EVALUATION OF M. AGALACTIAE EXPERIMENTAL INFECTION ON THE GENITAL TRACT AND MAMMARY GLAND OF GOATS USING THE HISTOPATHOLOGICAL EXAMINATION AND ULTRASONOGRAPHY

To assess the pathogenicity of Mycoplasma agalactiae on the genital tract and mammary gland of goats, experimental intravaginal and intramammary inoculation of the organism into the anterior vagina of 3 non-pregnant does and via the intra mammary route of 2 of them. One animal was kept as control. Clinical signs and ultrasonography findings were recorded. Pathological changes in the genital tract, udder tissue and the internal organs were recorded after sacrification of the inoculated goats. Cultural examination of the vaginal swabs, tissue specimens and milk samples for re-isolation of the inoculated Mycoplasma species was carried out. Also, evaluation of the serological response of the infected goats using the indirect haemagglutination (IHA) test at various stages of the experiment was done. Moreover, indirect immunofluorescent antibody technique (IFAT) to detect the causative agent in the fresh tissues of vagina, udder, spleen and supramammary lymph nodes was applied. Milk films from the intramammary inoculated does were microscopically examined. Congestion and development of edema in the vulvar mucosa of the infected does with moderate vaginal mucous discharge that changed to mucopurulent exudate were observed. Varying degrees of mastitis were developed in the inoculated udder halves. M.agalactiae was reisolated from the vaginal discharge and milk samples of the inoculated glands, 2-3 days PI. After slaughter, the organism was also re-isolated from the tissues of vagina, cervix, uterus, lungs and spleen as well as from the inoculated udder tissues and their corresponding supramammary lymph nodes. Moreover, the inoculated species was detected in udder parenchyma, supramammary lymph nodes and in the vaginal mucosa of infected animals using IFAT. Ultrasonogram showed thickening in the vaginal and cervical walls with
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Assiut Vet. Med. J. Vol. 51 No. 104 January 2005
increase in their diameters. Non-echoic cervical and vaginal secretions with opened cervical canal was also observed. Microscopically, all the inoculated goats developed vulvitis, vaginitis, cervicitis, endometritis as well as salpingitis which increased in severity with increasing period after infection. The tissues of the inoculated udder halves revealed diffuse chronic mastitis characterized by moderate to severe infiltration of the interstitial tissue with lymphocytes and few plasma cells. Lymphoid follicles and extensive interlobular and periacinar fibrosis replaced many of the secretory acini of the inoculated udder. Also, hyperplasia of lymphoid tissues of the supramammary lymph nodes and the spleens was evident. Microscopic examination of milk films of the intramammary inoculated goats showed numerous polymorphnuclear leucocytes compared to the control