The status of tularemia in Europe in a one-health context: a review

The Epidemiological Investigation of Yersinia pestis, Francisella tularensis, and Arenavirus Infections in Small Mammals in Northwestern Iran

Background: The control and prevention of rodent-borne diseases are mainly based on our knowledge of ecology and the infectious status of their reservoir hosts. This study aimed to evaluate the prevalence of Francisella tularensis, Yersinia pestis, and arenavirus infections in small mammals and to assess the potential of disease occurrence in East Azerbaijan, northwest of Iran, in 2017 and 2018. Methods: Spleen and lung samples were obtained from all trapped small mammals. The real-time quantitative PCR (qPCR) method was used to detect nucleic acid sequences of F. tularensis, Y. pestis, and arenaviruses. Serum samples were tested for antibodies indicating the host response to F. tularensis and Y. pestis infections using the standard tube agglutination test and enzyme-linked immunosorbent assay (ELISA), respectively. Results: A total of 205 rodents, four Eulipotyphla, and one carnivore were captured. The most common rodent species captured (123 of 205 rodents, 60%) belonged to the genus Meriones (mainly Persian jird, Meriones persicus). In total, 317 fleas were removed from trapped animals. Flea species belonged to Xenopsylla buxtoni, Xenopsylla nuttalli, Stenoponia tripectinata, Paraceras melis, Ctenophthalmus rettigi smiti, Rhadinopsylla bivirgis, Paradoxopsyllus grenieri, and Nosopsyllus iranus. Using the qPCR tests, five spleen samples from M. persicus were positive for F. tularensis. The qPCR tests were negative for the detection of Y. pestis and arenaviruses. Finally, all serum samples tested were negative for antibodies against Y. pestis and F. tularensis. Conclusions: F. tularensis was the only zoonotic agent detected in rodents captured in East Azerbaijan. However, the diversity of trapped rodents and fleas provides the potential for the spread of various rodent-borne viral and bacterial diseases in the studied areas.

Tick-Borne Bacterial Diseases in Europe: Threats to public health

BACKGROUND

Tick-borne diseases, caused by bacterial pathogens, pose a growing threat to public health in Europe. This paper provides an overview of the historical context of the discovery of the most impactful pathogens transmitted by ticks, including Borrelia burgdorferi sensu lato, Rickettsia spp., Anaplasma spp., Francisella spp., Ehrlichia spp., and Neoehrlichia mikurensis. Understanding the historical context of their discovery provides insight into the evolution of our understanding of these pathogens.

METHODS AND RESULTS

Systematic investigation of the prevalence and transmission dynamics of these bacterial pathogens is provided, highlighting the intricate relationships among ticks, host organisms, and the environment. Epidemiology is explored, providing an in-depth analysis of clinical features associated with infections. Diagnostic methodologies undergo critical examination, with a spotlight on technological advancements that enhance detection capabilities. Additionally, the paper discusses available treatment options, addressing existing therapeutic strategies and considering future aspects.

CONCLUSIONS

By integrating various pieces of information on these bacterial species, the paper aims to provide a comprehensive resource for researchers and healthcare professionals addressing the impact of bacterial tick-borne diseases in Europe. This review underscores the importance of understanding the complex details influencing bacterial prevalence and transmission dynamics to better combat these emerging public health threats.

The role of wildlife in the epidemiology of tick-borne diseases in Slovakia

Tick-borne diseases (TBD) represent an important challenge for human and veterinary medicine. In Slovakia, studies on the epidemiology of tick-borne pathogens (TBP) regarding reservoir hosts have focused on small mammals and to a lesser extent on birds or lizards, while knowledge of the role of the remaining vertebrate groups is limited. Generally, wild ungulates, hedgehogs, small- and medium-sized carnivores, or squirrels are important feeding hosts for ticks and serve as reservoirs for TBP. Importantly, because they carry infected ticks and/or are serologically positive, they can be used as sentinels to monitor the presence of ticks and TBP in the environment. With their increasing occurrence in urban and suburban habitats, wild ungulates, hedgehogs or foxes are becoming an important component in the developmental cycle of Ixodes ricinus and of TBP such as Anaplasma phagocytophilum or Babesia spp. On the other hand, it has been postulated that cervids may act as dilution hosts for Borrelia burgdorferi (sensu lato) and tick-borne encephalitis virus. In southwestern Slovakia, a high prevalence of infection with Theileria spp. (100%) was observed in some cervid populations, while A. phagocytophilum (prevalence of c.50%) was detected in cervids and wild boars. The following pathogens were detected in ticks feeding on free-ranging ungulates, birds, and hedgehogs: A. phagocytophilum, Rickettsia spp., Coxiella burnetii, Neoehrlichia mikurensis, B. burgdorferi (s.l.), and Babesia spp. The growing understanding of the role of wildlife as pathogen reservoirs and carriers of pathogen-infected ticks offers valuable insights into the epidemiology of TBP, providing a foundation for reducing the risk of TBD.

Francisella tularensis-specific antibody levels in sera from Swedish patients with suspected tularemia during a 13-year period

Introduction

For a majority of tularemia patients, serology is the basis for the diagnosis. The aim of this study was to perform an analysis of the samples analyzed at a Swedish reference laboratory for the presence of Francisella tularensis-specific antibody levels in sera from individuals with suspected tularemia. Annual and monthly variations of the total number of samples and proportions of positive samples were analyzed, as well as the influence of age and gender.

Methods

We performed a retrospective analysis of the presence of F. tularensis-specific antibodies in serological samples from patients with suspected tularemia analyzed during the period 2010 - 2022 at the University Hospital of Umeå in Sweden, a national reference laboratory, by use of various statistical methods. In total, some 15,100 serum samples had been analyzed for the presence of IgG and IgM antibodies by ELISA during the 13-year period.

Results

Overall, there were higher number of samples with IgG positive or borderline titers, 2,522 and 921, respectively, than with IgM positive or borderline titers, 1,802 and 409, respectively. Repeated samples were obtained from some 1,930 individuals and approximately a third of the cases, which were initially seronegative, had seroconverted when resampled. Peak number of monthly samples were recorded in August and September, > 3,000. Annual numbers varied greatly and peak numbers were observed in 2015 and 2019, 1,832 and 2,250, respectively, whereas some other years the numbers were 700 - 800. There was also much variation in the annual and monthly percentages of positive samples and they varied between less than 10% to greater than 20%. The highest percentages of positive samples were recorded in September and October. IgG and IgM titers declined with age and these differences were highly significant for IgG titers, with decreasing average titers for each 20-year interval.

Discussion

Collectively, the data demonstrate the marked annual and seasonal variations in tularemia sampling occurring in Sweden. Also, the proportion of positive samples increased during months and years with peak number of samples. Another notable finding was that average antibody titers decreased with increased age.

Investigation of Francisella tularensis Seroprevalence and Determination of Risk Factors for Tularemia among Hunters in Northern Cyprus

Background

Tularemia is a zoonotic disease (reservoir is usually rodents) caused by Francisella tularensis, especially seen in the northern hemisphere. Hunters are in the risk group for this disease. In this study, it was aimed to determine the seroprevalence of tularemia among hunters and determine the risk factors of tularemia in our country.

Methods

The Turkish Republic of Northern Cyprus (TRNC) is divided into four regions (Nicosia, Kyrenia, Famagusta/Trikomo, and Morphou/Lefka) and 100 volunteer hunters randomly selected from these regions were included in our study. Tube agglutination test (TAT) and F. tularensis IgG and IgM (ELISA method) were applied in all sera. All hunters were filled with a pre-prepared questionnaire to determine risk factors for tularemia.

Results

TAT positivity was found in 11%. While F. tularensis ELISA IgG positivity was 17%, IgM positivity was not found in any hunters. Hunters with positive F. tularensis ELISA IgG test (17%) were accepted as seropositive in terms of tularemia. There was no statistically significant difference between the mean age of IgG-positive and negative hunters (p= 0.915). Of the 86 hunters who kept at least one hunting dog in their garden, 15 (17.4%) were IgG-positive. There was no significant relationship between feeding hunting dogs and tularemia (p= 0.561).

