Hyalomma marginatum, a vector for the high-consequence pathogen, the Crimean-Congo hemorrhagic fever virus (CCHFV), needs particular attention due to its impact on public health. Although it is a known vector for CCHFV, its general virome is largely unexplored. Here, we report findings from a citizen science monitoring program aimed to understand the prevalence and diversity of tick-borne pathogens, particularly focusing on Hyalomma ticks in Hungary. In 2021, we identified one adult specimen of Hyalomma marginatum and subjected it to Illumina-based viral metagenomic sequencing. Our analysis revealed sequences of the uncharacterized Volzhskoe tick virus, an unclassified member of the class Bunyaviricetes. The in silico analysis uncovered key genetic regions, including the glycoprotein and the RNA-dependent RNA polymerase (RdRp) coding regions. Phylogenetic analysis indicated a close relationship between our Volzhskoe tick virus sequences and other unclassified Bunyaviricetes species. These related species of unclassified Bunyaviricetes were detected in vastly different geolocations. These findings highlight the remarkable diversity of tick specific viruses and emphasize the need for further research to understand the transmissibility, seroreactivity or the potential pathogenicity of Volzhskoe tick virus and related species.

Revealing interactions between ticks and wild animals is vital for gaining insights into the dynamics of tick-borne pathogens in the natural environment. We aimed to elucidate the factors that determine tick infestation in wild animals by investigating ticks on invasive raccoons (Procyon lotor) in Hokkaido, Japan. We first examined the composition, intensity, and seasonal variation of ticks infesting raccoons in six study areas in Hokkaido from March 2022 to August 2023. In one study area, ticks infesting tanukis (raccoon dog, Nyctereutes procyonoides albus) were collected in May to July in both 2022 and 2023, and questing ticks were collected from the vegetation by flagging every other week in the same period. Next, we screened 17 environmental and host variables to determine factors that affect the number of ticks infesting raccoons using generalized linear (mixed) models. From 245 raccoons, we identified a total of 3,917 ticks belonging to eight species of two genera: the most prominent species were Ixodes ovatus (52.9 %), followed by Haemaphysalis megaspinosa (14.4 %), Ixodes tanuki (10.6 %), and Ixodes persulcatus (9.5 %). Ixodes ovatus was also predominant among questing ticks and ticks infesting tanukis. Although I. tanuki was frequently collected from raccoons and tanukis, it was rarely collected in the field. The variables that significantly affected the infestation on raccoons differed by genus, species and developmental stage of the tick. For instance, the infestation of adult I. ovatus was significantly affected by four variables: night-time temperature during nine days before capturing the raccoon, the size of forest area around the capture site, sex of the raccoon, and sampling season. The first two variables were also responsible for the infestation on raccoons of almost all species and stages of ticks. Our study revealed that the number and composition of ticks infesting raccoons can be affected not only by landscape of their habitats but also by weather conditions in several days before capturing.

Recently, a machine learning molecular de-extinction paleoproteomic approach was used to recover inactivated antimicrobial peptides to overcome the challenges posed by antibiotic-resistant pathogens. The authors showed the possibility of identifying lost molecules with antibacterial capacity, but the other side of the coin associated with catastrophic selection should be considered for the development of new pharmaceuticals.
Hominids evolved with catastrophic selection through inactivation of genes/proteins with positive and negative effectsMachine learning paleoproteomic and paleogenomic approaches can identify and recover inactivated biomoleculesThese extinct biomolecules may be used to develop new pharmaceuticals; however possible negative effects should be considered.

