Insight into Hyalomma anatolicum biology by comparative genomics analyses

Hyalomma anatolicum is an obligatory blood-sucking ectoparasite and contributes to the transmission of Crimean-Congo haemorrhagic fever (CCHF) virus, Theileria spp. and Babesia spp. Progress in exploring the adaptive strategy of this ectoparasite and developing tools to fight it has been hindered by the lack of a complete genome. Herein, we assembled the genome using diverse sources of data from multiple sequencing platforms and annotated the 1.96 Gb genome of Hy. anatolicum. Comparative genome analyses and the predicted protein encoding genes reveal unique facets of this genome, including gene family expansion associated with blood feeding and digestion, multi-gene families involved in detoxification, a great number of neuropeptides and corresponding receptors regulating tick growth, development, and reproduction, and glutathione S-transferase genes playing roles in insecticide resistance and detoxification of multiple xenobiotic factors. This high quality reference genome provides fundamental data for obtaining insights into a variety of aspects of tick biology and developing novel strategies to fight notorious tick vectors of human and animal pathogens.

Guardians of the Herd: Molecular Surveillance of Tick Vectors Uncovers Theileriosis Perils in Large Ruminants

Theileria sp. (Piroplasmida: Theileriidae) is one of the most widely known infections transmitted by hard ticks (Acari: Ixodidae) and has been linked to significant economic losses across the globe. The study's main emphasis was theileriosis, a disease that is common in Pakistan and has an incidence ranging from 0.6% to 33%. Through DNA screening of the vector ticks and host blood, this study sought to determine the risk of tick-borne theileriosis in populations of buffalos (Bubalus bubalis) and cattle (Bos indicus) in Toba Tek Singh district of Punjab, Pakistan. Identified tick species include Hyalomma anatolicum (35.4%), Rhipicephalus (Boophilus) microplus (30.2%), and R. sanguineus (25%). Tick specimens were collected from animals and their respective microenvironments. PCR assays targeting Theileria annulata were used to investigate the infection in the DNA extracted from the collected blood samples from large ruminants and salivary glands (SGs) of the Hyalomma ticks. The 18S rRNA of T. annulata was amplified using specific primers. Positive T. annulata amplicons were sequenced and verified using BLAST analysis. Overall, 50% of SGs contained T. annulate DNA. Female ticks, and those collected from cattle and from riverine environments had significantly higher (p < 0.05) rates of Theileria infection in their acini. Overall prevalence of Theileria infection was 35.9% in blood collected from large ruminants. Cattle had a substantially greater frequency of bovine theileriosis (43.2%) than buffalos (28.7%). Age and sex of large ruminants were significantly positively associated (p < 0.05) with Theileria infection. Furthermore, compared to non-riverine cattle (35%) and buffalo (19.5%), riverine cattle (52.2%) and buffalo (36.2%) showed a considerably higher prevalence. The results of this study, which is the first in Pakistan to examine the blood of large ruminants and vectorial function of Ixodid ticks in the transmission of T. annulata along with associated risk factors, offer an important insight for risk assessment of Theileria infection in livestock using vectorial infectivity.

Protective Efficacy of Multiple Epitope-Based Vaccine against Hyalomma anatolicum, Vector of Theileria annulata and Crimean-Congo Hemorrhagic Fever Virus

Hyalomma anatolicum is the principal vector for Theileria annulata, T. equi, and T. Lestoquardi in animals and the Crimean-Congo hemorrhagic fever virus in humans. Due to the gradual loss of efficacy of the available acaricides against field tick populations, the development of phytoacaricides and vaccines has been considered the two most critical components of the integrated tick management strategies. In the present study, in order to induce both cellular and humoral immune responses in the host against H. anatolicum, two multi-epitopic peptides (MEPs), i.e., VT1 and VT2, were designed. The immune-stimulating potential of the constructs was determined by in silicoinvestigation on allergenicity (non-allergen, antigenic (0.46 and 1.0046)), physicochemical properties (instability index 27.18 and 35.46), as well as the interaction of constructs with TLRs by docking and molecular dynamics analysis. The immunization efficacy of the MEPs mixed with 8% Montanide^TM gel 01 PR against H. anatolicum larvae was determined as 93.3% and 96.9% in VT1- and VT2-immunized rabbits, respectively. Against adults, the efficacy was 89.9% and 86.4% in VT1- and VT2-immunized rabbits, respectively. A significant (p < 0.001) reduction in the anti-inflammatory cytokine (IL-4) and significantly higher IgG response was observed in a VT1-immunized group of rabbits as compared with the response observed in the control group. However, in the case of the VT2-immunized rabbits, an elevated anti-VT2 IgG and pro-inflammatory cytokine (IL-2) (>30 fold) along with a decreased level of anti-inflammatory cytokine IL-4 (0.75 times) was noted. The efficacy of MEP and its potential immune stimulatory responses indicate that it might be useful for tick management.