Conclusion

Our study showed that the seroprevalence of tularemia was high (17%) among hunters, who are considered a risk group, in our country. We think that more epidemiological research should be done on tularemia infection and it should not be overlooked in the clinic.

Water and mosquitoes as key components of the infective cycle of Francisella tularensis in Europe: a review

Francisella tularensis is the pathogen of tularemia, a zoonotic disease that have a broad range of hosts. Its epidemiology is related to aquatic environments, particularly in the subspecies holarctica. In this review, we explore the role of water and mosquitoes in the epidemiology of Francisella in Europe. F. tularensis epidemiology has been linked to natural waters, where its persistence has been associated with biofilm and amebas. In Sweden and Finland, the European countries where most human cases have been reported, mosquito bites are a main route of transmission. F. tularensis is present in other European countries, but to date positive mosquitoes have not been found. Biofilm and amebas are potential sources of Francisella for mosquito larvae, however, mosquito vector capacity has not been demonstrated experimentally, with the need to be studied using local species to uncover a potential transmission adaptation. Transstadial, for persistence through life stages, and mechanical transmission, suggesting contaminated media as a source for infection, have been studied experimentally for mosquitoes, but their natural occurrence needs to be evaluated. It is important to clear up the role of different local mosquito species in the epidemiology of F. tularensis and their importance in all areas where tularemia is present.

Mutation of wbtJ, a N-formyltransferase involved in O-antigen synthesis, results in biofilm formation, phase variation and attenuation in Francisella tularensis

Two clinically important subspecies, Francisella tularensis subsp. tularensis (type A) and F. tularensis subsp. holarctica (type B) are responsible for most tularaemia cases, but these isolates typically form a weak biofilm under in vitro conditions. Phase variation of the F. tularensis lipopolysaccharide (LPS) has been reported in these subspecies, but the role of variation is unclear as LPS is crucial for virulence. We previously demonstrated that a subpopulation of LPS variants can constitutively form a robust biofilm in vitro, but it is unclear whether virulence was affected. In this study, we show that biofilm-forming variants of both fully virulent F. tularensis subspecies were highly attenuated in the murine tularaemia model by multiple challenge routes. Genomic sequencing was performed on these strains, which revealed that all biofilm-forming variants contained a lesion within the wbtJ gene, a formyltransferase involved in O-antigen synthesis. A ΔwbtJ deletion mutant recapitulated the biofilm, O-antigen and virulence phenotypes observed in natural variants and could be rescued through complementation with a functional wbtJ gene. Since the spontaneously derived biofilm-forming isolates in this study were a subpopulation of natural variants, reversion events to the wbtJ gene were detected that eliminated the phenotypes associated with biofilm variants and restored virulence. These results demonstrate a role for WbtJ in biofilm formation, LPS variation and virulence of F. tularensis.

Population Density of European Hare Predicts Risk of Tularemia Infection, Czech Republic, 2006-2022

Background: Over 200 different animal species are susceptible to infection by tularemia, highly infectious disease caused by Francisella tularensis. Hares (Lepus sp.) and small rodents, such as common vole (Microtus arvalis), have been acknowledged as the most significant sources of human tularemia infection in most European countries. Our objective was to verify ability of these species in predicting incidence of human tularemia in a Central European country, the Czech Republic. Materials and Methods: We used 17 years of data on densities of European hare (Lepus europaeus) and common vole, and climate variability to test effects of these factors on temporal dynamics of tularemia incidence. The data were obtained from annual reports available from online e-repositories. Results: The analysis showed that 33% of the yearly variation in human tularemia incidence was explained solely by the abundance of European hare in the Czech Republic during 2007-2022. Density of common vole and North Atlantic Oscillation index, a measure of climate variability, did not significantly explain tularemia incidence. While hare population declined severely during 1993-2022, we did not detect any clear accompanied decrease in the prevalence of tularemia in humans and hares. Conclusion: Contrary to expectations, only hares proved capable in predicting yearly dynamics in human tularemia incidence in the Czech Republic. We call for continued monitoring of infection rates in hares and advocate the use of hunter estimates of hare abundance as a cheap and effective means of predicting the risk of tularemia.

Pathogenicity and virulence of Francisella tularensis

Tularaemia is a zoonotic disease caused by the Gram-negative bacterium, Francisella tularensis. Depending on its entry route into the organism, F. tularensis causes different diseases, ranging from life-threatening pneumonia to less severe ulceroglandular tularaemia. Various strains with different geographical distributions exhibit different levels of virulence. F. tularensis is an intracellular bacterium that replicates primarily in the cytosol of the phagocytes. The main virulence attribute of F. tularensis is the type 6 secretion system (T6SS) and its effectors that promote escape from the phagosome. In addition, F. tularensis has evolved a peculiar envelope that allows it to escape detection by the immune system. In this review, we cover tularaemia, different Francisella strains, and their pathogenicity. We particularly emphasize the intracellular life cycle, associated virulence factors, and metabolic adaptations. Finally, we present how F. tularensis largely escapes immune detection to be one of the most infectious and lethal bacterial pathogens.

The European Union One Health 2022 Zoonoses Report

This report by the European Food Safety Authority and the European Centre for Disease Prevention and Control presents the results of the zoonoses monitoring and surveillance activities carried out in 2022 in 27 Member States (MSs), the United Kingdom (Northern Ireland) and 11 non-MSs. Key statistics on zoonoses and zoonotic agents in humans, food, animals and feed are provided and interpreted historically. In 2022, the first and second most reported zoonoses in humans were campylobacteriosis and salmonellosis, respectively. The number of cases of campylobacteriosis and salmonellosis remained stable in comparison with 2021. Nineteen MSs and the United Kingdom (Northern Ireland) achieved all the established targets in poultry populations for the reduction of Salmonella prevalence for the relevant serovars. Salmonella samples from carcases of various animal species, and samples for Campylobacter quantification from broiler carcases, were more frequently positive when performed by the competent authorities than when own checks were conducted. Yersiniosis was the third most reported zoonosis in humans, followed by Shiga toxin-producing Escherichia coli (STEC) and Listeria monocytogenes infections. L. monocytogenes and West Nile virus infections were the most severe zoonotic diseases, with the most hospitalisations and highest case fatality rates. In 2022, reporting showed an increase of more than 600% compared with 2021 in locally acquired cases of human West Nile virus infection, which is a mosquito-borne disease. In the EU, the number of reported foodborne outbreaks and cases, hospitalisations and deaths was higher in 2022 than in 2021. The number of deaths from outbreaks was the highest ever reported in the EU in the last 10 years, mainly caused by L. monocytogenes and to a lesser degree by Salmonella. Salmonella and in particular S. Enteritidis remained the most frequently reported causative agent for foodborne outbreaks. Norovirus (and other calicivirus) was the agent associated with the highest number of outbreak human cases. This report also provides updates on brucellosis, Coxiella burnetii (Q fever), echinococcosis, rabies, toxoplasmosis, trichinellosis, infection with Mycobacterium tuberculosis complex (focusing on Mycobacterium bovis and Mycobacterium caprae) and tularaemia.

Three Cases of Tickborne Francisella tularensis Infection, Austria, 2022

Tularemia is increasing in Austria. We report Francisella tularensis subspecies holarctica isolated from 3 patients who had been bitten by arthropods. Next-generation sequencing showed substantial isolate similarity. Clinicians should consider bloodstream F. tularensis infections for patients with signs/symptoms of ulceroglandular tularemia, and surveillance of potential vectors should be intensified.

