Search Results (265)

Rickettsia, Anaplasma, and Ehrlichia species are emerging tick-borne pathogens that cause zoonotic diseases, including rickettsiosis, anaplasmosis, and ehrlichiosis in both human and animal populations. This study aimed to investigate the prevalence of these pathogens in cattle-associated ticks from Ganzhou City, Jiangxi Province, China. Through molecular characterization using multilocus sequence analysis (16S rRNA, gltA, groEL, and ompA genes), we analyzed 392 Rhipicephalus microplus ticks collected from March to September in 2022. The PCR results showed that eight Rickettsiales bacteria were detected, including two species of Rickettsia (51/392, 13.0%), four species of Anaplasma (52/392, 13.3%), and two species of Ehrlichia (70/392, 17.9%). Notably, the circulation of multiple pathogen species within R. microplus populations demonstrates significant microbial diversity in this region. Further consideration and investigation should be given to the possible occurrence of rickettsiosis, ehrlichiosis, and anaplasmosis in humans and domestic animals. Our study provides critical baseline data for developing targeted surveillance strategies and informing public health interventions against tick-borne diseases in southeastern China. Full article

This study aimed to assess the emergence and/or re-emergence of Tick-borne Diseases (TBD) in Portugal by linking the hemoparasite burden in companion animals to vector-borne disease dynamics through a One Health approach. Between 2015 and 2024, 1169 clinically suspected animals with hemoparasite infections, treated at the Hospital Veterinário de Santarém (HVS), underwent serological confirmation for Rickettsia conorii, Babesia canis, Ehrlichia spp., and Haemobartonella spp. A total of 3791 serological tests (3.2 tests per animal) were performed and 437 animals tested positive for at least one of the four hemoparasites under investigation. From 2020 to 2024, tests nearly tripled from 894 to 2883, raising positive cases and prevalence from 29.5% to 39.9%, especially for rickettsiosis and hemobartonellosis, indicating an increased circulation of their vectors. A national vector surveillance initiative identified Hyalomma spp., Rhipicephalus sanguineus, Ixodes ricinus, and Dermacentor sp. as primary tick vectors in Portugal for the hemoparasites mentioned above and for other agents like arbovirus, such as Crimean-Congo Hemorrhagic Fever Virus (CCHFV) and tick-borne encephalitis virus (TBEV). This study found that the vectors responsible for transmitting hemoparasitosis, given the high number of serologically positive cases detected in the HVS, represent an increasing risk for TBD. These findings highlight the relevance of companion animal monitoring as an early-warning component within a One Health surveillance approach. Full article

Rhipicephalus microplus is an important biological vector as it transmits several pathogens, including Babesia bovis, the causative agent of bovine babesiosis. The available strategies for controlling B. bovis are limited, resulting in substantial challenges for both animal health and livestock management. Infection of the tick midgut is the essential first step for the transmission cycle of B. bovis, yet this process remains largely unexamined. To better understand the first step of tick infection, this study employed a proteomic approach to identify a midgut protein that responds to B. bovis infection. We then used RNA interference for gene silencing to determine if the protein is essential for R. microplus infection. The protein we identified, Rm24, is twofold upregulated in the tick midgut during B. bovis infection. We silenced the gene encoding Rm24 and examined the effect of reduced expression on both tick fitness and B. bovis infection. Our results indicated that silencing the Rm24 gene impacted the survivability of adult female ticks, which exhibited a significant reduction in viability as compared to the control and non-injected groups. Importantly, we found that suppressing the gene encoding Rm24 led to a significant decrease in the number of engorged female ticks infected, with only 15% of female ticks testing positive for B. bovis kinetes as compared to over 50% in the control groups. We also detected a significant reduction in vertical transmission of B. bovis to larval progenies. These findings suggest that the Rm24 protein is critical for infection by B. bovis and could serve as a promising target for future transmission-blocking strategies. Full article

