Tick-borne Fever Research Articles

Serological evidence of tick-borne Crimean-Congo haemorrhagic fever and Dugbe orthonairovirus infections in cattle in Kwara State in northern Nigeria indicate independent endemics.

Crimean-Congo haemorrhagic fever orthonairovirus (CCHFV) and Dugbe orthonairovirus (DUGV) are zoonotic viruses transmitted by ticks. Whereas CCHFV has caused numerous human cases, DUGV, although less reported, shares ticks and ruminants as hosts. Since its first discovery in Nigeria in 1964, there has been no detailed sero-epidemiological investigation on DUGV in sub-Saharan Africa. This study is aimed at assessing the current seroprevalence and associated risk factors of CCHFV and DUGV infections in Nigerian cattle. Using a cross-sectional design with random sampling method, blood samples were collected from 877 cattle on pastoralist farms and at abattoirs in Kwara State, North-Central Nigeria. CCHFV IgG antibodies were detected in extracted sera using three panels of in-house indirect enzyme-linked immunosorbent assay (ELISA) based on bacteria-expressed recombinant nucleoprotein (rNP), the cattle-adapted VectoCrimean ELISA and the ID Screen CCHF double antigen multi-species ELISA, while DUGV IgG antibodies were detected using in-house indirect ELISA with bacteria-expressed rNP, indirect immunofluorescence assay and micro-Virus Neutralization test. Overall seroprevalence rates of 71.9% (631/877) and 52.8% (451/854) were obtained for CCHFV and DUGV, respectively. It was observed that 37.9% (314/829) of the cattle were co-exposed to both CCHFV and DUGV while 34.5% (286/829), 14.8% (123/829) and 12.8% (106/829) were exposed to single infections with CCHFV, DUGV or none of the two viruses, respectively. Multivariate analysis showed that only location, sex, age and tick infestation score were the risk factors that significantly affected CCHFV seroprevalence in cattle, while DUGV seroprevalence was significantly influenced by month of the year, location, cattle breed and sex (p<0.05). This is the first comprehensive sero-epidemiological surveillance for DUGV in sub-Saharan Africa. Our findings reveal widely distributed independent CCHFV and DUGV infections in cattle in Kwara State, Nigeria.

Taurolithocholic acid protects against viral haemorrhagic fever via inhibition of ferroptosis.

Bile acids are microbial metabolites that can impact infection of enteric and hepatitis viruses, but their functions during systemic viral infection remain unclear. Here we show that elevated levels of the secondary bile acid taurolithocholic acid (TLCA) are associated with reduced fatality rates and suppressed viraemia in patients infected with severe fever with thrombocytopenia syndrome virus (SFTSV), an emerging tick-borne haemorrhagic fever virus. TLCA inhibits viral replication and mitigates host inflammation during SFTSV infection in vitro, and indirectly suppresses SFTSV-mediated induction of ferroptosis by upregulating fatty acid desaturase 2 via the TGR5-PI3K/AKT-SREBP2 axis. High iron and ferritin serum levels during early infection were correlated with decreased TLCA levels and fatal outcomes in SFTSV-infected patients, indicating potential biomarkers. Furthermore, treatment with either ferroptosis inhibitors or TLCA protected mice from lethal SFTSV infection. Our findings highlight the therapeutic potential of bile acids to treat haemorrhagic fever viral infection.

A Longitudinal Analysis of Memory Immune Responses in Convalescent Crimean-Congo Hemorrhagic Fever Survivors in Uganda.

