Crimean-Congo Hemorrhagic Fever, Spain, 2013-2021

Serological evaluation of Crimean-Congo Hemorrhagic fever in humans with High-Risk professional exposure and in residual sera collected in 2022-2023 across Corsica (France)

Background

The Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne pathogen known to cause severe viral hemorrhagic fever.

Aim

We aimed to evaluate the potential circulation of CCHFV in Corsica through a serosurvey, including anonymized residual sera (RS) and high-risk individuals exposed to animals and/or tick bites due to occupational activities.

Methods

This cross-sectional study involved two groups: anonymized RS from medical biology laboratories and sera from high-risk individuals (slaughterhouse workers, veterinary professionals, animal farmers, and rangers) collected across Corsica during 2022-2023. Antibodies targeting the CCHFV viral nucleoprotein were detected using a double-antigen ELISA. ELISA-positive samples underwent neutralizing antibody testing. Sociodemographic and epidemiological data were collected using a structured questionnaire in the high-risk group.

Results

Total anti-CCHFV seropositivity was of 0.08 % (n = 2) [95 % Confidence Interval (CI): 0.06-0.09] in RS and of 0.50 % (n = 1) [95 % CI: 0.43-0.56] in high-risk groups (p < 0.01). Lifetime tick-bites was reported by 65.9 % (n = 118) of respondents, with higher rates among farmers (Odds Ratio (OR) = 3.4; 95 % CI 1.4-8.5) and participants with >10 years of occupational exposure (OR = 3.8; 95 % CI 1.7-8.5).

Conclusions

This study provides initial evidence of human exposure to CCHFV in Corsica, with rates consistent with those observed in other Western European regions. Our results indicate a risk of CCHF among the Corsican population, particularly among farmers and slaughterhouse workers. Continuous surveillance and public education are essential to mitigate this risk, especially among these targeted groups and healthcare professionals, ensuring prompt diagnosis and prevention of potential outbreaks.

Modelling the small spatial scale questing abundance of Hyalomma lusitanicum Koch, 1844 (Acari: Ixodidae), vector of Crimean-Congo haemorrhagic fever virus

Free-living ticks such as Hyalomma lusitanicum pose a risk to their hosts primarily due to their role as vectors of diseases, with Crimean-Congo haemorrhagic fever (CCHF) being an emerging disease of particular concern in the Iberian Peninsula. This study aims to understand the environmental determinants as well as the host effects that influence the abundance of H. lusitanicum at a small spatial scale. Understanding these factors is essential in identifying areas with a higher risk of tick abundance and, consequently, a greater likelihood of encountering a tick. We conducted 3,840 drags in 32 sampling points in a continental area of the Iberian Peninsula during the peak activity of H. lusitanicum, in May 2021 (1,800 drags in 15 points) and May 2022 (2,040 drags in 17 points). As potential factors influencing H. lusitanicum abundance, we modelled suitability for red deer and we estimated environmental variables that could influence the existence of optimal microhabitats for H. lusitanicum. We modelled H. lusitanicum abundance, performing generalized linear mixed models with a zero-inflated negative binomial distribution, using the abundance per drag as a response variable. We found that a higher local suitability for red deer is the primary determinant of small-scale abundance of H. lusitanicum in our study area. We found other significant factors that affect the abundance of H. lusitanicum which determine the presence of suitable microhabitats, such as adequate vegetation types (suggested by vegetation height), grasslands and mixed vegetation types, and low terrain permeability. This information will significantly aid in the development of more integrated, environmentally friendly, and effective long-term strategies for tick control and the prevention of tick-borne pathogens in regions with climatic and landscape conditions similar to those of our study site.

