RU2264628C2 - Method for predicting leukosis in cattle - Google Patents

Abstract

FIELD: veterinary science.

SUBSTANCE: one should detect positively reacting animals in RIA to conduct additional serological RIA testing, moreover, repeated serological testing in sero-negative animals should be carried out after provocation of immune response due to three-fold injection of inactivated vaccine against cattle leucosis at the dosage of 2 ml at 14-d-long interval and at obtaining positive result in RIA one should diagnose an animal to be infected one. The innovation accelerates detection of animals being virus-carriers, shortens leucosis-recovery period in farms and enables to decrease financial expenditures for recovery.

EFFECT: higher accuracy of diagnostics.

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Description

The invention relates to veterinary medicine, in particular to veterinary virology and immunology, and can be used in the diagnosis of cattle leukemia virus-infected animals.

A known method for the diagnosis of cattle, including the selection of animal blood, the preparation of a blood sample for photometric analysis. Blood hemolysate is used as a sample, and the absorption coefficient is recorded at a wavelength of 422 nm. With a value of more than 2, the animal is considered healthy, otherwise leukemia is diagnosed (see RF patent No. 2144189, according to class G 01 N 33/53, 2000).

This method is labor intensive and has expensive equipment.

The closest in technical essence to the proposed solution is a method for identifying patients with cattle leukemia, in which animals positively reacting to RID are detected. Additionally, a serum sample is prepared by dilution. and when a positive result is obtained in the RID, when it is bred in a titer of 1: 8 and above, the animal is recognized as a patient with cattle leukemia (see RF patent No. 2200955, class G 01 N 33/53, 2003).

The disadvantage of this method is the inability to identify animal virus carriers, the titer of VLCC - specific antibodies which are not sufficient for their identification in RID. Such animals remain in the herd of convalescence and serve as a potentially dangerous source of infection.

Known inactivated vaccine against cattle leukemia, made in the leukemia laboratory VIZV them. Ya.R. Kovalenko. Obtaining a vaccine includes the cultivation of virus-containing leukocytes of peripheral blood of cattle suffering from hematologic leukemia, inactivation and production of antigen (see RF patent No. 2202367, class MKI A 61 K 39/12, 2003).

The task of the invention is the identification of animal virus carriers at an earlier stage of the disease, namely in the incubation period.

The problem is solved by the proposed method for the diagnosis of leukemia in cattle, including serological examination of blood serum in the reaction of immune diffusion. Additionally, a serological blood test of seronegative animals is carried out after provoking their immune response by administering three times the inactivated vaccine against cattle leukemia in a dose of 2 ml with an interval of 14 days. Animals having a positive RID result after provocation are recognized as infected with cattle leukemia virus.

New in the proposed method is that a re-study in RID of seronegative animals is carried out after provoking their immune response by three times the introduction of an inactivated vaccine against leukemia in cattle at a dose of 2 ml with an interval of 14 days, upon receipt of a positive response in RID, the animal is recognized as an infected virus leukemia of cattle.

The proposed method for identifying VLCCR-infected but previously seronegative animals is based on the principle of a secondary immune response, in which the isolation of VLCK-specific drug causes an acceleration of antibody formation. This makes it possible to identify animal virus carriers in RID.

An example implementation of the method.

First, in a herd of herds being healed, a serological examination is carried out in the RID of the livestock of cattle older than 5 months. Seropositive animals are eliminated (slaughter, fattening, separation before calving, etc.).

Next, seronegative animals are subjected to three times the introduction of the above inactivated tissue vaccine against leukemia in cattle. The introduction is carried out subcutaneously in the middle third of the neck at a dose of 2 ml with an interval between administrations of 14 days.

7 days after the third injection of the vaccine, all animals subjected to vaccination are examined in the RID. Newly isolated animals having a positive result in RID after provocation of immunity are recognized as seropositive, i.e. VLKRS infected.

This method of early diagnosis of hidden virus carriers was tested on a livestock of more than 400 animals in 4 leukemia-poor farms in the Vologda Oblast (cows, heifers and heifers older than 5 months).

As shown by the results of serological studies, this method of serological diagnosis, including provocation of the immune response, allows on average to identify an additional 3.57% of virus carriers among seronegative cows and heifers and 6.12% among seronegative heifers over five months of age.

The proposed method accelerates the identification and removal of animal virus carriers from the herd, reduces the recovery period from leukemia and the material costs of organizing organizational and technical measures, is available to practical veterinarians, serologists of regional and regional laboratories.

Claims (1)

A method for the diagnosis of cattle leukemia, including the identification of animals that respond positively to RID and the conduct of additional serological tests in RID, characterized in that a repeated serological examination of seronegative animals is carried out after provoking an immune response by administering a 2-ml dose of 2 ml of inactivated bovine leukemia vaccine. with an interval of 14 days and when a positive result is obtained in the RID, the animal is diagnosed as infected.