Borreliella burgdorferi sensu lato infection rates in ticks and small mammals in the Northwestern Federal District of Russia

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Introduction

Lyme disease is one of the most widespread natural focal infections in Russia, posing a serious medical and social problem [1, 2]. The disease is characterized by a wide range of clinical manifestations involving multiple organs and systems [3].

The pathogens of Lyme disease—spirochetes of the Borrelia burgdorferi sensu lato complex — circulate in natural biogeocenoses within the “Ixodid ticks–small mammals” system [4]. The main vectors are Ixodes persulcatus and Ixodes ricinus ticks, which are widespread in taiga and mixed forests of the European part of Russia and Siberia [5].

A key element of epidemiological surveillance for Lyme disease is comprehensive monitoring of natural foci, including analysis of tick and reservoir host infection rates, as well as serological monitoring of the population [6].

The northwestern region of Russia is a unique territory characterized by a high level of urbanization alongside the preservation of natural biotopes, which contributes to the sustained existence of natural Lyme disease foci. High population density in certain regions, active use of forest and backyard plots, as well as the lengthening of the tick activity season under conditions of climate change create favorable conditions for an increase in disease incidence [7–9].

According to official statistics obtained from Federal Statistical Survey Form No. 2, “Data on Infectious and Parasitic Diseases,” over a five-year period (2020–2024), 3,037 cases of Lyme disease were registered in the Northwestern Federal District (NWFD), with an average annual incidence rate of 4.37 per 100,000 population (95% CI 2.15–6.60). Between 2020 and 2024, 281,572 visits for medical care related to tick bites were recorded, with an average annual incidence rate of 405.07 per 100,000 population (95% CI 344.11–466.04). However, data on the prevalence of ticks and their hosts with respect to B. burgdorferi s. l. in the North-West Federal District are limited [10–15].

Studying the regional epidemiological manifestations of Lyme disease and the structure of natural foci in the North-West Federal District is crucial for assessing the risk of human infection and optimizing preventive measures against this infection.

The aim of the study is to assess the prevalence of genetic material of Lyme disease pathogens in ticks and the organs of wild and synanthropic small mammals captured in the Northwest Federal District of Russia.

Materials and methods

The study was approved by the local ethics committee of the Saint-Petersburg Pasteur Institute (Protocol No. 88 dated October 3, 2023).

A total of 960 wild ticks and 4,818 Ixodidae ticks, captured in 2020–2025 in the city of St. Petersburg, the Republic of Karelia and the Arkhangelsk, Leningrad, Pskov, and Kaliningrad regions, were tested for the presence of B. burgdorferi s. l. genetic material.

The number and species diversity of the studied ticks and small mammals by region are presented in Table 1. In total, there were more than 80 sampling sites.

 

Table 1. Number and species of ticks and small mammals examined in the regions of the Northwest Federal District

Animal species under study	Region of the Northwest Federal District						Total
	Arkhangelsk region	Leningrad region	Pskov region	Republic of Karelia	St. Petersburg	Kaliningrad region
Wild and synanthropic small mammals
Myodes glareolus	18	70	89	15	262	–	454
Apodemus flavicollis	–	45	60	–	95	–	200
Apodemus agrarius	44	7	21	21	6	–	99
Sorex araneus	–	5	78	–	3	–	86
Apodemus uralensis	–	11	27	–	4	–	42
Microtus oeconomus	6	–	4	–	–	–	10
Microtus arvalis	4	2	16	–	1	–	23
Microtus agrestis	–	–	5	–	–	–	5
Sorex minutus	1	–	2	4	–	–	7
Sorex caecutiens	–	–	–	1	–	–	1
Neomys fodiens	1	–	1	1	1	–	4
Mus musculus	–	–	19	–	–	–	19
Micromys minutus	2	5	2	–	–	–	9
Myodes rutilus	1	–	–	–	–	–	1
Total:	77	145	324	42	372	–	960
Ticks
Ixodes persulcatus	299	1104	204	273	719	–	2599
Ixodes ricinus	–	537	763	1	599	53	1953
Dermacentor reticulatus	–	–	127	–	–	139	266
Total:	299	1641	1094	274	1318	192	4818

 

Ixodid ticks were collected from April to October in 2021–2025 in the North-West Federal District in accordance with MR 3.1.0322-23 using a flannel flag. The collected ticks were placed in individual plastic tubes and transported to the laboratory. Ticks were identified by species and sex using a stereomicroscope according to a standard procedure [16].