Analyses of human immune responses to Francisella tularensis identify correlates of protection

Francisella tularensis is the etiological agent of the potentially severe infection tularemia. An existing F: tularensis vaccine, the live vaccine strain (LVS), has been used to protect at-risk personnel, but it is not licensed in any country and it has limited efficacy. Therefore, there is a need of a new, efficacious vaccine. The aim of the study was to perform a detailed analysis of the characteristics of the human immune response to F. tularensis, since this will generate crucial knowledge required to develop new vaccine candidates. Nine individuals were administered the LVS vaccine and peripheral blood mononuclear cells (PBMC) were collected before and at four time points up to one year after vaccination. The properties of the PBMC were characterized by flow cytometry analysis of surface markers and intracellular cytokine staining. In addition, the cytokine content of supernatants from F. tularensis-infected PBMC cultures was determined and the protective properties of the supernatants investigated by adding them to cultures with infected monocyte-derived macrophages (MDM). Unlike before vaccination, PBMC collected at all four time points after vaccination demonstrated F. tularensis-specific cell proliferation, cytokine secretion and cytokine-expressing memory cells. A majority of 17 cytokines were secreted at higher levels by PBMC collected at all time points after vaccination than before vaccination. A discriminative analysis based on IFN-γ and IL-13 secretion correctly classified samples obtained before and after vaccination. Increased expression of IFN-γ, IL-2, and MIP-1β were observed at all time points after vaccination vs. before vaccination and the most significant changes occurred among the CD4 transient memory, CD8 effector memory, and CD8 transient memory T-cell populations. Growth restriction of the highly virulent F. tularensis strain SCHU S4 in MDM was conferred by supernatants and protection correlated to levels of IFN-γ, IL-2, TNF, and IL-17. The findings demonstrate that F. tularensis vaccination induces long-term T-cell reactivity, including TEM and TTM cell populations. Individual cytokine levels correlated with the degree of protection conferred by the supernatants. Identification of such memory T cells and effector mechanisms provide an improved understanding of the protective mechanisms against F. tularensis. mechanisms against F. tularensis.

Epidemic intelligence activities among national public and animal health agencies: a European cross-sectional study

Epidemic Intelligence (EI) encompasses all activities related to early identification, verification, analysis, assessment, and investigation of health threats. It integrates an indicator-based (IBS) component using systematically collected surveillance data, and an event-based component (EBS), using non-official, non-verified, non-structured data from multiple sources. We described current EI practices in Europe by conducting a survey of national Public Health (PH) and Animal Health (AH) agencies. We included generic questions on the structure, mandate and scope of the institute, on the existence and coordination of EI activities, followed by a section where respondents provided a description of EI activities for three diseases out of seven disease models. Out of 81 gatekeeper agencies from 41 countries contacted, 34 agencies (42%) from 26 (63%) different countries responded, out of which, 32 conducted EI activities. Less than half (15/32; 47%) had teams dedicated to EI activities and 56% (18/34) had Standard Operating Procedures (SOPs) in place. On a national level, a combination of IBS and EBS was the most common data source. Most respondents monitored the epidemiological situation in bordering countries, the rest of Europe and the world. EI systems were heterogeneous across countries and diseases. National IBS activities strongly relied on mandatory laboratory-based surveillance systems. The collection, analysis and interpretation of IBS information was performed manually for most disease models. Depending on the disease, some respondents did not have any EBS activity. Most respondents conducted signal assessment manually through expert review. Cross-sectoral collaboration was heterogeneous. More than half of the responding institutes collaborated on various levels (data sharing, communication, etc.) with neighbouring countries and/or international structures, across most disease models. Our findings emphasise a notable engagement in EI activities across PH and AH institutes of Europe, but opportunities exist for better integration, standardisation, and automatization of these efforts. A strong reliance on traditional IBS and laboratory-based surveillance systems, emphasises the key role of in-country laboratories networks. EI activities may benefit particularly from investments in cross-border collaboration, the development of methods that can automatise signal assessment in both IBS and EBS data, as well as further investments in the collection of EBS data beyond scientific literature and mainstream media.

Francisella tularensis subsp. holarctica bacteraemia in an immunocompetent male

Tularemia is a rare zoonotic disease caused by the two predominant subspecies of Francisella tularensis, namely subspecies tularensis and subspecies holarctica. The latter is less virulent than the former, is endemic in Europe, and usually has a mild disease course, although respiratory involvement and bacteraemia can occur. Tularemia in Belgium is rare, but the incidence seems to be increasing. It therefore seems prudent to raise awareness among clinicians for this potentially severe disease. We report the first case of pneumonic tularemia with bacteraemia from Belgium, and want to recommend including Francisella tularensis in the differential diagnosis of pneumonia when an unfavorable evolution is seen with standard treatment.

Francisella and tularemia in western Asia, Iran: a systematic review

Tularemia or rabbit fever is a transmissible disease from animals, rodents, and insects to human populations that is caused by Francisella tularensis. Epidemiological studies showed that tularemia is endemic throughout most different regions of the world. Recent evidence documented the transmission of the F. tularensis in a different part of Asia. Because there is no updated review information for tularemia in Iran, we performed this systematic review. In this study, we systematically explored biomedical databases (Google Scholar, Scopus, PubMed, and Web of sciences) to identify epidemiology, reservoirs, and carriers of Francisella in animal and human clinical specimens from 2010 to 2020, either in English or in Persian. Different studies have shown the different frequencies of F. tularensis among human and animal resources in eighteen provinces of Iran. In total, 1242 human clinical specimens, 1565 animal samples, and 355 environmental water samples were investigated to find F. tularensis in different provinces of Iran. According to the collected documents, 94 human clinical samples, 69 water samples, and 26 animal specimens were introduced as positive samples for the F. tularensis. According to studies, thirteen species of rodent and hare presented as an inter-epizootic reservoir. Only one species of tick (D. marginatus) was introduced as a vector for Francisella in Iran. According to these results, it is essential for exclusive attention to the prevalence of F. tularensis in different provinces of Iran. Furthermore, special planning should be done for prevention, control of the outbreak, and proper treatment of the tularemia.

Kinetics of the serological response up to one year after tularemia

Serological analysis is the predominant method used to diagnose tularemia, a zoonotic disease caused by the highly virulent bacterium F. tularensis. We determined F. tularensis-specific IgM and IgG antibody titers by an LPS-based ELISA assay on five occasions one to twelve months after onset of ulceroglandular tularemia in 19 individuals. Peak IgM antibody titers were observed at the one-month time point and peak IgG antibody titers at the two-month time point. Both IgG and IgM antibody levels declined linearly thereafter with rather similar kinetics. Compared to the average one-month antibody titers, average IgG titers were not significantly lower before the 12-month time point and IgM titers before the 4-month time point. All, but one average titer, were significantly increased compared to the cut-off of the assay. Average IgG and IgM titers were significantly lower for the group = 69 years old compared to the group < 69 years. Collectively, the data demonstrate a persistence of F. tularensis-specific IgM and IgG antibody titers for at least 12 months after ulceroglandular tularemia. Thus, low, but significantly elevated F. tularensis-specific antibody titers are of limited diagnostic value since they are not indicative of ongoing tularemia.

The European Union One Health 2021 Zoonoses Report

This report of the European Food Safety Authority and the European Centre for Disease Prevention and Control presents the results of zoonoses monitoring and surveillance activities carried out in 2021 in 27 MSs, the United Kingdom (Northern Ireland) and nine non-MSs. Key statistics on zoonoses and zoonotic agents in humans, food, animals and feed are provided and interpreted historically. In 2021, the first and second most reported zoonoses in humans were campylobacteriosis and salmonellosis, respectively. Cases of campylobacteriosis and salmonellosis increased in comparison with 2020, but decreased compared with previous years. In 2021, data collection and analysis at the EU level were still impacted by the COVID-19 pandemic and the control measures adopted in the MSs, including partial or total lockdowns. Sixteen MSs and the United Kingdom (Northern Ireland) achieved all the established targets in poultry populations for reduction in Salmonella prevalence for the relevant serovars. Salmonella samples from carcases of various animal species and samples for Campylobacter quantification from broiler carcases were more frequently positive when performed by the competent authorities than when own-checks were conducted. Yersiniosis was the third most reported zoonosis in humans, followed by Shiga toxin-producing Escherichia coli (STEC) and Listeria monocytogenes infections. L. monocytogenes and West Nile virus infections were the most severe zoonotic diseases, with the most hospitalisations and highest case fatality rates. Overall, MSs reported more foodborne outbreaks and cases in 2021 than in 2020. S. Enteritidis remained the most frequently reported causative agent for foodborne outbreaks. Salmonella in 'eggs and egg products' and in 'mixed foods' were the agent/food pairs of most concern. Outbreaks linked to 'vegetables and juices and products thereof' rose considerably compared with previous years. This report also provides updates on brucellosis, Coxiella burnetii (Q fever), echinococcosis, rabies, toxoplasmosis, trichinellosis, tuberculosis due to Mycobacterium bovis or M. caprae, and tularaemia.

