Anthrax in the Russian Federation in 2023 or in other words, «the same old story»

Abstract

Introduction. The current anthrax situation in Russia is characterized by instability. In 2023, there was an increase in the number of infection outbreaks compared to the long-term average (for five years). The aim of the study is to assess the epizootological and epidemiological situation regarding anthrax in the Russian Federation in 2023 and the reasons for its deterioration, and to analyze data from genomic epidemiological surveillance of this infection. Materials and methods. The information of the territorial bodies of Rospotrebnadzor on the investigation of anthrax outbreaks, reference materials about anthrax stationary hazardous areas and anthrax burials were used. The phylogenetic position of the identified Bacíllus anthracis strains and genomes structure were determined based on whole-genome sequencing data. Results. In 2023 anthrax outbreaks were registered in the Chuvash Republic — Chuvashia (1), the Tyva Republic (1), Tambov (1), Ryazan (1) and Voronezh (3) regions. 14 farm animals and 19 people fell ill. The infection of animals not vaccinated against anthrax, as well as vaccinated long before contact with the source of infection, occurred mainly during grazing in the territories of old (unregistered) anthrax soil foci. Human disease is caused by contact with sick animals during care, forced slaughter, cutting, transportation of carcasses and meat, cooking processing of contaminated meat and offal, and consumption of insufficiently heat-treated liver. 17 patients were diagnosed with a cutaneous form of anthrax, while 2 had an oropharyngeal form combined with a cutaneous form of the disease. In all cases, the genome structure typical of the B. anthracis species has been established. The phylogenetic relationship of B. anthracis isolates with B. anthracis strains previously isolated in Russia is shown. Conclusion. The reason for the trouble in anthrax in 2023 was a number of violations of veterinary and sanitary-epidemiological regulations against the background of the presence of soil foci of infection. Stabilization of the situation can be achieved only in full range of regulated preventive measures are constantly implementated. The results of molecular genetic typing of B. anthracis strains isolated during the epidemiologic investigation of seven anthrax outbreaks in the Russian Federation in 2023 allow us to conclude that they are of local origin and have a genome structure typical of the species. Genetic analysis of the isolated strains demonstrated the effectiveness of the developed wgSNP typing system in the epidemiologic investigation of outbreaks.

Keywords

• anthrax
• soil focus
• outbreak
• bacillus anthracis
• whole genome sequencing