A total of 300 cross-bred dairy cattle in Beni-Suef and El-Fayoum Governorates were screened for bovine tuberculosis using single intradermal (SID) cervical tuberculin test. 18 out of 300 (6%) tested cattle were found tuberculin positive. Blood samples from the positive reactors were tested by ELISA. ELISA plates were coated by either bovine purified protein derivative (PPD) or short term culture filtrate (ST-CF) antigens. The test sensitivity was compared at different serum dilutions. At serum dilution of 1/40, all of the 18 tuberculin positive samples, (100%), were ELISA positive using both ST-CF and PPD antigens, but at 1/80 dilution, 13 (72.22%) and 12 (66.66%) samples; at 1/160, 11 (61.11%) and 11 (61.11%) and finally at 1/320, 10 (55.55%) and 9 (50%) were ELISA positive on using ST-CF and PPD as a coating antigens respectively

Objective: To assess the prevalence of Mycobacterium bovis infection in cattle and wild ruminants (WRs) in a wildlife-livestock interface area (WLIA) of the Mexican highland plateau. Animals: 24,400 cattle from 793 herds (including 17,351 commercially slaughtered cattle) and 142 WRs (110 white-tailed deer [Odocoileus virginianus], 20 red deer [Cervus elaphus], and 12 North American elk [Cervus canadensis]) harvested via controlled hunting. Procedures: Cattle were serially tested for M bovis infection via caudal fold tuberculin and comparative cervical tuberculin tests during field surveillance. Carcasses of cattle and WRs were inspected for gross lesions; samples suggestive of tuberculosis were analyzed via histologic evaluation and mycobacterial culture (HMC). A PCR assay to detect Mycobacterium tuberculosis complex organisms was performed to confirm positive results of HMC. Results: WRs had inflammatory lesions in lungs and lymph nodes, although HMC results did not indicate M bovis infection. Eight cattle had positive results for both tuberculin tests, and 31 had positive results for HMC of grossly detected lesions; all were from 7 herds, and ≥ 1 cow in each herd had positive PCR assay results. These 7 herds were depopulated; adjacent herds and herds related via commerce were quarantined. Calculated true prevalence of M bovis infection was 0.86% (95% confidence interval, 0.24% to 1.49%) in cattle; M bovis was not detected in any WRs. Conclusions and Clinical Relevance: M bovis infection was present in cattle. Although transmission to WRs in this WLIA was not detected, diagnosis and prevention activities should be implemented and consolidated to prevent potential M bovis transmission between cattle and WRs.

Objective-To determine whether cats exposed at a residence were infected with Mycobacterium bovis, whether the tuberculin skin test can identify cats infected with M bovis, and whether an ELISA could identify tuberculosis-infected cats. Animals-20 domestic cats exposed to a cat with laboratory-confirmed disseminated M bovis infection. Procedure-Cats were administered a tuberculin skin test and monitored for 72 hours. Blood and fecal samples were collected. Cats were then euthanatized, and postmortem examinations were performed. Tissues were examined grossly and histologically for signs of mycobacteriosis. Pooled tissue samples and fecal samples were submitted for mycobacterial culture. Blood samples were examined for evidence of tuberculosis by use of a comparative ELISA. Results-4 cats had positive responses for the ELISA, and 2 cats had suspicious responses. All tuberculin skin tests yielded negative results. No gross or histologic lesions of tuberculosis were detected in any tissues, and mycobacteria were not isolated from tissues or feces obtained from the 20 cats. Conclusions and Clinical Relevance-All cats that had positive or suspicious responses for the ELISA were offspring of the cat with tuberculosis. Evidence of tuberculosis was not seen in other cats at the residence, the owner, or the attending veterinarian. The most likely source of tuberculosis for the infected cat was through the consumption of M bovis-infected wildlife carcasses or offal. Because M bovis is endemic in wildlife in northeastern Michigan, there is a risk of exposure to tuberculosis in companion animals, their owners, and attending veterinarians.

The trend in the prevalence of bovine tuberculosis (BTB) in Korean dairy cattle was investigated in relation to test programs used between 1961 and 2004, during which a total of 8,961,061 dairy cows were tested and 10,248 confirmed to have BTB. The annual prevalence increased in the late 1960s, then decreased during the 1970s and 1980s, and started to increase again from the late 1990s. It seemed that the prevalence varies according to the different test program used. The prevalence of BTB was higher when the tests were performed with heat-concentrated synthetic medium (HCSM) or purified protein derivative (PPD) tuberculin alone compared to that when using combined HCSM and PPD tuberculin testing.

Systemic administration of dexamethasone led to a significant reduction in the size of the tuberculin reaction in response to intradermal injection of bovine purified protein derivative in 18 cattle experimentally sensitized to Mycobacterium bovis (P < 0.01) and 8 cattle naturally infected with M bovis (P < 0.001). The reaction in 6 of the 7 M bovis-infected cattle that received dexamethasone was classified as negative for the standard interpretation of the single intradermal comparative tuberculin test. Significantly fewer BoCD2+ (P < 0.05) and BoCD4+ T cells (P < 0.001) were present at the reaction site and in blood of dexamethasone-treated cattle, compared with untreated control cattle. Significantly fewer cells expressing the interleukin-2 receptor and WC1+ gamma delta T cells (P < 0.001), and a significantly greater number of cells expressing the ACT2 antigen (P < 0.05) were found at the reaction site in dexamethasone-treated cattle than in controls. The number of BoCD8+ T cells at the reaction site and in blood was not significantly affected by administration of dexamethasone. In vitro production of interferon-gamma by lymphocytes incubated with bovine purified protein derivative also was significantly lower (P < 0.01) in the dexamethasone-treated cattle.