Prime-Boost Vaccination Based on Nanospheres and MVA Encoding the Nucleoprotein of Crimean-Congo Hemorrhagic Fever Virus Elicits Broad Immune Responses

Background/Objectives: Crimean-Congo hemorrhagic fever virus (CCHFV) is an emerging, widely distributed zoonotic tick-borne pathogen. The virus causes severe disease in humans, and numerous wild and domestic animals act as reservoirs of it. Unfortunately, there are no effective therapies or safe vaccines commercialized nowadays for this particular virus. As CCHF (Crimean-Congo hemorrhagic fever) is a serious threat to public health, there is an urgent need to investigate the development of safe and effective vaccination strategies further. Methods: In this work, we have employed two immunization platforms based on protein nanoparticles and a modified vaccinia Ankara (MVA) viral vector using the nucleoprotein (NP) as the target antigen. The humoral and cellular immune responses were characterized by ELISA, ICS, and cytokine measurement. Results: This work shows that a single dose of the vaccine candidates was not as immunogenic as the heterologous vaccination using nanoparticles and MVA. A prime with NP nanoparticles (NS-NP) and a boost with MVA-expressing NP were capable of triggering significant levels of humoral and cellular immune responses against CCHFV in mice. Conclusions: Our study shows that the NS-NP/MVA-NP vaccination strategy effectively elicits a robust humoral and cellular immune response in a mouse model, emphasizing its potential as a protective approach against CCHFV lineages.

Cases of high-consequence infectious diseases identified in the UK, 1962-2023

The management of patients with acute infectious diseases can present significant challenges, especially if the causative agent has a propensity for person-to-person transmission. In such cases, effective patient management is dependent on both rapid identification of disease and the provision of necessary medical care while adhering to suitable infection prevention and control measures to reduce the potential for onwards transmission. The UK has operated a defined system for managing patients with high-consequence infectious diseases (HCIDs) since the 1970s, when protocols were first implemented following the first descriptions of several viral haemorrhagic fever diseases, including Marburg virus disease, Lassa fever and Ebola virus disease (EVD). While more than 200 people with HCIDs have been treated in UK hospitals since the 1970s, most of these patients had COVID-19 or mpox during the early phases of new public health emergencies of international concern (PHEICs), prior to their removal from the UK HCID list in March 2020 and June 2022, respectively. Excluding PHEICs, 26 patients have been treated in HCID treatment centres between 1962 and 2023: 10 patients with Lassa fever, 7 with mpox prior to the 2022 PHEIC, 4 with Middle East respiratory syndrome (MERS), 4 with EVD and 1 with Crimean-Congo haemorrhagic fever (CCHF). In total, 15 additional HCID patients were identified where treatment in a specialist centre did not occur due to retrospective diagnosis (4 patients with Lassa fever), mild or moderate illness [5 patients with avian influenza A(H5N1), 1 with MERS and 1 with CCHF] or death prior to transfer (2 patients with Lassa fever, 1 with CCHF and 1 with pneumonic plague). Here we summarize the UK HCID experience, including details about their detection, patient management and outcomes.

Changes in the epidemiology of Crimean-Congo hemorrhagic fever: Impact of travel and a One Health approach in the European region

BACKGROUND

The World Health Organization has identified Crimean-Congo hemorrhagic fever (CCHF) as a priority disease for research and development in emergency contexts. The epidemiology of CCHF is evolving and this review highlights travel-associated cases and focuses on the need for a One Health approach in Europe.

METHODS

For this narrative review, two searches were performed in PubMed and Google Scholar for the period 1980-October 2024. The first search identified travel-associated CCHF cases globally, additional cases were identified in the ProMED mail database and through healthmap.org. The second search, with a focus on the European region, aimed to analyse reports of CCHF virus (CCHFV) detected in ticks, CCHF seroprevalence studies in animals and/or humans, and autochthonous CCHF cases.

