The first kit, INgezim PRRS Universal (Ingenasa, Madrid Spain), is prepared on the basis of both and recombinant nucleoproteins. was first isolated in Denmark in 1995; related (vaccine-related) strains were detected in Europe on numerous occasions. Despite wild-type PRRSV2 strains becoming isolated in Germany and Hungary, altered live vaccine Raxatrigine hydrochloride (MLV)-related strains remain a major group of genotype 2 PRRS viruses circulating in Europe [4,5,6,7,8,9]. Co-circulation of Raxatrigine hydrochloride and within one continent and the absence of cross-protection between them have logically resulted Raxatrigine hydrochloride in dual infections at farms. For instance, both and PRRSV2 were found at 24.2% of infected farms in South Korea [10]. In Russia, PRRS is mainly caused by (including the so-called atypical Russian group of viruses) and [9,11,12]. Only limited data are available on epidemiology in Russia. One PRRS outbreak caused by highly pathogenic (is definitely periodically detected on its own or simultaneously Raxatrigine hydrochloride with PRRSV1 by veterinary diagnostic laboratories in Russia. However, due to the comparably low incidence of detection, it is not regarded as and often goes unnoticed. In August 2019, an outbreak of acute respiratory disease was recorded at a swine farm in Kemerovo region, Russia. The outbreak was primarily characterized by dispone, fever, and anorexia. According to the farms veterinary division data, morbidity and mortality (up to 40%) peaked in 7- to 12-week-old piglets. This 1500-sow farrow-to-finish farm was located more than 100 km away from another swine unit. The sow vaccination routine included quarterly immunization having a killed vaccine against (computer virus, and leptospirosis. Piglets received a ((M.hyo). Considering the current outbreak and the long period of time that had approved since the last laboratory investigations were carried out, a decision was made to conduct a cross-sectional monitoring study. The main goal of this investigation was to identify the major causative agent of respiratory outbreak in the farm and partially characterize the genome sequences of the isolated viruses. 2. Materials and Methods 2.1. Samples The blood samples were taken from piglets age groups 0, 3, 7, 12, 16, 20, and 26 weeks (8 to 10 animals per age group). Serum samples were collected on the same day and stored frozen at ?70 C before analysis. 2.2. ELISA All serum samples were tested for the presence of antibodies against capsid protein using two commercial ELISA test packages. The first kit, INgezim PRRS Common (Ingenasa, Madrid Spain), is definitely prepared on the basis of both and recombinant nucleoproteins. This kit detects antibodies against both and designated as pan-antibodies. The second assay, RRSS-SEROTEST (Vetbiochem, Moscow, Russia), is definitely capable of detecting antibodies against only. Both ELISA test kits were used in accordance with the manufacturers instructions. 2.3. PCR and Sequencing (((and sequences might be chosen for classification [8]. We used the following primers for the amplification and sequencing of and HYRC was around 644 and 368 nucleotides, respectively. A one-tube, real-time RT-PCR kit (Alpha Ferment, Moscow, Russia) was used to perform reverse-transcription polymerase chain reaction (RT-PCR). The PCR amplification system consisted of 10 min at 50 C, 5 min at 95 C, 35 cycles at 95 C for 15 s, 55 C for 15 s, and 72 C for 30 s, as well as 1 cycle of 5 min at 72 C. The amplification products were visualized in 1% agarose gel inside a buffer comprising a mixture of Tris foundation, acetic acid and EDTA (x1 TAE) after which purification was performed using Monarch DNA Gel Extraction Kit (New England Biolabs, MA, USA) in accordance with the manufacturers instructions. Sanger sequencing was performed using the Big Dye? Terminator v.3.1 Cycle Sequencing Kit (Applied Biosystems, CA, USA) in accordance with the manufacturers instructions, and the primers specified above. The nucleotide sequences of the genome fragments were identified using an Abdominal3130 genomic automated analyzer (Applied Biosystems, USA). The nucleotide Raxatrigine hydrochloride sequences were analyzed using Lasergene 11.1.0. (DNASTAR, WI, USA). Multiple positioning was performed using Muscle mass (MEGA 7.0.18). Phylogenetic dendrograms were plotted using the maximum likelihood method, GTR model (MEGA 7.0.18). The topology of the trees was confirmed following 1000 bootstrapping replication methods. 3. Results.