Search Results (66)

Background: Latvia is one of the most endemic tick-borne encephalitis (TBE) countries in Europe. However, assessing TBE seroprevalence and true infection rates has been challenging. Current diagnostics cannot reliably distinguish between immune responses induced by natural infection from those induced by vaccination, especially in TBE endemic countries with recommended immunisation programmes. A recently developed ELISA targeting antibodies against TBEV non-structural protein 1 (NS1) offers improved specificity for natural infection and can differentiate among three clinically relevant TBEV subtypes. Methods: We conducted a cross-sectional TBEV seroprevalence study in the Latvian population during 2019–2022, consisting of two pools: 1020 residents living in different regions of Latvia and 200 random Latvian Biobank blood samples. We used the standard anti-TBEV IgG ELISA (VIDITEST, VIDIA, Czech Republic) for the screening and detection of TBEV (whole virus) IgG antibodies and the newly established research-use anti-TBEV NS1 IgG ELISA for the detection of subtype-specific TBEV NS1 IgG antibodies against three virus subtypes: European, Siberian and Far Eastern. Results: The total TBEV seroprevalence among 1020 residents was 39.7%, representing all age cohorts of the population from all regions of Latvia. In total, 33.4% of the enrolled population were vaccinated against TBE with at least one dose of the TBE vaccine. Among the unvaccinated population, 16.3% had positive TBEV-specific IgG antibodies by standard ELISA. On the contrary, NS1-specific antibodies, indicating past natural infection, were detected in only 4.3% of the overall study population. Subtype differentiation revealed infections from all three major TBEV subtypes present in Latvia. Conclusions: In conclusion, this population-based study highlights a high risk of TBE in Latvia, with substantial seroprevalence even among unvaccinated individuals. The NS1-based ELISA enhances the accuracy of TBE surveillance and offers important clinical utility by facilitating more reliable diagnosis and case classification, regardless of vaccination status. Full article

Background: Argas persicus is a hematophagous ectoparasite of poultry and is the vector of several agents infectious to poultry. This study aims to explore the key genes affecting the ovarian development of A. persicus. Methods: RNA-seq was performed on the ovaries of A. persicus before blood-feeding, on the day of engorgement, and 6 days post-engorgement. Utilizing the threshold padj < 0.05 and|log₂(foldchange)| > 1, differentially expressed genes were identified, and hub genes were determined by constructing protein–protein interaction (PPI) networks. Results: A total of 1008 differentially expressed genes were obtained during the feeding period, including 448 up-regulated and 560 down-regulated genes. Further, 2179 differentially expressed genes were screened in the preoviposition stage, including 1957 up-regulated and 222 down-regulated genes. These genes are mainly annotated in functions such as peptidase activity (especially serine protease activity), protein folding, protein assembly, and cell component assembly, and enriched in pathways such as protein processing in endoplasmic reticulum, lysosome, glutathione metabolism, and sphingolipid metabolism. In addition, some proteins that are closely related to ovarian development, including heat shock protein 70, protein disulfide isomerase, paramyosin, troponin I, hexosaminidase, serine protease, Kunitz serine protease inhibitors, and vitellogenin, were obtained. Conclusions: These findings fill the gap in the biological data for the ovarian development of soft ticks, provide a reference database for subsequent proteomics research, and offer fundamental support for the screening and development of candidate antigens for anti-tick vaccines. Full article

Argasid ticks Ornithodoros erraticus and Ornithodoros moubata are major vectors of zoonotic pathogens, including the African swine fever virus and relapsing fever Borrelia spp., and their control is essential to reduce disease transmission. In this study, we evaluated the immunogenicity and protective efficacy of four Ornithodoros tick antigens formulated as mRNA–lipid nanoparticles (mRNA-LNPs): OeSOD, OeTSP1, OmPLA2, and Om86. Rabbits were immunised with three doses of each mRNA-LNP construct, and immune responses and tick biological parameters were assessed following infestation with both tick species. All mRNA-LNP constructs induced antigen-specific IgG responses that recognised native proteins in tick saliva and midgut extracts. Vaccination resulted in significant reductions in female oviposition and fertility, which correlated with antibody levels, and yielded protective efficacies of 21.9–41.6% against O. moubata and 23.1–41.6% against O. erraticus. Notably, the mRNA-LNPs of OeSOD and OeTSP1 outperformed their recombinant counterparts against O. moubata, and Om86 mRNA-LNP conferred markedly improved protection against both O. moubata and O. erraticus. These findings highlight the potential of mRNA-LNP vaccines to induce effective anti-argasid tick immunity and provide a promising platform for the development of sustainable strategies to control argasid ticks and associated pathogens. Full article

