Natural Foci Research Articles

Results of Epizootiological Monitoring of Natural Foci for Bacterial Vector-Borne Infections in Caucasian Mineral Waters Region of the Stavropol Territory in 2018–2020

The aim of the study was to assess the epizootiological situation on bacterial vector-borne infections in Caucasian Mineral Waters area of the Stavropol Territory over the period of 2018–2020.Materials and methods. 3494 specimens of ticks (473 pools), 257 specimens of small mammals, 9 regurgitates of birds of prey and mammals, 7 excreta samples of small mammals, and 2 water samples were tested. Laboratory research of the field material was carried out using molecular-genetic, serological, biological methods. Statistical analysis of laboratory results was conducted using Microsoft Excel 2010. The data were mapped using QGIS 2.18 software.Results and discussion. The study revealed that the 44.8 % of collected ticks were positive for tick-borne borreliosis, 21.5 % – for tick-borne rickettsiosis, 10.3% – for human granulocytic anaplasmosis, 2.7 % – for Q fever, 0.84 % – for tularemia. There has been an increase in the percentage of positives for tick-borne borreliosis agent samples (more than three times) and a decrease in this indicator for human granulocytic anaplasmosis (1.5 times) as compared with 2010–2012. Investigation of tick infection with the agents of Q fever and tick-borne rickettsioses has not been previously conducted in the region. During the period under review, 19 pools of ticks had mixed infection, which indicates that there are combined foci of bacterial natural-focal infections with vector-borne transmission in the recreation zone of the Stavropol Territory. This necessitates preventive measures and systematical epizootiological surveys in the Caucasian Mineral Waters region.

Epizootic situation of bird ornithosis in the territory of the Russian Federation from 2018 to 2020

Relevance. Chlamydia (ornithosis) (Chlamydiosis) is a bacterial disease, which is a zooanthroponosis, with pronounced natural foci. Chlamydia (ornithosis) is widespread in the world among animals and birds; they are recorded on all continents. The key study is Chlamydia psittaci. Infections caused by this pathogen cause a group of endocarditis, myocarditis, arthritis, keratoconjunctivitis and encephalitis, pneumonia in people. C. psittaci causes recombination most often, which increases the likelihood of a possible role of recombination in the adaptation of C. psittaci to host owners (birds, mammals, including humans). Chlamydia is one of the most dangerous and especially significant infectious diseases, especially for humans and animals, causing great economic damage, which occurs from the following consequences: reduced productivity (up to 50–60%); death of young animals from pneumonia (up to 20%); loss of animal reproduction as a result of abortions and stillbirths (5–30%), the occurrence of non-viable offspring (about 10%), an increase in infertility (up to 50%); carrying out medical, quarantine and emergency measures. Therefore, annual epizootic monitoring of morbidity takes place on the territory of the Russian Federation. The article publishes the reporting data of veterinary laboratory years of the 4th form on the diagnosis of bird ornithosis on the territory of the Russian Federation for 2018–2020.Methodology. An assessment of the epizootic situation for chlamydia (ornithosis) in birds in the Russian Federation for 2018–2020, based on the results of the analysis, income from annual reports, observations of state veterinary laboratories in the Federal State Budgetary Institution CNMVL in the 4-vet (annual) form.Results. During the analyzed period, the number of cases of the disease was detected among 16%, while an increase in the number of detected cases of ornithosis among birds. In 2018–2020, positive cases of ornithosis were detected in the Volga Federal District, Northwestern Federal District, Ural Federal District, Siberian Federal District, Central Federal District, and in 2020 ornithosis was detected in the Southern Federal District and the Far East Federal District bird ornithosis situation in these territories.

First Indications of Omsk Haemorrhagic Fever Virus beyond Russia.

