Cattle Leukemia Research Articles

Zonal features of the spread of bovine leukemia virus in Dagestan

Relevance. A contagious disease widespread in economic damage among cattle (cattle) is viral leukemia, registered in the Dagestan province since the 60s of the XX century. The region has distinctive features due to the natural and climatic conditions of the area. In this regard, the analysis of the zonal features of the spread of the cattle leukemia virus (VLCRS) remains an urgent task in the further study of the epizootic process and the development of a comprehensive program of health measures.Methods. The object of serological research was livestock, kept on the territory of agricultural formations of all forms of ownership. In order to study the zonal features of the manifestation and persistence of the occurrence of VLCRS infection, a set of data was used, such as the number of identified, rehabilitated and disadvantaged points remaining on the end of the year, the number of seropositive animals in the immune diffusion reaction (AGID), reflected in the reporting documents of the Veterinary Committee of the Dagestan Republic for 2022.Results. The results of monitoring studies determined the difference in the epizootic situation on viral leukemia, due to the zonal classification of rural areas and urban districts of the region. In particular, out of 138 leukemia-affected localities, found during the analyzed period, 134 (97,1%) were officially registered on the plain territory. Of these, 65 are in the mountainous and high-altitude zones, 4 is in the foothills. In the foothill province of Dagestan 4 (2,9%) points were noted. Consequently, the mountainous and high-altitude zones are free from leukemia infection and do not pose an epizootic danger.

Analysis of infection and incidence of leukemia in cattle

This article analyzes the epizootic situation of leukemia of beef and dairy cattle in the farms of the Smolensk region. Laboratory diagnostic blood tests, which revealed infected and sick animals over certain years, played an important role in the study of the epizootic situation.Along with this, we have studied the manifestation of the epizootic process of bovine leukemia in the Smolensk region. All this was later used to carry out effective work on the prevention and control of bovine leukemia.The analysis data given in this article allow us to conclude that the disease of bovine leukemia in the region is gradually decreasing, and from 2017 to 2020 there is a more active decline. The most favorable epizootic situation for leukemia is in breeding and commodity farms for the cultivation of cattle. At the same time, the veterinary service is actively working to eliminate leukemia among cattle belonging to the population. Diagnostic studies on hematology to identify sick animals with leukemia have declined markedly, especially in recent years. This is due to both a decrease in the number of livestock and the elimination of the disease in many farms.The livestock of cattle is annually subjected to routine serological studies, while the discharge of infected animals is still noted. As a result, there is a source of infection in the territory of the region among animals susceptible to it and the epizootic situation for leukemia among cattle remains unfavorable.

Lymphoid or myelomonocytic leukemia in cattle

This datasheet on lymphoid or myelomonocytic leukemia in cattle covers Identity, Hosts/Species Affected, Diagnosis.

ВОЗМОЖНОСТИ ИММУНОПОТЕНЦИОМЕТРИИ В ДИАГНОСТИКЕ ЛЕЙКОЗА КРУПНОГО РОГАТОГО СКОТА

The article describes the results of studies to determine the difference in the electrochemical potentials of the indicator electrode in blood serum samples from healthy and infected with BLV animals before and after the formation of the CEC "in vitro". In the blood serum of healthy cows, potentiometric parameters change after the addition of the BLV antigen by no more than 0.05 units, and in blood serum samples from cows infected with the virus, under the same conditions, by 0.15 or more units. Measurement of the potential of the indicator electrode in the studied blood serum sample before and after the formation of immune complexes can serve as the basis for diagnostic studies in cattle leukemia and other infectious diseases.

Episootic situation of cattle leukemia in the Pavlodar region of the Republic of Kazakhstan

The results of evaluating the effectiveness of health-improving measures against cattle leukemia in the Pavlodar region are presented. In the Pavlodar region in 2018, 7065 heads of cattle were examined for leukemia, 434 reacted positively, the percentage of infection was 4.8. In 2019, 5354 heads were tested for leukemia, 187 responded positively, the percentage of infection was 3.9. In 2020 (6 months), 3394 heads were examined, 139 heads reacted positively, the percentage of infection was 5.4. Despite the health improvement measures carried out in the region, leukemia of cattle is still registered in five out of 13 districts. At the same time, in some regions, the number of animals studied (Lebyazhinsky, Zhelezinsky, Irtyshsky, Uspensky) noticeably decreases, and in some cases, the number of positively reacting animals increases two or more times. So, for example, in Zhelezinsky district, with a decrease in the number of animals studied (from 1672 to 456), the percentage of infection increases from 0.42 to 9.65. Thus, the results of the study showed that the Pavlodar region was and remains an unfavorable region for bovine leukemia. Recreation measures do not give the proper efficiency and the region remains among those who are not safe for leukemia in cattle along with Kostanay (6.6%), North Kazakhstan (4.7%), East Kazakhstan (3.7%), and studies in 2020 showed an increase in the incidence of up to 5.4%.

