RESUMEN
African swine fever virus (ASFV) is the etiological agent of African swine fever (ASF), a disease with detrimental effects on the health, welfare, and production of domestic and wild pigs. The ASF laboratory confirmation is based on the analysis of blood, serum and organ samples. However, testing these samples could not be always convenient, economically feasible or possible. This study describes the validation process of a PCR-based assay targeting a portion of p72 gene, used for the molecular detection of ASFV, from meat exudate samples obtained from pigs succumbed to ASFV. More specifically, we investigated the capability of a real-time PCR assay to detect ASFV DNA in meat exudates obtained from the diaphragmatic muscle along with the correspondent spleens of 55 ASFV-positive pigs and wild boars sampled from confirmed outbreaks in Romania and from 73 ASFV-negative and regularly slaughtered healthy pigs collected in the Abruzzo region (Italy). The test was able to detect viral DNA in both types of samples, with lower Ct values in spleens (mean=21.11, median=20.61) than meat exudates (mean=23.08, median=22.40). However, distributions of Ct values were strongly correlated each other (R2= 0.83, P<0.001). Considering the distribution of the observed Ct values in the 55 positive meat exudates, a 10-1 dilution would be able to detect 90% of positive samples, whereas a 10-2 dilution would reduce the detectability to 78% of more contaminated samples. As meat exudate could be obtained easily from muscles and considering the potential use of this test on pooled samples, it could represent a tool to aid the investigation of ASV spread.
RESUMEN
The aim was to evaluate the use of a bovine procalcitonin (PCT) ELISA kit (Cusabio, China) for assessing PCT in bovine milk samples. Validation was performed by using 10 plasma and corresponding milk samples from mastitic cows. The limit of detection (LOD) was calculated. The coefficient of variation (CV%) of the readings of five plasma samples measured five times in the same plate (intra-assay) and the CV% of the same five samples read five times in three separate plates was evaluated. Parallelism was determined by serial twofold dilutions of five plasma and corresponding milk samples. Milk samples were analyzed with and without centrifugation. Regarding plasma PCT, the method presented an inter- and intra-CV < 23.7% and parallelism had very good recovery values. The ELISA kit studied can measure bovine plasma PCT concentrations. The kit antibodies fail in binding PCT in milk samples because all centrifuged milk samples showed a lower LOD than blank samples. Only three uncentrifuged milk samples showed measurable PCT concentrations. Due to these results, the commercial ELISA kit investigated could not be employed for the detection of PCT in milk samples.