Omsk haemorrhagic fever virus (OHFV) is the agent leading to Omsk haemorrhagic fever (OHF), a viral disease currently only known in Western Siberia in Russia. The symptoms include fever, headache, nausea, muscle pain, cough and haemorrhages. The transmission cycle of OHFV is complex. Tick bites or contact with infected small mammals are the main source of infection. The Republic of Kazakhstan is adjacent to the endemic areas of OHFV in Russia and febrile diseases with haemorrhages occur throughout the country—often with unclear aetiology. In this study, we examined human cerebrospinal fluid samples of patients with suspected meningitis or meningoencephalitis with unknown origins for the presence of OHFV RNA. Further, reservoir hosts such as rodents and ticks from four Kazakhstan regions were screened for OHFV RNA to clarify if this virus could be the causative agent for many undiagnosed cases of febrile diseases in humans in Kazakhstan. Out of 130 cerebrospinal fluid samples, two patients (1.53%) originating from Almaty city were positive for OHFV RNA. Screening of tick samples revealed positive pools from different areas in the Akmola region. Of the caught rodents, 1.1% out of 621 were positive for OHFV at four trapping areas from the West Kazakhstan region. In this paper, we present a broad investigation of the spread of OHFV in Kazakhstan in human cerebrospinal fluid samples, rodents and ticks. Our study shows for the first time that OHFV can not only be found in the area of Western Siberia in Russia, but can also be detected up to 1.600 km away in the Almaty region in patients and natural foci.

Endoparasites of red deer (Cervus elaphus xanthopygus) in the Trans-Baikal Territory

The paper presents the results (2019-2021) of parasitological studies of pathological material from 91 individuals of red deer (Cervus elaphus xanthopygus). Infestation of red deer with eight species of endoparasites has been registered in the Trans-Baikal Territory was registered: Protostrongylus kochi, suborder Strongylata of the digestive tract, Moniezia benedeni, Trichostrongylus spp., Dicrocoelium lanceatum, Echinococcus granulosus larva, Cysticercus tenuicollis, Eimeria spp. The intensity of infestation is 86.8% (Cysticercus tenuicollis) and 57.1% (Echinococcus granulosus larva), indicating the presence of natural foci on these helminths and their widespread distribution. Helminths Dicrocoelium lanceatum unspecific for Trans-Baikal Territory were detected in the bile ducts of the liver of one of the examined red deer. This fact indicates the presence of all conditions (the presence of intermediate hosts) for the spread of invasion, including on farm animals. To maintain the veterinary and sanitary well-being of the hunting industry in the Trans-Baikal Territory, the main principles of prevention of registered helminth infections were formulated based on the data obtained. To prevent the spread of echinococcosis, cysticercosis (larval cestodoses) among wild ungulates, increased control of wolves, foxes and stray dogs, as well as mandatory systematic deworming of dogs (quarterly) allowed in hunting farms is necessary. In order to prevent larval cestodoses it is necessary to destroy entrails of hunted animals and not use them raw as food for dogs. To prevent imaginal helminth infestations in ungulates, continuous monitoring of helminth carriage is necessary. Based on the results of these studies, a plan of helminthic measures is drawn up. For deworming wild animals, oral anthelmintic drugs are used, which are laid out on feeding grounds mixed with loose feed (crushed grain).

THE HISTORY OF THE DISCOVERY AND RESEARCH OF LYME BORRELIOSIS IN ANIMALS AND HUMANS

The relevance of this study is conditioned upon the substantial importance of the history of the discovery and research of Lyme borreliosis for medical science and veterinary medicine, since new theories, experiments, conclusions are built on the research of scientists who have proved the existence of this disease in animals and humans, and positive practices are accumulated regarding methods and schemes of treatment and prevention. The purpose of this study was to analyse the literature primary sources covering the history of the discovery, the results of the study of Lyme borreliosis disease to understand the features of its course and search for effective diagnostic and treatment methods. The chronology of the main results confirming the existence of Lyme borreliosis caused by Ixodidae ticks is summarised. Scientific sources covering the history of the discovery and research of Lyme borreliosis were analysed to understand the features of its course and search for effective methods of laboratory diagnostics and treatment. The main projects of the European Union programme aimed at financing research and innovative development “Horizon 2020” were determined. It was found that the projects in the field of Lyme borreliosis research also relate to certain topics, namely the creation of tests for the detection of Lyme disease, the study of the vectors of the causative agents of this disease, the development of an appropriate vaccine, and the assessment of the risks of consequences for human and animal health. It was concluded that the main areas of research are as follows: persistence of diseases and their causative agents transmitted by Ixodidae ticks; natural control of Ixodidae ticks; detection of pathogens in Ixodidae ticks; level of infection of vertebrates; habitats and natural foci of vectors and their hosts; testing and medical trials; effect of magnetic field on Borrelia; genome mapping of Borrelia species, visualisation of the human brain for disease research; research by polymerase chain reaction; endocrine studies; immune complexes, diagnosis of neuropsychiatric complications in children and adults. The practical value of this study lies in the awareness of modern scientists about the chronology of the study of Lyme borreliosis, the main ways of distribution and methods of its diagnosis in animals and humans, determining the prospects for further research according to the topical issues covered in this paper, which are solved within the framework of international projects