RESULTS

Seventeen cases of imported CCHF, the majority acquired in Africa, were identified. Importation to European countries accounted for eight of the cases. Most patients presented with fever and hemorrhagic manifestations and the estimated case fatality rate was 35 %. In the WHO European region, at least 13 countries have reported ticks infected with different genotypes of CCHFV; 17 countries were found to have animals/humans with positive CCHF serology. Finally, 16 countries in the WHO European region have notified human cases of CCHF. The Russian Federation, Turkey, and several former USSR countries are considered highly endemic, followed by the Balkanic region, with sporadic cases emerging in Bulgaria, Greece, Spain, and recently Portugal.

CONCLUSIONS

Travel-associated CCHF is infrequent. However, given the recently reported increased geographical distribution in ticks and animals in the European region, additional human cases may be anticipated in the near future. Europe receives over half of all international tourist arrivals annually, so healthcare professionals should be aware of risk factors and current protocols for the management of suspected and confirmed cases.

Screening for Crimean-Congo Haemorrhagic Fever Virus antibodies in humans living in an endemic area of Spain

INTRODUCTION

Crimean-Congo haemorrhagic fever (CCHF) is an emerging tick-borne viral disease. It has been described in Spain in both ticks and humans. Until July 2024 most cases have been described in the central-western part of the Iberian Peninsula. This study aims to assess the seroprevalence of antibodies against CCHF virus (CCHFV) in humans in the area that has reported the highest number of cases in Spain.

METHODS

The study was conducted to estimate the seroprevalence of antibodies against CCHFV antibodies among patients referred to a hospital located in the central-western area of Spain, an endemic area for CCHFV of Spain. Patients were recruited from April 1, 2023, to June 30, 2023. A commercial ELISA was used to detect serum antibodies against the CCHFV.

RESULTS

We screened 658 samples from 370 (56.2%) men, with a mean (±SD) age of 58.6 years (±14.3). Of these, 4 were IgG positive, representing an IgG seropositivity of 0.6% (95% CI, 0.01-1.19). None of these four patients recalled having a clinical picture that strongly suggested CCHF. Over the study period, in the population analysed in an area with circulation of CCHFV the seroprevalence of antibodies was 0.6%.

CONCLUSION

Our results suggest active circulation of the virus in humans in western Spain. Although the risk of developing CCHF is currently considered low, physicians should be alert to the imminent possibility of developing new cases of CCHF.

Fatal Case of Crimean-Congo Hemorrhagic Fever, Portugal, 2024

We report a fatal case of Crimean-Congo hemorrhagic fever in Portugal. An 83-year-old man, initially suspected of having Mediterranean spotted fever, was later confirmed to have Crimean-Congo hemorrhagic fever by the detection of viral genome in the patient's serum and the presence of specific IgM antibodies.

Genomic characterization of Orthonairovirus haemorrhagiae (Crimean-Congo hemorrhagic fever virus) outbreak in North Macedonia

Crimean-Congo hemorrhagic fever virus (CCHFV) is a significant tick-borne virus causing severe hemorrhagic disease with high fatality rate. This report presents the genomic characterization of CCHFV strain from North Macedonia's first outbreak in over 50 years, emphasizing the importance of genomic surveillance in tracking virus evolution and spread patterns in this region.

Exposure to Crimean-Congo Hemorrhagic Fever Virus in Wild Ungulates in the Basque Country, Northern Iberian Peninsula

Crimean-Congo hemorrhagic fever virus (CCHFV) causes a serious human tick-borne disease. In animals, CCHFV infections are mainly subclinical. The circulation of the virus has received little attention in areas where the main vector (Hyalomma spp.) is not considered to be present or established (e.g., the Northern Iberian Peninsula). The presence of antibodies against CCHFV was evaluated in sera collected from 1190 wild boars, 36 red deer, and 36 roe deer in the Basque Country (Northern Iberian Peninsula) in 2014-2019. Antibodies were found in the three wild ungulate species with an overall prevalence of 2.5%. The highest seroprevalence was found in red deer (22.2%) and in the southwest province: Araba (8.6%). The presence of antibodies against CCHFV in wild ungulates reported in this study could be due to an underestimated presence of Hyalomma ticks, the sporadic exposure to infected Hyalomma ticks transported by animals (e.g., migratory birds), or the role of other tick species in the virus's circulation. The detection of exposed animals since 2014 suggests that the circulation of the virus beyond the southwestern regions of the Iberian Peninsula could have been more widespread than previously thought.