Evaluating the adaptive immune responses to natural infection with Crimean-Congo hemorrhagic fever (CCHF) virus (CCHFV) in human survivors is critical to the development of medical countermeasures. However, the correlates of protection are unknown. As the most prevalent tick-borne human hemorrhagic fever virus with case fatality rates of 5%-30% and worldwide distribution, there is an urgent need to fill these knowledge gaps. Here, we describe adaptive immune responses in a cohort of Ugandan CCHF survivors via serial sampling over 6 years. We demonstrate persistent antibodies after infection and cross-neutralization against various clades of authentic CCHFV, as well as potent effector function. Moreover, we show for the first time persistent, polyfunctional antigen-specific memory T-cell responses to multiple CCHFV proteins up to 9 years after infection. Together, this data provides immunological benchmarks for evaluating CCHFV medical countermeasures and information that can be leveraged toward vaccine immunogen design and viral target identification for monoclonal antibody therapies.

Epidemiological patterns of natural focal diseases of the Voronezh region

Diseases of animals and humans are widespread and are confined to the habitat of the reservoir. Urbanization has led to the expansion of the range of natural focal diseases with the formation of persistent anthropurgic foci.The purpose of the work was to study the epizootic manifestations of natural focal diseases and analyze the morbidity of the population of the Voronezh region. The research material was based on data from federal statistical observation forms No. 2 for 2012–2022, and the results of epizootological monitoring of the department of natural focal infections and laboratories of the Center for Hygiene and Epidemiology in the Voronezh region. A retrospective epidemiological analysis of the morbidity rate of the population of the Voronezh region was carried out, ranking administrative territories based on the method of standard deviations. The results obtained were processed using Microsoft Excel; the long-term average incidence rate, error of the mean, confidence intervals, and significance level (p) less than 0.05 were calculated. The result of the analysis showed that the long-term average incidence rate of natural focal diseases in the Voronezh region was 9.91 per 100,000 population. In the structure of nosological forms, 85.98 % were tick-borne borreliosis and hemorrhagic fever with renal syndrome. The long-term average incidence rate of Lyme disease is 4.45 per 100,000 population, hemorrhagic fever with renal syndrome is 0.87 per 100,000 population. According to the ranking results, the Ramonsky, Ternovsky and Anninsky administrative territories were classified as risk areas for the average long-term incidence of borreliosis, and the Ramonsky, Verkhnekhava and Paninsky administrative territories for hemorrhagic fever with renal syndrome. The results obtained indicate active natural foci of infections in the Voronezh region.

Recent research advances in the development of Dabie Banda virus vaccines.

Severe fever with thrombocytopenia syndrome (SFTS) is a newly identified tick-borne viral hemorrhagic fever caused by Dabie Banda virus (DBV). The virus was first discovered in eastern China in 2009 and is now considered an infectious disease with a mortality rate ranging from 6.3% to 30%. The best strategy for controlling SFTS is to develop effective vaccines. However, no approved vaccines are currently available to prevent this disease, despite the number of extensive and in-depth studies conducted on DBV in the past few years. This review focuses on the structure of DBV and the induced host immune responses which are the fundamental factors in vaccine development, and thoroughly summarizes the current research progress on DBV vaccines. The developing DBV vaccines include protein subunit vaccines, live attenuated vaccines, recombinant virus vector vaccines, and DNA vaccines. At present, almost all candidate vaccines for DBV are in the laboratory development or preclinical stages. There remain challenges in successfully developing clinically approved DBV vaccines.

A survey of the tick-borne disease Crimean-Congo hemorrhagic fever in southern Algeria: First serological evidence in the dromedary camel population

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne viral zoonosis caused by a Nairovirus, Crimean-Congo hemorrhagic fever virus (CCHFV). Despite its wide geographical distribution, the epidemiology of CCHF in northern Africa is incompletely understood and its occurrence in Algeria is virtually unknown. The present survey aimed to determine the prevalence of CCHF antibodies and to identify the potential risk factors associated with CCHFV seropositivity among the one-humped camel (Camelus dromedarius) in southern Algeria. A total of 269 camels selected randomly from slaughterhouses in three wilayas were employed in the study. Sera sampled were tested for the presence of CCHFV-specific IgG antibodies using enzyme-linked immunosorbent assay (ELISA). CCHFV seropositivity was recorded in 255 out of 269 camels accounting for a prevalence rate of 94.8% (95%CI = 92.14–97.45). The seroprevalence by origin was determined to be 97% (193/199) in imported camels and 86% (49/57) in local ones (p > 0.25). Tick presence (OR = 12.35, 95%CI = 1.41–107.43, p < 0.05) was recorded as the only potential risk factor for contracting CCHFV. This study shows for the first time that camels are exposed to CCHFV in Algeria with a significantly high seroprevalence. It also underlines the need for further research to investigate the broader extent of circulating CCHFV in the country, whether in humans, animals, or ticks.