On the Effectiveness of Vaccination against Infections Common to Humans and Animals, as Part of the Immunization Schedule for Epidemic Indications in the Russian Federation

Relevance . The immunization schedule of the Russian Federation for epidemic indications includes vaccinations against infections common to humans and animals. Routine vaccination is scheduled for risk groups, which include persons with a high probability of infection, and urgently – in foci of infection. Aim of the study. Evaluation of the impact of vaccine prevention on the incidence of infections common to humans and animals. Materials and methods . Evaluation of the preventive effectiveness of vaccinations was carried out by comparing the volume of vaccination with the incidence rates of the corresponding vaccine-preventable infections according to the State Statistical Observation Forms No. 2 and No. 5 for the period from 2013 to 2020. Results and discussion. The scopes of immunization of the population against tularemia, brucellosis, anthrax, leptospirosis and tick-borne encephalitis are unstable. Against the background of a decrease in the number of vaccinations against tick-borne encephalitis in 2020, the trend towards a decrease in the incidence rate was replaced by an increase in rates in all age groups. For other infectious diseases, no significant deterioration in the epidemiological situation is observed. Due to active routine vaccination of the population living in areas with active natural foci of plague, cases of this disease are not registered in Russia. Conclusions. The reduction and instability of the volume of immunization of the population against tularemia, brucellosis, anthrax, leptospirosis and tick-borne encephalitis against the background of an increased risk of infection can lead to an increase in morbidity rates. The regulatory and methodological framework of the surveillance for vaccine prevention of infections common to humans and animals needs to be improved in terms of developing algorithms for assessing the number and coverage of target population groups, introducing accounting for vaccination and revaccination vaccinations, as well as registering the incidence of vaccinated and unvaccinated persons.

Epidemiological monitoring of the natural focus of Astrakhan spotted fever

Epidemiological monitoring of the natural focus of Astrakhan spotted fever

Spatiotemporal Variations of Plague Risk in the Tibetan Plateau from 1954-2016.

Simple SummaryClimate variability has influence on plague outbreaks worldwide. Usually, plague cases increase with increasing precipitation. Currently there are many studies on the epidemics of plague in human beings, whereas there are few studies on the dynamic of plague in animal. Nevertheless, animal plague is key in the natural epidemiological cycle of plague. We identified spatiotemporal changes of the plague territories in the Tibetan Plateau only using animal plague records. Our risky plague maps are far superior to the county-based maps used currently and have valuable applications for directly informing conservation and management decisions locally and regionally.Plague persists in the plague natural foci today. Although previous studies have found climate drives plague dynamics, quantitative analysis on animal plague risk under climate change remains understudied. Here, we analyzed plague dynamics in the Tibetan Plateau (TP) which is a climate-sensitive area and one of the most severe animal plague areas in China to disentangle variations in marmot plague enzootic foci, diffusion patterns, and their possible links with climate and anthropogenic factors. Specifically, we developed a time-sharing ecological niche modelling framework to identify finer potential plague territories and their temporal epidemic trends. Models were conducted by assembling animal records and multi-source ecophysiological variables with actual ecological effects (both climatic predictors and landscape factors) and driven by matching plague strains to periods corresponding to meteorological datasets. The models identified abundant animal plague territories over the TP and suggested the spatial patterns varied spatiotemporal dimension across the years, undergoing repeated spreading and contractions. Plague risk increased in the 1980s and 2000s, with the risk area increasing by 17.7 and 55.5 thousand km2, respectively. The 1990s and 2010s were decades of decreased risk, with reductions of 71.9 and 39.5 thousand km2, respectively. Further factor analysis showed that intrinsic conditions (i.e., elevation, soil, and geochemical landscape) provided fundamental niches. In contrast, climatic conditions, especially precipitation, led to niche differentiation and resulted in varied spatial patterns. Additionally, while increased human interference may temporarily reduce plague risks, there is a strong possibility of recurrence. This study reshaped the plague distribution at multiple time scales in the TP and revealed multifactorial synergistic effects on the spreading and contraction of plague foci, confirming that TP plague is increasingly sensitive to climate change. These findings may facilitate groups to take measures to combat the plague threats and prevent potential future human plague from occurring.