Tick-borne viruses (TBVs), notably Orthonairovirus haemorrhagiae (Crimean–Congo hemorrhagic fever virus, CCHFV), are emerging global health threats intensified by climate change. Rising temperatures and altered precipitation patterns are expanding the habitats of key tick vectors, increasing their survival and reproductive success. The African continent is characterized by many different climatic zones, and climatic shifts have increased or changed CCHFV transmission patterns, becoming greater risk to humans and livestock. Beyond Africa, CCHFV spread in Europe, the Middle East, and Asia and has been facilitated by factors such as livestock movement, deforestation, and migratory birds. Climate-driven shifts in tick seasonality, behavior, and vector competence may further enhance viral transmission. Addressing these challenges requires integrated responses, including enhanced surveillance, predictive modeling, and climate-adaptive vector control strategies. A One Health approach—linking environmental, animal, and human health domains—is essential. Innovative strategies such as anti-tick vaccines and sustainable vector control methods offer promise in reducing the burden of these diseases. Proactive, collaborative efforts at regional and international levels are crucial in tackling this growing public health challenge. Full article

Lyme disease (LD), caused by infection with the tick-borne bacteria, Borrelia burgdorferi, is associated with a wide array of symptoms in human patients. Variations in clinical manifestations are thought to be influenced by genetic differences among B. burgdorferi strains. In this study, we evaluated the infectivity, tissue bacterial load, pathology, and immunogenicity of five strains of B. burgdorferi sensu stricto (297 Ah130, Bb16-54, B31-A3, Bb16-126, JD1) in female C3H/HeN mice at three infectious doses (10⁴, 10⁵, 10⁶ spirochetes). We found that strains Bb16-126 and JD1 were the most infectious, resulting in 100% infection across all the tested doses. Strain Bb16-126 caused the highest bacterial burden in the heart tissue and significant carditis, whereas JD1 exhibited the lowest spirochete load in the heart and minimal carditis. In comparison, strain B31-A3 demonstrated the highest abundance in the tibiotarsal joint. Infection with all the strains induced severe lymph node hyperplasia, with JD1 producing the greatest increase in cellularity. Using a diagnostic C6 peptide ELISA, all the strains induced significant anti-C6 IgM and IgG antibody titers at 14 days post-infection; however, strain B31-A3 elicited the highest anti-C6 IgM titers. Our findings demonstrate the importance of strain diversity in shaping B. burgdorferi pathogenesis in a mouse model and provide insights for developing strain-specific diagnostic, therapeutic, and vaccine strategies. Full article

The advancement of multi-omics technologies is crucial to deepen knowledge on tick biology. These approaches, used to study diverse phenomena, are applied to experiments that aim to understand changes in gene transcription, protein function, cellular processes, and prediction of systems at global biological levels. This review addressed the application of omics data to investigate and elucidate tick physiological processes, such as feeding, digestion, reproduction, neuronal, endocrine systems, understanding population dynamics, transmitted pathogens, control, and identifying new vaccine targets. Furthermore, new therapeutic perspectives using tick bioactive molecules, such as anti-inflammatory, analgesic, and antitumor, were summarized. Taken together, the application of omics technologies can help to understand the protein functions and biological behavior of ticks, as well as the identification of potential new antigens influencing the development of alternative control strategies and, consequently, the tick-borne disease prevention in veterinary and public health contexts. Finally, tick population dynamics have been determined through a combination of environmental factors, host availability, and genetic adaptations, and recent advances in omics technologies have improved our understanding of their ecological resilience and resistance mechanisms. Future directions point to the integration of spatial omics and artificial intelligence to further unravel tick biology and improve control strategies. Full article