Separating Proactive Conservation from Species Listing Decisions

Proactive Conservation is a paradigm of natural resource management in the United States that encourages voluntary, collaborative efforts to restore species before they need to be protected through government regulations. This paradigm is widely used to conserve at-risk species today, and when used in conjunction with the Policy for Evaluation of Conservation Efforts (PECE), it allows for successful conservation actions to preclude listing of species under the Endangered Species Act (ESA). Despite the popularity of this paradigm, and recent flagship examples of its use (e.g., greater sage grouse, Centrocercus urophasianus), critical assessments of the outcomes of Proactive Conservation are lacking from the standpoint of species status and recovery metrics. Here, we provide such an evaluation, using the New England cottontail (Sylvilagus transitionalis), heralded as a success of Proactive Conservation efforts in the northeastern United States, as a case study. We review the history and current status of the species, based on the state of the science, in the context of the Conservation Initiative, and the 2015 PECE decision not to the list the species under the ESA. In addition to the impacts of the PECE decision on the New England cottontail conservation specifically, our review also evaluates the benefits and limits of the Proactive Conservation paradigm more broadly, and we make recommendations for its role in relation to ESA implementation for the future of at-risk species management. We find that the status and assurances for recovery under the PECE policy, presented at the time of the New England cottontail listing decision, were overly optimistic, and the status of the species has worsened in subsequent years. We suggest that use of PECE to avoid listing may occur because of the perception of the ESA as a punitive law and a misconception that it is a failure, although very few listed species have gone extinct. Redefining recovery to decouple it from delisting and instead link it to probability of persistence under recommended conservation measures would remove some of the stigma of listing, and it would strengthen the role of Species Status Assessments in endangered species conservation.

Five Years of Surveillance for Tularemia Serovar B (Francisella tularensis holarctica) (Olsufjev) (Thiotrichales: Francisellaceae) Including Two Human Cases at an Endemic Site in San Mateo County, California

Tularemia is a highly infectious, potentially fatal disease of humans and animals caused by the gram negative, intracellular bacterium Francisella tularensis. The San Mateo County Mosquito and Vector Control District conducted surveillance for F. tularensis from 2017 to 2021 in Dermacentor occidentalis (Marx) (Ixodida: Ixodidae), D. variabilis (Say) (Ixodida: Ixodidae), and Haemaphysalis leporispalustris (Packard) (Ixodida: Ixodidae) ticks in coastal southwestern San Mateo County, California. A total of 3,021 D. occidentalis and 1,019 D. variabilis were collected. Of those, 25 positive pools of F. tularensis were detected (five ticks per pool, overall minimum infection prevalence: 0.62%). Twenty-two of the 25 positive pools (88%) contained D. occidentalis. Eighty-eight percent (88%) of all positive pools were collected from the western half of the site, nearest to the ocean. We did not detect a seasonal effect on the probability of detecting a positive tick pool. There were two human cases of tularemia during the summers of 2019 and 2021. We conducted rodent surveillance in June of 2019, before the human case report. Twenty-four small mammals were collected, but none of their sera tested positive for F. tularensis. It is clear that tularemia is endemic to this region of San Mateo County, but the extent of its range and its ecology is not currently well understood.

Ulceroglandular form of tularemia after squirrel bite: a case report

Background

The diagnosis of tularemia is not often considered in Germany as the disease is still rare in this country. Nonetheless, Francisella tularensis, the causative agent of tularemia, can infect numerous animal species and should, therefore, not be neglected as a dangerous pathogen. Tularemia can lead to massively swollen lymph nodes and might even be fatal without antibiotic treatment. To our knowledge, the case described here is the first report of the disease caused by a squirrel bite in Germany.

Case presentation

A 59-year-old German woman with a past medical history of hypothyroidism and cutaneous lupus erythematosus presented at the emergency room at St. Katharinen Hospital with ongoing symptoms and a swollen right elbow persisting despite antibiotic therapy with cefuroxime for 7 days after she had been bitten (right hand) by a wild squirrel (Eurasian red squirrel). After another 7 days of therapy with piperacillin/tazobactam, laboratory analysis using real-time polymerase chain reaction (PCR) confirmed the suspected diagnosis of tularemia on day 14. After starting the recommended antibiotic treatment with ciprofloxacin, the patient recovered rapidly.

Conclusion

This is the first report of a case of tularemia caused by a squirrel bite in Germany. A naturally infected squirrel has recently been reported in Switzerland for the first time. The number of human cases of tularemia has been increasing over the last years and, therefore, tularemia should be taken into consideration as a diagnosis, especially in a patient bitten by an animal who also presents with headache, increasing pain, lymphadenitis, and fever, as well as impaired wound healing. The pathogen can easily be identified by a specific real-time PCR assay of wound swabs and/or by antibody detection, for example by enzyme-linked immunosorbent assay (ELISA), if the incident dates back longer than 2 weeks.

Vector-Borne Tularemia: A Re-Emerging Cause of Cervical Lymphadenopathy

Tularemia is a zoonosis caused by the highly invasive bacterium Francisella tularensis. It is transmitted to humans by direct contact with infected animals or by vectors, such as ticks, mosquitos, and flies. Even though it is well-known as a tick-borne disease, it is usually not immediately recognised after a tick bite. In Slovenia, tularemia is rare, with 1–3 cases reported annually; however, the incidence seems to be increasing. Ulceroglandular tularemia is one of its most common forms, with cervical colliquative lymphadenopathy as a frequent manifestation. The diagnosis of tularemia largely relies on epidemiological information, clinical examination, imaging, and molecular studies. Physicians should consider this disease a differential diagnosis for a neck mass, especially after a tick bite, as its management significantly differs from that of other causes. Tularemia-associated lymphadenitis is treated with antibiotics and surgical drainage of the colliquated lymph nodes. Additionally, tularemia should be noted for its potential use in bioterrorism on behalf of the causative agents’ low infectious dose, possible aerosol formation, no effective vaccine at disposal, and the ability to produce severe disease. This article reviews the recent literature on tularemia and presents a case of an adult male with tick-borne cervical ulceroglandular tularemia.

A case report of ulceroglandular tularemia caused by Francisella tularensis subsp. holarctica in Iran

BACKGROUND

Tularemia is a zoonotic disease that has been reported in many countries of the Northern Hemisphere. However, in some countries, such as Iran, this disease has been neglected by the health care system, and it is under-reported.

CASE PRESENTATION

Here we report an unusual case of ulceroglandular tularemia occurring in a 35-year-old woman who presented with a skin lesion of the left flank, inguinal lymphadenopathy, and an abdominal abscess. The serological and real-time PCR tests for tularemia were positive for this patient, and infection by Francisella tularensis subsp. holarctica was confirmed.

CONCLUSIONS

It is necessary to implement various educational programs to increase the awareness of physicians with tularemia.

Metabolic Reprogramming Mediates Delayed Apoptosis of Human Neutrophils Infected With Francisella tularensis

Neutrophils (polymorphonuclear leukocytes, PMNs) have a distinctively short lifespan, and tight regulation of cell survival and death is imperative for their normal function. We demonstrated previously that Francisella tularensis extends human neutrophil lifespan, which elicits an impaired immune response characterized by neutrophil dysfunction. Herein, we extended these studies, including our transcriptional profiling data, and employed Seahorse extracellular flux analysis, gas chromatography-mass spectrometry metabolite analysis, flow cytometry and several other biochemical approaches to demonstrate that the delayed apoptosis observed in F. tularensis-infected neutrophils is mediated, in part, by metabolic reprogramming. Specifically, we show that F. tularensis-infected neutrophils exhibited a unique metabolic signature characterized by increased glycolysis, glycolytic flux and glucose uptake, downregulation of the pentose phosphate pathway, and complex glycogen dynamics. Glucose uptake and glycolysis were essential for cell longevity, although glucose-6-phosphate translocation into the endoplasmic reticulum was not, and we identify depletion of glycogen as a potential trigger of apoptosis onset. In keeping with this, we also demonstrate that ablation of apoptosis with the pan-caspase inhibitor Q-VD-OPh was sufficient to profoundly increase glycolysis and glycogen stores in the absence of infection. Taken together, our data significantly advance understanding of neutrophil immunometabolism and its capacity to regulate cell lifespan.