Development of targeted whole genome sequencing approaches for Crimean-Congo haemorrhagic fever virus (CCHFV)

Crimean-Congo haemorrhagic fever (CCHF) is the most prevalent human tick-borne viral disease, with a reported case fatality rate of 30 % or higher. The virus contains a tri-segmented, negative-sense RNA genome consisting of the small (S), medium (M) and large (L) segments encoding respectively the nucleoprotein (NP), the glycoproteins precursor (GPC) and the viral RNA-dependent RNA polymerase (RDRP). CCHFV is one of the most genetically diverse arboviruses, with seven distinct lineages named after the region they were first reported in and based on S segment phylogenetic analysis. Due to the high genetic divergence of the virus, a single targeted tiling PCR strategy to enrich for viral nucleic acids prior to sequencing is difficult to develop, and previously we have developed and validated a tiling PCR enrichment method for the Europe 1 genetic lineage. We have developed a targeted, probe hybridisation capture method and validated its performance on clinical as well as cell-cultured material of CCHFV from different genetic lineages, including Europe 1, Europe 2, Africa 2 and Africa 3. The method produced over 95 % reference coverages with at least 10x sequencing depth. While we were only able to recover a single complete genome sequence from the tested Europe 1 clinical samples with the capture hybridisation protocol, the data provides evidence of its applicability to different CCHFV genetic lineages. CCHFV is an important tick-borne human pathogen with wide geographical distribution. Environmental as well as anthropogenic factors are causing increased CCHFV transmission. Development of strategies to recover CCHFV sequences from genetically diverse lineages of the virus is of paramount importance to monitor the presence of the virus in new areas, and in public health responses for CCHFV molecular surveillance to rapidly detect, diagnose and characterise currently circulating strains.

Knowledge, perception and attitude about Crimean-Congo Haemorrhagic Fever (CCHF) among veterinary students and professionals of Spain

The Crimean-Congo haemorrhagic fever (CCHF) is a tropical viral zoonosis first reported in Spain with 17 detected cases since 2010-2024. Health professionals, including veterinarians, play a crucial role in controlling and preventing this disease. This study aimed to analyse and compare the knowledge, perceptions, and attitudes of veterinary students and professionals in Spain regarding CCHF and zoonoses in general. Additionally, the study highlighted the value of epidemiological surveys as a tool for identifying knowledge gaps related to specific diseases. A cross-sectional survey was conducted from January to April 2024 among 4th and 5th-year veterinary students, Masters and Doctorate students, and veterinarians from the public and private sectors using a validated online questionnaire. A total of 135 individuals participated, 80.7 % professionals and 19.3 % students. The study found that 76.9 % of students and 64.2 % of veterinarians had good or very good knowledge of CCHF, yet significant gaps remained, particularly in epidemiology and diagnosis. Notably, only 34.8 % had good or very good knowledge of the disease's situation in Spain, and many respondents felt their training and the information provided by official sources were inadequate. Additionally, the perception of infection risk from pets and attitudes towards preventing zoonoses through medication, vaccination, or regular analysis were concerning. Despite CCHF being an emerging disease in Spain, this survey-the first in Spain and Europe-reveals that veterinarians' knowledge and attitudes in affected regions are not as advanced as needed, underscoring the importance of targeted epidemiological surveys on the knowledge of the disease.