The role of non-commercial cyprinids in maintenance and spread of the opisthorchiasis focus in the middle Ob River basin (Tomsk region, Russia)

The study assessed the role of non-commercial cyprinid species in maintaining the opisthorchiasis focus in the middle Ob River basin, Tomsk region, Russia. The source of O. felineus infection for humans and carnivores is fish of the family Cyprinidae. This is the most numerous family, 14 species live in the middle Ob River basin, which includes 6 commercial species and 8 non-commercial species.This study aimed to investigate the current situation on infestation of non-commercial cyprinids with O. felineus metacercariae and their role in maintaining and spreading the natural focus of opisthorchiasis in the middle Ob River basin.We investigated 4 non-commercial species (tench, sunbleak, common bleak, gudgeon), which are highly abundant in water bodies. Tench, common bleak and gudgeon are objects of amateur fishing. These species are traditionally included in the diet of the local population.Opisthorchis felineus metacercariae were recorded in muscles of all the examined fish species. The identification of metacercariae was confirmed by morphological methods and PCR diagnostics.Tench and sunbleak are the main sources of opisthorchiasis infection in the floodplain lakes of the Ob River basin (the prevalence of tench infection is 89.3% and mean intensity of infection is 11.2 metacercariae per fish, the prevalence of sunbleak infection is 50.9% and the intensity of infection is 4.25 metacercariae per fish).The prevalence of infection in the introduced common bleak from the rivers of the middle Ob River basin is rapidly increasing from 2.4 (2016–2018) to 37.5% (2020−2021), and mean intensity of infection increased from 1 to 4.15.The epizootic state of water bodies in the middle Ob River basin remains unfavorable in relation to opisthorchiasis. Tench, common bleak and sunbleak, along with ide and dace, are the main source of infection for humans and animals, which is evidenced by high infection with Opisthorchis felineus metacercariae in these numerous fish species. They pose the greatest danger of infection of people and animals with opisthorchiasis. These species should be included in the campaign to avoid raw and poorly cooked fish in the diet. In addition, such species as roach, bream and sunbleak also pose the danger of infection with opisthorchiasis, but to a lesser extent.

Охридский минер Cameraria ohridella Deschka&Dimic: особенности инвазионных очагов и перспективы биологического контроля численности

The ecological mechanisms of one of the most dynamic biological invasions such as a colonization of artificial plantations of horse chestnut Aesculus hippocastanum L. by the ohrid miner, or chestnut miner Cameraria ohridella Deschka & Dimic (Lepidoptera, Gracillariidae) have been analyzed. The materials of publications on the bioecological features of C. ohridella in the conditions of native and invasive areas are summarized. The survey results of phytophage invasive foci in plantations of Moscow are presented. Particular attention is paid to the change in population characteristics (density, level of damage by entomophages) in connection with the biotopic conditions of horse chestnut plantations and meteorological features of the growing season. Measures to reduce the harm by C. ohridella by means of a biological control are considered. The information on the influence of various biotic factors on the phytophage is analyzed. Particular attention is paid to parasitoids as a means of the classical biological method. A suitable agent among parasitoids from natural foci of the miner has not yet been identified, and the level of local parasitism in European invasive foci is low. The perspective method of enhancing local parasitism through the accumulation and controlled release of parasitoids from leaf litter is substantiated. This technique makes it possible to synchronize the appearance of parasitoids with the phenology of the pest. This technology has already been tested by European researchers. Prospects are substantiated, the technology of seasonal colonization of parasits, which can be massively bred in biological laboratories such as parasitoids of Trichogramma (Hymenoptera, Chalcidoidea, Trichogrammatidae) and chrysopids (Neuroptera, Chrysopidae) is presented. Inside the invasive foci of C. ohridella, the effectiveness of seasonal colonization is proposed to be enhanced by using synthetic analogs of herbivore-induced plant volatiles (HIPV) that attract entomophages.