The Tick Saliva Peptide HIDfsin2 TLR4-Dependently Inhibits the Tick-Borne Severe Fever with Thrombocytopenia Syndrome Virus in Mouse Macrophages.

Ticks transmit a variety of pathogens to their hosts by feeding on blood. The interactions and struggle between tick pathogens and hosts have evolved bilaterally. The components of tick saliva can directly or indirectly trigger host biological responses in a manner that promotes pathogen transmission; however, host cells continuously develop strategies to combat pathogen infection and transmission. Moreover, it is still unknown how host cells develop their defense strategies against tick-borne viruses during tick sucking. Here, we found that the tick saliva peptide HIDfsin2 enhanced the antiviral innate immunity of mouse macrophages by activating the Toll-like receptor 4 (TLR4) signaling pathway, thereby restricting tick-borne severe fever with thrombocytopenia syndrome virus (SFTSV) replication. HIDfsin2 was identified to interact with lipopolysaccharide (LPS), a ligand of TLR4, and then depolymerize LPS micelles into smaller particles, effectively enhancing the activation of the nuclear factor kappa-B (NF-κB) and type I interferon (IFN-I) signaling pathways, which are downstream of TLR4. Expectedly, TLR4 knockout completely eliminated the promotion effect of HIDfsin2 on NF-κB and type I interferon activation. Moreover, HIDfsin2 enhanced SFTSV replication in TLR4-knockout mouse macrophages, which is consistent with our recent report that HIDfsin2 hijacked p38 mitogen-activated protein kinase (MAPK) to promote the replication of tick-borne SFTSV in A549 and Huh7 cells (human cell lines) with low expression of TLR4. Together, these results provide new insights into the innate immune mechanism of host cells following tick bites. Our study also shows a rare molecular event relating to the mutual antagonism between tick-borne SFTSV and host cells mediated by the tick saliva peptide HIDfsin2 at the tick-host-virus interface.

Anaplasma phagocytophilum in urban and peri-urban passerine birds in Ile-de-France

Wild animals in general, birds in particular, play a key role in transporting ticks and propagating tick-borne pathogens. Several studies have confirmed the infection of birds with Anaplasma phagocytophilum, with overall prevalence varying widely from country to country and/or study to study. This zoonotic bacterium, transmitted mainly by ticks of the genus Ixodes, is responsible for granulocytic anaplasmosis in humans (HGA) and domestic animals (cats, dogs, horses). The disease is also called tick-borne fever (TBF) in ruminants. Extremely rare in the USA, TBF is very common in Europe, where it causes economic losses in livestock. Conversely, HGA is well established in the USA whereas only a few less severe cases have been observed in Europe. Current typing techniques support the existence of multiple variants with differences in virulence/pathogenicity and tropism for certain tick and host species. However, epidemiological cycles remain difficult to characterize in Europe. Several studies describe a cycle apparently involving only birds in Europe, but no such study has been conducted in mainland France. Our objectives were to search for A. phagocytophilum in passerine birds in the Ile-de-France region and to explore their diversity using groEL and ankA gene typing and multilocus sequence typing (MLST). Various tissues (spleen, liver, and skin) were collected from cadavers of 680 passerines between March and December 2021. The presence of A. phagocytophilum was detected by qPCR Taqman targeting the msp2 gene. Three blackbirds (Turdus merula) were found positive, representing detection rates of 0.4 % in all birds tested and 3.3 % in blackbirds. The higher frequency of detection in blackbirds could be at least partially explained by their lifestyle, as they feed on the ground. Analysis of the results of groEL and ankA typing and MLST from positive blackbirds support the hypothesis that the avian A. phagocytophilum strains in Ile-de-France are distinct from those found in mammals, and that they form their own cluster in Europe.