Kyasanur Forest Disease (KFD), first reported in 1957 in the Shimoga district of Karnataka, India, has spread significantly over the past two decades, reaching both northern and southern states, with reports of monkey deaths. Haemaphysalis spp. ticks are the primary vectors, transmitting the disease to monkeys, humans, and other mammals. This study aimed to assess the prevalence, mean abundance, and mean intensity of Ixodidae ticks, including the KFD vector, in domestic animals across selected localities of the Western Ghats. A total of 2877 domestic animals were surveyed, revealing an overall tick prevalence of 44.91% (CI: 43.10–46.73), with sheep showing the highest prevalence at 47.92% (CI: 40.96–54.95). The most abundant tick species was Rhipicephalus (Boophilus) microplus, with a mean of 2.53 ± 0.66 ticks per host, which also represented the most proportionally dominant species, accounting for 39.63% of the total ticks collected. The highest mean intensity was recorded for Haemaphysalis intermedia (7.35 ± 2.03 ticks per infested animal). Regionally, Rh. (Bo.) microplus was found in 96.15% of buffaloes examined in Tamil Nadu, Haemaphysalis bispinosa in 85.19% of cattle in Maharashtra, and in 98.46% of goats in Goa. Ha. intermedia was common in 99.11% of sheep examined in Karnataka, while Ha. bispinosa was observed in 90.82% of goats in Kerala. The proportional representation of the KFD vector Haemaphysalis spinigera was 0.97%, with a mean intensity of 2.34 ± 0.04 ticks per infested animal and an overall mean abundance of 0.06 ± 0.01 ticks per host. Adult Ha. spinigera were recorded from cattle, buffaloes, sheep, goats, and dogs; however, no nymphs were detected. This study also reports the first documented occurrence of Ixodes ceylonensis in domestic animals. These findings suggest a notable presence of tick infestations in the region and emphasize the importance of continued surveillance and targeted control measures to better understand and manage potential KFD transmission risks in the Western Ghats. Full article

Gastrointestinal parasites (GIPs) and tick infestations remain critical health challenges limiting cattle productivity in rural South Africa, particularly within communal farming systems. The Eastern Cape Province, characterized by high livestock densities and variable management practices, provides a unique context in which to examine parasitic burdens across systems. This study aimed to compare the prevalence, intensity, and diversity of GIPs and tick species in cattle raised under rural communal grazing versus communal feedlot systems in the Eastern Cape Province of South Africa. A total of 160 cattle (n = 80 per system) were randomly selected for fecal and tick examinations in community-based feedlots in Holela (Centane) and Gxwalibomvu (Tsomo), as well as from surrounding rural villages. Fecal samples were analyzed using the McMaster technique to determine fecal egg counts (FEC), while tick species were identified and counted from standardized body regions. Body condition scores (BCS) were recorded, and farmer practices related to parasite control were surveyed. Results showed significantly higher GI parasite prevalence and FEC in rural community cattle compared to feedlot cattle (p < 0.05), with Haemonchus contortus and Trichostrongylus spp. being the most prevalent. Similarly, rural cattle had significantly higher tick infestation rates, dominated by Rhipicephalus microplus and Amblyomma hebraeum. Logistic regression identified rural production system, poor body condition (BCS ≤ 2), and absence of recent deworming as significant risk factors for GI parasitism (p < 0.05). Strong negative correlations were found between BCS and both FEC (r = −0.63) and tick burden (r = −0.57). Additionally, rural farmers reported lower acaricide usage and greater reliance on traditional remedies. The study confirms that rural communal systems expose cattle to higher parasitic risks due to unmanaged grazing, limited veterinary support, and poor parasite control strategies. Communal feedlots, by contrast, offer more controlled conditions that reduce parasitic burden. Integrating strategic parasite management, farmer training, and expanded veterinary outreach is essential to improving cattle health and productivity in communal areas. Full article

Ehrlichia canis is a tick-transmitted zoonotic pathogen in dogs. We conducted a molecular survey for screening of E. canis infection in Rhipicephalus sanguineus ticks infesting dogs and identified its genetic identity in Taiwan. A total of 1195 R. sanguineus ticks were collected and examined for Ehrlichia infection by nested-PCR assay targeting the 16S ribosomal RNA (rRNA) gene. In general, Ehrlichia infection was detected in 1.5% of examined ticks, and was detected in nymph, male and female stages with infection rates of 0.6%, 1.31% and 2.76%, respectively. The highest monthly prevalence was observed in August with an infection rate of 5.91%. Genetic identity was analyzed by comparing the 16S rRNA gene sequences obtained from 11 Taiwan strains and 15 other strains representing five genospecies of Ehrlichia spp., including two outgroups (Anaplasma phagocytophilum and Rickettsia rickettsii). Results revealed that all Taiwan strains were genetically affiliated to the same clade within various E. canis strains documented in GenBank with a high sequence similarity (99.7–100%) and that they can be clearly distinguished from other genospecies of Ehrlichia. This study provides the first evidence of E. canis identified in R. sanguineus ticks and highlights the potential threat for human infections in Taiwan. Full article