Why an Integrated Approach to Tick-Borne Pathogens (Bacterial, Viral, and Parasitic) Is Important in the Diagnosis of Clinical Cases

Tick-borne diseases have emerged as a major global public health problem in recent decades. The increasing incidence and geographical dissemination of these diseases requires the implementation of robust surveillance systems to monitor their prevalence, distribution, and public health impact. It is therefore not unexpected that tick-borne pathogens coexist in the same vectors, but the interactions of these agents between vectors and vertebrate hosts, including humans, remain poorly understood. The impact of infection in humans extends to the diagnostic challenges that arise when the same symptomatology can be associated with any tick-borne pathogen, and therapeutic recommendations only focus on the major or best-known tick-borne diseases, ignoring other lesser-known or less prevalent infections. Both surveillance systems and the holistic diagnosis of tick-borne pathogens are necessary tools to address the emergence of vector-borne diseases. In this study, we will focus on the main tick-borne viral, bacterial, and parasitic diseases in Spain to reflect the need to establish syndromic diagnostics in samples from patients with a history of tick bites and symptomatology compatible with them. On the other hand, and highlighting this need, innovations in molecular techniques, syndromic surveillance, and surveillance programs for ticks and tick-borne pathogens with public health implications are expected to be developed.

Vectorial dynamics underpinning current and future tick-borne virus emergence in Europe

Tick-borne diseases pose a growing threat to human and animal health in Europe, with tick-borne encephalitis virus (TBEV) and Crimean-Congo haemorrhagic fever virus (CCHFV), vectored by Ixodes ricinus and Hyalomma marginatum, respectively, emerging as primary public health concerns. The ability of ticks to transmit pathogens to multiple hosts and maintain infections across life stages makes them highly efficient vectors. However, many aspects of tick ecology and vectorial capacity remain understudied. This review examines key factors contributing to the vectorial competence of European ticks and their associated viruses. We first explore the influence of climate change on vector and disease ecology, using TBEV and CCHFV as case studies. We then analyse the role of the tick antiviral response in shaping vector competence. By integrating these elements, this review aims to enhance our understanding of tick-borne viral diseases and support the development of public health strategies, particularly through the One Health framework, to mitigate their impact in Europe.

Tick-Borne Diseases and Pregnancy: A Narrative Review Evaluating Pregnancy Complications Caused by Tick-Borne Diseases

Ticks are vectors of public health concern because the pathogens they transmit can cause detrimental diseases in humans. Lyme disease, tick-borne relapsing fever, human granulocytic anaplasmosis, Rocky Mountain spotted fever, tick-borne encephalitis, Crimean-Congo hemorrhagic fever, and babesiosis are some of the most common diseases caused by the pathogens transmitted by ticks. The overlap between human activities and tick habitats is growing, contributing to an increase in tick-borne disease cases. Unfortunately, pregnancy as a risk factor for tick-borne diseases is largely ignored. In this narrative review we use case reports, epidemiological studies, and animal studies to evaluate the maternal, pregnancy, and fetal outcomes caused by Lyme disease, tick-borne relapsing fever, human granulocytic anaplasmosis, Rocky Mountain spotted fever, tick-borne encephalitis, Crimean-Congo hemorrhagic fever, and babesiosis during pregnancy.

Implementation of a High-Level Isolation Unit Readiness Checklist in the Irish Setting

A high-level isolation unit (HLIU) is a specially designed biocontainment unit for suspected or confirmed high-consequence infectious diseases. For most HLIUs, maintaining readiness during times of inactivity is a challenge. In this case study, we describe a checklist approach to assess HLIU readiness to rapidly operate upon activation. This checklist includes readiness criteria in several domains, such as infrastructure, human resources, and material supplies, that are required to safely activate the unit at any time. The checklist audit tool was derived from a novel activation readiness checklist published by the biocontainment unit at The Johns Hopkins Hospital in Baltimore, Maryland. It was then adapted for the Irish healthcare setting and implemented at the Mater Misericordiae University Hospital, Ireland's current isolation facility. Results from the audit were also used to inform recommendations for the construction of a new HLIU to open in 2025. The audit tool is user friendly, practical, and focuses on the essential elements of readiness to ensure a successful rapid operation.