Small mammals were captured in accordance with MR 3.1.0211-20 using Hero traps. After species identification, the carcasses were placed in individual muslin bags and transported to the laboratory. The animals were then dissected, and tissue samples were collected from the heart, liver, spleen, and brain.

All samples were examined individually. The samples were homogenized in 400 μL of 0.9% NaCl using a FastPrep-24 mechanical homogenizer (MP Biomedicals). After centrifugation, 100 μL of the supernatant was collected for nucleic acid (NA) extraction. NA extraction was performed using the RIBO-prep reagent kit (Central Research Institute of Epidemiology).

To detect the genetic material of Lyme disease pathogens, real-time polymerase chain reaction was used with commercial reagent kit AmpliSens TBEV, B. burgdorferi s. l., A. phagocytophilum, E. chaffeensis/E. muris — FL (Central Research Institute of Epidemiology, Rospotrebnadzor) on a CFX96 C1000 TouchTM thermocycler (Bio-Rad).

Data analysis was performed using the R (v. 4.5.2) software. To assess differences in proportions, we applied the χ² test with Yates’ correction and Fisher’s exact test. For multivariate analysis of the influence of factors (region, sex) on the probability of infection, binary logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CI). CIs for proportions were calculated using the Wilson method. Statistical significance was set at p <  0.05.

Results

Of the 4,818 ticks examined, genetic markers for B. burgdorferi s. l. were detected in 1,159; the overall infection rate in ticks was 24.06% (95% CI 22.92–25.23). The highest infection rate in ticks was observed in the Republic of Karelia, and the lowest in the Arkhangelsk Region. The results of studies on ticks and small mammals for B. burgdorferi s. l. infection by federal subjects and administrative territories are presented in Table 2.

 

Table 2. Results of a study on the prevalence of B. burgdorferi s. l. in ticks and small mammals by region and administrative unit in the Northwest Federal District

Federal subject of Russia	Administrative territory	Amount of studied ticks	Prevalence of ticks, % (95% CI)	Amount of small mammals examined	Prevalence of small mammals (95% CI)
Arkhangelsk region	Arkhangelsk	70	5.71 (2.24–13.79)	–	–
	Novodvinsk	46	10.87 (4.73–23.04)	–	–
	Severodvinsk	56	21.43 (12.71–33.82)	14	0.00 (0.00–21.53)
	Vinogradovsky District	–	–	21	4.76 (0.85–22.67)
	Onezhsky District	67	8.96 (4.17–18.19)	–	–
	Pinezhsky District	47	0.00 (0.00–7.56)	–	–
	Kholmogorsky District	13	0.00 (0.00–22.81)	42	11.90 (5.19–25.00)
Total:		299	9.03 (6.28–12.82)	77	7.79 (3.62–15.98)
Kaliningrad region	Guryevsky Municipal District	100	4.00 (1.57–9.84)	–	–
	Zelenogradsky Municipal District	92	32.61 (23.89–42.72)	–	–
Total		192	17.71 (12.96–23.73)		–
Leningrad region	Vsevolozhsky District	119	27.73 (20.48–36.37)	17	23.53 (9.56–47.26)
	Vyborgsky District	98	17.35 (11.12–26.04)	32	3.12 (0.55–15.74)
	Gatchinsky District	73	31.51 (22.00–42.86)	–	–
	Kingiseppsky District	97	20.62 (13.76–29.71)	20	40.00 (21.88–61.34)
	Kirovsky District	668	20.81 (17.90–24.05)	46	41.30 (28.29–55.66)
	Lodeynopolsky District	317	27.13 (22.53–32.28)		–
	Lomonosovsky District	111	23.42 (16.52–32.11)	–	–
	Luzhsky District	53	47.17 (34.38–60.34)	–	–
	Priozersky District	99	34.34 (25.73–44.12)	30	13.33 (5.31–29.68)
	Tosnensky District	6	33.33 (9.68–70.00)	–	–
Total:		1641	24.68 (22.65–26.82)	145	24.83 (18.51–32.45)
Pskov region	Bezhanitsky District	_	–	59	10.17 (4.74–20.46)
	Nevelsky District	_	–	15	13.33 (3.74–37.88)
	Novorzhevsky District	_	–	25	12.00 (4.17–29.96)
	Ostrovsky District	41	7.32 (2.52–19.43)	51	0.00 (0.00–7.00)
	Palkinsky District	69	4.35 (1.49–12.02)	–	–
	Pechorsky District	105	15.24 (9.60–23.33)	20	20.00 (8.07–41.60)
	Porkhovsky District	39	17.95 (8.98–32.67)	–	–
	Pskovsky District	47	10.64 (4.63–22.59)	25	4.00 (0.71–19.54)
	Pustoshkinsky District	99	26.26 (18.60–35.70)	39	7.69 (2.65–20.32)
	Pytalovsky District	_	–	16	0.00 (0.00–19.36)
	Sebezhsky District	586	30.89 (27.28–34.74)	64	32.81 (22.57–45.00)
	Strugo-Krasnensky District	108	26.85 (19.39–35.90)	10	0.00 (0.00–27.75)
Total:		1094	24.68 (22.22–27.32)	324	12.35 (9.20–16.38)
Republic of Karelia	Kondopoga District	168	36.31 (29.42–43.81)	42	30.95 (19.07–46.03)
	Petrozavodsk City District	99	49.49 (39.85–59.18)	–	–
	Prionezhsky District	7	14.29 (2.57–51.31)	–	–
Total:		274	40.51 (34.87–46.42)	42	30.95 (19.07–46.03)
St. Petersburg	Kurortny District	1318	23.67 (21.46–26.04)	372	4.57 (2.87–7.20)
Total		4818	24.06 (22.92–25.23)	960	11.67 (9.66–13.90)