Hard ticks are vectors of a wide range of pathogens, with tick-borne bacteria being among the most frequently detected. This study presents a first approach to the identification of human-biting ticks in the Basque Country (northern Iberian Peninsula), where previous research has mainly focused on ticks from vegetation and domestic and wild animals. The aim of this study was (i) to identify tick species collected in hospitals and health centres and (ii) to determine the presence and identify of pathogenic bacteria that they may carry using PCR, RLB and sequencing methods. A total of 181 ticks were collected and grouped in pools of one, two or three specimens, resulting in 157 samples. Morphological and molecular identification of collected ticks revealed that most specimens belonged to Ixodes ricinus (88.5%). Additionally, Rhipicephalus bursa, Haemaphysalis punctata, Dermacentor reticulatus and Dermacentor marginatus were also identified. A total of 25 samples (15.9%) tested positive for DNA from the targeted pathogens. The most prevalent vector-borne bacteria were Borrelia spp. (6.4%), followed by Rickettsia spp. (5.1%), Anaplasma phagocytophilum (2.5%) and Coxiella spp. (1.9%). Species identified included B. afzelii, B. garinii, B. miyamotoi, B. valaisiana, B. burgdorferi s. s., R. monacensis, “Candidatus R. rioja”, R. helvetica and R. massiliae. This study highlights the usefulness of combining molecular diagnostics with passive surveillance of human-attached ticks as an effective tool for regional monitoring of ticks and tick-borne pathogens. Full article

Emerging tick-borne infections pose growing public health threats, causing global disease burdens and economic losses. In this study, tick-borne pathogens were detected in ticks collected from ruminants in 19 sites of Khyber Pakhtunkhwa Province, Pakistan, between 2023 and 2024. A total of 989 ticks, belonging to five species, i.e., Hyalomma marginatum, Rhipicephalus microplus, Rhipicephalus sanguineus, Rhipicephalus haemaphysaloides, and Haemaphysalis bispinosa, were tested by specific PCR followed by Sanger sequencing. In total, fourteen pathogens including two Anaplasma species, three Ehrlichia species, three Rickettsia species, one Babesia species, and five Theileria species were identified, with an overall infection rate of 20.2% (95% CI: 17.7–22.7%). Phylogenetic analyses revealed two undefined Ehrlichia species: Candidatus Ehrlichia hyalommae was exclusively detected in Hy. marginatum ticks, while Candidatus Ehrlichia rhipicephalis was only found in R. microplus. Additionally, an undefined Rickettsia, provisionally named Candidatus Rickettsia pakistanensis, was identified, which is phylogenetically close to R. sibirica in North Asia and R. africae in Africa, suggesting its potential pathogenicity to humans. Although coinfections of two pathogens were observed, the coinfection rates were quite low. The findings revealed a significant diversity of tick-borne pathogens in Pakistani ticks, which may pose risks to livestock and humans. Full article

This study sought to investigate the presence of anti-Rickettsia spp. antibodies in georeferenced serum samples from equids across all regions of the state of Goiás, while also presenting variables that indicate risk factors for the circulation of rickettsiae, and evaluating the presence of rickettsial DNA in ticks collected from equids and the surrounding environment in the municipalities of Uruaçu and Porangatu, located in the northern region of the state. A total of 1156 equid serum samples provided by the Goiás Agricultural Defense Agency (Agrodefesa) were analyzed for antibodies against 4 Rickettsia antigens. Additionally, 39 blood samples were collected from equids during a 3-day field expedition in January 2024, alongside 938 ticks collected from both animals and the environment. In total, 297 adult ticks were randomly selected for molecular analysis and tested by qPCR targeting the rickettsial gltA gene. Positive samples were further analyzed using cPCR to target the ompA and gltA genes. Results revealed that 9.6% (111/1156) of the serum samples were seroreactive to at least one Rickettsia antigen. Among these, 36% had antibodies against Rickettsia rickettsii, 18.9% against Rickettsia parkeri, 69.4% against Rickettsia amblyommatis, and 14.4% against Rickettsia bellii. Furthermore, the possible antigen responsible for a homologous reaction was found in 3.6% of equids for R. rickettsii, and in the same proportion for R. bellii, while 23.4% of animals showed antibodies for R. amblyommatis, and none exhibited a homologous reaction to R. parkeri. Meanwhile, 28.2% of the serum samples collected during the field expedition had antibodies against R. amblyommatis, with 72.7% identifying R. amblyommatis as the antigen involved in the homologous reaction. In the logistic regression analysis, the variables of education level, altitude below 500 m, and presence of female mules demonstrated a positive effect on seropositivity. Ticks from animals were identified as Amblyomma cajennense sensu lato, Amblyomma sculptum, Dermacentor nitens, and Rhipicephalus microplus, while environmental ticks were identified as A. cajennense s.l., A. sculptum, and Amblyomma nodosum. In the qPCR assays, two specimens of A. cajennense s.l., one of A. sculptum, and one of D. nitens amplified a fragment of the gltA gene. Of these, one A. cajennense s.l. specimen amplified a fragment of both the ompA and gltA genes, and one A. sculptum specimen amplified a fragment of the gltA gene through conventional PCR. Sequencing confirmed the detection of R. amblyommatis. These findings highlight the presence of anti-Rickettsia spp. antibodies in equid serum samples from all regions of the state of Goiás, emphasizing the important role of equids as sentinels for Rickettsia spp. To our knowledge, this study represents the largest effort to detect anti-Rickettsia spp. antibodies in equid serum samples in Brazil. Additionally, it is the first nationwide investigation of its kind conducted in collaboration with the Agricultural Defense Agency (Agrodefesa), serving as a significant example of the One Health approach. Full article