Analysis of the episootic situation of cattle leukemia in the Siberian Federal District

The analysis of the epizootic situation of cattle leukemia in the Siberian Federal District as a whole and in individual regions of the district is given. The study was carried out in the Republics of Altai, Tuva and Khakassia, in the Altai and Krasnoyarsk Territories and in five regions: Irkutsk, Kemerovo, Novosibirsk, Omsk and Tomsk. The materials of diagnostic studies obtained by veterinary specialists of the Siberian Federal District for 2017-2019 are presented. This information has been analyzed and summarized both for the Siberian Federal District as a whole and for its individual constituent entities. Studies show the spread of bovine leukemia virus infection in the whole district. A tense epizootic situation with cattle leukemia was noted, since the Siberian Federal District ranks second in Russia in terms of the number of adverse locations (322). However, compared to 2017, the number of adverse locations in 2019 decreased by 57, sick animals - by 977 heads, infected animals - by 70836 heads. The number of adverse locations has decreased slightly, while the number of infected animals in some regions has increased. As of January 1, 2020, no hematologically sick animals were found in the Republics of Altai, Khakassia, Buryatia and Tuva, but the number of animals infected with BLV increased. The experience of individual regions of the country that are free from BLV infection (Sverdlovsk, Vologda, Leningrad, Murmansk, Arkhangelsk, Kostroma, Kirov regions, Khanty-Mansi Autonomous District, etc.) shows that bovine leukemia is an infection that can be controlled. It is possible to eliminate the disease in herds of cattle with any level of BLV infection as a result of carrying out complex health-improving measures, as well as organizational and veterinary-sanitary measures with the obligatory removal of sick and BLV infected animals from the herd.

Risk factor for breast cancer development under exposure to bovine leukemia virus in Colombian women: A case-control study.

Viruses have been implicated in cancer development in both humans and animals. The role of viruses in cancer is typically to initiate cellular transformation through cellular DNA damage, although specific mechanisms remain unknown. Silent and long-term viral infections need to be present, in order to initiate cancer disease. In efforts to establish a causative role of viruses, first is needed to demonstrate the strength and consistency of associations in different populations. The aim of this study was to determine the association of bovine leukemia virus (BLV), a causative agent of leukemia in cattle, with breast cancer and its biomarkers used as prognosis of the severity of the disease (Ki67, HER2, hormonal receptors) in Colombian women. An unmatched, observational case–control study was conducted among women undergoing breast surgery between 2016–2018. Malignant samples (n = 75) were considered as cases and benign samples (n = 83) as controls. Nested-liquid PCR, in-situ PCR and immunohistochemistry were used for viral detection in blood and breast tissues. For the risk assessment, only BLV positive samples from breast tissues were included in the analysis. BLV was higher in cases group (61.3%) compared with controls (48.2%), with a statistically significant association between the virus and breast cancer in the unconditional logistic regression (adjusted-OR = 2.450,95%CI:1.088–5.517, p = 0.031). In this study, BLV was found in both blood and breast tissues of participants and an association between breast cancer and the virus was confirmed in Colombia, as an intermediate risk factor.

Objective epizootic situation on cattle leukemia in Dagestan

Based on reliable factual material, the article presents an analysis of the objective epizootic situation on cattle leukemia that developed in 2020 in Dagestan Republic as a whole and in individual rural areas, urban districts and areas of distant pasture farming. The number of unfavorable points, cases of illness and the coefficient of focality are indicated. The level of infection of animals with BLV for the analyzed period was 1,35 %, the incidence rate - 17,43 %. At the same time, the value of the focal incidence indicator was 3,45. BLV infection is registered in most municipal districts and has an uneven distribution. According to epizootological data for the period under review, 11 administrative districts, the cities Dagestanskie Ogni, Derbent, Kizlyar and Bakres, Derbent, Ulankholsk zones of distant-pasture animal husbandry, are safe in terms of BLV infection. In 30 municipalities, the number of animals infected with the leukemia virus ranged from 0,10 to 3,00 %, in other 10 districts - from 3,25 to 7,51 %. At the beginning of 2020, there were 111 leukemia-unfavorable points in the region. During the year, 24 new foci were identified, 19 foci of infection were healed and by the end of the year 116 remained, including 38 - in the public sector, 78 - in the individual. The values on morbidity and ill-being are of an increasing nature. This situation is explained by the introduction of large-scale anti-leukemic measures of serological diagnostics, which made it possible to concentrate the implementation of health-improving measures in farms with the most widespread infection. In this situation, one of the ways to solve the problem is full coverage of diagnostic studies of animals, isolated rearing of young animals, exclusion of joint keeping, grazing and calving of healthy and infected animals, increasing the frequency of serological testing of seronegative animals until two consecutive negative results are obtained.