 

The highest infection rate was observed in I. persulcatus ticks — 25.82% (24.17–27.53). The infection rates for I. ricinus and D. reticulatus were 23.20% (21.38–25.12) and 13.16% (9.62–17.75), respectively. The differences were statistically significant (χ²; p <  0.001). In a one-way analysis, the infection rate among female ticks (25.81%; 95% CI 24.02–27.68) was significantly higher than among males (23.72%; 95% CI 21.99–25.52; p <  0.001). However, in a logistic regression model accounting for region, the effect of sex ceased to be statistically significant (p = 0.112).

Genetic markers of B. burgdorferi s. l. were detected in 112 of the 960 small mammals examined. The overall infection rate was 11.67% (9.66–13.90). The highest levels of small mammal infections were observed in the Republic of Karelia and the Leningrad Region, and the lowest in the Arkhangelsk Region and the city of St. Petersburg.

Infection rates among different small mammal species varied significantly: M. glareolus—14.76% (11.79–18.32) (n = 454); A. flavicollis — 14.50% (10.29–20.05) (n = 200); S. araneus — 4.04% (1.58–9.93) (n = 99); A. agrarius — 10.47% (5.60–18.71) (n = 86); A. uralensis — 2.38% (0.42–12.32) (n = 42); M. oeconomus — 10.00% (1.79–40.42) (n = 10); N. fodiens — 25.00% (4.56–69.94) (n = 4). Differences in infection rates between species were statistically significant (χ² = 20.17; degrees of freedom (df) = 7; p = 0.005). No infected individuals were detected among rodents of other species.

B. burgdorferi s. l. DNA was detected in all organs examined. It was most frequently found in the heart (n = 95; 84.82% of infected rodents), less frequently in the brain (n = 66; 58.93%), liver (n = 32; 28.57%), and the spleen (n = 24; 21.42%). In 72 (64.29%) of the 112 infected animals, the infection was generalized, affecting two or more organs, a finding that was particularly common in the Leningrad Region and the Republic of Karelia.

Differences in the proportion of infected individuals between regions were statistically significant for both ticks (χ², p <  0.001) and small mammals (χ², p <  0.001). Logistic regression showed that for ticks, the Republic of Karelia was the only region with a statistically significantly increased risk of infection compared to St. Petersburg (OR = 2.18; 95% CI 1.66–2.86; p <  0.001). For small mammals, a significantly increased risk was characteristic of the Republic of Karelia (OR = 9.37; 95% CI 4.42–19.87; p <  0.001), Leningrad (OR = 6.90; 95% CI 3.72–12.78; p <  0.001), and Pskov regions (OR = 2.94; 95% CI 1.58–5.48; p <  0.001).

Analysis at the district level identified local active natural foci. Among ticks, the highest prevalence was recorded in the Petrozavodsk urban district (49.49%; 95% CI 39.85–59.18) and the Luzhsky District of the Leningrad Region (47.17%; 95% CI 34.38–60.34). Among small mammals, the highest rates were observed in the Kirovsky (41.30%; 95% CI 28.29–55.66) and Kingiseppsky (40.00%; 95% CI 13.76–29.71) districts of the Leningrad Region.

