Vlad Petrovan

The incursion of African swine fever virus (ASFV) into Eurasia presents a threat to the world’s swine industry. Highly sensitive and specific diagnostic assays are urgently needed for rapid detection during an outbreak, post-outbreak investigation, and disease surveillance. In this study, a highly specific and repeatable blocking ELISA (bELISA) was developed using a recombinant p30 protein as the antigen combined with biotinylated mAb against p30 as the detection antibody. Initial test validation included sera from 810 uninfected animals and 106 animals experimentally inoculated with ASFV or recombinant alphavirus/adenovirus expressing p30. Receiver operating characteristic (ROC) analysis of the data calculated an optimal percentage of inhibition (PI) cutoff value of 45.92%, giving a diagnostic sensitivity of 98.11% and diagnostic specificity of 99.42%. The coefficient of variation of an internal quality control serum was 6.81% for between runs, 6.71% for within run, and 6.14% for within plate. A time course study of infected pigs showed that bELISA was able to detect seroconversion as early as 7 days post-inoculation. Taken together, these results demonstrate that bELISA can be used as an alternative serological test for detecting ASFV infection.

Due to the current pandemic, a global shortage of reagents has drawn interest in developing alternatives to increase the number of coronavirus tests. One such alternative is sample pooling. We compared commercial kits that are used in COVID-19 diagnostics in terms of their sensitivity and feasibility for use in pooling. In this preliminary study, we showed that pooling of up to 80 samples did not affect the efficacy of the kits. Additionally, the RNA-dependent RNA polymerase (RdRp) gene is a more suitable target in pooled samples than the envelope (E) gene. This approach could provide an easy method of screening a large number of samples and help adjust different governmental regulations.

Due to the current pandemic, global shortage of reagents has drawn interest in developing alternatives to increase the number coronavirus tests. One such alternative is sample pooling. Here we compared commercial kits that are used in COVID-19 diagnostics, in terms of sensitivity and feasibility for use in pooling. We showed that pooling of up to 60 samples did not affect the efficiency of the kits. Also, the RNA dependent RNA polymerase (RdRp) is a more suitable target in pooled samples than the Envelope (E) protein. This approach could provide an easy method of screening large number of samples and help adjust different government regulations.

Porcine reproductive and respiratory syndrome (PRRS) is a disease produced by the (PRRS) virus, characterized by endemic evolution in the majority of countries, which remains in actuality being a permanent threat to health and economic free farms, as well as for those infected. The aim of this study was to evaluate the genetic diversity of Romanian PRRSV isolates from the four most important pig farms in Romania by comparing the nucleotide sequences obtained for ORF5 and ORF7 with a wide range of sequences from GenBank belonging to the main types of PRRSV; the type 1. Eighteen different sequences were obtained for ORF5 gene and 10 for ORF7 gene. One Romanian isolate (Rom3) was found in three of the four different investigated farms. The phylogenetic analysis revealed that the Romanian PRRSV nucleotide sequences clustered in three groups within the subtype 1 of the virus. The analysis of amino acid sequences evidenced for GP5 and N-nucleocapsid proteins confirmed that the Romanian virus belonged to type 1.