IFITM3 inhibits severe fever with thrombocytopenia syndrome virus entry and interacts with viral Gc protein.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne hemorrhagic fever disease with high fatality rate of 10%-20%. Vaccines or specific therapeutic measures remain lacking. Human interferon inducible transmembrane protein 3 (hIFITM3) is a broad-spectrum antiviral factor targeting viral entry. However, the antiviral activity of hIFITM3 against SFTS virus (SFTSV) and the functional mechanism of IFITM3 remains unclear. Here we demonstrate that endogenous IFITM3 provides protection against SFTSV infection and participates in the anti-SFTSV effect of type Ⅰ and Ⅲ interferons (IFNs). IFITM3 overexpression exhibits anti-SFTSV function by blocking Gn/Gc-mediated viral entry and fusion. Further studies showed that IFITM3 binds SFTSV Gc directly and its intramembrane domain (IMD) is responsible for this interaction and restriction of SFTSV entry. Mutation of two neighboring cysteines on IMD weakens IFITM3-Gc interaction and attenuates the antiviral activity of IFITM3, suggesting that IFITM3-Gc interaction may partly mediate the inhibition of SFTSV entry. Overall, our data demonstrate for the first time that hIFITM3 plays a critical role in the IFNs-mediated anti-SFTSV response, and uncover a novel mechanism of IFITM3 restriction of SFTSV infection, highlighting the potential of clinical intervention on SFTS disease.

Identification of CCL20 as a Prognostic Predictor for Severe Fever With Thrombocytopenia Syndrome Based on Plasma Proteomics.

Severe fever with thrombocytopenia syndrome (SFTS), a lethal tick-borne hemorrhagic fever, prompted our investigation into prognostic predictors and potential drug targets using plasma Olink Proteomics. Employing the Olink assay, we analyzed 184 plasma proteins in 30 survivors and 8 nonsurvivors of SFTS. Validation was performed in a cohort of 154 patients with SFTS via enzyme-linked immunosorbent assay. We utilized the Drug-Gene Interaction Database to identify protein-drug interactions. Nonsurvivors exhibited 110 differentially expressed proteins as compared with survivors, with functional enrichment in the cell chemotaxis-related pathway. Thirteen differentially expressed proteins-including C-C motif chemokine 20 (CCL20), calcitonin gene-related peptide alpha, and pleiotrophin-were associated with multiple-organ dysfunction syndrome. CCL20 emerged as the top predictor of death, demonstrating an area under the curve of 1 (P = .0004) and 0.9033 (P < .0001) in the discovery and validation cohorts, respectively. Patients with CCL20 levels exceeding 45.74 pg/mL exhibited a fatality rate of 45.65%, while no deaths occurred in those with lower CCL20 levels. Furthermore, we identified 202 Food and Drug Administration-approved drugs targeting 37 death-related plasma proteins. Distinct plasma proteomic profiles characterize SFTS cases with different outcomes, with CCL20 emerging as a novel, sensitive, accurate, and specific biomarker for predicting SFTS prognosis.

Big Epidemic of Small City: Crimean-Congo Hemorrhagic Fever.