Assessment of the Application of Erythrocytal Diagnosticum (Lyophilizate) in Detecting Tularemia Agent in Natural Foci

Tularemia is a zoonotic disease with a wide geographical dissemination, and its causative agent Francisella tularensis can be used as a bioterrorism agent. The aim of the study was to evaluate the use of a set of reagents “Erythrocytic immunoglobulin dry tularemia diagnosticum” (“DET-Ig”) with the help of control test strains and field material from natural tularemia foci. Materials and methods. Using the introduced erythrocyte diagnosticum, we studied the decontaminated cultures of test strains (F. tularensis Miura, F. tularensis 55, F. tularensis Schu, F. tularensis 15 NIIEG, Brucella abortus 544, B. melitensis 16-M, B. suis 1330, and Yersinia enterocolitica 64, Y. enterocolitica 178, Y. enterocolitica 383) and environmental samples suspected of containing F. tularensis. Results and discussion. It has been proven that the developed diagnosticum is specific, sensitive, and easy to use for routine diagnostics of tularemia. In the course of laboratory tests of the experimental series of the DET-Ig reagent kit, the possibility of qualitative determination of the tularemia agent in bacterial cultures, biological material and environmental samples in the reaction of indirect hemagglutination was demonstrated. Comparison of the results of use of erythrocyte diagnosticum in liquid and lyophilized forms showed the advantages of drugs after lyophilization: the possibility of transportation and long-term storage at any temperature conditions in various climatic conditions; the setting of the reaction is possible without the use of special diluents. The guaranteed storage term is set for two years (observation period). The results obtained indicate the prospects of introducing the developed drug into healthcare practice.

Ecological-Epizootiological Differentiation of Natural Plague Foci

Plague foci differentiation is at the core of surveillance and forecasting of epizootic activity and hence achieving high effectiveness of prophylactic measures for prevention of human plague cases. Improvement of the plague foci differentiation taking into account recent data on their status and functioning is a relevant objective. The aim of the study was to differentiate natural plague foci according to the significance of ecology factors in the dynamics of epizootic activity. Materials and methods. Various models for forecasting epizootic activity of natural plague foci, based on the consistent statistical pattern recognition procedure were applied. 11 plague focal territories for which predictive models had ever been developed were surveyed. Results and discussion. The plague foci differ by impact of biotic and abiotic factors on epizootic activity. If epizootic activity depends on the biotic factors, forecasting can only be made on the basis of the data obtained directly during epizootiological surveillance. If epizootic activity depends on abiotic factors, such plague foci can be more depended on the global climate change. The put forward differentiation of focal areas allows for searching the common patterns of plague epizootic process in foci with different species of hosts and vectors, plague microbe variants and geographic setting, as well as for additional typification alongside the existing ones.

Epizootiological and Epidemiological Situation on Tularemia in the Republic of Karelia

The aim of this study was to assess the epidemiological and epizootiological situation on tularemia in the Republic of Karelia, and to develop a set of preventive (anti-epidemic) measures. Materials and methods. On the basis of statistical observation data, primary medical documentation and literature data, the morbidity of the population, the number of vaccinated persons, the results of laboratory studies of small mammals, arthropods and environmental objects, the species composition of hosts and vectors of infection were assessed. The situation in the republic was compared to the situation in Finland and neighboring regions of Russia. Results and discussion. The incidence of tularemia was registered in the Republic of Karelia in 1950–1971 (52 cases) and in 2010–2020 (121 cases). In the last decade, mainly the ulceroglandular forms have been diagnosed, the urban population predominated among the patients. In all cases, infection was transmitted through mosquito bites, i. e., not associated with professional activities. There are floodplainswamp and forest types of natural foci in the republic. The results of their monitoring are indicative of the activation of the epizootic process, covering almost the entire territory of Karelia. In several areas bordering tularemia disadvantaged areas of Finland and Russia, a high infection rate of rodents was detected, but tularemia patients were not registered. For an adequate assessment of the situation, it is necessary to increase the efficiency of surveying natural foci, study the immune structure of the population and improve the diagnosis of infection. The main areas of preventive (anti-epidemic) measures are vaccination of persons with professional risk of infection and persons living near the activated micro-foci of infection; reduction of the area of fields not used in agriculture; reclamation work, combating landfills, regular removal of waste from the territories of permanent and temporary residence of the population; the use of effective repellents; raising awareness of the population and authorities about the situation, symptoms of the disease, measures of its prevention.