OBJECTIVE: To increase knowledge about the varied clinical manifestations of human infection with the emerging tick-borne pathogen Neoehrlichia mikurensis.
METHODS: All patients diagnosed in Sweden with N. mikurensis infection during a 10-year period (2013-2023) were investigated regarding their demographic factors, risk factors, comorbidities, clinical signs and symptoms, and laboratory results. Multivariate models were generated using \"Orthogonal Projections to Latent Structures-Discriminant Analysis\" to identify clinical and immune parameters associated with N. mikurensis infection.
RESULTS: During the 10-year period, 134 patients were diagnosed with N. mikurensis infection, 102 of whom were included in this study. Most of the patients (79%) were immunosuppressed. The main comorbidities were malignant B-cell lymphomas, multiple sclerosis, and rheumatoid arthritis. Rituximab therapy (59%) and splenectomy (14%) featured prominently. All patients resided in the southern tick-endemic part of Sweden, yet one-third of them were diagnosed in wintertime when ticks are inactive. Two asymptomatically infected blood donors were identified but transfusion-transmitted infection was not confirmed. Increased levels of C-reactive protein, orosomucoid, and total IgM in serum were associated with neoehrlichiosis. Previously unreported symptoms such as ankle edema, neck pain, numbness, and sudden deafness were detected in some patients. One case of aplastic anemia partially improved after eradication of the infection.
CONCLUSIONS: Neoehrlichiosis is a multi-faceted emerging infectious disease.

Galactose-alpha-1,3-galactose (alpha-gal) is a carbohydrate expressed by all mammals except for humans and certain old-world primates. It can be found in a plethora of products derived from mammals, including milk, organs, skeletal muscle and gelatin, in addition to products prepared with mammalian cells or constituents. In the late 2000s, an association between tick bites and the development of immunoglobulin E antibodies to the alpha-gal carbohydrate was discovered. The term \"alpha-gal syndrome\" (AGS) was then coined to describe allergic reactions to mammalian meat or other alpha-gal-containing products derived from mammals. Symptoms are often delayed several hours from consumption and can be urticarial and/or gastrointestinal. Medications and bioprosthetic inserts derived from mammals were also noted to cause allergic reactions in affected patients. Cardiac surgery, in particular, is considered high risk, given that unfractionated heparin has a bovine or porcine origin and is administered in large doses for cardiopulmonary bypass. Bioprosthetic valves have similar origins and risks. Awareness of AGS in cardiac surgery patients can lead to decreased risk preoperatively and inform management perioperatively and postoperatively. In this narrative review, we have reviewed the published literature relevant to AGS in patients undergoing cardiac surgery and shared our treatment approach.

Ticks, as hematophagous ectoparasites, can manipulate host immune and metabolic processes, causing tick-borne allergies such as α-Gal syndrome (AGS). Glycolipids with bound galactose-alpha-1-3-galactose (α-Gal) are potential allergenic molecules associated with AGS. Nevertheless, proteins and lipids lacking α-Gal modifications may contribute to tick salivary allergies and be linked to AGS. In this study, we characterized the effect of deglycosylated tick salivary proteins without lipids on treated zebrafish fed with dog food formulated with mammalian (beef, lamb, pork) meat by quantitative proteomics analysis of intestinal samples. The characterization and functional annotations of tick salivary lipids with low representation of glycolipids was conducted using a lipidomics approach. Results showed a significant effect of treatment with saliva and saliva deglycosylated protein fraction on zebrafish abnormal or no feeding (p < 0.005). Treatment with this fraction affected multiple metabolic pathways, defense responses to pathogens and protein metabolism, which correlated with abnormal or no feeding. Lipidomics analysis identified 23 lipid classes with low representation of glycolipids (0.70% of identified lipids). The lipid class with highest representation was phosphatidylcholine (PC; 26.66%) and for glycolipids it corresponded to diacylglycerol (DG; 0.48%). Qualitative analysis of PC antibodies revealed that individuals bitten by ticks were more likely to produce PC-IgG antibodies (p < 0.001). DG levels were significantly higher in tick salivary glands (p < 0.05) compared with tick saliva and salivary fractions. The α-Gal content was higher in tick saliva than in deglycosylated saliva and lipid fractions. These results support a possible role for tick salivary proteins and lipids without α-Gal modifications in AGS.