Crimean-Congo hemorrhagic fever (CCHF) is the most common tick-borne viral hemorrhagic fever in our country and the world. While investigating the etiology of fever, tick contact should be questioned, especially in rural areas, and CCHF should be remembered. This study aimed to review the characteristics of the cases detected in Bayburt, one of the cities where CCHF is endemic. A total of 100 patients aged 16 years and older who were diagnosed with CCHF in our clinic between April 2020 and October 2022 were included in the study. Demographic, epidemiological, and clinical characteristics, treatments, and prognoses of the patients were reviewed retrospectively through the hospital automation system and CCHF information system of The Ministry of Health. Sixty one (61%) of the patients included in the study were male, and their primary age (± standard deviation) was 50.4±15.7. 77% of the patients engaged in farming and or animal husbandry, and 71% were living in rural areas. The highest number of cases was in June and July. 63% of the patients had a history of a tick bite. At the first presentation, there were complaints of fatigue (95%), generalized body pain (84%), headache (67%), and fever (65%), in order of frequency. Ribavirin was started in 52 (52%) patients. One patient admitted in the late period died, and 99 patients were discharged with good recovery. CCHF is an important public health problem that has been causing seasonal epidemics in our country for nearly two decades. Although sporadic cases have been reported from almost every region, the disease is endemic in some areas. Since signs and symptoms are not specific, the disease can be easily missed when tick contact is not questioned. Therefore CCHF should be considered in patients presenting with fever and thrombocytopenia in rural areas, especially in the spring and summer months.

Temporal patterns of gene expression in response to inoculation with a virulent Anaplasma phagocytophilum strain in sheep

The aim of this study was to characterize the gene expression of host immune- and cellular responses to a Norwegian virulent strain of Anaplasma phagocytophilum, the cause of tick-borne fever in sheep. Ten sheep were intravenously inoculated with a live virulent strain of A. phagocytophilum. Clinical-, observational-, hematological data as well as bacterial load, flow cytometric cell count data from peripheral blood mononuclear cells and host’s gene expression post infection was analysed. The transcriptomic data were assessed for pre-set time points over the course of 22 days following the inoculation. Briefly, all inoculated sheep responded with clinical signs of infection 3 days post inoculation and onwards with maximum bacterial load observed on day 6, consistent with tick-borne fever. On days, 3–8, the innate immune responses and effector processes such as IFN1 signaling pathways and cytokine mediated signaling pathways were observed. Several pathways associated with the adaptive immune responses, namely T-cell activation, humoral immune responses, B-cell activation, and T- and B-cell differentiation dominated on the days of 8, 10 and 14. Flow-cytometric analysis of the PBMCs showed a reduction in CD4+CD25+ cells on day 10 and 14 post-inoculation and a skewed CD4:CD8 ratio indicating a reduced activation and proliferation of CD4-T-cells. The genes of important co-stimulatory molecules such as CD28 and CD40LG, important in T- and B-cell activation and proliferation, did not significantly change or experienced downregulation throughout the study. The absence of upregulation of several co-stimulatory molecules might be one possible explanation for the low activation and proliferation of CD4-T-cells during A. phagocytophilum infection, indicating a suboptimal CD4-T-cell response. The upregulation of T-BET, EOMES and IFN-γ on days 8–14 post inoculation, indicates a favoured CD4 Th1- and CD8-response. The dynamics and interaction between CD4+CD25+ and co-stimulatory molecules such as CD28, CD80, CD40 and CD40LG during infection with A. phagocytophilum in sheep needs further investigation in the future.

Crimean-Congo Haemorrhagic Fever: A Potentially Fatal Outbreak in Pakistan

Africa, the Balkans, parts of the Middle East, and Asia are endemic for tick-borne Crimean-Congo hemorrhagic fever (CCHF)1. The disease is more common in persons infected with Hyalomma ticks or who come in contact with sick cattle tissues after slaughter2. The virus, which has a high case-fatality rate, can cause epidemics in anyone who comes across infected bodily fluids and has caused health facility outbreaks.3The four illness load in Pakistan includes transmissible, not transmissible, mental disorders, and accidents. Additionally, some rising health problems are straining limited national healthcare resources. A good instance is Crimean-Congo Haemorrhagic Fever (CCHF).CCHF-endemic countries fight the infection. A World Health Organisation statement stated that roughly 212 instances, 27 of them life-threatening, were documented in Iraq in 2022 among different governorates. CCHF-free nations still test ticks for the disease4. The Ministry of Health in France found the very first CCHF in Hyalomma ticks from livestock in the southern Eastern Pyrenees5. Ticks have been reported in the Mediterranean coast, especially Corsica. Spain has documented domestically acquired illnesses in humans since 2016, including in medical practitioners6. The first documented CCHF patient in Pakistan was identified in 1976, with the following isolated instances and epidemics7.

