Epizootological Significance of Rice Weevil as a Mycobacterium Bovis Reservoir

Abstract

This article presents materials on the role of the rice weevil (lat. Sitophilus oryzae) in the process of transmission of Mycobacterium of tuberculosis. The relevance of the study is conditioned by the rapid spread of tuberculosis around the world and the need to develop more advanced methods for diagnosing this disease, which, for its part, is impossible without expanding knowledge on all possible reservoirs of the causative agent of infection. Long-term research around the world has proven that insects are carriers of various microflora, including pathogenic ones. Therefore the purpose of study was to establish the epizootological role of the rice weevil as a reservoir for Mycobacterium bovis in the process of occurrence and spread of tuberculosis. The study determined the duration of transfer and isolation of Mycobacterium of tuberculosis in the external environment by infected beetles. The museum dissociative strain of Mycobacterium bovis (118 passage) was used for the study, the subject of the study was rice weevils. For the furtherance of this goal, the culture, microscopic, and statistical studies were conducted, and the viability of mycobacteria was determined after passages through the beetle body by evaluating colony-forming units. The epizootological role of the rice weevil in the development and spread of tuberculosis has been established. It is proved that the beetle can keep mycobacteria in its body for 50 days with a gradual decrease in their number and is then able to secrete the pathogen for another 30 days, contaminating environmental objects. When evaluating colony-forming units of mycobacteria in the dynamics of the experiment, a decrease in their viability after persistence through the body of beetles was revealed from 5.3*108 in 1 g of the original crop up to 1.4*108 in 1 g of crop that grew from beetle homogenisate for 30 days. These study results will allow developing and improving existing measures for the prevention of tuberculosis and prevent the introduction of this infection into safe territory

Keywords

• mycobacteria
• dissociative strain
• infection
• beetles-pests of grain stocks
• colony-forming units