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In ovo pathogenicity of Mycoplasma iners strain Oz
P S Wakenell1, A J DaMassa, R Yamamoto
1Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis 95616, USA.
Abstract:
Embryonating chicken eggs were inoculated with the type strain (PG30) of Mycoplasma iners and with an additional strain of this species designated Oz. Marked gross and histopathologic lesions were observed in the embryos inoculated with strain Oz but not in those infected with strain PG30. Gross lesions were manifested by an enlargement of one or more joints that often contained a caseous exudate, both in the joint space and periarticularly. In the order of frequency, the most common lesions were found in the following joints: tibiotarsal, distal humoral, proximal humoral, femoral, mandibular, tibiofemoral, and phalangial. Similar caseous foci were also seen in the liver and, rarely, in the heart. Histologically, the most prominent lesion found in the joints and viscera was a multifocal caseous necrosis accompanied by the formation of granulomas. Many joints had progression of the inflammatory cells outward from the joint spaces along the periosteal surfaces, and the articular cartilages contained erosions and focal necrosis.
Insights
Mycoplasma iners strain Oz caused significant lesions in chicken embryos, unlike strain PG30. This study highlights Mycoplasma iners pathogenicity differences and associated lesions in avian embryos.
Area of Science:
- Veterinary Pathology
- Microbiology
- Avian Health
Background:
- Mycoplasma iners is a common avian pathogen.
- Pathogenicity can vary between strains of the same species.
Purpose of the Study:
- To compare the pathogenicity of two Mycoplasma iners strains (PG30 and Oz) in embryonating chicken eggs.
- To characterize the gross and histopathologic lesions induced by Mycoplasma iners.
Main Methods:
- Inoculation of embryonating chicken eggs with Mycoplasma iners strains PG30 and Oz.
- Gross examination of embryos for lesions.
- Histopathologic examination of affected tissues.
Main Results:
- Strain Oz induced marked gross and histopathologic lesions, while strain PG30 did not.
- Lesions included joint enlargement with caseous exudate, affecting multiple joints.
- Histopathology revealed multifocal caseous necrosis, granuloma formation, and cartilage erosion in joints and viscera.
Conclusions:
- Mycoplasma iners strain Oz exhibits significant pathogenicity in chicken embryos.
- The observed lesions, including caseous necrosis and granulomas, are characteristic of Mycoplasma iners infection.