Anaplasma phagocytophilum Ecotype Analysis in Cattle from Great Britain.

Anaplasma phagocytophilum (A. phagocytophilum) is the aetiological agent of tick-borne fever in cattle and sheep, and granulocytic anaplasmosis in human and dogs. Livestock, companion animal and human infections with A. phagocytophilum have been reported globally. Across England and Wales, two isolates (called ecotypes) have been reported in ticks. This study examined A. phagocytophilum isolates present in livestock and wildlife in Great Britain (GB), with a particular focus on cattle. Clinical submissions (EDTA blood) from cattle (n = 21) and sheep (n = 3) were received by APHA for tick-borne disease testing and the animals were confirmed to be infected with A. phagocytophilum using a PCR targeting the Msp2 gene. Further submissions from roe deer (n = 2), red deer (n = 2) and Ixodes ricinus ticks (n = 22) were also shown to be infected with A. phagocytophilum. Subsequent analysis using a nested PCR targeting the groEL gene and sequencing confirmed the presence of ecotype I in cattle, sheep, red deer and Ixodes ricinus, and ecotype II in roe deer and I. ricinus removed from deer carcasses. Despite the presence of two ecotypes, widely distributed in ticks from England and Wales, only ecotype I was detected in cattle in this study.

Detection of Anaplasma phagocytophilum in fetal and placental tissue of bovine abortions and perinatal mortalities.

Anaplasma phagocytophilum is a tick-borne zoonotic bacterium that is the aetiologic pathogen of tick-borne fever (TBF) in ruminants. In clinical bovine cases of TBF, abortion and stillbirth may be observed. However, in this regard, the pathophysiology of TBF has not yet been completely elucidated, and no clear guidelines to diagnose A. phagocytophilum-related abortions and perinatal mortalities (APM) are available. This exploratory study aimed to investigate the presence of A. phagocytophilum in bovine cases of APM and determine whether placental or fetal spleentissuehas the greatest sensitivity for A. phagocytophilum identification. The placenta and fetal spleen of 150 late-term bovine APM cases were analysed using real-time PCR to detect A. phagocytophilum. A total of 2.7% of sampled placentas were positive for A. phagocytophilum, while none of the fetal spleen samples was. No histopathology to detect associated lesions was performed. Consequently, no evidence of causality between the detection of A. phagocytophilum and APM events could be achieved. The detection of A. phagocytophilum suggests a potential role of this pathogen in bovine APM, and placental tissue seems to be the most suitable tissue for its identification.

The role of social vulnerability in improving interventions for neglected zoonotic diseases: The example of Kyasanur Forest Disease in India.