Background/Objective: Anti-tick vaccines represent a promising alternative to chemical acaricides for the management of ticks on wildlife; however, little progress has been made to produce a vaccine effective in wild hosts that are critical for tick reproduction, such as the white-tailed deer (Odocoileus virginianus). We recently tested Amblyomma americanum salivary and midgut extracellular vesicles as vaccine candidates in white-tailed deer, which resulted in on-host female tick mortality. The objective of this study was to identify the proteins recognized by the antibodies regenerated during these vaccinations to determine potential antigens for vaccine development for white-tailed deer. Methods: Using a proteomic approach, we characterized the cargo within salivary and midgut vesicles. Label-free quantitative proteomics were used to investigate significant changes in protein loading within extracellular vesicles in these two organs. The pre-vaccination and post-vaccination serum from three animals vaccinated with salivary and midgut vesicles and one control animal were used to identify proteins recognized by circulating antibodies. Results: We show that these salivary and midgut vesicles contain a “core-cargo” enriched in chaperones, small GTPases, and other proteins previously reported in small EVs. Label-free quantitative proteomics show significant differences in protein cargo between salivary and midgut vesicles (333 proteins out of 516). Proteomic analysis of immunoprecipitated proteins identified thirty antigens with potential for use in anti-tick vaccines, seven of which we have categorized as high priority. Conclusions: Proteins within tick salivary and midgut vesicles are recognized by antibodies from vaccinated white-tailed deer. These proteins can be further evaluated for their function and potential as vaccine candidates against ticks. Full article

The cattle tick, Rhipicephalus microplus, is the most significant ectoparasite in the cattle industry. The application of acaricides constitutes the main control method. However, inadequate treatments have serious drawbacks, including the appearance of multi-resistant ticks. Tick vaccines offer a safe and economically sustainable alternative for controlling R. microplus. Nevertheless, the efficacy of existing vaccines has been limited by polymorphisms in target antigens among strains from different geographical regions. In this study, we characterized a putative Metalloprotease from the ADAMTSL family. We analyzed three regions to evaluate their transcriptional profiling in different R. microplus tick tissues, using two constitutive genes (β-tubulin and Elfa-1) as references. The expression levels showed that ADAMTSL-R1 was upregulated 39.37-fold (p ≤ 0.05) in salivary glands. The ADAMTSL-R2 showed the highest expression, rising 7.69-fold (p ≤ 0.05) in ovaries and up to 59.39-fold (p ≤ 0.05) in egg mass. Furthermore, this region showed the highest level of conservation among Rhipicephalus isolates. The ADAMTSL-R3 was upregulated only in the egg mass. The results of this study provide a basis for future research focused on elucidating the role of these protein variants in tick biology, including their feeding mechanisms and potential implications in pathogen transmission. Understanding these factors may aid in developing an effective tick vaccine. Full article

Background/Objectives: Amblyomma sculptum is among the most dangerous ticks in South America, as it is the species most associated with humans and is the main vector of Rickettsia rickettsii. In the face of the problems related to tick control based on chemical acaricides, vaccines emerge as a promising method. In previous works, three salivary recombinant proteins (rAs8.9kDa, rAsKunitz, and rAsBasicTail) and one protein based on intestinal immunogenic regions (rAsChimera) were described with 59 to 92% vaccine efficacy against A. sculptum females. Here, we evaluate novel vaccine formulations containing binary or multiple combinations of the antigens rAs8.9kDa, rAsKunitz, rAsBasicTail, and rAsChimera against the three instars of the tick. Methods: A control group of mice was immunized with adjuvant alone (aluminum hydroxide gel) and compared to five groups immunized with formulations containing two, three, or four of the antigens. Results: The formulations were safe, with no significant alterations to host behavior and hematological or biochemical parameters. Immunizations induced a significant increase in the CD19⁺ B lymphocyte percentage in all groups, but no difference was seen for CD8⁺ and CD4⁺ T lymphocytes or CD14⁺ monocytes. The best protection was observed for the formulations containing two antigens, which reached above 98% efficacy, while the groups containing three or four antigens presented 92.7 and 94.4% efficacy, respectively. Conclusions: All antigen combinations were promising as vaccine formulations against A. sculptum. The formulation containing rAs8.9kDa and rAsChimera showed the best efficacy and should be focused on in further experiments. Full article