Crimean Congo hemorrhagic fever virus nucleoprotein and GP38 subunit vaccine combination prevents morbidity in mice

Immunizing mice with Crimean-Congo hemorrhagic fever virus (CCHFV) nucleoprotein (NP), glycoprotein precursor (GPC), or with the GP38 domain of GPC, can be protective when the proteins are delivered with viral vectors or as a DNA or RNA vaccine. Subunit vaccines are a safe and cost-effective alternative to some vaccine platforms, but Gc and Gn glycoprotein subunit vaccines for CCHFV fail to protect despite eliciting high levels of neutralizing antibodies. Here, we investigated humoral and cellular immune responses and the protective efficacy of recombinant NP, GP38, and GP38 forms (GP85 and GP160) associated with the highly glycosylated mucin-like (MLD) domain, as well as the NP + GP38 combination. Vaccination with GP160, GP85, or GP38 did not confer protection, and vaccination with the MLD-associated GP38 forms blunted the humoral immune responses to GP38, worsened clinical chemistry, and increased viral RNA in the blood compared to the GP38 vaccination. In contrast, NP vaccination conferred 100% protection from lethal outcome and was associated with mild clinical disease, while the NP + GP38 combination conferred even more robust protection by reducing morbidity compared to mice receiving NP alone. Thus, recombinant CCHFV NP alone is a promising vaccine candidate conferring 100% survival against heterologous challenge. Moreover, incorporation of GP38 should be considered as it further enhances subunit vaccine efficacy by reducing morbidity in surviving animals.

Infectious risks associated with outdoor sports activities

In France, outdoor sports and activities account for 36% of sports engagement, making outdoor venues the most popular settings for sports participation. Discussing the links between sports and health almost always highlights the beneficial impact of engaging in sports. However, due to a lack of specific notifications, infectious risks are not subject to epidemiological monitoring, and need to be better understood. Since the practice of outdoor sports has become part and parcel of many individuals' daily routines, it is essential to more accurately characterize the knowledge we have gained about the risks associated with exposure. However, directly associating the practice of a sport with an elevated risk of infectious diseases is a challenging endeavor. Sociological factors based on risk awareness and adoption of protective behaviors in response to the risk are crucial to the orientation of prevention efforts. This review deals with several (bacteriological, viral, parasitic, and mycological) infectious risks related to outdoor activities practiced in a natural field via contamination routes such as tick-bite, enteric pathogen, skin, and aerosol transmission. We have also detailed a number of preventive measures taking into account the outdoor setting (e.g., vaccination).

Approaching the complexity of Crimean-Congo hemorrhagic fever virus serology: A study in swine

Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne zoonotic orthonairovirus of public health concern and widespread geographic distribution. Several animal species are known to seroconvert after infection with CCHFV without showing clinical symptoms. The commercial availability of a multi-species ELISA has led to an increase in recent serosurveillance studies as well as in the range of species reported to be exposed to CCHFV in the field, including wild boar (Sus scrofa). However, development and validation of confirmatory serological tests for swine based on different CCHFV antigens or test principles are hampered by the lack of defined control sera from infected and non-infected animals. For the detection of anti-CCHFV antibodies in swine, we established a swine-specific in-house ELISA using a panel of swine sera from CCHFV-free regions and regions with reported CCHFV circulation. We initially screened more than 700 serum samples from wild boar and domestic pigs and observed a correlation of ≃67% between the commercial and the in-house test. From these sera, we selected a panel of 60 samples that were further analyzed in a newly established indirect immunofluorescence assay (iIFA) and virus neutralization test. ELISA-non-reactive samples tested negative. Interestingly, only a subset of samples reactive in both ELISA and iIFA displayed CCHFV-neutralizing antibodies. The observed partial discrepancy between the tests may be explained by different test sensitivities, antibody cross-reactivities or suggests that the immune response to CCHFV in swine is not necessarily associated with eliciting neutralizing antibodies. Overall, this study highlights that meaningful CCHFV serology in swine, and possibly other species, should involve the performance of multiple tests and careful interpretation of the results.