Discussion

Our study examined the prevalence of B. burgdorferi s. l. in 3 tick species and 14 small mammal species captured across 6 regions of the Northwest Federal District. Our study demonstrates a complex, nonlinear spatial organization of natural foci. Analysis at the district level (n = 37) did not reveal a statistically significant correlation between the infection rates in ticks and small mammals (r = –0.022; p = 0.895). This indicates that, at the local scale, the intensity of pathogen circulation in vector populations and primary reservoir hosts may be regulated by various ecological factors and be spatially disjointed. Consequently, an assessment of epidemic risk based solely on tick infection rates may lead to an underestimation of the risk in areas where high reservoir potential is concentrated in rodent populations, and vice versa.

The territory of the Northwestern Federal District lies within the shared range of two major Lyme disease vectors — I. persulcatus and I. ricinus [17]. In the Arkhangelsk Region and across most of the Republic of Karelia, I. persulcatus is the absolutely dominant species; in the Kaliningrad Region, D. reticulatus sharply predominated in the species composition (72.39%); in St. Petersburg, a slight predominance of I. persulcatus over I. ricinus was observed. In the Leningrad Region, the distribution of tick species is patchy: in the northwestern districts, I. ricinus was the dominant species, while I. persulcatus was dominant in the rest of the region. In the Pskov Region, I. ricinus (69.74%) predominated over I. persulcatus (18.65%) and D. reticulatus (11.61%) in the tick species composition; however, D. reticulatus was found mainly in the Sebezh District. The data obtained are generally consistent with those of other researchers [12–15, 18–21], with the exception of the Leningrad Region, where the picture differs from previously published results [22].

The highest levels of B. burgdorferi s. l. infection rate were observed in I. persulcatus and I. ricinus, as they play the primary epidemiological role, traditionally being the main vectors of Borrelia in Eurasia. The higher prevalence of I. persulcatus compared to I. ricinus may be due to the fact that I. persulcatus is epidemiologically more active with respect to B. burgdorferi s. l. [1, 23].

Higher B. burgdorferi s .l. infection rates were found in female ticks compared to males. The absence of an independent effect of tick sex in the multivariate model (p = 0.112) after accounting for region suggests that the differences between females and males observed in the univariate analysis may also be mediated by their unequal spatial distribution.

The overall prevalence of B. burgdorferi s. l. infection among ticks in the Northwestern Federal District was 24.06%, which is consistent with data from other studies [24, 25]. The tick infection rates we obtained in the Republic of Karelia (40.51%) and the Kaliningrad Region (17.71%) were slightly higher than previously published rates [8, 12, 21]. In the Pskov region, the frequency of ticks infected with B. burgdorferi s. l. was 24.68%, which is significantly lower than the previously published figure of 34.5% [15]. In St. Petersburg, the Leningrad and Arkhangelsk regions, the obtained in the current study B. burgdorferi s. l. infection rates in ticks generally corresponded to data from other studies [13–15, 26].

Such discrepancies between the obtained data and previously published data may be associated with the spatial and temporal heterogeneity of foci: even within a single region, the frequencies of infected ticks and small mammals may vary significantly between biotopes and across years [27]. Furthermore, climate change, shifts in the ranges of ticks and hosts, and landscape changes can lead to changes in the activity of foci [28].

Small mammals, particularly rodents, play a crucial role in maintaining natural foci of Lyme disease. They serve as the primary food source for the pre-imaginal stages of Ixodid ticks and act as a significant natural reservoir for Borrelia. Rodents are capable of harboring and transmitting the pathogen to new generations of ticks, thereby sustaining a continuous cycle of pathogen circulation within the ecosystem [29].

According to the data obtained, the species M. glareolus (14.76%) and A. flavicollis (14.50%) play a key role as pathogen reservoirs in the Northwest Federal District; these are the most numerous representatives of forest biocenoses that actively interact with ticks [22]. Less significant carriers include A. agrarius (10.47%), S. araneus (4.04%), A. uralensis (2.38%), and M. oeconomus (10.00%). It is noteworthy that a single case of infection was observed in N. fodiens (25%). These data are likely of a random nature and reflect individual rather than population-level infection.