Forecast of cattle leukemia virus epizootic development in West Kazakhstan region

Bovine leukemia is a chronic viral infectious disease that is widespread in many countries of the world, including the Republic of Kazakhstan. Based on our spectral and combinatorial analysis, this paper presents the results of supposed scenarios of leukemia infection development in the territory of West Kazakhstan region, where there is the alternating change of ups and downs virus level having a direct dependence on solar activity. To solve this problem, we used previously developed computer programs to decompose the dynamics of the cattle infection rate in the West Kazakhstan region for 2006-2016 into a Fourier series, then generate all possible combinations, create a database table with forecast values for several years and select the best numerical series. As a result of this research, it was noted that the computer mathematical model simulating the dynamics of bovine leukemia virus (BLV) carrier, based on the properties of the trigonometric Fourier polynomial, has 100% coincidence with the actual trend. Then in order to identify trends that would maximally reflect the real trend, we conducted a combinatorial analysis of the spectral model which allowed us to increase the number of alternative scenarios for the development of BLV infection for the next five years (2021-2026). According to the above mentioned mathematical model, based on combinatorial analysis, in 2022 the forecast of infectability corridor will average from 4.15 to 11.01%; in 2023 from 3.89 to 9.76%; in 2024 from 8.04 to 16.47%; in 2025 from 6.86 to 15.23% and in 2026 from 3.98 to 8.79%.

Dynamics of blood morphological indicators of Wistar line rats under parenteral BLV infection

Hematological studies of Wistar rats with intraperitoneal infection of their lymphocytes from BLV-infected cows revealed markers characteristic of the leukemic process induced by the pathogen enzootic leukemia in cattle. In 75% of experimental animals, lymphocytic leukemia and neutropenia were detected. The number of lymphocytes in the blood of rats of the experimental group was 17-36 % more than in the control group, leukocytes in average by 30 %. The animals of the experimental group showed signs of erythrocyte aplasia, hemolytic or aplastic anemia. Allergy markers were observed in individual rats. This allows us to recommend an intraperitoneal method of infecting laboratory rats with suspended lymphocytes from infected livestock for rapid and informative reproduction of experimental BLV infection.

Development of approaches to the diagnosis of cattle leukemia in the system of antiepizootic measures in the Belgorod Region

The aim of the research is the use of serological and molecular genetic methods for detecting virus-infected cattle leukemia, as well as determining the significance of PCR in identifying BLV infected calves in the system of antiepizootic health measures. The developed technique for early diagnosis of leukemia in cattle made it possible to accelerate the process of recovery of disadvantaged farms in the Belgorod region by increasing the frequency of studies from 6 months to 2-3 months and an increase in the sensitivity of the agar-gel immunodiffusion test. This, in turn, leads to an increase in the sensitivity of the agar-gel immunodiffusion test and makes it possible to detect, on average, from 8.8% to 20.25% more animals infected with the leukemia virus compared to the standard reaction of the agar-gel immunodiffusion test. The additional use of molecular genetic tests for the detection of proviral DNA of the leukemia virus makes it possible to identify at the early stages of the development of the leukemia process, in calves from 15 days of age, the genomic material of bovine leukemia virus, which will also allow in a shorter time to carry out a qualitative improvement of young cattle in dysfunctional farms.