Crimean-Congo Hemorrhagic Fever Virus in Ticks Collected from Cattle, Corsica, France, 2023

We report the detection of Crimean-Congo hemorrhagic fever virus (CCHFV) in Corsica, France. We identified CCHFV African genotype I in ticks collected from cattle at 2 different sites in southeastern and central-western Corsica, indicating an established CCHFV circulation. Healthcare professionals and at-risk groups should be alerted to CCHFV circulation in Corsica.

Third International Conference on Crimean-Congo Hemorrhagic Fever in Thessaloniki, Greece, September 19-21, 2023

The Third International Conference on Crimean-Congo Hemorrhagic Fever (CCHF) was held in Thessaloniki, Greece, September 19-21, 2023, bringing together a diverse group of international partners, including public health professionals, clinicians, ecologists, epidemiologists, immunologists, and virologists. The conference was attended by 118 participants representing 24 countries and the World Health Organization (WHO). Meeting sessions covered the epidemiology of CCHF in humans; Crimean-Congo hemorrhagic fever virus (CCHFV) in ticks; wild and domestic animal hosts; molecular virology; pathogenesis and animal models; immune response related to therapeutics; and CCHF prevention in humans. The concluding session focused on recent WHO recommendations regarding disease prevention, control strategies, and innovations against CCHFV outbreaks. This meeting report summarizes lectures by the invited speakers and highlights advances in the field.

Crimean-Congo Hemorrhagic Fever Virus for Clinicians-Epidemiology, Clinical Manifestations, and Prevention

Crimean-Congo hemorrhagic fever (CCHF) is a tickborne infection that can range from asymptomatic to fatal and has been described in >30 countries. Early identification and isolation of patients with suspected or confirmed CCHF and the use of appropriate prevention and control measures are essential for preventing human-to-human transmission. Here, we provide an overview of the epidemiology, clinical features, and prevention and control of CCHF. CCHF poses a continued public health threat given its wide geographic distribution, potential to spread to new regions, propensity for genetic variability, and potential for severe and fatal illness, in addition to the limited medical countermeasures for prophylaxis and treatment. A high index of suspicion, comprehensive travel and epidemiologic history, and clinical evaluation are essential for prompt diagnosis. Infection control measures can be effective in reducing the risk for transmission but require correct and consistent application.

New records of pathogenic bacteria in different species of fleas collected from domestic and peridomestic animals in Spain. A potential zoonotic threat?

Climate change is causing many vectors of infectious diseases to expand their geographic distribution as well as the pathogens they transmit are also conditioned by temperature for their multiplication. Within this context, it is worth highlighting the significant role that fleas can play as vectors of important pathogenic bacteria. For this purpose, our efforts focused on detecting and identifying a total of 9 bacterial genera (Rickettsia sp.; Bartonella sp.; Yersinia sp.; Wolbachia sp., Mycobacterium sp., Leishmania sp., Borrelia sp., Francisella sp. and Coxiella sp.) within fleas isolated from domestic and peridomestic animals in the southwestern region of Spain (Andalusia). Over a 19-months period, we obtained flea samples from dogs, cats and hedgehogs. A total of 812 fleas was collected for this study. Five different species were morphologically identified, including C. felis, C. canis, S. cuniculi, P. irritans, and A. erinacei. Wolbachia sp. was detected in all five species identified in our study which a total prevalence of 86%. Within Rickettsia genus, two different species, R. felis and R. asembonensis were mainly identified in C. felis and A. erinacei, respectively. On the other hand, our results revealed a total of 131 fleas testing positive for the presence of Bartonella sp., representing a prevalence rate of 16% for this genus identifying two species B. henselae and B. clarridgeiae. Lastly, both Y. pestis and L. infantum were detected in DNA of P. irritans and C. felis, respectively isolated from dogs. With these data we update the list of bacterial zoonotic agents found in fleas in Spain, emphasizing the need to continue conducting future experimental studies to assess and confirm the potential vectorial role of certain synanthropic fleas.

