Epizootological monitoring and basic principles of measures for the prevention and control of leukemia in cattle

O.V. Dovgal, R.V. Tyrsin, P.I. Shulga, Y.M. Tyrsina, S.A. Bilyk, B.M. Yarchuk

A large number of both domestic and foreign scientists turned to the issue of study of leukemias and other hemoblastomas of humans and animals, which is predetermined by the significant social and economic role of this problem.

Leukemia of cattle (hemoblastosis) is called infectious slow-moving disease of tumor nature, which is characterized by lymphocytosis and malignant growth of hematopoietic and lymphoid cells in various organs and tissues of the body. The causative agent of leukemia of cattle (LUC) is a virus of the family Retroviridae.

Leukemia of bovine cattle is diagnosed with the use of a number of research methods, in particular clinical, hematological, serological, pathologic-anatomical and histological methods [10-18].

Earlier, most often in the diagnosis of CK leukemia, they turned to clinical, hematological, pathologic-anatomical methods, as well as a necessary condition for obligatory histological confirmation. The advent of the viral etiology of the disease contributed to the development of modern diagnostic methods, which in most cases are based on the study of serum samples to detect virus-specific antibodies that help detect infected animals on any (which is the most important sign) stage of the disease, while not there was no change in blood, but the animal at this stage is a potential source of infection.

The basis of modern approaches to the principles of prevention and control of leukemia of cattle is the isolation and removal of the source of the pathogen of infection from the general herd, as well as the method of isolated growth of young animals for the subsequent replacement of infected livestock.

With the help of the system of epizootic monitoring, it is possible to broaden the views of the epizootic process in the lymphatic drainage of a very thin skin, as well as to reveal many questions of the methodology and organization of antiepileptic seizures, to take decisions, etc.

In 1996, the use of mass serological (RID) studies on leukemia of cattle in farms in the area.

In the next period of time there is an increase in the number of farms in which the population is covered by mass serological studies, which makes it possible to establish a real epizootic situation with regard to leukemia.

At delivery RID + a livestock for slaughter there is a decrease in livestock, which is studied by serological method.

For the farms of the district on the issue of organizational measures to combat leukemia in cattle, 2005 became a turning point. Within the 11 farms where the sick animals were crossed, a complete or partial division of the herd, RID + animals was isolated in separate sections or sent to separate rooms (groups). With the help of serological diagnostics of leukemia, it became possible to study the epizootic state of leukemia within the farms of the Bila Tserkva district, and, at the isolation of RID-positive animals, with their subsequent slaughter, as one of the principal factors in the system of health measures, to conduct a full healing of farms.

At the present stage, 12,772 heads of cattle are kept within the farms of the Bila Tserkva district. All these farms are considered to be well-off for leukemia in cattle. Within the private sector, the stock of cattle is significantly different and smaller: 2015 – 2772, in 2016 – 2524, in 2017 – 2369 heads.

Unfortunately, the registration of new cases of the presence of leukemia in cattle in the private sector is constantly underway. According to our research, cattle leukemia was detected in different settlements during the last period of time.

Data on the allocation of RID-positive livestock in private sector farms confirm the stationary nature of leukemia in cattle as one of its epizootic features. In the last 3 years, the diagnosis of leukemia has been carried out in 21 settlements, which is evidence of a wide geographical outbreak of the spread of the disease. During this period, 78 RID-positive animals were allocated. The epizootic situation was characterized by different tensions: the fluctuation of the incident index of the number of sick animals from 1 to 24 was recorded. The village of Shkarivka has the largest number of diseased animals for the analyzed period – 24 animals (30.8% of the total number being 78), in vil. Sidorsy- 10 registered (12.8%), in vil. Matyushi – 7 (9%), in vil. Droces – 5 (6.4%) respectively.

The remaining settlements are characterized by a small number of registered animals, patients with leukemia (1 to 4).

Timely diagnosis and implementation of measures to isolate patients and suspects in animal diseases are the most important conditions for the prevention and control of leukemia in cattle.

Despite the different epizootic situation in the case of bovine leukosis within the private sector of the Bila Tserkva district, it is worth emphasizing its relative stability over the last three years, which is the result of an effective system of control measures.

In the course of measures to improve the number of animals in the private sector, the basic provisions of the current instruction "Guidelines for the prevention and rehabilitation of bovine leukosis from leukemia" are taken into account and the efforts of veterinary medicine specialists are being implemented. Through ongoing work to explain the provisions of this manual, animal owners can reach their understanding of the risk of leukemia for other animals and humans. Considering the high competence of veterinary medicine experts and understanding with the owners, most of the animals that were infected were slaughtered.

Conclusions The complexity of the epizootic situation with regard to leukemia is due to insufficient compliance with the requirements of the current "Guidelines for the prevention and improvement of bovine leukosis from the leukemia", and the plan for organizing economic and special measures for the elimination of leukemia of cattle. In the last 3 years, leukemia has been diagnosed in 21 settlements, which is evidence of a wide geographical distribution of the disease. The epizootic situation is characterized by different tensities, the fluctuation of the incident index of the number of sick animals from 1 to 24 is recorded. The number of RID-positive cows, in general, correlates with the total number of antibody carriers.

Such a character of the dynamics of the epizootic process is due to incomplete removal from the herds of the source of the pathogen of infection.

Key words: Leukemia of cattle, epizootic process, infected with bovine leukosis virus (VLVRH) animals, hematologic diseased animals.