Analysis of the effectiveness of the use of enzyme-linked immunosorbent assay for the diagnosis of leukemia in cattle during health-improving activities

The aim of the work is to analyze the efficiency of using enzyme-linked immunosorbent assay in the diagnosis of cattle leukemia when carrying out health-improving measures in livestock enterprises that are unfavorable for this disease. Indicators of infection of cattle with leukemia virus on 6 farms of agricultural enterprises of the Tomsk region are presented. For serological diagnostics, the immunodiffusion reaction and enzyme immunoassay were used. It has been established that while carrying out health-improving measures in enterprises unfavorable for leukemia in cattle, the use of enzyme-linked immunosorbent assay for serological diagnosis of the disease enabled to identify a greater number of seropositive animals in comparison with a low-sensitivity immunodiffusion reaction. With a decrease in the herd infection rate to single cases of detection of animals infected with the leukemia virus at the final stages of rehabilitation of the enterprise, the number of additional seropositive animals detected by enzyme immunoassay increases. In the final period of herd recovery, the number of animals with a low level of antibodies to the leukemia virus, inaccessible to detection by immunodiffusion, increases. The use of an expensive and labor-consuming delivery of an enzymelinked immunosorbent assay to detect antibodies to the cattle leukemia virus is advisable at the final stages of an enterprise’s recovery. This enables to identify animals with a low level of antibodies to the leukemia virus, to speed up the negative result of a serological test of the entire herd and to exclude repeated outbreaks of infection of animals with this virus in a rehabilitated enterprise.

Diagnostic Role of Circulating Immune Complexes During Cow Leukemia

In chronic infections caused by retroviruses, antigen antibody immune complexes (AAC) appear in body fluids. In the course of the studies to clarify the structure of the AAC we proved that immune complexes in cattle leukemia could contain the virus's viral DNA. The role of circulating immune complexes in the pathogenesis of the bovine leukemia virus (BLV) infection is not sufficiently studied. AAC containing the viral DNA may be formed during the death of infected B-lymphocytes by linking non-invasive viral DNA to surface IgMs with high DNA affinity. Determining the appearance of AAC with the viral DNA in biological fluids depending on the stages of the infectious process is an important criterion in antileukemia measures. The article describes the results of research to determine circulating immune complexes containing the provirus DNA in the milk of cows infected with BLV as compared with hematological changes at different stages of the infection process. It is reported that the viral DNA in the AAC of the milk of cows infected with BLV is detected much earlier than hematological changes that allow to consider them leukemia patients. Of the 12 cows studied, by the end of the experiment, six cows had AAC containing the viral DNA in their milk samples. And only one cow with the detection of the viral DNA in the AAC of milk showed parallel hematological changes typical for leukemia. The use of milk samples for molecular genetic analysis to identify BLV in AAC is quite a promising area for assessing the epizootic situation on farms and is very informative in determining the animal status.

Pathogenetic aspects of rabbits’ experimental infection caused by bovine leukemia virus

Bovine leukemia virus (BLV) is an infectious disease of cattle, causing high economic losses worldwide, especially in the field of dairy farming. There is no common vision on the problem of interspecies transmission of BLV. Therefore, a detailed study of the etiologic relationship between leukemia in cattle and other animal species is relevant. Various laboratory animal models provide insight into the pathogenesis of viral infections. The article presents the research results of two series rabbits’ intravenous infection with bovine leukemia virus (BLV) using the culture antigen FLK-BLV and the blood of rabbits with clinical, hematological and immunological signs of viral tumor growth. Blood from all animals was taken from the ear vein after 14, 21, 30 days, and then monthly for six months: to study the morphological parameters of blood and to determine the titer of antibodies to BLV. Blood serum for the presence of antibodies to BLV was examined using a diagnostic kit for the indication of animals infected with the leukemia virus in an immunodiffusion reaction produced by LLC “SRE Veterinary Medicine”, Kharkiv. It was found that the stage of the BLV provirus in the blood leukogram of infected animals was characterized by pronounced lymphocytosis on the 21st day of the experiment. The highest concentration of antibodies to BLV in the blood serum was found on the 90th day after the administration of the virus-containing material, which disappeared from the blood on the 150–180th day after infection. In experimental rabbits, after five months for thirty days, in the absence of antibodies to leukemia in the blood serum, multiple tumors of a dense consistency began to develop throughout the body. Such clinical signs and changes in the of rabbits’ blood of the experimental group are characteristic of serologically positive cows on the hematological development stage of leukemic process and correlate with the results of domestic and foreign authors. The presence of a large number of lymphoblasts, as well as leukolysis cells, in the histological preparation of lymph nodes, lungs, heart and the accumulation of lymphocytes’ immature forms around the interlobular vessels of the liver, which were found in pathohistological studies of the experimental rabbits’ organs, may indicate the development of the leukemia process on early stage in them. The results obtained indicate the ability of BLV to overcome successfully the interspecies barrier upon parenteral ingestion of heterologous individuals from infected lymphocytes and in the form of a culture antigen.