The overall B. burgdorferi s.l. prevalence in small animals in this study was 11.67%, which corresponds to the results of previous European studies, which showed a prevalence of 6–18% [30–32], and to the results of studies conducted in the Northwestern Federal District. For example, in a study conducted in the Leningrad Region, up to 31.9% of M. glareolus individuals and 20.5% of A. uralensis individuals were infected with B. garinii, depending on the season [29].

Our study noted a relatively high incidence (64%) of generalized forms of infection involving multiple organs, particularly in active foci in the Leningrad Region and Karelia. This indicates that the pathogen persists in the host, which significantly increases the likelihood of infection in feeding ticks.

Prevalence rates of small mammals and ticks vary significantly across different regions. The highest proportions of infected rodents and ticks were observed in the Republic of Karelia (30.95% and 40.51%, respectively) and the Leningrad Region (24.83% and 24.68%), which is likely due to regional characteristics: these regions are characterized by extensive forest and marshland habitats, which provide more favorable conditions for the survival of ticks and small mammals and the circulation of B. burgdorferi s. l. In contrast, the Arkhangelsk Region, with its more northern climate and short tick activity season, shows significantly lower rates of Borrelia infection in ticks (9.03%) and small mammals (7.79%).

The analysis conducted allows us to identify three groups of regions based on risk level:

• low — Kaliningrad and Arkhangelsk regions;
• moderate — Leningrad and Pskov regions, Saint Petersburg;
• high — the Republic of Karelia.

The combination of the highest infection rates in tick (40.51%), an extremely high infection risk for rodents (OR = 9.37), and frequent generalized forms of infection suggests the presence of specific conditions in the region that facilitate exceptionally effective circulation of the pathogen. The overall tick infection rate in the Northwestern Federal District (24.06%) and the regional values obtained generally correspond to data from other studies [13–15, 24–26], although notable discrepancies were observed in Karelia, the Kaliningrad, and Pskov regions [8, 12, 15, 21]. These differences, in addition to spatiotemporal heterogeneity and climate change [27, 28], may be a consequence of the dissociation between outbreak components at the local level that we identified.

Conclusion

A comprehensive study of tick infection and the prevalence of B. burgdorferi s. l., based on the analysis of more than 5,700 specimens, has made it possible for the first time to characterize natural foci of Lyme disease in the Northwestern Federal District at such a detailed level and to draw the following key conclusions relevant to epidemiological surveillance:

1. The epidemiological risk has a clear hierarchical structure. The Republic of Karelia is statistically identified as a hyperendemic region requiring special monitoring protocols. The Leningrad and Pskov regions, as well as St. Petersburg, form a zone of comparable moderate risk, within which local super-foci exist.
2. Mandatory two-component monitoring is necessary for an adequate risk assessment. The lack of correlation between tick and rodent infection rates at the local level indicates that assessment based on only one link in the parasitic system may provide a distorted picture.
3. The key role of glareolus and A. flavicollis as primary reservoirs of B. burgdorferi s. l. has been confirmed. The high frequency of systemic infections in individuals of those species in active foci underscores their central importance in maintaining the intense circulation of the pathogen.
4. The data obtained serve as the scientific basis for transitioning from a standardized to a targeted system for managing Lyme disease risk in the Northwestern Federal District.

About the authors

Daria I. Grechishkina

St. Petersburg Pasteur Institute

Author for correspondence.
Email: grechishkina@pasteurorg.ru
ORCID iD: 0000-0001-7295-5736

