•Detecting M. bovis antibodies in cattle sera after a tuberculin skin test (TST) may improve bovine tuberculosis control.•Used as an anamnestic test, the ELISA reported herein had high levels of ...specificity and positive predictive value.•The ELISA fulfilled the World Organization for Animal Health criteria.•This serological ELISA used 15–17 days after a negative TST could be used on dairy farms to improve livestock health.
Programs for the eradication of bovine tuberculosis (bTB) focus on the tuberculin skin test (TST) and slaughter of reactor cattle. However, the disease remains an animal health concern in several countries and improving the efficiency of the TST has become a critical issue. The detection of Mycobacterium bovis antibodies in serum, within weeks after the TST, may be a rapid and inexpensive way to improve bTB control. This study reports the validation of an enzyme-linked immunosorbent assay (ELISA) to detect bovine tuberculosis as an ancillary test to TST in dairy farms in Argentina.
The estimated validation parameters were within the established requirements of the World Organization for Animal Health (OIE). The test demonstrated high repeatability, with coefficients of variation <25%. High test reproducibility through interlaboratory testing was also found, with an estimated Pearson coefficient of 0.9648 (95% confidence intervals 0.9315–0.9820). The ELISA detected tuberculous cattle unidentified by the TST. Of 43 animals sent to slaughterhouses that were ELISA positive 15–17 days after a negative TST, 36 were confirmed as infected with M. bovis by histopathology and IS6110 PCR. According to ROC curve analysis of results of 145 cattle from M. bovis-free herds and the 36 M. bovis-infected cattle, at a corrected optical density cut-off point of 0.3853, specificity was 95.95% and the positive predictive value at this cut-off was 83.72%. The ELISA detection test validated in this study could be readily applied in dairy farms, to complement a prior TST and improve livestock health.
The chemical coupling of a protoplasmatic antigen from Mycobacterium avium subsp. paratubeculosis onto core-shell carboxylated particles was investigated with the aim of producing latex-protein ...complexes to be used in immunoagglutination assays capable of detecting bovine paratuberculosis disease. For this purpose, sensitizations were carried out using both colored and not colored carboxylated latexes as well as the protoplasmatic antigen at pH close to its isoelectric point to favor the antigenic protein to approach the particle surface. In all cases, higher fractions of proteins were chemically-bound to carboxyl groups on the surface of the particles. The assessment of the performance of the visual immunoagglutination assays consisted of evaluating 111 sera from healthy and infected bovines with Mycobacterium avium subsp. paratuberculosis. Complexes obtained from the colored latex allowed an acceptable visual discrimination between the studied positive and negative sera. Most of the positive samples showed strong to very strong agglutination and only a few samples reacted weakly, i.e. a sensitivity of 70%. The specificity of the assay, on the other hand, was 86%. Therefore, this rapid detection technique allows an easy and inexpensive identification of animals possibly infected with paratuberculosis “in situ” in the herds.
Display omitted
•A visual immunoagglutination assay for the diagnosis of bovine paratuberculosis was developed.•The reagent is based on colored latex particles and a commercial paratuberculosis protoplasmic antigen.•The agglutination can be read after 5 min “in situ” in the herds and it is easy to implement.•The agglutination test may be a rapid and inexpensive diagnostic strategy to control PTB.
Mycobacterium avium sp. avium (MAA), M. avium sp. hominissuis (MAH), and M. avium sp. paratuberculosis (MAP) are the main members of the M. avium complex (MAC) causing diseases in several hosts. The ...aim of this study was to describe the genetic diversity of MAC isolated from different hosts. Twenty-six MAH and 61 MAP isolates were recovered from humans and cattle, respectively. GenoType CM® and IS1311-PCR were used to identify Mycobacterium species. The IS901-PCR was used to differentiate between MAH and MAA, while IS900-PCR was used to identify MAP. Genotyping was performed using a mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) scheme (loci: 292, X3, 25, 47, 3, 7, 10, 32) and patterns (INMV) were assigned according to the MAC-INMV database (http://mac-inmv.tours.inra.fr/). Twenty-two (22/26, 84·6%) MAH isolates were genotyped and 16 were grouped into the following, INMV 92, INMV 121, INMV 97, INMV 103, INMV 50, and INMV 40. The loci X3 and 25 showed the largest diversity (D: 0·5844), and the global discriminatory index (Hunter and Gaston discriminatory index, HGDI) was 0·9300. MAP (100%) isolates were grouped into INMV 1, INMV 2, INMV 11, INMV 8, and INMV 5. The HGDI was 0·6984 and loci 292 and 7 had the largest D (0·6980 and 0·5050). MAH presented a higher D when compared with MAP. The MIRU-VNTR was a useful tool to describe the genetic diversity of both MAH and MAP as well as to identify six new MAH patterns that were conveniently reported to the MAC-INMV database. It was also demonstrated that, in the geographical region studied, human MAC cases were produced by MAH as there was no MAA found among the human clinical samples.
We here identified for the first time the presence of Mycobacterium avium paratuberculosis (MAP) sheep (S) strain in Argentina. IS900 polymerase chain reaction (PCR) was positive. The S strain was ...compared with MAP cattle (C) strains by using IS1311 PCR-restriction endonuclease analysis (PCR-REA), multiplex PCR and restriction fragment length polymorphism (RFLP) analysis.
Bovine leukaemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). In Argentina, where a program to eradicate EBL has been introduced, sensitive and reliable diagnosis has ...attained high priority. Although the importance of the agar gel immunodiffusion test remains unchanged for routine work, an additional diagnostic technique is necessary to confirm cases of sera with equivocal results or of calves carrying maternal antibodies.Utilizing a nested shuttle polymerase chain reaction, the proviral DNA was detected from cows experimentally infected with as little as 5 ml of whole blood from BLV seropositive cows that were nonetheless normal in haematological terms. It proved to be a very sensitive technique, since it rapidly revealed the presence of the provirus, frequently at 2 weeks postinoculation and using a two-round procedure of nested PCR taking only 3 hours. Additionally, the primers used flanked a portion of the viral genome often employed to differentiate BLV type applying BamHI digestion. It is concluded that this method might offer a highly promising diagnostic tool for BLV infection.
A new manufacturing process and a new family of composite materials (bronze matrix + friction modifiers) for lubricated tribological systems, such as synchronizer rings in manual gear boxes, has been ...developed. The research has provided a better understanding of lubricating oil film formation and how to stabilize it by a suitable surface chemistry and morphology, as well as the ability to produce such a surface by means of non flat powder-metallurgical (P/M) composite coatings.
Commonly used synchronizers are of two types: forged brass and sintered steel with molybdenum coating. Brass synchronizers work very well when new but degrade with use. Molybdenum coatings are produced by a high cost plasma spraying. The new bronze based friction materials have reached the performance level of molybdenum coating in tribometer measurements. The tribological behaviour of the Mo and bronze ring types was characterized in lubricated conditions (temperature: - 10°C to 120°C). XPS and SEM/EDX analysis allowed to verify tribochemical reactions taking place during the working process.
Kniest syndrome and anesthesia Martín Felius, G; Mohamed Mabrouk, M; Traveria Casanova, F J ...
Revista española de anestesiología y reanimación,
1985 May-Jun, Letnik:
32, Številka:
3
Journal Article
PDF