Host Immunity and Francisella tularensis: A Review of Tularemia in Immunocompromised Patients

Tularemia, caused by the bacterium Francisella tularensis, is an infrequent zoonotic infection, well known in immunocompetent (but poorly described in immunocompromised) patients. Although there is no clear literature data about the specific characteristics of this disease in immunocompromised patients, clinical reports seem to describe a different presentation of tularemia in these patients. Moreover, atypical clinical presentations added to the fastidiousness of pathogen identification seem to be responsible for a delayed diagnosis, leading to a” loss of chance” for immunocompromised patients. In this article, we first provide an overview of the host immune responses to Francisella infections and discuss how immunosuppressive therapies or diseases can lead to a higher susceptibility to tularemia. Then, we describe the particular clinical patterns of tularemia in immunocompromised patients from the literature. We also provide hints of an alternative diagnostic strategy regarding these patients. In conclusion, tularemia should be considered in immunocompromised patients presenting pulmonary symptoms or unexplained fever. Molecular techniques on pathological tissues might improve diagnosis with faster results.

The European Union One Health 2020 Zoonoses Report

This report of the EFSA and the European Centre for Disease Prevention and Control presents the results of zoonoses monitoring activities carried out in 2020 in 27 EU Member States (MS) and nine non-MS. Key statistics on zoonoses and zoonotic agents in humans, food, animals and feed are provided and interpreted historically. Two events impacted 2020 MS data collection and related statistics: the Coronavirus Disease 2019 (COVID-19) pandemic and the withdrawal of the United Kingdom from the EU. In 2020, the first and second most reported zoonoses in humans were campylobacteriosis and salmonellosis, respectively. The EU trend for confirmed human cases of these two diseases was stable (flat) from 2016 to 2020. Fourteen of the 26 MS reporting data on Salmonella control programmes in poultry met the reduction targets for all poultry categories. Salmonella results for carcases of various species performed by competent authorities were more frequently positive than own-checks conducted by food business operators. This was also the case for Campylobacter quantification results from broiler carcases for the MS group that submitted data from both samplers, whereas overall at EU level, those percentages were comparable. Yersiniosis was the third most reported zoonosis in humans, with 10-fold less cases reported than salmonellosis, followed by Shiga toxin-producing Escherichia coli (STEC) and Listeria monocytogenes infections. Illnesses caused by L. monocytogenes and West Nile virus infections were the most severe zoonotic diseases with the highest case fatality. In 2020, 27 MS reported 3,086 foodborne outbreaks (a 47.0% decrease from 2019) and 20,017 human cases (a 61.3% decrease). Salmonella remained the most frequently reported causative agent for foodborne outbreaks. Salmonella in 'eggs and egg products', norovirus in 'crustaceans, shellfish, molluscs and products containing them' and L. monocytogenes in 'fish and fish products' were the agent/food pairs of most concern. This report also provides updates on tuberculosis due to Mycobacterium bovis or Mycobacterium caprae, Brucella, Trichinella, Echinococcus, Toxoplasma, rabies, Coxiella burnetii (Q fever) and tularaemia.

Epidemiological investigation of a tularaemia outbreak after a hare hunt in Bavaria, Germany, 2018

In November 2018, a tularaemia outbreak occurred in Bavaria, Germany, among participants of a hare hunt and butchery employees handling the hares. We conducted an epidemiological outbreak investigation, including a retrospective cohort study among hunting participants, to identify likely transmission routes and activities associated with infection. Twelve of 41 participants were antibody-positive for Francisella (F.) tularensis (attack rate: 29%). Cases reported influenza-like symptoms (n = 11), lymphadenopathy (n = 1) and conjunctivitis (n = 1). Infection only occurred in those hunting participants present while hares were processed, while risk of infection was highest when directly involved (RR = 10.0; 95%CI: 2.6-392). F. tularensis was isolated from 1/4 hares. Only two individuals reported using some of the recommended personal protective equipment (PPE). Occurrence of mainly non-specific symptoms, likely due to early treatment, was not indicative of a specific transmission route. Transmissions via direct (skin/mucosa) contact and by inhalation of contaminated aerosols seem plausible. Promoting and increasing appropriate use of PPE among people processing hares is crucial to prevent future outbreaks.

Natural Infection of a European Red Squirrel (Sciurus vulgaris) with Francisella tularensis subsp. Holarctica

Postmortem examination and immunohistochemical and bacteriologic analyses on a free-ranging European red squirrel (Sciurus vulgaris) revealed a systemic infection with Francisella tularensis. Genome sequencing and single-nucleotide polymorphism analysis were consistent with F. tularensis subs. holarctica clade B.45. Tularemia has not previously been reported in this species.

Linking Zoonosis Emergence to Farmland Invasion by Fluctuating Herbivores: Common Vole Populations and Tularemia Outbreaks in NW Spain

The expansion and intensification of agriculture are driving profound changes in ecosystems worldwide, favoring the (re)emergence of many human infectious diseases. Muroid rodents are a key host group for zoonotic infectious pathogens and frequently invade farming environments, promoting disease transmission and spillover. Understanding the role that fluctuating populations of farm dwelling rodents play in the epidemiology of zoonotic diseases is paramount to improve prevention schemes. Here, we review a decade of research on the colonization of farming environments in NW Spain by common voles (Microtus arvalis) and its public health impacts, specifically periodic tularemia outbreaks in humans. The spread of this colonizing rodent was analogous to an invasion process and was putatively triggered by the transformation and irrigation of agricultural habitats that created a novel terrestrial-aquatic interface. This irruptive rodent host is an effective amplifier for the Francisella tularensis bacterium during population outbreaks, and human tularemia episodes are tightly linked in time and space to periodic (cyclic) variations in vole abundance. Beyond the information accumulated to date, several key knowledge gaps about this pathogen-rodent epidemiological link remain unaddressed, namely (i) did colonizing vole introduce or amplified pre-existing F. tularensis? (ii) which features of the “Francisella—Microtus” relationship are crucial for the epidemiology of tularemia? (iii) how virulent and persistent F. tularensis infection is for voles under natural conditions? and (iv) where does the bacterium persist during inter-epizootics? Future research should focus on more integrated, community-based approaches in order to understand the details and dynamics of disease circulation in ecosystems colonized by highly fluctuating hosts.

Detection of Tick-Borne Pathogens of the Genera Rickettsia, Anaplasma and Francisella in Ixodes ricinus Ticks in Pomerania (Poland)

Tick-borne pathogens are an important medical and veterinary issue worldwide. Environmental monitoring in relation to not only climate change but also globalization is currently essential. The present study aimed to detect tick-borne pathogens of the genera Anaplasma, Rickettsia and Francisella in Ixodes ricinus ticks collected from the natural environment, i.e., recreational areas and pastures used for livestock grazing. A total of 1619 specimens of I. ricinus were collected, including ticks of all life stages (adults, nymphs and larvae). The study was performed using the PCR technique. Diagnostic gene fragments msp2 for Anaplasma, gltA for Rickettsia and tul4 for Francisella were amplified. No Francisella spp. DNA was detected in I. ricinus. DNA of A. phagocytophilum was detected in 0.54% of ticks and Rickettsia spp. in 3.69%. Nucleotide sequence analysis revealed that only one species of Rickettsia, R. helvetica, was present in the studied tick population. The present results are a part of a large-scale analysis aimed at monitoring the level of tick infestation in Northwest Poland.