Forest-based communities manage many risks to health and socio-economic welfare including the increasing threat of emerging zoonoses that are expected to disproportionately affect poor and marginalised groups, and further impair their precarious livelihoods, particularly in Low-and-Middle Income (LMIC) settings. Yet, there is a relative dearth of empirical research on the vulnerability and adaptation pathways of poor and marginalised groups facing emerging zoonoses. Drawing on a survey of 229 households and a series of key-informant interviews in the Western Ghats, we examine the factors affecting vulnerability of smallholder and tribal households to Kyasanur Forest Disease (KFD), an often-fatal tick-borne viral haemorrhagic fever endemic in south India. Specifically, we investigate how different socio-demographic and institutional factors interact to shape KFD vulnerability and the strategies employed by households to adapt to disease consequences. Although surveyed households generally perceived KFD as an important health issue in the study region, there was variability in concern about contracting the disease. Overall results showed that poor access to land (AOR = 0.373, 95% CI: 0.152-0.916), being at or below the poverty line (AOR = 0.253, 95% CI: 0.094-0.685) and being headed by an older person (AOR = 1.038, 95% CI: 1.006-1.071) were all significant determinants of perceived KFD vulnerability. Furthermore, KFD vulnerability is also modulated by important extra-household factors including proximity to private hospitals (AOR = 3.281, 95% CI: 1.220-8.820), main roads (AOR = 2.144, 95% CI: 1.215-3.783) and study location (AOR = 0.226, 95% CI: 0.690-0.743). Our findings highlight how homogenous characterisation of smallholder and tribal communities and the 'techno-oriented' approach of existing interventions may further marginalise the most vulnerable and exacerbate existing inequalities. These findings are important for designing context-specific and appropriate health interventions (including the prioritisation of awareness raising, knowledge networks, livelihood diversification) that enhances the resilience of at-risk social groups within the KFD context. More broadly, our findings highlight how a focus on social vulnerability can help national and international health planners improve health interventions and prioritise among diseases with respect to neglected endemic zoonoses.

Investigating the effect of ribavirin treatment on genetic mutations in Crimean-Congo haemorrhagic fever virus (CCHFV) through next-generation sequencing.

Crimean-Congo haemorrhagic fever (CCHF) is the most widespread tick-borne viral haemorrhagic fever affecting humans, and yet a licensed drug against the virus (CCHFV) is still not available. While several studies have suggested the efficacy of ribavirin against CCHFV, current literature remains inconclusive. In this study, we have utilised next-generation sequencing to investigate the mutagenic effect of ribavirin on the CCHFV genome during clinical disease. Samples collected from CCHF patients receiving ribavirin treatment or supportive care only at Sivas Cumhuriyet University Hospital, Turkey, were analysed. By comparing the frequency of mutations in each group, we found little evidence of an overall mutagenic effect. This suggests that ribavirin, administered at the acute stages of CCHFV infection (at the World Health Organization-recommendeddose) is unable to induce lethal mutagenesis that would cause an extinction event in the CCHFV population and reduce viremia.

Presence of Anaplasma phagocytophilum Ecotype I in UK Ruminants and Associated Zoonotic Risk.

Anaplasma phagocytophilum is the causative agent of tick-borne fever in sheep, pasture fever in cattle, and granulocytic anaplasmosis in humans. The increasing prevalence and transboundary spread of A. phagocytophilum in livestock, ticks, and wildlife in the UK poses a potential zoonotic risk that has yet to be estimated. Several ecotypes of A. phagocytophilum show variable zoonotic potential. To evaluate the possible risk associated with the transmission of A. phagocytophilum from ruminants to humans, the ecotype was determined by sequencing the groEL gene from 71 positive blood and tissue samples from UK ruminants. Thirty-four groEL sequences were obtained, fourteen of which were identified in multiple samples. Of the 13 nucleotide polymorphisms identified through pairwise comparison, all corresponded to synonymous substitutions. The subsequent phylogenetic estimation of the relationship with other European/world isolates indicated that all the groEL sequences clustered with other ecotype I sequences. The presence of ecotype I closely reflects that observed in ruminants in continental Europe and suggests a lower risk of zoonotic transmission from this reservoir.

Metatranscriptomics Reveals the Diversity of the Tick Virome in Northwest China.