The Current State of the Vertebrate Animals Populations and their Role in the Persistence of Natural Zoonoses Foci in the Stavropol Territory

The aim of this study was to investigate the current state of vertebrates populations and to determine their role in maintaining natural foci of zoonoses in the Stavropol Territory in 2015–2019. Material and methods. Organ suspensions and blood samples from small mammals and birds were studied using certified diagnostic test-systems for the markers of Crimean hemorrhagic fever, West Nile fever, hemorrhagic fever with renal syndrome, tularemia, and leptospirosis pathogens. The data were statistically processed using Wilson’s method. Results and discussion. Identified have been the main reservoirs of natural-focal infections in the Stavropol Territory at the present stage: birds – for the West Nile fever virus, mammals and birds inhabiting the areas of semi-desert landscape-geographical zone – for Crimean hemorrhagic fever agent. The main natural reservoir of orthohantaviruses in the Stavropol Territory is the common vole Microtus arvalis, which lives in all landscape-geographical zones. The circulation of tularemia and leptospirosis pathogens has been established throughout the whole territory of the region, the small wood mouse Sylvaemus uralensis is of the greatest epizootic significance. Findings indicate the need for further epizootiologic monitoring of Stavropol Territory in order to identify the biocenotic patterns of the pathogens’ existence and the reasons that determine the dynamics of the epizootic process and epidemic manifestations of natural foci. It is advisable to determine the sites of long-term monitoring over the number of carriers and vectors of natural-focal infections and strengthen the epizootiological control over the territory, especially during periods of seasonal activity in carriers and vectors of natural focal infections.

Prevalence of Arboviruses in Vietnam

For many years, arbovirus infections have been a global health problem and one of the urgent threats to the sanitary and epidemiological well-being of the population. Climatic conditions, species diversity and abundance of vectors, epidemiological and demographic factors are of fundamental importance for the emergence and persistence of natural foci of arbovirus infections. In the Socialist Republic of Vietnam (SRV) and other countries of the Asia-Pacific region, the most complex epidemiological situation is observed in regard to a number of arboviral infectious diseases transmitted by mosquitoes, inter alia to dengue fever. In this review we analyzed the literature data to identify the features of the circulation of some arboviruses in Vietnam, such as dengue virus, Zika, Chikungunya, Japanese encephalitis virus, Dabie virus, and the routes of their transmission and spread. It is shown that the climatic, ecological, epidemiological and demographic conditions existing on the territory of Vietnam contribute to the spread of pathogens of many arboviruses. Areas of more active circulation and ways of spreading pathogens of arbovirus infections have been identified. Based on the data obtained, it is necessary to conduct annual epidemiological and epizootiological survey of the territory of the SRV in order to identify markers of pathogens and determine the boundaries of natural foci of arbovirus infectious diseases which will enhance and increase the effectiveness of preventive and anti-epidemic measures.

New and Confirmed Foci of Tick-Borne Encephalitis Virus (TBEV) in Northern Germany Determined by TBEV Detection in Ticks.