Seroprevalence of Crimean Congo Hemorrhagic Fever Virus in Occupational Settings: Systematic Review and Meta-Analysis

Crimean Congo Hemorrhagic Fever (CCHF) Virus can cause a serious human disease, with the case fatality ratio previously estimated to be 30-40%. Our study summarized seroprevalence data from occupational settings, focusing on the following occupational groups: animal handlers, abattoir workers, farmers, healthcare workers, veterinarians, rangers, and hunters. Systematic research was performed on three databases (PubMed, EMBASE, MedRxiv), and all studies reporting seroprevalence rates (IgG-positive status) for CCHF virus were retrieved and their results were reported, summarized, and compared. We identified a total of 33 articles, including a total of 20,195 samples, i.e., 13,197 workers from index occupational groups and 6998 individuals from the general population. Pooled seroprevalence rates ranged from 4.751% (95% confidence intervals (95% CI) 1.834 to 11.702) among animal handlers, to 3.403% (95% CI 2.44 to 3.932) for farmers, 2.737% (95% CI 0.896 to 8.054) among rangers and hunters, 1.900% (95% CI 0.738 to 4.808) for abattoir workers, and 0.644% (95% CI 0.223-1.849) for healthcare workers, with the lowest estimate found in veterinarians (0.283%, 95% CI 0.040-1.977). Seroprevalence rates for abattoir workers (odds ratio (OR) 4.198, 95% CI 1.060-16.464), animal handlers (OR 2.399, 95% CI 1.318-4.369), and farmers (OR 2.280, 95% CI 1.419 to 3.662) largely exceeded the official notification rates for CCHF in the general population. CCHF is reasonably underreported, and pooled estimates stress the importance of improving the adherence to personal protective equipment use and appropriate preventive habits.

Temporal tendency, seasonality and relationship with climatic factors of Crimean-Congo Hemorrhagic Fever cases (East of Turkey: 2012-2021)

Crimean-Congo Hemorrhagic Fever continues to be an important public health problem by expanding its borders. To evaluate the temporal trend, seasonality, and relationship with the climatic factors of Crimean-Congo Hemorrhagic Fever. Study data included cases treated in two different tertiary healthcare institutions between 2012 and 2021. The demographic characteristics of the cases and the dates of admission to the hospital were determined, and they were matched with the average of the measurements (temperature, cumulative precipitation, relative humidity, wind speed) of two different meteorology stations in the study area. By calculating the crude incidence rates, the trend in years was investigated. Estimates were created by removing the incidence rates, seasonality, and trend components using the additive decomposition technique. The temporal relationship between incidence rates and climatic factors was evaluated with the help of the Autoregressive Distributed Lag Bound Test. Toda Yamamoto test was used for causality verification. The mean age of the cases (n = 974) included in the study was 47.6 ± 17.7 years, and the majority (57.3%) were in the group above 45 years of age. 56.6% of the cases were male and there was a male predominance in all age groups. Incidence rates ranged from 5.5 to 23.1/100,000 over the ten-year period and there was a significant upward trend (R2 = 0.691, p = 0.003). Cases of Crimean-Congo Hemorrhagic Fever that started in March, peaked in July and ended in October, showed a clear seasonality. A cointegration relationship was observed between case incidence rates and air temperature, cumulative precipitation, and relative humidity (p < 0.05 for all). Climatic factors can only indirectly affect the occurrence of Crimean-Congo Hemorrhagic Fever cases. However, climatic conditions that become progressively more favorable for vector ticks lead to the spread of the disease. The control measures to be taken should be prepared by considering the changing climatic conditions and prioritizing the risk groups. There is a need for information and awareness-raising studies about climate change and the growing dangers associated with it, also outside of endemic regions.