ABSTRACTBlood-sucking ticks are obligate parasites and vectors of a variety of human and animal viruses. Some tick-borne viruses have been identified as pathogens of infectious diseases in humans or animals, potentially imposing significant public health burdens and threats to the husbandry industry. Therefore, identifying the profiles of tick-borne viruses will provide valuable information about the evolution and pathogen ecology of tick-borne viruses. In this study, we investigated the viromes of parasitic ticks collected from the body surfaces of herbivores in Xinjiang Uyghur Autonomous Region and Inner Mongolia Autonomous Region of China, two regions in northwest China. By using a metatranscriptomic approach, 17 RNA viruses with high diversity in genomic organization and evolution were identified. Among them, nine are proposed to be novel species. The classified viruses belonged to six viral families, including Phenuiviridae, Rhabdoviridae, Peribunyaviridae, Lispiviridae, Chuviridae, and Reoviridae, and unclassified viruses were also identified. In addition, although some viruses from different sampling locations shared significant similarities, the abundance and diversity of viruses notably varied among the different collection locations. This study demonstrates the diversity of tick-borne viruses in Xinjiang and Inner Mongolia and provides informative data for further study of the evolution and pathogenicity of these RNA viruses.IMPORTANCE Ticks are widely distributed in pastoral areas in northwestern China and act as vectors that carry and transmit a variety of pathogens, especially viruses. Our study revealed the diversity of tick viruses in Xinjiang and Inner Mongolia and uncovered the phylogenetic relationships of some RNA viruses, especially the important zoonotic tick-borne severe fever with thrombocytopenia syndrome virus in Inner Mongolia. These data suggest a complex and diverse evolutionary history and potential ecological factors associated with pathogenic viruses. The pathogenicity of these tick-borne viruses currently remains unclear. Therefore, future research should focus on evaluating the transmissability and pathogenicity of these tick-borne viruses.

Distribution of the causative agent of relapsing tick-borne fever &lt;i&gt;Borrelia miyamotoi&lt;/i&gt; in natural focus in the Tomsk region

BACKGROUND: Knowledge about the infectious potential of the causative agent of recurrent tick-borne fever Borrelia miyamotoi and the role of this pathogen in the etiological structure formation of transmissible natural focal infections in a number of regions remains incomplete. Among them is the Tomsk region where in 2021 the incidence of ixodic tick-borne borreliosis was 15.7 per 100,000 population, which is 3.6 times higher than the all-Russian indicator.&#x0D; AIMS: This study aimed to summarize and analyze epidemiological data, as well as the results of our own clinical observations and laboratory studies conducted in 20152021 confirming the distribution of the causative agent of relapsing tick-borne fever B. miyamotoi in the Tomsk region.&#x0D; MATERIALS AND METHODS: Epidemiological data on the manifestation of the natural foci of tick-borne infections were analyzed in the Tomsk region for the period 20152021. A clinical case of febrile infection caused by B. miyamotoi infection is described as an example of underdiagnosis of relapsing tick-borne fever. Verification of the etiological variant of borreliosis was carried out using real-time PCR. DNA extraction and detection of B. miyamotoi genetic markers were performed using RealBest series kits (Vector-Best, Novosibirsk), followed by nucleic acid sequencing of B. miyamotoi 23SrRNA, glpQ, and recA gene sequences. Ixodid ticks (Ixodes persulcatus, Ixodes pavlovskyi, Dermacentor reticulatus) collected from the Tomsk region were studied for infestation with B. miyamotoi. The detection of genetic markers of pathogenic Borrelia was carried out in nucleic acid samples isolated from tick homogenates using kits of the RealBest series (Vector-Best, Novosibirsk).&#x0D; RESULTS: In 2016, the first clinical case of borreliosis caused by B. miyamotoi was confirmed by molecular genetic methods in the Tomsk region. During the period 20152021, the infection rate of B. miyamotoi ticks of the genus Ixodes in the Tomsk region was up to 7%, ticks of the genus Dermacentor ― up to 3%.&#x0D; CONCLUSION: The results of this study demonstrated the distribution of the causative agent of relapsing tick-borne fever B. miyamotoi in the natural foci of the Tomsk region, which requires further monitoring of the epizootic situation and study of the role of this pathogen in the formation of the etiological structure of transmission natural focal infections.