Clinical and epidemiological characteristics of a pseudotuberculosis outbreak in Kamchatka territory
Year: 2026
Type: article
Study design: Observational Study
Abstract: BACKGROUND: Pseudotuberculosis remains a relevant public health problem worldwide. It is characterized by uneven territorial distribution, sporadic outbreaks and clusters of cases, predominant involvement of children, and heterogeneity of the pathogen’s molecular and genetic properties, necessitating a clinical and epidemiological analysis to evaluate the regional characteristics of the epidemic process. AIM: To conduct an epidemiological and clinical-laboratory analysis of a cluster of pseudotuberculosis cases in Kamchatka Territory in 2024. METHODS: An outbreak comprising 63 registered cases occurred in Petropavlovsk-Kamchatsky and Elizovo from June 8 to July 13, 2024. A comprehensive examination of hospitalized patients diagnosed with pseudotuberculosis and an epidemiological investigation into the causes of the outbreak were conducted using descriptive and analytical epidemiological methods. RESULTS: A clinical analysis of pseudotuberculosis during the outbreak demonstrated that the typical presentation was characterized by heterogeneity, systemic clinical manifestations, and, less frequently, a relapsing course. Pseudotuberculosis was confirmed bacteriologically (isolation of Yersinia pseudotuberculosis cultures) in 59 patients (93.7%), and by molecular genetics (PCR) in 45 patients (71.4%). Using ELISA and immunoblotting, antibodies to genus specific protein antigens of Yersinia spp. were detected in 33 out of 40 examined patients (82.5%). The epidemic process primarily involved children of two age groups: 0–2 years (14.3%) and 3–17 years (82.5%). The absence of outbreaks in institutional settings (such as childcare facilities and schools) indicates that the infection occurred in household settings. The vehicle of transmission was fruits and vegetables from retail stores, which was confirmed by the isolation of one culture and the detection of Y. pseudotuberculosis DNA fragments (1.72% ± 0.6%). High Norway rat populations (6.7% per 100 trap-days) were documented at wholesale and retail warehouses in Petropavlovsk-Kamchatsky, with no scheduled rodent control measures implemented. A study of the genetic determinants of pathogenicity of the Y. pseudotuberculosis strains assigned them to genogroup G3, subgroup 3a (YPMa+ HPI− YAPI− pYV+ pVM82), which is prevalent in the Russian Far East and is associated with a mild disease course in the majority of patients. CONCLUSION: The high variability of pseudotuberculosis clinical forms and its similarity to numerous other diseases require vigilance among physicians of various specialties to ensure timely diagnosis and targeted antimicrobial therapy. A retrospective analysis of the epidemiological features of this outbreak substantiates the need for improving preventive measures, particularly regarding the prevention of fruit and vegetable contamination.
DOI: 10.17816/eid705054
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W7204174167