Modern Development and Production of a New Live Attenuated Bacterial Vaccine, SCHU S4 ΔclpB, to Prevent Tularemia

Inhalation of small numbers of Francisella tularensis subspecies tularensis (Ftt) in the form of small particle aerosols causes severe morbidity and mortality in people and many animal species. For this reason, Ftt was developed into a bona fide biological weapon by the USA, by the former USSR, and their respective allies during the previous century. Although such weapons were never deployed, the 9/11 attack quickly followed by the Amerithrax attack led the U.S. government to seek novel countermeasures against a select group of pathogens, including Ftt. Between 2005–2009, we pursued a novel live vaccine against Ftt by deleting putative virulence genes from a fully virulent strain of the pathogen, SCHU S4. These mutants were screened in a mouse model, in which the vaccine candidates were first administered intradermally (ID) to determine their degree of attenuation. Subsequently, mice that survived a high dose ID inoculation were challenged by aerosol or intranasally (IN) with virulent strains of Ftt. We used the current unlicensed live vaccine strain (LVS), first discovered over 70 years ago, as a comparator in the same model. After screening 60 mutants, we found only one, SCHU S4 ΔclpB, that outperformed LVS in the mouse ID vaccination-respiratory-challenge model. Currently, SCHU S4 ΔclpB has been manufactured under current good manufacturing practice conditions, and tested for safety and efficacy in mice, rats, and macaques. The steps necessary for advancing SCHU S4 ΔclpB to this late stage of development are detailed herein. These include developing a body of data supporting the attenuation of SCHU S4 ΔclpB to a degree sufficient for removal from the U.S. Select Agent list and for human use; optimizing SCHU S4 ΔclpB vaccine production, scale up, and long-term storage; and developing appropriate quality control testing approaches.

A Rare Case of Tularemia Complicated by Rhabdomyolysis with a Successful Outcome

We present a case of tularemia complicated by rhabdomyolysis in a 43-year-old male who presented with fever, swelling, and pain of the right groin and a history of a week-old tick bite. Empirical parenteral amoxicillin/clavulanic acid treatment was initiated. Suspecting tularemia, parenteral gentamycin was added. Later, the patient started to complain of muscle pain, weakness, and difficulties in breathing and walking. Heightened levels of creatine kinase and myoglobin concentration (42,670 IU/L and >12,000 μg/L, respectively) were found. Due to rhabdomyolysis, large amounts of intravenous fluid therapy were initiated to prevent kidney damage, continuing intravenous antibiotic therapy. Francisella tularensis IgG in serum was found to be positive only on the sixteenth day of hospitalization. Upon discharge, the laboratory analyses returned to normal levels, and the patient was in good condition. The successful outcome could be associated with the early appropriate therapy of tularemia and its rare complication of rhabdomyolysis.

The European Union One Health 2019 Zoonoses Report

This report of the EFSA and the European Centre for Disease Prevention and Control presents the results of zoonoses monitoring activities carried out in 2019 in 36 European countries (28 Member States (MS) and eight non-MS). The first and second most reported zoonoses in humans were campylobacteriosis and salmonellosis, respectively. The EU trend for confirmed human cases of these two diseases was stable (flat) during 2015-2019. The proportion of human salmonellosis cases due to Salmonella Enteritidis acquired in the EU was similar to that in 2017-2018. Of the 26 MS reporting on Salmonella control programmes in poultry, 18 met the reduction targets, whereas eight failed to meet at least one. The EU prevalence of Salmonella target serovar-positive flocks has been stable since 2015 for breeding hens, laying hens, broilers and fattening turkeys, with fluctuations for breeding turkey flocks. Salmonella results from competent authorities for pig carcases and for poultry tested through national control programmes were more frequently positive than those from food business operators. Shiga toxin-producing Escherichia coli (STEC) infection was the third most reported zoonosis in humans and increased from 2015 to 2019. Yersiniosis was the fourth most reported zoonosis in humans in 2019 with a stable trend in 2015-2019. The EU trend of confirmed listeriosis cases remained stable in 2015-2019 after a long period of increase. Listeria rarely exceeded the EU food safety limit tested in ready-to-eat food. In total, 5,175 food-borne outbreaks were reported. Salmonella remained the most detected agent but the number of outbreaks due to S. Enteritidis decreased. Norovirus in fish and fishery products was the agent/food pair causing the highest number of strong-evidence outbreaks. The report provides further updates on bovine tuberculosis, Brucella, Trichinella, Echinococcus, Toxoplasma, rabies, West Nile virus, Coxiella burnetii (Q fever) and tularaemia.

Francisella tularensis survey among ranchers and livestock in western Iran

Tularemia is a zoonotic disease that transmitted to humans and domestic animals by wildlife, especially rodents. There are some evidences of the circulation of F. tularensis in rodents, livestock, human populations, and surface waters in western parts of Iran. In this study, we investigated the exposure of livestock and ranchers to F. tularensis in the endemic regions of western Iran. Blood samples were collected from 289 sheep, 103 cattle, and 51 ranchers in 2018. Animal sera were tested by standard tube agglutination method. The specific IgGs against F. tularensis were evaluated by ELISA in human sera. Moreover, the extracted DNAs from 50 sheep spleen samples were evaluated using TaqMan real-time PCR for the presence of ISFtu2 and FopA genes. All animal sera and spleen samples were negative for tularemia. Of the 51 human samples, two samples were seropositive and one sample showed a borderline status for tularemia. Serologic evidence of F. tularensis in the ranchers but negative results in the livestock indicates different transmission routes in human populations and domestic animals in western Iran. Therefore, drinking contaminated water, contact to wildlife or rodents and arthropod bite should be considered as probable routes in the suspicious areas.

Tularemia Goes West: Epidemiology of an Emerging Infection in Austria

The zoonotic disease tularemia is caused by the Gram-negative bacterium Francisella tularensis, with the two major subspecies tularensis and holarctica being responsible for infections in humans and animals. The F. tularensis subspecies holarctica is less virulent and prevalent in Europe and Asia. Over the last few centuries, few epidemic outbreaks and low numbers of infections have been registered in the eastern part of Austria, specifically in the provinces of Lower Austria, Burgenland, and Styria. The reported infections were mostly associated with hunting hares and the skinning of carcasses. Within the last decade, ticks have been identified as important vectors in Tyrol and served as first evidence for the spread of F. tularensis to Western Austria. In 2018, the pathogen was detected in hares in the provinces of Tyrol, Vorarlberg, and Salzburg. We presume that F. tularensis is now established in most regions of Austria, and that the investigation of potential host and vector animals should be spotlighted by public institutions. Tularemia in humans presents with various clinical manifestations. As glandular, ulceroglandular, and typhoidal forms occur in Austria, this infectious disease should be considered as a differential diagnosis of unknown fever.

Francisella tularensis Subspecies holarctica and Tularemia in Germany

Tularemia is a zoonotic disease caused by Francisella tularensis a small, pleomorphic, facultative intracellular bacterium. In Europe, infections in animals and humans are caused mainly by Francisella tularensis subspecies holarctica. Humans can be exposed to the pathogen directly and indirectly through contact with sick animals, carcasses, mosquitoes and ticks, environmental sources such as contaminated water or soil, and food. So far, F. tularensis subsp. holarctica is the only Francisella species known to cause tularemia in Germany. On the basis of surveillance data, outbreak investigations, and literature, we review herein the epidemiological situation-noteworthy clinical cases next to genetic diversity of F. tularensis subsp. holarctica strains isolated from patients. In the last 15 years, the yearly number of notified cases of tularemia has increased steadily in Germany, suggesting that the disease is re-emerging. By sequencing F. tularensis subsp. holarctica genomes, knowledge has been added to recent findings, completing the picture of genotypic diversity and geographical segregation of Francisella clades in Germany. Here, we also shortly summarize the current knowledge about a new Francisella species (Francisella sp. strain W12-1067) that has been recently identified in Germany. This species is the second Francisella species discovered in Germany.

