Abstract
Pasteurellosis is an infectious bacterial disease common among agricultural and wild animals, caused by the bacterium Pasteurella multocida. This disease affects the respiratory system and occurs in both clinical and subclinical forms, especially in immunocompromised animals; disease progression is often observed. The spread of pasteurellosis in Kazakhstan remains an important issue for agriculture, and cases of transmission among saigas have also been reported. In this regard, serological methods, particularly the agglutination reaction (AR), are widely used to assess the epizootological status and for early diagnosis of clinical and latent forms of the disease.This article presents the results of serological studies conducted on pasteurellosis. During the study, 157 blood serum samples were analyzed from several farms in the West Kazakhstan region: 127 samples were from cattle (clinical form) and 30 from saiga antelopes (assessed as carriers). The agglutination reaction was performed macroscopically, and the immune status of the animals was assessed based on the degree of agglutination resulting from the interaction between antigen and antibody.The results showed a positive reaction in 18.9% of cattle, of which 41.7% exhibited a strong (+++), 33.3% a moderate (++), and 25.0% a weak (+) degree of agglutination. This indicates that the disease is active and present at different clinical stages. Among saigas, a positive result was registered at 3.3%, indicating the presence of latent carriers. The high sensitivity and accuracy of the agglutination reaction make it a reliable method for serological monitoring.The findings presented in this article allowed us to determine the dynamics of the spread of pasteurellosis and the immune status within animal populations