In Italy, the epidemiology of tick-borne pathogens is still poorly characterized. This prospective study was conducted at the IRCCS Sacro Cuore Don Calabria Hospital in Negrar di Valpolicella (Verona), northeastern Italy, from 2018 to 2022. Ticks from asymptomatic individuals visiting the hospital after a recent tick bite were characterized using microscopy and tested for pathogens using molecular tests. A total of 317 ticks collected from 280 subjects were analyzed, with most identified as Ixodes species (95.6%), followed by Rhipicephalus spp. (0.6%) and Dermacentor spp. (0.3%). Molecular analysis was performed on 257 single ticks and 23 pooled samples. Overall, 15.4% tested positive for at least one pathogen. The most frequently detected pathogen was Borrelia spp. (n = 22, 7.8%), including B. afzeli (n = 8), B. miyamotoi (n = 6), B. valaisiana (n = 2), B. garinii (n = 2), Borrelia spp. (n = 2), B. burgdorferi sensu stricto (n = 1), and B. spielmanii (n = 1). Rickettsia spp. was detected in 20 samples (7.1%), comprising R. helvetica (n = 11), R. monacensis (n = 7), and Rickettsia spp. (n = 2). Other pathogens included Anaplasma phagocytophilum (n = 5, 1.8%), Babesia venatorum (n = 2, 0.7%), and tick-borne encephalitis virus (n = 1, 0.4%). This study calls for enhanced surveillance in the province of Verona to clarify these pathogens’ clinical impact. Full article

Canine monocytic ehrlichiosis (CME) is a highly infectious disease with zoonotic potential. Ehrlichia canis, the causative agent, is primarily transmitted by Rhipicephalus sanguineus. Tick infestation and tick-borne diseases (TBDs) are serious human and veterinary health problems due to the lack of efficient control measures. This review aims to provide information about CME, detailing epidemiology, pathogenesis, clinical manifestations, and current strategies for diagnosis, treatment, and prevention. The review delves into the biology of R. sanguineus, exploring its lifecycle, habitat, and mechanisms of E. canis transmission. Ehrlichia canis infection follows a three-phase transition: acute, subclinical, and chronic, with distinct clinical signs, from mild to severe and even life-threatening in some cases, with the potential for asymptomatic long-term carriers acting as reservoirs. Pathogenesis involves complex interactions between the pathogen and host immune responses, influencing disease severity and progression. Additionally, the review highlights challenges in controlling CME due to the widespread distribution of R. sanguineus. Genetic diversity within R. sanguineus populations and their varying vector competence further complicate control efforts. The role of environmental changes in tick distribution aligns the control of CME within the One Health concept, integrating approaches to improve outcomes for humans, animals, and the environment. Preventive measures on tick control and potential vaccine development are also reviewed. Full article

