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ABSTRACTBovine leukemia virus (BLV) is an oncogenic retrovirus of the Deltaretrovirusgenus, which causes persistent infection in its natural hosts – cattle, zebu, and water buffalo with diverse clinical manifestations through the defeat of B-cells. The BLV proviral genome, along with structural genes (gag, pro, pol, and env), includes nonstructural ones (R3, G4, tax, rex, AS, pre-miRs(for miRNAs). We have shown in our previous data the association of some pre-miRs-B’(for BLV miRNA) alleles with leukocyte (WBC – white blood cell) number in BLV-infected cows. Multifunctional properties of Tax protein have led us to an assumption that taxgene/Tax protein could have too population variations related to WBC counts. Here we report about several taxalleles/Tax protein variants, which have a highly significant association with an increase or a decrease of WBC number in BLV-infected cows. We have provided evidence that Tax A, H variants (tax b, c, d, f, ealleles) are correlated with reduced WBC counts at the level of BLV-negative groups of animals and thus could be the feature of the aleukemic (AL) form of BLV infection. We suggest this finding could be used in BLV testing for the presence of Tax A, H in the proviral DNA consider such strains of BLV as AL ones, and because of this, minimize the clinical losses due to BLV infection in cattle.

Anaplasma marginaleis an intraerythrocytic tick-borne rickettsial pathogen that causes bovine anaplasmosis, an economically important disease of cattle worldwide. Major surface protein MSP1α has been used as a stable marker in identifying geographical strains of A. marginale. The genetic diversity of A. marginalebased on MSP1α has been reported in several countries all over the world. Only a few molecular surveys of A. marginalestrains have been conducted in Russia. The aim of this study was molecular detection and characterization of A. marginaleisolates in cattle from two regions of Russia. Blood samples from 62 cattle were collected and screened for the presence of A. marginaleby real-time PCR targeting the msp4gene. Anaplasma marginaleDNA was detected in 26 cattle (42%). The partial msp1αgene containing tandem repeat sequences and msp4gene were amplified from msp4-positive samples, cloned and sequenced. Sequence analysis revealed that two msp4genotypes were found. The genetic diversity of A. marginalestrains was analyzed based on the MSP1α tandem repeats structure and 5′-UTR microsatellite. Sixteen new genotypes of A. marginalewere found in 17 animals. Seven animals (41%) were infected by more than one genotype. Eight new tandem repeats are described for the first time. The number of repeats differed between 1 and 6 across the isolates. The msp1αmicrosatellite analysis revealed that six genotypes were identified; one of them was not previously described. Phylogenetic analysis revealed that Russian isolates formed four separate clades. The tandem repeat and microsatellite analyses of the msp1αgene showed a high genetic diversity among the isolates. The present study provided the first evidence of genetic diversity of A. marginalein cattle in Russia.

Theileriae are obligate intracellular protozoan parasites which are transmitted by ixodid ticks and infect both wild and domestic ruminants worldwide. Theileriosis causes significant economic losses to the livestock industry in many countries due to the high morbidity and mortality in cattle herds. In Russia, information concerning prevalence of Theileriaspp. in cattle is very limited. This study reports on molecular characterization and phylogenetic analysis of Theileriaspp. parasites detected in cattle from the Moscow region of Russia. Phylogenetic analysis based on the full length 18S rRNA gene revealed that the Russian Theileriaparasites belong to the Theileria orientalis / Theileria buffeli / Theileria sergentigroup and share a common genotype with T. buffeliMarula from Kenya, T. buffeliisolates from Japan and South Korea, T. orientalisisolate from Australia and T. sergentiisolate from Japan, which belong to the pathogenic Chitose genotype.

Erysipelothrix rhusiopathiaeVR-2 is a commercially available live attenuated vaccine strain widely used in Russia, Kazakhstan, and a number of European countries for immunization of pigs against swine erysipelas. The draft genome sequence of E. rhusiopathiaestrain VR-2 reported in this paper is 1,704,727 bp in length, has CG content of 36.5%, and contains 1680 genes, including 51 tRNA, 3 rRNA, and 1408 protein-coding genes. Comparative sequence analysis between Fujisawa (serovar 1a), VR-2 and six other serovar Nstrains of E. rhusiopathiaerevealed wide genetic variability of the chromosomal region essential for serovar-specific antigenicity and virulence of E. rhusiopathiaestrains. We have performed a BLAST search and found 12 genomic loci potentially specific for the E. rhusiopathiaeVR-2 strain. These data could be helpful for developing genetic assays for differentiation of field isolates and this live attenuated vaccine strain, which is especially important for epizootical monitoring of swine erysipelas in countries, where the live vaccine strain E. rhusiopathiaeVR-2 is used for pig immunization, as well as for the design of recombinant vaccines against swine erysipelas. The genome of E. rhusiopathiaeVR-2 has been submitted in GenBank under accession number RJTK00000000.1.

Bovine anaplasmosis is a tick-borne rickettsial disease, causing significant economic losses in many countries. The main causative agent of bovine anaplasmosis is Anaplasma marginale(Rickettsiales, Anaplasmataceae). To date, several PCR assays for A. marginaleDNA detection were proposed, but most of them do not provide an internal amplification control, which allows to prevent false-negative results and is required for reliability of the results of pathogen DNA detection by PCR assay. In the present study, a real-time PCR assay based on the species-specific and highly conserved fragment of msp1αgene was developed for detection and quantification of A. marginalein bovine blood. The real-time PCR assay is able to detect as few as one copу of msp1αgene per reaction. To prevent false-negative results, simultaneous amplification and detection of the bovine genomic DNA fragment as an endogenous internal amplification control (IAC) was provided. The assay can be used as a highly specific and sensitive method for detection and quantification of A. marginalein infected cattle, and for the evaluation of the efficacy of anti-rickettsial drugs and anaplasmosis vaccines.