Tick-borne encephalitis (TBE) is a tick-transmitted, virus-induced neurological disease with potentially fatal outcomes in humans and animals. Virus transmission takes places in so-called tick-borne encephalitis virus (TBEV) microfoci, which constitute small areas of sustained virus circulation. In southern Germany, TBEV has been endemic for decades; however, a northward expansion of risk areas, based on disease incidence in the human population, has been observed in recent years. The present study investigated TBEV occurrence in questing ticks at eight locations in the federal state of Lower Saxony, northwestern Germany, chosen due to reported associations with human TBE cases (N = 4) or previous virus detection (N = 4). A total of 20,056 ticks were collected in 2020 and 2021 and tested for TBEV RNA in pools of ten nymphs or five adults by quantitative reverse transcription-PCR (RT-qPCR). Positive results were confirmed by RT amplification of the viral E gene. In total, 18 pools from five different sampling locations were positive for TBEV RNA. One previously unknown transmission focus was detected, while ongoing virus circulation was confirmed at the four further locations. Phylogenetic analysis showed that two different virus strains with different origins circulate in the locations identified as natural foci.

A Novel Genospecies of Borrelia burgdorferi Sensu Lato Associated with Cricetid Rodents in Brazil.

Borrelia burgdorferi sensu lato (Bbsl) spirochetes thrive in sylvatic transmission cycles infecting vertebrates and their ticks. Rodents and ticks of the genus Ixodes are important hosts of these spirochetes globally. Although evidence suggests that Borrelia burgdorferi sensu stricto does not exist in South America, genospecies of the group (Bbsl) can be found in this region but have been poorly characterized from a genetic viewpoint, and data on their ecoepidemiology are still incipient. Aiming to detect the natural foci of Borrelia in Brazil, we targeted small mammals inhabiting seven forests fragments during a period of three years (2015–2018). Organs (lung) from two Oligoryzomys rodents over a total of 382 sampled mammals were positive, and we performed a molecular characterization of 10 borrelial genes to achieve a robust analysis. Phylogenetic trees inferred from 16S rRNA, flaB, ospC, and seven MLST loci (clpA, nifS, pepX, pyrG, recG, rlpB, and uvrA) support the characterization of a novel genospecies of Bbsl that we herein name “Candidatus Borrelia paulista” Rp42. Remarkably, “Ca. B. paulista” is phylogenetically related to Borrelia carolinensis, a genospecies that infects Ixodes ticks and cricetid rodents in North America. A previous study performed in the same area identified Ixodes schulzei feeding on Oligoryzomys rodents. Although this tick species could be considered a probable host for this novel Borrelia sp., further research is needed to confirm this hypothesis.

Epidemiological Community and Differences of Transmissive Infections in Astrakhan Region

Relevance. The territory of the Astrakhan region hosts natural foci of severe infections of arbovirus etiology – Crimean-Congo hemorrhagic fever (CCHF) and Astrakhan fever (spotted fever resembling the Mediterranean spotted fever, Astrakhan spotted fever (ASF). The long-term average incidence of CCHF and ASF in the Astrakhan region is to 11 and 135 times higher, respectively, than the average incidence in the Russian Federation. Aims. To present, based on epidemiological data, a comparative characterization of transmissible infections of CCHF and ASF in the Astrakhan region. Materials & Methods. The main method of the study was epidemiological. The data for 2000−2016 of primary medical documentation Ф.058/у «Emergency notification of infectious disease, food, acute occupational poisoning, unusual reaction to vaccination», federal statistical observation Ф. 2 «Information on infectious and parasitic diseases», Ф. 357/у «Epidemiological examination card of infectious disease focus», Ф. .003/у «Medical card of inpatient patient», presented by Center of hygiene and epidemiology in Astrakhan region. For retrospective epidemiological analysis, we studied the absolute and intensive morbidity indicators (per 100 ths population), by age, professional groups, and among the urban and rural population. Based on the average long-term morbidity indicators of the population, a mapping of the territory of the Astrakhan region was carried out. The influence of natural and climatic conditions on the epidemic process of CCHF and ASF was assessed by meteorological data (amount of precipitation, air temperature, etc.). Materials of long-term observation over 11 districts of Astrakhan region and Astrakhan city were analyzed, including data on the spread of Ixodid ticks, population contact with them (according to the attendance of people to treatment-and-prophylactic organizations of the region). Statistical data processing was carried out using the method of straight-line alignment of dynamic series of morbidity indicators, calculation of the average annual rate of decrease/increase. Correlation analysis was used to assess the direction and strength of the relationship between the indicators, and quantitative dependence between epidemic process characteristics. Differences between the indicators were considered to be reliable if p < 0.05. Results. During the analyzed period 151 cases of CCHF and 3951 cases of ASF were identified. By 2016. CCHF was registered in all 11 districts of the region and the area of foci covered 44,000 km2 and 44,100 km2, respectively. There are no differences significantly affecting the epidemic process of CCHF and ASF, so preventive measures are mainly aimed at controlling the vectors of the pathogens of these infections. The comprehensive study of the territory of Astrakhan region carried out in 2000–2016 revealed expansion of CCHF and ASF areal of disease (by 11.8% and 23.4% respectively) and determined the territories with the highest risk of infection, which allowed to increase and redistribute the volumes of acaricide treatments of the territories with the highest infection risk and ensure the decrease of CCHF and ASF morbidity rates. Conclusion. As a result of the comprehensive study conducted in 2000–2016 in the territory of Astrakhan region, the expansion of CCHF and ASF areal of disease was revealed (by 11.8% and 23.4% respectively) and the areas of highest infection risk were identified, which allowed to increase and redistribute the volume of acaricide treatments of the areas of highest infection risk and ensure the reduction of CCHF and ASF morbidity.

