Dynamics and Trends in the Incidence of Rabies in the Russian Federation and some Adjacent Regions of Eurasia in 2013–2021

Abstract

Relevance. Rabies, hydrophobia is an acute viral zoonotic neuroinfection with 100% mortality in the case of clinical signs in humans or animals. The main biological reservoirs and distributors of the rabies pathogen (Lyssa virus, Rhabdo viridae) on the territory of the Russian Federation (RF) are wild predators of the canine family responsible for the circulation of the classic rabies virus (Rabies virus). Also on the territory of the RF and the countries of Eastern Europe, Asia Minor and Central Asia, the circulation of 6 more species of viruses of the genus Lyssavirus, with biological reservation in bat populations, has been established. Despite the existing genetic and environmental differences, all types of lyssaviruses registered in the territory of the RF pose a threat to humans and animals. Due to the growing processes of interpenetration of the anthropogenic environment and wildlife, in recent years, rabies has been increasingly registered in domestic carnivores, which significantly increases epidemiological risks. Aim. A retrospective comparative analysis of data on the incidence of rabies in humans and animals in the RF and on the territory of some regions of Eurasia adjacent to the RF for the period from 2013 to 2021 to characterize the current manifestations of the epidemic (epizootic) process of rabies. Materials and methods. The materials for the study were data from epidemiological surveillance of rabies in the RF and data from veterinary statistics for 2013–2021. Conventional methods and computer programs were used for the analysis: Microsoft Office Excel analysis package, as well as an online statistical calculator. The level of reliability of the data obtained was evaluated using the Pearson consensus criterion χ2, with a reliability level of p = 0.05 and p = 0.01. Results. It is shown that, on average, 2312.33 ± 752.24 cases of rabies in animals were registered on the territory of the RF for the period 2013–2021. With the observed trend towards a gradual decrease in the annual incidence of rabies among animals, the share of dogs and cats in the epizootic process has increased by 7.,4 and 3,8%, respectively,  over the past 2 years. At the same time, an increase in the incidence of rabies in humans by 4,33 times was recorded when comparing indicators with the previous period 2018-2019. Russia in total for 2013-2021 ranks first in the number of officially registered cases of rabies in humans (63%) among the countries of Europe, the Caucasus, Transcaucasia and Central Asia.  The European part of the RF accounts for 41,7–44,3% of cases of rabies among domestic and farm animals and 46,7% among wild animals compared to these regions. The recorded trend towards a decrease in the number of cases of rabies in animals  can be explained by long-term oral vaccination of wild carnivores. But the decrease in the number of natural foci of the disease did not provoke a proportional decrease in the incidence of rabies in domestic animals. As a result, the proportion of dogs and cats in the morbidity structure has significantly increased, which, given their proximity to humans, ensures the maintenance of a high level of epidemiological risk. In the pan-European incidence of rabies, the RF is in second place after the countries of Eastern and Southern Europe. All reported cases of rabies in the RF are caused by the natural circulation of the «classic» rabies virus. In recent years, no lyssaviruses have been detected in bat populations on the territory of the RF, which contrasts with the high incidence of lyssaviruses in other European countries. The RF shares land borders with the countries of Europe, the Caucasus, Transcaucasia and Central Asia, at the same time, the territory of the RF has extensive areas of Eptesicus serotinus and Myotis daubentonii, which are biological reservoirs for EBLV-1, EBLV-2. Based on the above, the risk of the permanent presence of lyssaviruses in bat populations in the territory of the RF is very high and requires monitoring on a regular basis. Conclusion. The analysis of epidemiological and epizootological risks shows the need to adjust the ongoing preventive anti-rabies measures. It is necessary to intensify the campaign of anti-rabies vaccination of domestic carnivores, reduce the number of neglected animals, expand the program for oral vaccination of wild carnivores, monitor the prevalence of lyssaviruses in bat populations in the territory of the RF.