BLV early diagnosis - key to successful farm recovery

The aim of the research is to use the early diagnosis of cattle leukemia virus-infected animals using serological and molecular genetic methods, as well as to determine the significance of PCR in detecting BLV infected calves. The studies were carried out in the leukemia laboratory of the department for monitoring and forecasting of infectious diseases of the Ural Federal Agrarian Research Center, at the department of infectious and invasive pathology of the Belgorod State Agrarian University named after V.Ya. Gorin, as well as in 20 livestock agricultural enterprises of the Tyumen, Chelyabinsk, Kurgan, Belgorod regions and the Republic of Bashkortostan. The studies were carried out in the framework of the 160th direction of the FNI Program of State Academies of Sciences for 20132020 on the topic «Development of theoretical foundations for the creation and implementation of a monitoring, diagnostic, treatment and wellness program for the protection of animals from epizootically significant infectious diseases» The system of anti-leukemic health measures using complex serological and hematological testing helps to reduce the number of RID+ animals and hematologically sick individuals for a 6-month period by 32.0% and 6.28%, respectively. The use of the polymerase chain reaction method contributes to the detection of an additional 18 to 39% of calves from 15 days of age, infected with the virus of bovine leukemia, in dysfunctional leukemia livestock enterprises. In a PCR study of cows, 29% to 54% of individuals infected with BLV can be detected. This indicates the need for consistent use of serological studies and the importance of molecular genetic tests for the detection of BLV infected calves.

Study of episootic situation and dynamics of episootic and infectious processes of bovine leukemia infection

One of the problems in dairy cattle breeding has become bovine leukemia since the middle of the 20th century in the Republic of Belarus. Initially, isolated cases of the disease were recorded according to the data of clinical signs and pathological changes in the case of death of animals and the results of veterinary sanitary examination at the section of meat processing plants. After the establishment of the infectious etiology of the disease and the introduction of the immune diffusion reaction into veterinary laboratory practice, the massive nature of its spread was established with corresponding economic losses for the livestock industry. Under the prevailing conditions, it was necessary to reliably study the indicators of the epizootic situation and the trends of the epizootic process affecting the spread of infection with the bovine leukemia virus in order to take effective measures to eliminate it. The authors considered the methodological approaches to the study of the epizootic situation and the dynamics of the epizootic process of bovine leukemia virus infection in the Republic of Belarus formed the basis of the developed monitoring system. It included 132 epizootic significant indicators, divided into 8 groups, reflecting the epizootic situation of bovine leukemia virus infection, taking into account age, sex, production, territorial and other characteristics of infectious and epizootic processes of the disease in the conditions of the Republic of Belarus, established the procedure for collecting and transmitting epizootic information for making management decisions. This made it possible to control the epizootic situation and predict its development, to determine the features and patterns of the epizootic process, to evaluate the results of diagnostic studies, the effectiveness of anti-leukemic measures and their socio-economic significance. The use of epizootic, clinical, pathomorphological, laboratory methods of research with subsequent statistical processing of the data obtained and their analysis in the monitoring system of infection of the cattle leukemia virus in the Republic of Belarus made it possible to control the epizootic situation, predict its development, determine the features and patterns of the epizootic process, evaluate the results of diagnostic research, the effectiveness of anti-leukemic measures and their socio-economic significance.

Genotypes diversity of env gene of Bovine leukemia virus in Western Siberia

BackgroundThis study describes the biodiversity and properties of Bovine leukemia virus in Western Siberia. This paper explores the effect of different genotypes of the env gene of the cattle leukemia virus on hematological parameters of infected animals. The researchers focused on exploring the polymorphism of the env gene and, in doing so, discovered the new genotypes Ia and Ib, which differ from genotype I. Several hypotheses on the origin of the different genotypes in Siberia are discussed.ResultsWe obtained varying length of the restriction fragments for genotypes I. Additionally using restrictase Hae III were received fragments was named genotype Ia, and genotype Ib. There are 2.57 ± 0.55% (20 out of 779) samples of genotype Ib which does not differ significantly from 1% (χ2 = 2.46). Other genotypes were observed in the cattle of Siberia as wild type genotypes (their frequency varied from 17.84 to 32.73%). The maximum viral load was observed in animals with the II and IV viral genotypes (1000–1400 viral particles per 1000 healthy cells), and the minimum viral load was observed animals with genotype Ib (from 700 to 900 viral particles per 1000 healthy cells).ConclusionsThe probability of the direct introduction of genotype II from South America to Siberia is extremely small and it is more likely that the strain originated independently in an autonomous population with its distribution also occurring independently. A new variety of genotype I (Ib) was found, which can be both a neoplasm and a relict strain.

