Temperature evaluation of a hyper-rapid plasma jet by the method of high-speed video recording

In this paper the procedure of comparative evaluation of plasma temperature using high-speed video filming of fast processes is presented. It has been established that the maximum plasma temperature reaches the value exceeding 30 000 K for the hypervelocity electric-discharge plasma, generated by a coaxial magnetoplasma accelerator with the use of the 'Image J' software

Infectious bursal disease virus: identification of the novel genetic group and reassortant viruses

The results of the phylogenic analysis of the nucleotide sequence of the IBDV A and B genome segments have been presented. Traditionally the IBDV isolates are classified based on the phylogenic analysis of the hypervariable region of the VP2 gene. The analysis of the VP2 gene segments of the isolates detected in the Russian Federation demonstrated that most of them belong to the genetic group comprising highly virulent IBDV isolates. However, not all isolates belonging to one genetic group have the same phenotypic characteristics. This is related to the fact that the virulence is determined not only based on the characteristics of the VP2 gene (A segment) but on the characteristics of the VP1 gene (B segment) as well. The IBDV genome segmentation allows formation of reassortant viruses which can be identified as a result of the genome segment analysis. The phylogenic analysis of the nucleotide sequences of VP2 and VP1 genes of 28 IBDV isolates detected at RF, Ukrainian and Kazakh poultry establishments in 2007 and 2019 showed that 15 of them are reassortant viruses. Different combinations of the genome segments have been identified among these reassortant viruses. Detection of different combinations of IBDV genome segments is indicative of the fact that the heterogeneous virus population circulates on the poultry farms. Pathogenicity studies of the three IBDV isolates showed that the most virulent was an isolate having two genome segments characteristic of the highly virulent virus. Two reassortant viruses having only one genome segment A or B, characteristic of the infectious bursal disease, demonstrated less pronounced virulent properties

GENETIC CHARACTERIZATION OF AVIAN INFECTIOUS BRONCHITIS VIRUS ISOLATES RECOVERED IN CIS COUNTRIES IN 2015–2017

Avian infectious bronchitis virus is a cause of major economic losses in poultry industry. However, control of the virus is very complicated due to its high variability. The mutation frequency in the hypervariable region of the S1 gene of the virus isolated from the vaccinated birds annually amounts to 1.5%. Long-term observations of the circulation of IBV isolates detected in a number of poultry farms demonstrated that the virus genetic lineages circulating on the poultry farms could eventually change. This stipulates the need for the continuous monitoring of the virus isolates for the prevention schedule optimization. The paper demonstrates test results of 840 biological samples collected from chickens on the poultry farms in Russia and some CIS countries in 2015–2017. From 311 positive samples 147 IBV isolates were recovered, the majority of which belonged to eight genetic lines of GI genotype: GI-1, GI-12, GI-13, GI-14, GI-16, GI-19, GI-22, GI-23. Moreover, recombinant isolates were detected as well as variant isolates that belonged to none of the known genotypes

Heterogeneity of avian infectious bronchitis virus population

Avian infectious bronchitis is one of the most common viral infections causing enormous economic losses in the global poultry industry. Due to the lack of mechanisms to correct errors during genome replication, the virus can quickly mutate and generate new strains. This is facilitated by widespread use of live vaccines, simultaneous circulation of field viruses belonging to different serotypes in one flock and rapid spread of the virus. Previous studies of avian infectious bronchitis virus strains and isolates identified in the Russian Federation poultry farms showed that 50% of samples tested positive for the 4-91, D274, H-120, Ma5 vaccine strains, and the other half of samples tested positive for the field viruses belonging to eight GI genetic lineages, while the G1-19 (QX) lineage was dominant. The paper presents identification and genotyping results of the avian infectious bronchitis virus in one of the poultry farms in the Saratov Oblast (the Russian Federation) in 2018–2019. The samples of internal organs and blood, as well as oropharyngeal and cloacal swabs were taken from chicks and layers of different ages in the parent and replacement flocks. The vaccine strain, GI-19 field isolates and variant isolates that do not belong to any of the known genetic lineages were detected. Analysis of test results within a two-year period showed that it is important to study samples taken from birds of different ages. The virus undergoes modification and adaptation inducing new genetic forms by infecting several poultry generations, due to which the heterogeneity of the virus population is ob­served not only in the poultry farm as a whole or in a separate department, but also within one organism. The identified isolates showed tropism for the tissues of intestine, reproductive organs, and, in rare cases, trachea and lungs. The data obtained indicate that, despite the vaccination used, a genetically diverse population of the infectious bronchitis virus circulates in the poultry farm, while the infection may not manifest itself at an early age, but may affect the flock productivity in the future due to pathological changes in the reproductive organs of laying chickens