative necrosis, characterized by persistent infection that seems poorly responsive to many antibiotics. An understanding of the disease has been recently advanced by comparisons of natural and experimentally induced disease, development of molecular diagnostic tools, and understanding some aspects of virulence, yet uncertainties regarding protective immunity, the importance of genotypic diversity, mechanisms of virulence, and the role of co-pathogens have restricted our understanding of pathogenesis and our ability to effectively control the disease. This review critically considers the relationship between M. bovis infection and the various manifestations of the bovine respiratory disease complex, and addresses the pathogenesis, clinical and pathologic sequelae, laboratory diagnosis and control of disease resulting from M. bovis infection in the bovine respiratory tract.
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ABSTRACT: Blood samples from 32 groups of calves (n = 700) were taken on arrival and after 28-35 days at the feedlot. Eleven groups were housed in feedlots in Ontario, and 21 groups in feedlots in Alberta. Serum antibody titers to bovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV), parainfluenza virus type 3 (PIV-3), infectious bovine rhinotracheitis virus (IBRV), Mycoplasma dispar and M. bovis, plus data on bovine corona virus (BCV) from a previous study were investigated for their association with the risk of bovine respiratory disease (BRD), and with 28-day weight change, both before and after controlling for titers to Pasteurella haemolytica and Haemophilus somnus. Exposure to IBRV and M. bovis was infrequent, and although exposure to PIV-3 was more common, none of these agents had important associations with BRD. Higher titers to BVDV, BRSV, and BCV on arrival were associated with reduced risks of BRD and increased weight gains. However, there was some variation in these relationships and higher arrival titers to BVDV and BRSV in a subset of the calves were associated with increased risks of BRD. Titer increases to BVDV were associated with a higher risk of BRD and lower weight gains. Titer increases to BRSV were not usually associated with the occurrence of BRD, but titer increases to BRSV in a subset of calves that were vaccinated against BRSV, on arrival, were associated with an elevated risk of BRD. Of all the agents studied, BVDV had the most consistent associations with elevated risk of BRD and lower weight gains. Higher BRSV arrival titers were related to lower risk of BRD and higher weight gains; in some instances titer increases to BRSV were associated with higher BRD risk. Higher titers to BCV on arrival were related to reduced risks of BRD. Practical ways of adequately preventing the negative effects of these agents are still needed.The Canadian veterinary journal. La revue veterinaire canadienne 09/1999; 40(8):560-7, 570. · 0.77 Impact Factor
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ABSTRACT: A real-time polymerase chain reaction (PCR) assay using hybridization probes on a LightCycler platform was developed for detection of Mycoplasma bovis from individual bovine mastitis milk and pneumonic lung tissues. The detection limit was 550 colony forming units (cfu)/ml of milk and 650 cfu/25 mg of lung tissue. A panel of bovine Mycoplasma and of other bovine-origin bacteria were tested; only M. bovis strains were positive, with a melting peak of 66.6 degrees C. Mycoplasma agalactiae PG2 was also positive and could be distinguished because it had a melting peak of 63.1 degrees C. In validation testing of clinical samples, the relative sensitivity and specificity were 100% and 99.3% for individual milks and 96.6% and 100% for the lung tissue. Using M. bovis real-time PCR, the M. bovis culture-positive milk samples were estimated to contain between 5 x 10(4) and 7.7 x 10(8) cfu/ml and the M. bovis culture-positive lungs between 1 x 10(3) and 1 x 10(9) cfu/25 mg. Isolation, confirmed with the real-time PCR and colony fluorescent antibody test, showed that at the herd level, the proportion of samples positive for M. bovis isolation in mastitis milk samples submitted to the Mastitis Laboratory, Animal Health Laboratory, University of Guelph, Ontario, Canada, was 2.4% (5/201). We conclude that this probe-based real-time PCR assay is a sensitive, specific, and rapid method to identify M. bovis infection in bovine milk and pneumonic lungs.Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 12/2005; 17(6):537-45. · 1.18 Impact Factor
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ABSTRACT: Mycoplasma bovoculi and Mycoplasma bovis were both isolated from conjunctival swabs taken from young calves showing symptoms consistent with infectious bovine keratoconjunctivitis (pinkeye). No Moraxella spp. or other nonmycoplasma bacteria were isolated in association with this severe clinical outbreak. Based on laboratory tests and clinical observations, the first phase of the disease was likely pneumonic in nature, possibly caused by bovine respiratory syncytial virus and M. bovis. In the subsequent phase of the disease course, infection with both M. bovoculi and M. bovis resulted in ocular disease. A combination of microbiological, serological, and molecular diagnosticmethods was used to elucidate the etiology of the outbreak.Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc 12/2004; 16(6):579-81. · 1.18 Impact Factor