Implications of Projected Hydroclimatic Change for Tularemia Outbreaks in High-Risk Areas across Sweden

Hydroclimatic change may affect the range of some infectious diseases, including tularemia. Previous studies have investigated associations between tularemia incidence and climate variables, with some also establishing quantitative statistical disease models based on historical data, but studies considering future climate projections are scarce. This study has used and combined hydro-climatic projection outputs from multiple global climate models (GCMs) in phase six of the Coupled Model Intercomparison Project (CMIP6), and site-specific, parameterized statistical tularemia models, which all imply some type of power-law scaling with preceding-year tularemia cases, to assess possible future trends in disease outbreaks for six counties across Sweden, known to include tularemia high-risk areas. Three radiative forcing (emissions) scenarios are considered for climate change projection until year 2100, incuding low (2.6 Wm⁻²), medium (4.5 Wm⁻²), and high (8.5 Wm⁻²) forcing. The results show highly divergent changes in future disease outbreaks among Swedish counties, depending primarily on site-specific type of the best-fit disease power-law scaling characteristics of (mostly positive, in one case negative) sub- or super-linearity. Results also show that scenarios of steeper future climate warming do not necessarily lead to steeper increase of future disease outbreaks. Along a latitudinal gradient, the likely most realistic medium climate forcing scenario indicates future disease decreases (intermittent or overall) for the relatively southern Swedish counties Örebro and Gävleborg (Ockelbo), respectively, and disease increases of considerable or high degree for the intermediate (Dalarna, Gävleborg (Ljusdal)) and more northern (Jämtland, Norrbotten; along with the more southern Värmland exception) counties, respectively.

First European report of Francisella tularensis subsp. holarctica isolation from a domestic cat

Francisella tularensis subsp. holarctica is a select agent causing life-threatening tularemia. It has been isolated from humans and animals, mainly lagomorphs and rodents, rarely other wild carnivore species. Increasing numbers of human tularemia cases have been reported during the last 5 years in Switzerland. Here we report the first isolation of Francisella tularensis subsp. holarctica from a domestic cat in Europe and compare its genome sequence with other Swiss isolates. The cat isolate shows a close phylogenetic relationship with a contemporary hare isolate from close geographic proximity, indicating a possible epidemiological link.

The clinical spectrum of tularemia-Two cases

We report two cases of tularemia with different clinical manifestations, both suspected of tick-borne transmission and with near-complete remission of all symptoms within 3 months after antimicrobial treatment. The first patient presented with a classical ulceroglandular manifestation; general malaise, an ulcer and lymphadenopathy, occurring two weeks after a tick bite. Diagnosis was established by polymerase chain reaction of a skin biopsy from the ulcer. The second patient presented with a rare systemic manifestation including bacteremia and myocarditis resulting in severe clinical heart failure, pulmonary edema and secondary kidney failure. Previous tick bites were elucidated after the bacteremia was discovered. The cases underscore the heterogeneity of manifestations, the diagnostic approach and the importance of thorough medical history including recent exposures especially in cases with infection of unknown origin.

Molecular identification of the source of an uncommon tularaemia outbreak, Germany, autumn 2016

Background

In 2016, an uncommon outbreak of oropharyngeal tularaemia involving six human cases occurred in Germany, caused by drinking contaminated fresh must after a grape harvest.

Aim

We describe the details of laboratory investigations leading to identification of the outbreak strain, its characterisation by next generation sequencing (NGS) and the finding of the possible source of contamination.

Methods

We incubated wine samples in different media and on agar plates. NGS was performed on DNA isolated from young wine, sweet reserve and an outbreak case’s lymph node. A draft genome of the outbreak strain was generated. Vertebrate-specific PCRs using primers targeting the mitochondrial cytochrome b gene and product analyses by blast search were used to identify the putative source of must contamination.

Results

No bacterial isolate could be obtained. Analysis of the draft genome sequence obtained from the sweet reserve attributed this sequence to Francisella tularensis subsp. holarctica, belonging to the B.12/B.34 phylogenetic clade (erythromycin-resistant biovar II). In addition, the DNA sequence obtained from the case’s isolate supported our hypothesis that infection was caused by drinking contaminated must. The vertebrate-specific cytochrome b sequence derived from the young wine and the sweet reserve could be assigned to Apodemus sylvaticus (wood mouse), suggesting that a wood mouse infected with F. tularensis may have contaminated the must.

Conclusion

The discovered source of infection and the transmission scenario of F. tularensis in this outbreak have not been observed previously and suggest the need for additional hygienic precautionary measures when processing and consuming freshly pressed must.

Pulmonary tularaemia: a differential diagnosis to lung cancer

Background

Pulmonary manifestations of tularaemia are reported to be infrequent in previous publications. During 2016, we noticed an increase in the number of hospitalised patients with pulmonary tularaemia in Eastern Norway. We aimed to investigate primary pulmonary tularaemia in Eastern Norway in terms of symptoms, radiological and microbiological findings, incidence and risk exposure.

Methods

A retrospective analysis of consecutive primary pulmonary tularaemia cases from 2016 until 2018 was conducted.

Results

From 1 September, 2016 until 31 December, 2018, 22 patients were diagnosed with primary pulmonary tularaemia at Innlandet Hospital Trust, representing 48% of all reported tularaemia cases in the region. A peak annual incidence of 3.4 in 100 000 was found in 2017.

All 22 patients lived in, or had recently visited, rural areas. Eighteen patients reported risk exposure for tularaemia, such as wood chopping, outdoor activities and farming prior to symptom onset. All patients experienced fever, and 19 patients had respiratory symptoms. Ten patients were in spontaneous recovery at diagnosis.

All patients had a chest computed tomography scan. Overall, 19 patients had pulmonary lesions and 18 had enlarged intrathoracic lymph nodes. The computed tomography images were described as suspicious of malignancy in 17 patients.

Conclusion

Pulmonary manifestations in tularaemia occurred more frequently in our region than expected from previous reports. Although all patients had symptoms consistent with infection, the majority were primarily investigated considering lung cancer due to the radiology report. In endemic areas, pulmonary tularaemia may be an important differential diagnosis to lung cancer.

Pulmonary tularaemia is possibly more frequent than previously reported. Due to similar radiological findings, pulmonary tularaemia may be an important differential diagnosis to lung cancer in endemic areas.https://bit.ly/2RcEPfN

OpiA, a Type Six Secretion System Substrate, Localizes to the Cell Pole and Plays a Role in Bacterial Growth and Viability in Francisella tularensis LVS

Francisella tularensis is an intracellular pathogen and the causative agent of tularemia. The F. tularensis type six secretion system (T6SS) is required for a number of host-pathogen interactions, including phagolysosomal escape and invasion of erythrocytes. One known effector of the T6SS, OpiA, has recently been shown to be a phosphatidylinositol-3 kinase. To investigate the role of OpiA in erythrocyte invasion, we constructed an opiA-null mutant in the live vaccine strain, F. tularensis LVS. OpiA was not required for erythrocyte invasion; however, deletion of opiA affected growth of F. tularensis LVS in broth cultures in a medium-dependent manner. We also found that opiA influenced cell size, gentamicin sensitivity, bacterial viability, and the lipid content of F. tularensis A fluorescently tagged OpiA (OpiA-emerald-green fluorescent protein [EmGFP]) accumulated at the cell poles of F. tularensis, which is consistent with the location of the T6SS. However, OpiA-EmGFP also exhibited a highly dynamic localization, and this fusion protein was detected in erythrocytes and THP-1 cells in vitro, further supporting that OpiA is secreted. Similar to previous reports with F. novicida, our data demonstrated that opiA had a minimal effect on intracellular replication of F. tularensis in host immune cells in vitro However, THP-1 cells infected with the opiA mutant produced modestly (but significantly) higher levels of the proinflammatory cytokine tumor necrosis factor alpha compared to these host cells infected with wild-type bacteria. We conclude that, in addition to its role in host-pathogen interactions, our results reveal that the function of opiA is central to the biology of F. tularensis bacteria.IMPORTANCE F. tularensis is a pathogenic intracellular pathogen that is of importance for public health and strategic defense. This study characterizes the opiA gene of F. tularensis LVS, an attenuated strain that has been used as a live vaccine but that also shares significant genetic similarity to related Francisella strains that cause human disease. The data presented here provide the first evidence of a T6SS effector protein that affects the physiology of F. tularensis, namely, the growth, cell size, viability, and aminoglycoside resistance of F. tularensis LVS. This study also adds insight into our understanding of OpiA as a determinant of virulence. Finally, the fluorescence fusion constructs presented here will be useful tools for dissecting the role of OpiA in infection.

