الفهرس 
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Abstract
Respiratory diseases are commonly encountered in sheep and goats population. Mycoplasma species are considered one of the most common bacterial causes that characterized by cough, fever, loss of appetite, slow growth and reduced milk production.
Diseased sheep and goats exhibited various signs of respiratory disorder as fever (temperature above 40°C) with anorexia, depression and isolated from the flock. All these animals showed bilateral mucopurulent nasal discharges, lacrimation, and mouth breathing in most cases as well as cough with expulsion of nasal discharges after coughing. Through auscultation of lung of diseased sheep and goats exaggerated vesicular sound was found.
The most postmortem findings in samples collected after examination of 400 rams in El basateen abattoir, 104 lungs (26%) showed signs of pneumonia including reddening, consolidation, and localized necrosis in different areas of the lung, fibrinopurulent membrane on the pleural surface and serofibrinous fluid in the thoracic and abdominal cavities.
Histopathological sections were done for 10 samples which were positive for mycoplasma isolation. The Histopathological examination of lung tissue samples from diseased rams showed extensive hemorrhagic pneumonia with eosinophilic exudate and extensive alveolar hemorrhage with infiltration of mononuclear cells also degeneration and deciliation of the surface epithelium of bronchiolar mucosa. Interstitial pneumonia, thickening of interalveolar septa and desquamation of bronchial mucosa in bronchial lumen.
Regarding to the bacteriological examination of cultured samples (104 lung tissues from sheep and 130 nasal swabs from sheep and goats) on PPLO media then microscopic examination of the positive culture plates revealed spherical colonies, with fried-egg appearance in which a dark central zone is usually surrounded by a lighter peripheral zone or finely granular berry-like colonies that penetrate the agar surface.
Out of 104 lung tissue samples collected from diseased sheep, 56 samples (53.8%) were positive on PPLO media. While only 3 samples (30%) out of 10 nasal swabs collected from apparently healthy sheep. In diseased sheep only 8 samples (40%) were positive from 20 nasal swab samples.
In goats, 40 nasal swab samples collected from apparently healthy goats, only 7 samples (17.5%) were positive on PPLO media. While 34 samples (56.66%) were positive on PPLO media from 60 nasal swab samples collected from diseased goats.
The molecular identification of mycoplasma species isolated from sheep and goats was done using common primer used for detection of Mycoplasma species targeting (16S rRNA gene). Also M. ovipneumoniae were detected by using 16S–23S intergenic spacer gene in which the amplified band at (390bp). Moreover, M. arginini were molecularly Identified by a specific primer in which the amplified band detected at expected bp (326bp). Molecular identification of 56 positive cultured samples by PCR revealed that M. ovipneumoniae (5) in lung tissues of sheep, 3 in nasal swabs from goats (1 in apparently healthy sheep, 2 in
diseased sheep and abscent in nasal swabs of goats while M. arginine ( 28) in lung tissues of sheep and 23 in nasal swabs of goats ( 3 from apparently healthy goats & 20 from diseased goats ) .
In studying the Minimum inhibitory concentration of mycoplasma field strain (M.ovipeumoniae) aganist seven different antibacterials (Danofloxacin 25%, Draxxin 10 %, Flurfenicol 30 %, Lincospectin 100/50, Oxytetracycline 5%, Streptomycin 100% and Tylosin 100%).The results revealed that M.ovipneumoniae was sensitive to lincospectin (0.5 ug/ml), and Tylosin (0.5 ug / ml) ).
Finally it can be concluded that:
• The clinical signs and PM lesions described in this work were considered as indicator for mycoplasma infection in sheep and goats.
• Isolation and biochemical tests are the basics for preliminary diagnosis for mycoplasma.
• PCR is a confirmatory method for detection and identification of different mycoplasma species using common and specific primers.
• Tylosin and lincospectin are the most effective antimicrobial agents for treatment of mycoplasmosis in sheep and goats