To question of vaccine prevention of bovine leucose

Approaches of scientists from Russia, Ukraine and near and far abroad to the production of anti-leukemia vaccines in chronological order, and their protective properties both in laboratory conditions and in the conditions of an epizootological experiment, possible ways of using these vaccines in animal husbandry in perspective are presented in the review. The development of an effective vaccine against cattle leukemia is one of the complex science-intensive and high-tech promising tasks of veterinary medicine.

Characterization of B1-cells during experimental leukomogenesis.

Bovine leukemia causes a significant polyclonal expansion of CD5+, IgM+ B lymphocytes, known as persistent lymphocytosis (PL), in approximately 30% of infected cattle. However, it is not yet clear what happens to this subpopulation of B cells in the early period of infection of animals. Quantitative characterization of IgM+ and CD5+ B cells during the immune response, which can provide important information on the mechanisms of lymphocyte priming in BLV infection. The experiment used BLV-negative calves of black-motley breed at the age of 8 months (n = 11). Animals (n = 8) were intravenously injected with blood of a BLV-positive cow. Control calves (n = 3) were injected with saline. Studies were performed before and after infection on days 5, 7, 14, 21, 28 and 65 of the immune response. The determination of the number of B-lymphocytes in the blood was carried out by the method of immunoperoxidase staining based on monoclonal antibodies to IgM, CD5. As a result of the studies, it was found that the level of CD5+ B cells increases on the 14th day of the primary immune response, characterized by polyclonal proliferation of CD5+ B cells, which are the primary target for BLV. Our research data confirm that in the lymphocytes of experimentally infected cattle, surface aggregation of IgM and CD5 molecules on B-lymphocytes is absent. It is known that the wave-like nature of IgM synthesis, which was shown in previous studies, depends on a subpopulation of B1 cells. After 7 days of the immune response, IgM+ and CD5+ cells do not correlate, which shows their functional difference. The increase in CD5+ cells is probably not associated with B cells, but with T cells differentiating under the influence of the virus. A subset of B1 cells is the primary target of cattle leukemia virus. The 65th day of the immune response is characterized by the expansion of IgM+ B cells, a decrease in the number of CD5+ cells and a uniform distribution of receptors around the perimeter of the cells.

Single nucleotide polymorphism rs110861313 in the intergenic region of chromosome 23 is associated with the development of leukosis in the Russian Black Pied cattle

In recent years, using a genome-wide association study (GWAS), a number of single nucleotide polymorphisms (SNPs) have been suggested to be associated with susceptibility to leukemia in cattle. However, all studies have been done with purebred Holstein cows and their hybrids. In this regard, it is important to confirm the functional role of polymorphisms previously identified in a GWAS study in Russian cattle breeds. The aim of this study was to verify the association between rs110861313 in the intergenic region of bovine chromosome 23 and leukemia in the Russian Black Pied cattle. Based on the levels of bovine leukemia virus (BLV)-specific antibodies detected in serum using serodiagnostic techniques, animals were divided into three groups: healthy animals (n = 115), asymptomatic virus carriers (n = 145) and animals with leukemia (n = 107). Genotyping of rs110861313 was carried out using polymerase chain reaction followed by analysis of restriction fragment length polymorphisms. A significant decrease in the frequency of the A/A genotype (11.2 %) was revealed in animals with persistent lymphocytosis compared to virus carriers (27.6 %) (p < 0.002). At the same time, the frequency of animals with the C/C genotype in animals with persistent lymphocytosis (41.1 %) was significantly higher than that of virus carriers (21.4 %) (p < 0.001). In this case, asymptomatic virus carriers can be considered a more suitable control than healthy animals that have not been in contact with the virus. According to bioinformatics analysis, resistance to BLV can be due to the presence of the transcription factor FOXM1 binding site in the region of rs110861313. FOXM1 is expressed in immune cells and can potentially affect the expression of the neighboring genes (LY6G5B, GPANK1, ABHD16A, LY6G6F, LY6G6E, CSNK2B, ApoM). Thus, we found that SNP rs110861313 in the intergenic region of bovine chromosome 23 is associated with the development of leukemia following BLV infection in the Russian Black Pied cattle.