Seroepidemiology, Spatial Distribution, and Risk Factors of Francisella tularensis in Jordan

There is a paucity of data on Francisella tularensis in the Middle East and North Africa. This is the first countrywide study to determine the seroprevalence, spatial distribution, and risk factors for F. tularensis in Jordan. A total of 828 Jordanians were serologically tested for F. tularensis by ELISA. These individuals filled out a self-administered questionnaire to collect demographic and risk factor information. Bivariate and multivariate logistic regressions were performed to determine which variables are associated with seropositivity. The overall seroprevalence of F. tularensis was 7.7% (95% CI: 6.10-9.75). The bivariate analyses showed that age, region of residence, small ruminant ownership, and practicing horticulture were significantly associated with seropositivity, and these variables were controlled for in the multivariate analysis. The multivariate analysis showed an increased odds of seropositivity among individuals living in northern desert, middle, and northern highland areas, compared with individuals living in the drier southern area, as 7.27 (95% CI: 2.49-21.19), 3.79 (95% CI: 1.53-9.39), and 3.52 (95% CI: 1.45-388.55), respectively. Individuals owning a small ruminant had 1.86 (95% CI: 1.02-3.40) greater odds for seropositivity than individuals who do not own a small ruminant. Individuals practicing horticulture had 2.10 (95% CI: 1.20-3.66) greater odds for seropositivity than individuals who do not practice horticulture. This is the first study to address the seroprevalence of F. tularensis in Jordan and the Middle East. Further research is needed to identify clinical cases of tularemia in Jordan and to determine the circulating F. tularensis subspecies.

Epidemiologic and Epizootic Data of Tularemia in the Past and in the Recent History in Croatia

Tularemia is a zoonotic disease caused by Francisella tularensis. A large number of recent studies have provided an update on the disease characteristics and the distribution across Europe. In Croatia, most of the clinical cases, as well as the reports of the disease in animals, date from the 20th century. In that period, epidemic and epizootic research had given detailed information about endemic regions and their characteristics, including suspected animal hosts and vectors. The region along the middle course of the Sava River, called Middle Posavina, is described as an endemic region, i.e., a “natural focus” of tularemia, in Croatia. In the 21st century, cases of human tularemia are being reported sporadically, with ulceloglandular, oropharyngeal and typhoid forms of disease. A majority of the described cases are linked with the consumption of contaminated food or water. The disease outbreaks still occur in areas along the course of the river Sava and in northwest Croatia. In this review article, we have summarized epidemiologic and epizootic data of tularemia in the past and in recent Croatian history.

Coxiella burnetii and Francisella tularensis in wild small mammals from the Czech Republic

Wild rodents are an important source of the tick-borne pathogens Coxiella burnetii and Francisella tularensis. The aim of our study was to assess the prevalence of antibodies and possible coexistence of these pathogens in wild small mammals from three localities in the Czech Republic. A total of 614 wild small mammals (324 Apodemus flavicollis, 145 Myodes glareolus, 50 Sorex araneus, 48 A. sylvaticus, 40 A. agrarius, six Microtus arvalis and one Talpa europaea) were trapped between 2012 and 2015. Their sera or heart extracts were examined by modified indirect enzyme-linked immunosorbent assay, with the detection of antibodies against C. burnetii and F. tularensis in 12 % and 7 % of animals, respectively; coinfection was identified in 4.4 % of animals. The prevalence of C. burnetii and F. tularensis antibodies statistically differed according to animal species and sex (p < 0.05); the seroprevalence of C. burnetii (p < 0.05) also differed in the sampling period. The highest prevalence of antibodies against C. burnetii and F. tularensis was detected in the case of M. glareolus (24 % and 14 %, respectively).

Ecology of Francisella tularensis

Tularemia is a Holarctic zoonosis caused by the gamma proteobacterium Francisella tularensis and is considered to be a vector-borne disease. In many regions, human risk is associated with the bites of flies, mosquitoes, or ticks. But the biology of the agent is such that risk may be fomite related, and large outbreaks can occur due to inhalation or ingestion of contaminated materials. Such well-documented human risk factors suggest a role for these risk factors in the enzootic cycle as well. Many arthropods support the growth or survival of the agent, but whether arthropods (ticks in particular) are obligately required for the perpetuation of F. tularensis remains to be demonstrated. As with most zoonoses, our knowledge of the ecology of F. tularensis has been driven with the objective of understanding human risk. In this review, we focus on the role of the arthropod in maintaining F. tularensis, particularly with respect to long-term enzootic persistence.

The European Union One Health 2018 Zoonoses Report

This report of the European Food Safety Authority and the European Centre for Disease Prevention and Control presents the results of zoonoses monitoring activities carried out in 2018 in 36 European countries (28 Member States (MS) and 8 non‐MS). The first and second most commonly reported zoonoses in humans were campylobacteriosis and salmonellosis, respectively. The European Union (EU) trend for confirmed human cases of these two diseases was stable during 2014–2018. The proportion of human salmonellosis cases due to Salmonella Enteritidis was at the same level in 2018 as in 2017. Of the 27 reporting MS, 16 met all Salmonella reduction targets for poultry, whereas 11 MS failed meeting at least one. The EU flock prevalence of target Salmonella serovars in breeding hens, laying hens, broilers and fattening turkeys decreased during recent years but stalled in breeding turkeys. Salmonella results from Competent Authorities for pig carcasses and for poultry tested through National Control Programmes were more frequently positive compared with food business operators. Shiga toxin‐producing Escherichia coli (STEC) infections in humans were the third most commonly reported zoonosis in the EU and increased from 2014 to 2018. Yersiniosis was the fourth most frequently reported zoonosis in humans in 2018 with a stable trend in 2014–2018. The number of reported confirmed listeriosis cases further increased in 2018, despite Listeria rarely exceeding the EU food safety limit tested in ready‐to‐eat food. In total, 5,146 food‐ and waterborne outbreaks were reported. Salmonella was the most commonly detected agent with S. Enteritidis causing one in five outbreaks. Salmonella in eggs and egg products was the highest risk agent/food pair. A large increase of human West Nile virus infections was reported in 2018. The report further updates on bovine tuberculosis, Brucella, Trichinella, Echinococcus, Toxoplasma, rabies, Coxiella burnetii (Q fever) and tularaemia.

A serological and molecular study on Francisella tularensis in rodents from Hamadan province, Western Iran

INTRODUCTION AND PURPOSE

Tularemia is a zoonotic disease, the most important hosts of which are rodents. Endemic regions and reservoirs of F. tularensis are not well-researched areas in Iran. The present study aimed to study F. tularensis infection in the rodent populations of western Iran.

MATERIALS AND METHODS

Samples were collected in different areas of Kabudar Ahang County in Hamadan province (west of Iran) from 2014 to 2017. Tularemia serological and molecular tests were conducted using the tube agglutination test and Real-time PCR method tracking the ISFtu2 gene. Positive serum samples were evaluated for cross-reactivity with brucellosis.

RESULTS

A total of 433 rodents, collected from 33 localities, were included in the study. The most abundant species belonged to the Persian jird (Meriones persicus; 75.5%), and Libyan jird (Meriones libycus; 10.1%). Among the studied samples, three (0.74 %) were seropositive and five (1.15%) were PCR positive. Seropositive samples were two M. persicus and one M. libycus, and PCR positive rodents were four M. persicus and one M. vinogradovi. Tularemia seropositive samples showed no cross-reactivity with brucellosis.

CONCLUSION

Given the presence of infection in rodents with tularemia agent in the studied area, it is crucial to elucidate the risks of rodent exposure to tularemia for physicians, health personnel and the general population.