Ticks and tick-borne diseases (TBDs) significantly impact African animal health and agricultural productivity, especially at the wildlife–livestock interface. This systematic review analyzed 20 eligible studies from East, Southern, and limited parts of Central Africa to determine the distribution and prevalence of key tick species and associated pathogens. Rhipicephalus appendiculatus and Amblyomma variegatum were the most commonly reported tick species, with R. appendiculatus exhibiting up to 50.5% prevalence in cattle and buffalo in Uganda. The most frequently detected pathogens included Theileria parva, Anaplasma marginale, and Coxiella burnetii, with T. parva showing high prevalence in cattle populations coexisting with wildlife. Notably, geographic disparities were observed, with Central and West Africa being underrepresented. Most pathogen detections occurred in Kenya, Uganda, Tanzania, Botswana, and South Africa, indicating regional hotspots for tick-borne disease transmission. This review highlights the urgent need for enhanced surveillance, region-specific vector control programs, and integrated One Health approaches to address the ecological, agricultural, and zoonotic challenges of tick-borne pathogens across Africa. Full article

Ticks and tick-borne pathogens pose a significant threat to human and animal health, yet the diversity and prevalence of tick-borne microorganisms in karst regions remains inadequately explored. In October 2023, a total of 274 Rhipicephalus microplus ticks were collected from livestock in Guizhou Province, which boasts the largest karst area in China. Pathogen identification was subsequently performed using PCR amplification, Sanger sequencing, and phylogenetic analysis. High microbial diversity was noted, with five bacterial species from the order Rickettsiales detected, including those from the genera Rickettsia (family Rickettsiaceae), Anaplasma, and Ehrlichia (family Anaplasmataceae). The overall prevalence of infection with at least one pathogen was remarkably high at 94.5%. The highest positive rate was observed for Candidatus Rickettsia jingxinensis at 90.9%. A novel Ehrlichia species, provisionally designated as Candidatus Ehrlichia carsus, was identified with a positive rate of 16.8%. In addition, Anaplasma marginale, Ehrlchia minasensis and Ehrlichia canis were detected in 15.3%, 4.7% and 1.5%, respectively. The co-infections involving two or three rickettsial species were observed in 34.3% ticks. These findings highlight the high diversity and prevalence of tick-borne rickettsial agents in the karst area, underscoring the need for enhanced surveillance and effective tick control to mitigate disease risks to both humans and livestock. Full article

Although quilombola individuals and their dogs may be exposed to hemoparasites such as A. phagocytophilum, B. microti, and E. chaffeensis, no study to date has been conducted in these populations. The aim of this study was to investigate the presence of antibodies against Anaplasma phagocytophilum, Babesia microti, and Ehrlichia chaffeensis in humans and dogs from quilombola communities in Brazil. Serum samples from humans and dogs were collected from four rural quilombola communities and analyzed using indirect immunofluorescence assays. The results revealed antibody levels of 8% for A. phagocytophilum, 3% for B. microti, and 1% for E. chaffeensis in humans and 60%, 50%, and 65%, respectively, in dogs. Notably, women were significantly more likely to be seropositive for A. phagocytophilum than men (p = 0.0289). Dogs from the Serra do Apon community more commonly had A. phagocytophilum (p = 0.0477) and B. microti (p = 0.0448) than those from the other areas. To the best of our knowledge, this is the first study to report human exposure to A. phagocytophilum and the ocurrence of B. microti in Brazil. The antibody level of vector-borne diseases in humans is a public health concern, particularly in vulnerable populations and rural areas. The dogs were universally hosted Rhipicephalus sanguineus ticks, suggesting their possible role in transmission. Thus, further epidemiological surveillance studies should be conducted in vulnerable populations to mitigate the impact of such zoonotic diseases. Full article

As crucial vectors that transmit pathogens to humans and livestock, ticks pose substantial global health threats and economic burdens. We analyzed 328 tick genomes to explore the population’s genetic structure and the adaptive evolution of H. longicornis and R. microplus, two tick species with distinct life cycle characteristics. We observed distinct genetic structures in H. longicornis and R. microplus. Gene flow estimation revealed a closer genetic connection in R. microplus than H. longicornis, which was facilitated by geographical proximity. Notably, we identified a set of candidate genes associated with possible adaptations. Specifically, the immune-related gene DUOX and the iron transport gene ACO1 showed significant signals of natural selection in R. microplus. Similarly, H. longicornis exhibited selection in pyridoxal-phosphate-dependent enzyme genes associated with heme synthesis. Moreover, we observed significant correlations between the abundance of pathogens, such as Rickettsia and Francisella, and specific tick genotypes, which highlights the role of R. microplus in maintaining these pathogens and its adaptations that influence immune responses and iron metabolism, suggesting potential coevolution between vectors and pathogens. Our study highlights the vital genes involved in tick blood feeding and immunity, and it provides insights into the coevolution of ticks and tick-borne pathogens. Full article