Brucellosis constitutes an infectious re-emerging zoonosis. Spread of diseases could be exacerbated by stress-induced immunosuppression. This study evaluated relationship between Brucella melitensis infection, shedding dynamics, dexamethasone-induced stress, pathological alterations and resveratrol ameliorative effects in goats. Twelve nonpregnant goats were divided into four groups A, B, C, and D of three animals each. Groups A and B were administered 107 CFU/mL of B. melitensis ocularly, 21 days prior to 7 days consecutive administration of dexamethasone (2 mg/kg). Group A was further administered resveratrol (5 mg/kg) intravenously for 5 consecutive days from day 31 post B. melitensis inoculation. Group C was administered similar dose of B. melitensis while group D was inoculated normal saline. Blood, nasal, ocular, and vaginal swabs were collected at intervals for analysis. The does were sacrificed at day 42 post inoculation (pi). Tissues were collected for tissue bacterial load determination, histopathology, and immunohistochemistry. Dexamethasone administration from day 21 pi increased the frequency in the shedding dynamics, tissue bacterial load, pathological alterations (frequency of microgranuloma and intensity of immunostaining) in group B while 5 days treatment with resveratrol following dexamethasone administration significantly reduced tissue bacterial load, decline in shedding dynamics, and ameliorate damage by dexamethasone administration/B. melitensis infection.
This study investigated dexamethasone-treatment, shedding routes, tissue antigen distribution, and pathology of caprine Brucellosis. Eighteen non-pregnant goats were randomly grouped into A, B, and C. Group A was administered dexamethasone for 7 days at 2 mg/kg before inoculating 0.5 mL B. melitensis at 107 CFU ocularly while group B was inoculated 0.5 mL B. melitensis only, and C as control negative. Blood samples, ocular, nasal, and vaginal swabs were obtained for evaluation. Three goats were sacrificed from each group at days 21 and 42 post-inoculation (pi) and selected tissues collected for PCR, histopathology, and immunohistochemistry. Brucella melitensis was detected in the ocular swabs of group A significantly higher than group B. Shedding was prolonged in group A compared to B. The overall shedding was 22.2% in group A and 9.4% in group B. The uterus of both groups A and B revealed mild inflammation and microgranuloma, extensive necrotic lesions in lymph nodes. Liver showed multifocal necrosis predominantly in group A. Lesion scoring showed significantly higher scores in A compared to B. Strong immunostaining was observed in the liver, lungs, and spleen, predominantly at day 21 pi. This study demonstrated dexamethasone prolonged shedding, tissue antigen distribution, and pathology in dexamethasone-treated goats.