Evaluation of P22 ELISA for the Detection of Mycobacterium bovis-Specific Antibody in the Oral Fluid of Goats

The ante-mortem diagnosis of tuberculosis (TB) in ruminants is based mainly on the intradermal tuberculin test and the IFN-γ assay. Antibody (Ab)-based tests have emerged as potential tools for the detection of TB infected animals using serum, plasma, or even milk samples. Oral fluids have also been evaluated as alternative samples with which to detect specific Abs against Mycobacterium bovis in pigs or wild boars, but not in ruminants. The objective of this study was, therefore, to evaluate the performance of an in house-ELISA for TB diagnosis (P22 ELISA) in goats as an experimental model for the diagnosis of TB using oral fluid samples. Oral fluid samples from 64 goats from a TB-infected herd (n = 197) and all the animals from a TB-free herd (n = 113) were analyzed using the P22 ELISA. The estimated sensitivity (Se) and specificity (Sp) were 34.4% (95% CI: 22.4–45.6) and 100% (95% CI: 97.4–100), respectively. The optimal cut-off point was set at 100% according to the ROC analysis. Those animals with a higher level of Abs in their oral fluid attained a higher lesion score (p = 0.018). In fact, when taking into account only the setting of the animals with severe lesions (n = 16), the ELISA showed a Se of 75% (95% CI: 53.7–96.2). Results of the present study suggest that the P22 ELISA is highly specific but has a limited value detecting infected animals in oral fluid samples. Nevertheless, its performance is significantly higher in the presence of severe lesions.

Relative Contribution of Each Component of the French Ante-Mortem Surveillance System for Bovine Tuberculosis in Its Overall Sensitivity

The aim of this study was to assess the contribution to the sensitivity of the French ante-mortem surveillance system for bovine tuberculosis in cattle of each of the system’s components (periodic screening, epidemiological investigations, and screening exchanged animals), on a local scale defined by administrative areas. These components were individually assessed in previous studies by scenario tree modeling. We used scenario tree modeling at the herd level and combined the results to evaluate the overall sensitivity of the ante-mortem surveillance system. The probability to detect at least one infected herd was consistent with the location of the outbreaks detected in 2016. In areas with a high apparent incidence, the probability of an infected herd to be detected was satisfactory (for an infected herd there was a 100% probability to be detected over a two-year period). Periodic screening was the most important component for the overall sensitivity in infected areas. In other areas, where periodic screening had stopped, tracing-on epidemiological investigation was the most sensitive component of the system. Screening exchanged animals had a negligible part in the overall sensitivity of the surveillance system.

Vaccination of Sows against Porcine Circovirus Type 2 (PCV2) in a Subclinically Infected Herd Does Not Impact Reproductive Performance

Porcine circovirus type 2 (PCV2) vaccination in piglets has become one of the crucial and indisputable procedures in modern swine production. The role of PCV2 vaccination in breeding animals is less explored. In the present study, the evaluation of the impact of sow vaccination on reproductive parameters was performed in a high health status, PCV2 subclinically infected herd of 3200 sows. The comparison of the number of liveborn, stillborn, and weak born piglets between groups of sows vaccinated on 1 or 28 days after weaning, or nonvaccinated, did not show any statistically significant differences. Although in the tested farm the vaccination of sows appeared to have no effect on reproductive performance, the results should not be generalized. Careful and individualized analysis of diagnostic and production data is crucial in economizing infectious disease control programs in sow herds and pig populations.