No effective vaccines or treatments are currently available for severe fever with thrombocytopenia syndrome (SFTS), a fatal tick-borne infectious disease caused by the SFTS virus (SFTSV). This study evaluated the potential of ¹¹¹In-labeled anti-SFTSV antibodies targeting SFTSV structural proteins as single-photon emission computed tomography (SPECT) imaging agents for the selective visualization of SFTSV-infected sites. This study used nuclear medicine imaging to elucidate the pathology of SFTS and assess its therapeutic efficacy. Immunostaining experiments confirmed that the anti-SFTSV antibody (N-mAb), which targets the N protein, specifically accumulated in SFTSV-infected Vero E6 cells. ¹¹¹In-labeled N-mAb was successfully prepared using a diethylenetriaminepentaacetic acid (DTPA) chelator, resulting in [¹¹¹In]In-DTPA-N-mAb with high radiochemical purity exceeding 95% and a radiochemical yield of 55%. Cell-binding assays using SFTSV-infected Vero E6 cells demonstrated that [¹¹¹In]In-DTPA-N-mAb binding was detectable even without membrane permeabilization, with the binding intensity correlating with infection levels. In vivo studies using SFTSV-infected A129 mice showed high spleen accumulation of [¹¹¹In]In-DTPA-N-mAb (87.5% ID/g), consistent with SFTSV tropism, compared to 12.3% ID/g in mock-infected mice. SPECT/CT imaging clearly revealed high radioactivity in these regions. Although nonspecific accumulation was noted in the liver and spleen, this issue may be mitigated through antibody modifications such as fragmentation or PEGylation. Overall, [¹¹¹In]In-DTPA-N-mAb is a promising imaging agent for non-invasive visualization of SFTSV-infected sites and may aid in elucidating SFTS pathology and assessing therapeutic efficacy. Full article

Ticks are obligate hematophagous ectoparasites that affect animals, and some of them transmit a wide range of pathogens including viruses, bacteria, and protozoa to both animals and humans. Several vaccines have shown immunogenicity and protective efficacy against ticks in animal models and definitive hosts. After several decades on anti-tick vaccine research, only a commercial vaccine based on a recombinant antigen is currently available. In this context, plants offer three decades of research and development on recombinant vaccine production to immunize hosts and as a delivery vehicle platform. Despite the experimental advances in plant-made vaccines to control several parasitosis and infectious diseases, no vaccine prototype has been developed against ticks. This review examines a panorama of ticks of veterinary importance, recombinant vaccine experimental developments, plant-made vaccine platforms, and perspectives on using this technology as well as the opportunities and limitations in the field of tick vaccine research. Full article

Despite the availability of tick-borne encephalitis (TBE) vaccines, the incidence of TBE is increasing. To understand the historical patterns of infection, we conducted a global meta-analysis of studies before December 2023 reporting human antibody prevalence against TBEV (TBE virus) among general or high-risk population groups stratified by country, collection year, serological method, and vaccination status. Pooled data were compared within groups over time by random-effects modeling. In total, 2403 articles were retrieved; 130 articles published since 1959 were included. Data were extracted from 96 general populations (117,620 participants) and 71 high-risk populations (53,986 participants) across 33 countries. Germany had the most population groups (21), and Poland had the most participants (44,688). Seven serological methods were used; conventional IgG/IgM ELISAs were the most common (44%). Four studies (1.7%) used NS1-ELISA serology. Between 1956–1991 and 1992–2022, anti-TBEV seroprevalence remained at ~2.75% across all population groups from “high-risk” areas (p = 0.458) but decreased within general populations (1.7% to 1%; p = 0.001) and high-risk populations (5.1% to 1.3%; p < 0.001), possibly due to differences in the study methodologies between periods. This global summary explores how serological methods can be used to assess TBE vaccination coverage and potential exposure to TBEV or measure TBE burden and highlights the need for standardized methodology when conducting TBE seroprevalence studies to compare across populations. Full article