junior researcher, Laboratory of zooanthroponozes

Russian Federation, St. Petersburg

Regina R. Baimova

St. Petersburg Pasteur Institute

Email: baimova@pasteurorg.ru
ORCID iD: 0000-0002-0145-2653

junior researcher, Laboratory of zooanthroponozes

Russian Federation, St. Petersburg

Islam A. Karmokov

St. Petersburg Pasteur Institute

Email: karmokov@pasteurorg.ru
ORCID iD: 0000-0003-3820-7106

junior researcher, Laboratory of zooanthroponozes

Russian Federation, St. Petersburg

Ekaterina G. Riabiko

St. Petersburg Pasteur Institute

Email: riabiko@pasteurorg.ru
ORCID iD: 0000-0001-8738-3021

м. н. с. лаб. зооантропонозных инфекций

Russian Federation, St. Petersburg

Ivan S. Lyzenko

St. Petersburg Pasteur Institute

Email: lyzenko@pasteurorg.ru
ORCID iD: 0000-0001-8112-7879

junior researcher, Laboratory of zooanthroponozes

Russian Federation, St. Petersburg

Gelena A. Lunina

St. Petersburg Pasteur Institute

Email: lunina@pasteurorg.ru
ORCID iD: 0009-0006-5832-4966

junior researcher, junior researcher, Laboratory of zooanthroponozes

Russian Federation, St. Petersburg

Olga A. Freylikhman

St. Petersburg Pasteur Institute

Email: freilikhman@pasteurorg.ru
ORCID iD: 0000-0002-2850-728X

Cand. Sci. (Biol.), senior researcher, Laboratory of zooanthroponozes

Russian Federation, St. Petersburg

Lyubov A. Bespyatova

Karelian Research Centre of the Russian Academy of Sciences

Email: gamasina@mail.ru
ORCID iD: 0009-0006-4269-1016

Cand. Sci. (Biol.), senior researcher, Laboratory for animal and plant parasitology, Institute of biology

Russian Federation, Petrozavodsk

Sergey V. Bugmyrin

Karelian Research Centre of the Russian Academy of Sciences

Email: sbugmyr@mail.ru
ORCID iD: 0000-0001-5285-6933

Cand. Sci. (Biol.), leading researcher, Laboratory for animal and plant parasitology, Institute of Biology

Russian Federation, Petrozavodsk

Maxim S. Petrov

Center for Hygiene and Epidemiology in the Arkhangelsk Region and the Nenets Autonomous Okrug

Email: petrov_ms@fbuz29.rospotrebnadzor.ru
ORCID iD: 0000-0001-6692-1150

chief medical officer

Russian Federation, Arkhangelsk

Olga A. Voronina

Center for Hygiene and Epidemiology in the Arkhangelsk Region and the Nenets Autonomous Okrug

Email: vorola85@rambler.ru
ORCID iD: 0009-0002-2188-0337

zoologist, Department of natural focal and dangerous infections

Russian Federation, Arkhangelsk

Julia S. Lapikova

Center for Hygiene and Epidemiology in the Arkhangelsk Region and the Nenets Autonomous Okrug

Email: yula-shka@mail.ru
ORCID iD: 0009-0000-1110-4583

zoologist, Department of natural focal and dangerous infections

Russian Federation, Arkhangelsk

Olga N. Neverova

Center for Hygiene and Epidemiology in the Arkhangelsk Region and the Nenets Autonomous Okrug

Email: konstnev@yandex.ru
ORCID iD: 0009-0004-8833-8088

bacteriologist, Laboratory of natural focal, dangerous infections and parasitosis

Russian Federation, Arkhangelsk

Ksenia O. Titarchuk

Center for Hygiene and Epidemiology in the Arkhangelsk Region and the Nenets Autonomous Okrug

Email: k.titarchuk@mail.ru
ORCID iD: 0009-0009-9939-5025

Head, Department of natural focal and dangerous infections, epidemiologist

Russian Federation, Arkhangelsk

Vera V. Agasoi

Pskov State University

Email: agasoi_87@mail.ru
ORCID iD: 0000-0003-3774-6546

Cand. Sci. (Biol.), Associate Professor, Department of general biology and biomedicine

Russian Federation, Pskov

Nikolai E. Kalinin

Center for Hygiene and Epidemiology in the Pskov Region

Email: info@60cgie.ru
ORCID iD: 0009-0003-0351-9457

Сhief doctor

Russian Federation, Pskov

Olga V. Vorobyeva

Center for Hygiene and Epidemiology in the Pskov Region

Email: pskovfgus@yandex.ru
ORCID iD: 0009-0001-5711-3044

zoologist

Russian Federation, Pskov

Olga P. Mikheenko

Center for Hygiene and Epidemiology in the Kaliningrad Region

Email: kdfbuz@cge39.ru
ORCID iD: 0009-0000-3633-908X

Сhief doctor

Russian Federation, Kaliningrad

Tatiana S. Iakimenko

Center for Hygiene and Epidemiology in the Kaliningrad Region

Email: kononenkots94@mail.ru
ORCID iD: 0009-0000-2087-7000

biologist, Epidemiological surveillance support department

Russian Federation, Kaliningrad

Nikolay K. Tokarevich

St. Petersburg Pasteur Institute

Email: zoonoses@mail.ru
ORCID iD: 0000-0001-6433-3486

D. Sci. (Med.), Professor, Head, Laboratory of zoonoses

Russian Federation, St. Petersburg

References

Supplementary files