Comparison of four serological tests for the diagnosis of swine brucellosis

The purpose of this article is to present results of a research in which the results of four serological tests were compared for the diagnosis of swine brucellosis in pigs from Brazilian herds in which the outbreak occurred in relation to other brucellosis-free. Rose Bengal (RBT), complement fixation (CFT), agglutination plus 2-mercaptoethanol test (TAT+ME), and commercial fluorescence polarization assay (FPA) were used to test 333 sera (271 sows and 62 finishing pigs) from a Brucella suis infected swine herd and 1,100 swine sera from brucellosis free pigs taken at a slaughterhouse. Considering infected all the 271 sows from the outbreak, and interpreting results of the FPA according to the manufacturer directions, sensitivities observed were 95.94% for FPA, 94.83% for RBT, 93.73% for CFT, and 92.25% for TAT+ME. Considering infected all the pigs from the infected herd with a positive result in at least one test, sensitivities observed were 98.92% for RBT, 97.13% for CFT, 96.06% for FPA, and 94.98% for TAT+ME. Specificities of the tests were CFT and TAT+ME, 100%; FPA, 99.55%; and RBT 99.27%. Results indicated a good performance of all the tests, and the agreement among them was almost perfect.

Risk Factors for Zoonotic Tuberculosis at the Wildlife–Livestock–Human Interface in South Africa

A cross-sectional study was conducted to investigate the risk factors associated with zoonotic tuberculosis in humans and its transmission to people living at the wildlife–livestock–human interface. A questionnaire was administered to collect information on food consumption habits, food handling practices, and knowledge of zoonotic TB. Sputum samples were also collected from 150 individuals that belonged to households of cattle farmers with or without a bTB infected herd. In addition, 30 milk samples and 99 nasal swabs were randomly collected from cattle in bTB infected herds for isolation of Mycobacterium bovis (M. bovis). The sputum samples were screened for TB using the GeneXpert test and this was followed by mycobacterial culture and speciation using molecular techniques. No M. bovis was isolated from TB positive sputum samples and only one sample was confirmed as Mycobacterium tuberculosis (M. tuberculosis). M. bovis was isolated from 6.6% (n = 2/30) milk samples and 9% (n = 9/99) of nasal swabs. Ownership of a bTB infected herd and consumption of milk were recognized as highly significant risk factors associated with a history of TB in the household using multiple correspondence analysis (MCA) and logistic regression. The findings from this study have confirmed the potential for zoonotic TB transmission via both unpasteurized milk and aerosol thus, the role of M. bovis in human TB remains a concern for vulnerable communities.

Early cytokine response after vaccination with Coxiella burnetii phase I in an infected herd of dairy cattle

Introduction:Coxiella (C.) burnetii, the aetiological agent of Q fever, is able to modulate the macrophage/T-lymphocyte axis in an infected organism and impair synthesis of monokines and lymphokines.Material and Methods: The purpose of this research was to determine the levels of the cytokines that play a key role in the response to C. burnetii antigens (IL-1β, IL-2, IL-6, IL-10, IFN-γ and TNF-α) in the serum of animals originating from an infected herd prior to vaccination (day 0) and at 1, 7, and 21 days afterwards.Results: The vaccination of animals did not affect the production of IL-6, IL-1β, or IL-2. The serum levels of these cytokines were too low to measure in most of the samples. The initial levels of TNFα, IFNγ, and IL-10 were higher in seropositive than in seronegative animals, although significant differences between seropositive shedders and seropositive nonshedders appeared only in the levels of IFNγ and IL-10. Additionally, the course of the post-vaccination response concerning these two cytokines was different among seronegative nonshedders, seropositive nonshedders, and seropositive shedders.Conclusion: It seems that analysis of the IFNγ and IL-10 concentrations in animal blood serum may have some practical value in an assessment of the health status of seropositive animals and post-vaccination response.

Detection of specific antibodies in cows after injection of PPD

The diagnosis of bovine tuberculosis aims to identify the immune response against mycobacterial antigens. Although Single Intradermal Comparative Cervical Tuberculin test (SICCT) is broadly used for first identification of the disease, the performance of ELISAs has been investigated for diagnosis improvement. The present study expected to find out the influence of intradermal skin tests on the results of ELISAs using the recombinant proteins MPB70 and MPB83 as antigens on cows from a naturally infected herd. Results were analyzed by the F-test, Mann-Whitney and Friedman tests Although comparable to both proteins, results showed that positive animals presented a tendency of augment reactivity to MPB70, representing a tendency for a booster effect, but not to MPB83.