The pseudocowpox virus (PCPV) is recognized for causing exanthematic lesions in cattle and humans. The diagnosis is important because it is a zoonosis and its clinical signs can be confused with ...foot-and-mouth disease, a high-impact bovine disease in livestock. The objective of this work is to validate a SYBR Green qPCR and a conventional PCR for virus detection in bovine samples. Detection limit tests, repeatability, reproducibility, sensitivity, and specificity were compared. When two analysts were compared, results demonstrated that training and pipetting influence the repeatability. The qPCR was more sensitive than conventional PCR but showed nonspecific reactions distinguishable by the melting curve. Both showed high repeatability and reproducibility.
A multiresidue method for the quantification of 13 sulfonamides in animal feed is described. It involves the application of a modified QuEChERS procedure followed by HPLC–MS/MS (high performance ...liquid chromatography coupled to tandem mass spectrometry) analysis. The best conditions for the extraction solution and PSA (primary secondary amine) mass were determined. After optimization, the method was validated according to the European Commission Decision 2002/657/EC. The validation levels employed were 25, 50 and 75 μg kg−1. Acceptable values were obtained for the following parameters: linearity (0.9864 < r2 < 0.9993), decision limit (50.4 μg kg−1 < CCα < 55.8 μg kg−1), detection capability (50.7 μg kg−1<CCβ < 55.8 μg kg−1), limit of quantification (0.9 μg kg−1 < LOQ < 7.1 μg kg−1), accuracy (86.0 < recovery rates < 106.8), precision (3.6 < repeatability < 19.5), (5.5 < intermediate precision < 21.6), measurement uncertainty (MU) (4.1 < MU < 32.6) and selectivity. These findings met the Codex requirements, which allow for the routine use of the method by the laboratories linked to the Ministry of Agriculture, Livestock and Food Supply of Brazil. Finally, the method was applied to real samples and only one of them showed positive for sulfamethazine, however, with a concentration below the LOQ of the method.
