BACKGROUND: Corynebacterium pseudotuberculosis biotype ovis is a bacterium that causes caseous lymphadenitis (CLA), a chronic disease of sheep and goats characterized by the formation of suppurative abscesses in superficial and visceral lymph nodes and internal organs of small ruminants. This study was designed to evaluate the reproductive hormonal changes (estrogen and progesterone) and histopathology in the reproductive organs and associated lymph nodes of does challenged with C. pseudotuberculosis biotype ovis and its immunogen; corynomycolic acid. A total of 12 healthy non-pregnant female goats were grouped into three: A, B and C consisting of four does each. Group A was intradermally inoculated with 2 mL of sterile phosphate buffered saline (PBS) pH 7 (negative control group); group B was intradermally inoculated with 2 mL of corynomycolic acid extract (CMAs), while group C was intradermally inoculated with 2 mL of 10⁹ colony-forming unit (cfu) of live C. pseudotuberculosis. Blood samples were also collected at predetermined intervals for estrogen and progesterone hormonal assays. The does were euthanized 90 days post challenge and tissue samples of the uterus, ovaries, fallopian tubes, cervix and associated lymph nodes were collected and fixed in 10% neutral buffered formalin for histopathological processing. The result showed various degrees of histopathological changes (hemorrhage, congestion, degeneration, necrosis, edema, leucocytic infiltrations) in the reproductive organs and associated lymph nodes of both inoculation groups. Increases in estrogen hormone concentration were observed in both inoculation groups in comparison to the control group. However, progesterone concentration was only increased in group C. This study highlighted that corynomycolic acid extract from C. pseudotuberculosis biotype ovis resulted in significant histopathology in the reproductive organs and associated lymph nodes of does and increase estrogen concentration.
Haptoglobin (Hp) and Serum Amyloid A (SAA) are a group of blood proteins whose concentrations in animals can be influenced by infection, inflammation, surgical trauma or stress. Corynebacterium pseudotuberculosis is the causative agent of caseous lymphadenitis (CLA), and Mycolic acid is a virulent factor extracted from C. pseudotuberculosis. There is a dearth of sufficient evidence on the clinical implication of MAs on the responses of Hp and SAA in goats. Therefore, this study was conducted to evaluate the potential effects of Mycolic acid (MAs) and C. pseudotuberculosis on the responses of Hp and SAA in female goats. A total of 12 healthy female goats was divided into three groups; A, B and C each comprising of 4 goats and managed for a period of three months. Group (A) was inoculated with 2 mL of sterile phosphate buffered saline (as a negative control group) intradermally, while group (B) and (C) were inoculated intradermally with 2 ml each of mycolic acid and 1 × 109 cfu of active C. pseudotuberculosis respectively. The result of the study showed that the Hp concentration in goats inoculated with C. pseudotuberculosis was significantly increased up to 7-fold (1.17 ± 0.17 ng/L) while MAs showed a 3-fold increased (0.83 ± 0.01 ng/L) compared with the control. Whereas SAA concentration in C. pseudotuberculosis and MAs groups showed a significant 3-fold (17.85 ± 0.91 pg/mL) and 2-fold (10.97 ± 0.71 pg/mL) increased compared with the control. This study concludes that inoculation of C. pseudotuberculosis and MAs have significant effects on Hp and SAA levels, which indicates that MAs could have a role in the pathogenesis of caseous lymphadenitis.
Caseous lymphadenitis is an infectious disease of almost all animals, particularly small ruminants that are caused by Corynebacterium pseudotuberculosis. The organism causes the formation of suppurative abscesses in superficial and visceral lymph nodes and in visceral organs. This current study was designed to elucidate the clinicopathological responses and PCR detection of the aetiological agent in the vital organs of goats challenged with C. pseudotuberculosis and its immunogenic mycolic acid extract. A total of twelve clinically healthy crossbred Boer female goats were divided into three groups: A, B, and C (four goats per group). Group A was inoculated intradermally with 2 ml of sterile phosphate buffered saline (PBS) pH 7 as a control group. Group B was inoculated intradermally with 2 ml of mycolic acid extract (1 g/ml), while group C was inoculated intradermally with 2 ml of 10⁹ colony-forming unit (cfu) of live C. pseudotuberculosis. The experimental animals were observed for clinical responses for 90 days post-inoculation and the clinical signs were scored according to the severity. The clinical signs observed in this study were temperature, heart rate, respiratory rate, rumen motility, enlargement of lymph nodes, and body condition score. The experimental animals were euthanised and tissue samples from different anatomical regions of the vital organs were collected in 10% buffered formalin, processed, sectioned, and stained with H&E. Results of both C. pseudotuberculosis and mycolic acid treated groups indicated a significant difference (p