Related Experiment Videos
Mycoplasmas and bovine respiratory disease: studies related to pathogenicity and the immune response--a selective
Abstract:
Three species of mycoplasma have been established as being of importance as causes of pneumonia in housed calves, based on pathogenicity studies and frequency of association with the disease. These three species are Mycoplasma bovis, M. dispar, and Ureaplasma diversum. M. bovis is the most pathogenic of these species but the disease outbreaks with which it is associated are sporadic. M. dispar is regularly isolated from pneumonic calves but is also found causing mild superficial and asymptomatic infections of the respiratory mucosa. The bovine ureaplasmas are serologically complex. They are distinct from ureaplasmas isolated from other non-ruminants by PAGE analysis, G + C content of DNA, and serology. A second species within the genus ureaplasma has been proposed to accommodate the bovine ureaplasmas, U. diversum. Control of mycoplasma respiratory infections of cattle based on immunization might be possible. Calves have been immunized against M. bovis and immunity has been related to antibody in the lung. M. dispar appears less immunogenic in calves than M. bovis and this may contribute to its pathogenicity.
Insights
Three Mycoplasma species, including Mycoplasma bovis, Mycoplasma dispar, and Ureaplasma diversum, are key causes of calf pneumonia. Mycoplasma bovis is most pathogenic, while Mycoplasma dispar is common but less immunogenic.
Area of Science:
- Veterinary Microbiology
- Bovine Respiratory Diseases
Background:
- Mycoplasma species are significant pathogens causing pneumonia in housed calves.
- Three species, Mycoplasma bovis, Mycoplasma dispar, and Ureaplasma diversum, are identified as primary causative agents.
Purpose of the Study:
- To establish the importance of specific mycoplasma species in calf pneumonia.
- To differentiate the pathogenicity and immunological characteristics of Mycoplasma bovis, Mycoplasma dispar, and Ureaplasma diversum.
Main Methods:
- Pathogenicity studies in calves.
- Frequency of isolation from diseased animals.
- Serological analysis, PAGE, and DNA G+C content for ureaplasma characterization.
Main Results:
- Mycoplasma bovis identified as the most pathogenic, though outbreaks are sporadic.
- Mycoplasma dispar frequently isolated from pneumonic calves, also causing asymptomatic infections.
- Bovine ureaplasmas, proposed as Ureaplasma diversum, are serologically distinct from other ureaplasmas.
Conclusions:
- Mycoplasma bovis, Mycoplasma dispar, and Ureaplasma diversum are critical Mycoplasma pathogens in calf pneumonia.
- Immunization against Mycoplasma bovis shows promise, with immunity linked to lung antibodies.
- Lower immunogenicity of Mycoplasma dispar may contribute to its pathogenicity in calves.