Ticks are ectoparasites of a wide range of animals and are important vectors of numerous pathogens affecting humans, livestock, and pets. This study investigates possible correlations between selected factors, altitude, soil pH, and a factor called \'amount\' (number of ticks examined in pooled samples) on the occurrence of I. ricinus ticks positive for selected tick-borne microorganisms. Questing I. ricinus ticks were collected in 2016 and 2017 across various altitudes, at two mountain ranges in central Slovakia. Tick pools were screened for the presence of Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato (Bbsl), Babesia/Theileria spp., Rickettsia spp., and tick-borne encephalitis virus (TBEV) using molecular methods. Regression analysis was employed to evaluate relationships between selected factors and the occurrence of vector-borne microorganisms. This study revealed a statistically significant influence of altitude on the occurrence of A. phagocytophilum; increasing altitude of the sampling site was associated with increased probability of pathogen occurrence. For Babesia/Theileria spp., neither altitude nor soil pH significantly affected pathogen occurrence. The occurrence of Bbsl was notably impacted by both altitude and soil pH; higher altitudes were associated with a decreased probability of pathogen presence, whereas higher soil pH increased the likelihood of pathogen occurrence. The presence of Rickettsia in a pooled sample was not affected by altitude and soil pH, but the \'amount\' factor was a significant predictor, increasing the probability of pathogen detection. Neither altitude nor soil pH had a significant impact on TBEV occurrence. The regression models showed moderate goodness-of-fit levels to the data, underscoring their utility in examining the role of altitude and soil pH on pathogen occurrence. However, they explained only a small portion of the overall variance in pathogen occurrence, indicating the presence of other significant factors not covered in this study.

The Rickettsia species transmitted by ticks are mostly classified within the spotted fever group rickettsiae (SFGR), which causes tick-borne rickettsiosis. Although efforts have been made to investigate their prevalence in the Republic of Korea (ROK), research has been limited to certain areas. Furthermore, the pooling method for ticks does not fully reflect the exact infection rate. Therefore, we aimed to perform molecular identification of SFGR in ticks to elucidate the current prevalence of tick-borne rickettsiosis in the ROK. The SFGR of ticks was identified using polymerase chain reaction targeting the 17 kDa antigen, ompA, and gltA, followed by sequencing for species identification and phylogenetic analysis. In total, 302 ticks belonging to four species (Haemaphysalis flava, H. longicornis, Ixodes nipponensis, and Amblyomma testudinarium) were collected between April and November 2022. The overall SFGR infection rate was 26.8% (81/302 patients). Both adult and nymphal ticks and the SFGR infection rate increased during April-May, reaching their peaks in June, followed by a marked decline in August and July, respectively. Phylogenetic analysis revealed three species (R. monacensis, R. heilongjiangensis, and Candidatus R. jingxinensis) of SFGR. Thus, our results emphasize the importance of tick surveys for the prevention and management of tick-borne rickettsiosis.

Cholesterol is a molecule vital for tick physiology, but ticks cannot synthesize it and rely on dietary cholesterol. Therefore, tick proteins involved in cholesterol absorption and transport, such as the Niemann-Pick type C1 domain-containing (NPC1) proteins, are promising targets for anti-tick vaccine development. The aim of this study was to assess the structure, function, and protective efficacy of the NPC1 orthologues identified previously in the midgut transcriptomes of argasid ticks Ornithodoros erraticus and Ornithodoros moubata. For this purpose, their corresponding cDNA coding sequences were cloned and sequenced, their secondary and 3D structures were predicted, and their function was evaluated through RNAi-mediated gene knockdown and in vitro feeding on blood supplemented with ezetimibe, which inhibits cholesterol binding by NPC1 proteins. Subsequently, the protective efficacy of a recombinant form of NPC1 from O. moubata (rOmNPC1) was tested in a rabbit vaccine trial. While inhibiting cholesterol absorption with ezetimibe resulted in up to 77 % mortality in adult O. moubata, NPC1 gene knockdown and vaccination with rOmNPC1 decreased female reproductive performance in terms of the number and fertility of laid eggs. This study presents the initial molecular and functional insights into NPC1 proteins in soft ticks and supports the hypothesis that disrupting cholesterol metabolism diminishes tick viability and reproduction, rendering Niemann-Pick type C1 domain-containing proteins promising targets for drugs or vaccines.

Ticks can transmit many pathogens, including arboviruses, to their vertebrate hosts. Arboviruses must overcome or evade defense mechanisms during their passage from the tick gut to the hemolymph, salivary glands, and the feeding site in the host skin. This review summarizes current knowledge of defense mechanisms in specific tick tissues and at the feeding site in the host skin. We discuss the possible roles of these defense mechanisms in viral infection and transmission. The responses of tick salivary proteins to arbovirus infection are also discussed. This review provides information that may help accelerate research on virus-tick interactions.