Background. The coronavirus pandemic, also known as the COVID-19 pandemic, introduced significant changes in vital activities of the population and spread of airborne infectious diseases, the study of which enables ranking of preventive measures. The objective of our study was to assess the degree of influence of the lockdown and social distancing imposed in the Krasnodar Krai in 2020 due to the pandemic on the incidence of airborne communicable diseases based on the example of varicella. Materials and methods. We conducted a retrospective analysis of a 10-year incidence of varicella in the population of the Tuapse district, Krasnodar Krai using monthly and annual data on the incidence of infectious and parasitic diseases (Form No. 2) in the Tuapse district for 2011–2020 and the “Population Incidence” software, version 5, by applying standard techniques and methods of studying the epidemic process. Results. Stringent restrictive measures taken in the country in 2020 in the context of the COVID-19 pandemic caused a significant decrease (by 741 %) in the incidence of chickenpox among the population of the Tuapse district compared to the long-term average rate. In April – May and July – September 2020, varicella incidence rates were 30.98 and 7.75 per 100 thousand population or 7.4 and 18.8 times lower than the long-term average, respectively. The majority of chickenpox cases in the Tuapse district (as in the country as a whole) were pediatric – 94.02 % (RF – 94.3 %), with children aged 3 to 6 years making up 61 % of the total. Conclusion. The lockdown and social distancing imposed during the COVID-19 pandemic has a significant reducing effect on the incidence of airborne infectious diseases in the population in the absence of effective vaccination.

factors, and inadequate hygiene practices contribute to high incidence of tuberculosis in the world. Effective disease prevention shall be based on scientific substantiation of causality and the mechanisms of its development. Objective: The study aimed to investigate the etiopathogenesis of autoimmune disorders associated with the exposure of warm-blooded animals to heat killed M. tuberculosis. Materials and methods: We determined hematological parameters of old Wistar rats using standard methods and estimated the activity of lactate and succinate dehydrogenases (LDH, SDH) in lymphocytes (mitochondria) using a cytobiochemical method. The clinical and laboratory results were confirmed by X-ray tests. Results: Inflammation induced by administration of heat inactivated M. tuberculosis (complete Freund’s adjuvant (CFA)) reached the maximum during the third week: the number of white blood cells increased from (9.8 to 11.3) × 109/L compared to the control animals, normalizing by the seventh week. By the end of the first week, there was a pronounced immune response manifested by the increased erythrocyte sedimentation rate, which later exceeded the threshold limit by 87–100 %. The autoimmune disease progression was accompanied by impaired cellular respiration (glycolysis and oxidative phosphorylation) by 40 % and 77 %, respectively (p < 0.01). X-ray revealed disorders in the articular apparatus of the exposed animals including signs of rheumatoid arthritis and bone resorption. Conclusion: The mechanism of immunotoxicity of M. tuberculosis is associated with impaired energy supply of immune cells and changes in their morpho-functional properties. Based on our findings, we recommend inclusion of drugs with immunomodulatory, antihypoxic and osteoprotective mechanisms in treatment and prevention regimens for tuberculosis and associated diseases to enhance therapeutic efficacy.

Introduction. The search for methods of correcting pathogenetic disorders related to Mycobacterium tuberculosis, the causative agent of tuberculosis, a highly hazardous communicable and socially significant disease, determines the relevance of the research and its objective to study the role of citric and succinic acids in protective and adaptive processes in warm-blooded animals with connective tissue disorders induced by inactivated mycobacteria. Materials and methods. The study was conducted on male Wistar rats with diseases induced by complete Freund’s adjuvant (a mineral oil emulsion containing heat-killed Mycobacterium tuberculosis). The animals were given a feed-added mixture of organic acids at 17 mg/kg body weight (minimum) and 88 mg/kg body weight (maximum) for 4 weeks. Hematology and bio�chemistry tests were performed using standard methods. The activity of succinate dehydrogenase in blood lymphocytes was determined by the cytobiochemical method. X-rays were obtained using stationary veterinary imaging equipment. Results. The protective effect of carboxylic acids in the exposed animals with Freund’s adjuvant-induced leukocytosis (expressed by a 28 % increase in white blood cells compared to the negative control, p < 0.05), oxidative stress (expressed by an increase in the concentration of malondialdehyde (MDA) by 40 %, p < 0.001, and in inhibition of catalase by 4 %), and subchondral bone sclerosis was characterized by a dose-dependent reduction in immunotoxic manifestations of the disease such as normalization of the number of white blood cells (p < 0.05 compared to model animals); a 27 % reduction in MDA, p < 0.001, a 10 % catalase activation, p < 0.01; succinate dehydrogenase normalization, and a decrease in dystrophic changes in the articular system of animals. Conclusion. The results of hematological, biochemical and radiological tests prove that pathological biochemical and morphological changes related to administration of inactivated M. tuberculosis to warm-blooded animals can be modified by a mixture of citric and succinic acids added to feed, which allows a better understanding of the pathogenesis and an increased therapy effectiveness.