A ten-year assessment of the epidemiological features and fatal risk factors of hospitalised severe fever with thrombocytopenia syndrome in Eastern China.

Severe fever with thrombocytopenia syndrome (SFTS) virus has caused a large number of human infections since discovered in 2009. This study elucidated epidemiological features and fatal risk factors of SFTS cases accumulated up to ten years in Taizhou, a coastal prefecture of Zhejiang Province in Eastern China. A total of 188 hospitalised SFTS cases (including 40 deaths) reported to Taizhou Center for Disease Control and Prevention (CDC) during 2011-2020 were enrolled in the study. In the past decade, the annual incidence of SFTS increased over the years (P < 0.001) along with an expanding epidemic area, and the case fatality of hospitalised cases has remained high (21.3%). Although most cases occurred in hilly areas, a coastal island had the highest incidence and case fatality. The majority of cases were over the age of 60 years (72.3%), and both incidence and case fatality of SFTS increased with age. Multivariate logistic regression analysis showed that age (OR 7.47, 95% CI 1.32-42.33; P = 0.023), and haemorrhagic manifestations including petechiae (OR 7.76, 95% CI 1.17-51.50; P = 0.034), gingival haemorrhage (OR 5.38, 95% CI 1.25-23.15; P = 0.024) and melena (OR 5.75, 95% CI 1.18-28.07; P = 0.031) were significantly associated with the death of SFTS cases. Five family clusters identified were farmers, among four of which the index patients were female with a history of hypertension. Based on the study, age is a critical risk factor for incidence and case fatality of SFTS. With an increased annual incidence over the last ten years, SFTS remains a public health threat that should not be ignored. Further study is needed to look at the natural foci in the coastal islands.

Susceptibilities of Yersinia pestis to Twelve Antimicrobial Agents in China

Objective: Streptomycin is the preferred choice for therapy of plague in China and other countries. However, Yersinia pestis exhibiting plasmid-mediated antimicrobial agent–resistant traits had been reported in Madagascar. In this study, we evaluated the susceptibility of traditional or newer antimicrobial agents used for treatment and/or prophylaxis of plague. Methods: Following Clinical and Laboratory Standards Institute (CLSI) recommendations, the susceptibility of 12 antimicrobial agents was evaluated by the agar microdilution method in 1,012 strains of Y. pestis isolated from 1943 to 2017 in 12 natural plague foci in China. Results: One clinical Y. pestis isolate (S19960127) was found to be highly resistant to streptomycin, while the strain was still sensitive to other 11 antibiotics, that is, ciprofloxacin, ofloxacin, kanamycin, chloramphenicol, ampicillin, ceftriaxone, cefuroxime, trimethoprim-sulfamethoxazole, tetracycline, spectinomycin and moxifloxacin. The remaining 1,011 Y. pestis strains in this study demonstrated susceptibility to the above-mentioned 12 antimicrobial agents. Conclusion: Antimicrobial sensitivity surveillance of Y. pestis isolates, including dynamic monitoring of streptomycin resistance during various clinical plague treatments, should be carried out routinely.