Tkachenko Semen
Candidate of Veterinary Sciences, Acting Head of the Sector for the Study of Bacterial Diseases of Poultry
semen270181@gmail.com,

Rula Oleksandr
Candidate of Veterinary Sciences, Acting Head of the Department of Poultry Diseases
aleksrula75@gmail.com,
Maxim Tymoshenko
director
Music Denis
Doctor of Science, Senior Researcher
dmuzyka77@gmail.com
National Scientific Center "Institute of Experimental and Clinical
of Veterinary Medicine" NAAS, Kharkiv
Fire Group LLC, Kyiv

One of the main links in the system of preventing the occurrence and spread of Newcastle disease is monitoring and prevention. At the same time, an important stage in the system of veterinary and sanitary measures is the disinfection of veterinary control facilities. A number of disinfectants have been developed and proposed for practical use. Large-scale production and implementation of disinfectants in practice is not possible without prior laboratory assessment of their virucidal properties.

The aim of our work was to study the virucidal properties of the new aldehyde disinfectant "DesⱯ Ultra" on a test model of the Newcastle disease virus (NDV).

The NH virus has been stored in the museum of the laboratory for the study of poultry diseases since 1972, deposited in the National Center "IEKVM" under number 7-02, when cultivated on chicken embryos (CE) it causes the accumulation of hemagglutinins in titers of 1:1024 - 1:2028. Infectious activity of the virus
is 11.36 EID/0.2 cm3.

   The study was conducted using two methods. – suspension and contact-suspension.

Suspension method. The principle of the method is the ability of a disinfectant in certain dilutions to neutralize the infectious properties of the virus in a certain volume.

A virus dilution (10-1, with the addition of antibiotics) was prepared in phosphate-saline buffer, then the disinfectant under study was added to the obtained virus dilution at a final concentration of 0.5; 1; 2 and 3 % and further sequential dilutions were made to 10-3. Before use on KE, the mixture of virus and drug was kept for 20 min. Infection and KE dissection were carried out according to generally accepted requirements. Ovoscopy was performed daily twice a day.

The selected extraembryonic fluid (EEF) was tested for the presence of hemagglutinating virus in the hemagglutination reaction (HAR) with 1 % suspension of rooster erythrocytes. The HAR was performed in V-shaped plates according to the generally accepted method.

A total of two consecutive passages were performed on developing KE. For the second passage, native KE EER from the first passage with antibiotic was used. Infection of KE was performed as described above.

Analysis of the results obtained shows that the drug "DezV Ultra" starting from the working concentration of 1% and above with an exposure of 30 min has virucidal properties. Incomplete disinfection and virus replication occurs when using drug concentrations from 0.0005% (maximum dilution of the disinfectant) to 0.5%. In control samples without disinfectant, hemagglutination in the EER of KE was present.

Contact-suspension method. The principle of the method is the ability of a disinfectant on the surfaces of test objects to neutralize the infectious properties of the virus with a biological load (a mixture of bovine serum and virus).

After receiving positive results from previous studies, the final determination of the virucidal action of the drug "DezV Ultra" against the NX virus was carried out using test objects, namely: plates made of unpainted wood, metal and tiles (size 100x100mm). A mixture of the virus and bovine serum diluted in PBS 1:2 was applied to the test objects. After 10-15 min after the applied mixture dried, the drug was sprayed in final concentrations of 0.5, 1, 2 and 3 %. After 30, 60, 90 and 120 min, a sterile applicator was used to wash it off, transfer it to a bottle with a solution of antibiotics on PBS and after contact (20 min) infection with KE was carried out as indicated above.

Thus, as a result of the conducted studies, it was established that the disinfectant "DesⱯ Ultra" in concentrations of 0.5; 0.1; 2.0 and 3.0 % with an exposure of 30 minutes already disinfects test objects that were contaminated with the NH virus. On control test objects without the addition of disinfectant, hemagglutination in the EER of KE was present throughout the entire study period (up to 120 min).