The West Nile Virus (WNV), a member of the family Flaviviridae, is an emerging mosquito-borne flavivirus causing potentially severe infections in humans and animals involving the central nervous system (CNS). Due to its emerging tendency, WNV now occurs in many areas where other flaviviruses are co-occurring. Cross-reactive antibodies with flavivirus infections or vaccination (e.g., tick-borne encephalitis virus (TBEV), Usutu virus (USUV), yellow fever virus (YFV), dengue virus (DENV), Japanese encephalitis virus (JEV)) therefore remain a major challenge in diagnosing flavivirus infections. Virus neutralization tests are considered as reference tests for the detection of specific flavivirus antibodies, but are elaborate, time-consuming and need biosafety level 3 facilities. A simple and straightforward assay for the differentiation and detection of specific WNV IgG antibodies for the routine laboratory is urgently needed. In this study, we compared two commercially available enzyme-linked immunosorbent assays (anti-IgG WNV ELISA and anti-NS1-IgG WNV), a commercially available indirect immunofluorescence assay, and a newly developed in-house ELISA for the detection of WNV-NS1-IgG antibodies. All four tests were compared to an in-house NT to determine both the sensitivity and specificity of the four test systems. None of the assays could match the specificity of the NT, although the two NS1-IgG based ELISAs were very close to the specificity of the NT at 97.3% and 94.6%. The in-house WNV-NS1-IgG ELISA had the best performance regarding sensitivity and specificity. The specificities of the ELISA assays and the indirect immunofluorescence assays could not meet the necessary specificity and/or sensitivity. Full article

Acaricides are the most widely used method to control the cattle tick Rhipicephalus microplus. However, its use increases production costs, contaminates food and the environment, and directly affects animal and human health. The intensive use of chemical control has resulted in the selection of genes associated with resistance to acaricides, and consumers are increasingly less tolerant of food contamination. This scenario has increased the interest of different research groups around the world for anti-tick vaccine development, in order to reduce the environmental impact, the presence of residues in food, and the harmful effects on animal and human health. There is enough evidence that vaccination with tick antigens induces protection against tick infestations, reducing tick populations and acaricide treatments. Despite the need for an anti-tick vaccine in Mexico, vaccination against ticks has been limited to one vaccine that is used in some regions. The aim of this review is to contribute to the discussion on tick control issues and provide a reference for readers interested in the importance of using anti-tick vaccines encouraging concerted action on the part of Mexican animal health authorities, livestock organizations, cattle producers, and academics. Therefore, it is suggested that an anti-tick vaccine should be included as a part of an integrated tick management program in Mexico. Full article

This comprehensive review explores the field of anti-tick vaccines, addressing their significance in combating tick-borne diseases of public health concern. The main objectives are to provide a brief epidemiology of diseases affecting humans and a thorough understanding of tick biology, traditional tick control methods, the development and mechanisms of anti-tick vaccines, their efficacy in field applications, associated challenges, and future prospects. Tick-borne diseases (TBDs) pose a significant and escalating threat to global health and the livestock industries due to the widespread distribution of ticks and the multitude of pathogens they transmit. Traditional tick control methods, such as acaricides and repellents, have limitations, including environmental concerns and the emergence of tick resistance. Anti-tick vaccines offer a promising alternative by targeting specific tick proteins crucial for feeding and pathogen transmission. Developing vaccines with antigens based on these essential proteins is likely to disrupt these processes. Indeed, anti-tick vaccines have shown efficacy in laboratory and field trials successfully implemented in livestock, reducing the prevalence of TBDs. However, some challenges still remain, including vaccine efficacy on different hosts, polymorphisms in ticks of the same species, and the economic considerations of adopting large-scale vaccine strategies. Emerging technologies and approaches hold promise for improving anti-tick vaccine development and expanding their impact on public health and agriculture. Full article