Acaricidal, Larvacidal, and Repellent Activity of Elettaria cardamomum Essential Oil against Hyalomma anatolicum Ticks Infesting Saudi Arabian Cattle

Background: In this experimental study, we aimed to assess the acaricidal effects of Elettaria cardamomum L. essential oil (ECEO) against Hyalomma anatolicum tick in cattle from Saudi Arabia. Methods: Gas chromatography-mass spectrometry (GC-MS) was performed to identify the chemical composition of ECEO. The acaricidal, larvicidal, and repellent activity of ECEO against H. anatolicum was studied through the adult immersion test (AIT), the larval packet test (LPT), the vertical movement behavior of tick’s larvae technique, anti-acetylcholinesterase (AChE) activity, and oxidative enzyme activity. Results: By GC/MS, the most compounds were 1,8-cineole (34.3%), α-terpinyl acetate (23.3%), and α-pinene (17.7%), respectively. ECEO significantly (p < 0.001) increased the mortality rate as a dose-dependent response. After ECEO Treatment, number of eggs, egg weight, and hatchability significantly declined as a dose-dependent response. ECEO at concentrations of 5 µL/mL and above completely killed the larva. The LC50 and LC90 values for ECEO were 1.46 and 2.68 µL/mL, respectively. ECEO at concentrations of 10, 20, and 40 µL/mL showed 100% repellency activity up to 60, 120, and 360 min incubation, respectively. ECEO, especially at ½ LC50 and LC50, significantly inhibited GST and AChE activities of H. anatolicum larvae compared to the control group. Conclusions: We found promising adulticidal, larvicidal, and repellent effects of ECEO against H. anatolicum as a vector of theileriosis in Saudi Arabia. We also found that ECEO displayed these activities through inhibiting AChE and GST. Nevertheless, additional investigations are required to confirm the accurate mechanisms and the relevance of ECEO in practical application.

Prediction and validation of cross-protective candidate antigen of Hyalomma asiaticum cathepsin L between H. asiaticum and H. anatolicum

Hyalomma asiaticum and H. anatolicum are tick species in Eurasia and Africa with major medical and veterinary significance. Beside their direct pathogenic effects, H. asiaticum and H. anatolicum are vectors of important diseases of livestock and in some instances of zoonoses. In search of ways to address the increasing incidence of global acaricide resistance, tick control through vaccination is regarded as a sustainable alternative approach. Cathepsin L-like cysteine protease (CPL) is a potent hemoglobinase, and plays important roles in the digestion of blood acquired from a host. CPL from H. anatolicum (HanCPL) with high similarity (> 90%) for H. asiaticum CPL (HasCPL) were aligned by in silico analysis. After further in vitro validation, the anti-HasCPL sera have cross-reactivity between the different total native protein of life stages and tissues for H. asiaticum and H. anatolicum. Furthermore, we further confirmed that recombinant HasCPL (rHasCPL) immunized rabbits were partially cross-protected (54.8%) by H. anatolicum infestation.

Microbial composition in Hyalomma anatolicum collected from livestock in the United Arab Emirates using next-generation sequencing

BACKGROUND

Hyalomma anatolicum is a widely distributed tick species that acts as a vector transmitting tick-borne pathogens (TBPs) in livestock. Such pathogens affect the health of livestock and consequently reduce their productivity. Knowledge about the microbial communities (pathogens and endosymbionts) of ticks in the United Arab Emirates (UAE) is scarce. Therefore, the aim of the present study was to quantify microbial diversity in H. anatolicum using next-generation sequencing (NGS) technology.

METHODS

Hyalomma anatolicum ticks were collected from livestock in the emirates of Abu Dhabi, Dubai and Sharjah in the UAE during 2019. DNA was extracted from 175 male ticks sampled from livestock (n = 78) and subjected to NGS. The 16S rRNA gene was analyzed using the Illumina MiSeq platform to determine the bacterial communities. Principal coordinates analysis (PCA) was performed to identify patterns of diversity in the bacterial communities.

RESULTS

Twenty-six bacterial families with high relative abundance were identified, of which the most common were Staphylococcaceae, Francisellaceae, Corynebacteriaceae, Enterobacteriaceae, Moraxellaceae, Bacillaceae, Halomonadaceae, Xanthomonadaceae, Pseudomonadaceae, Enterococcaceae, Actinomycetaceae and Streptococcaceae. The diversity of the microbial communities in terms of richness and evenness was different at the three study locations, with the PCA showing clear clusters separating the microbial communities in ticks collected at Abu Dhabi, Dubai, and Sharjah. The presence of bacterial families harboring pathogenic genera showed that H. anatolicum could pose a potential threat to livestock and food security in the UAE.

CONCLUSIONS

The study is the first to document important data on the microbial communities associated with H. anatolicum in the UAE. This knowledge will facilitate a better understanding of the distribution pattern of microbes in livestock ticks in the UAE and, ultimately, will aid in deciphering the relationships between microbes and in the exploration of potential factors towards developing effective management strategies.

Screening for the "Achilles Heel" of Hyalomma anatolicum Ticks by RNA Interference Technology and an Update on Anti-Tick Vaccine Design

Over the years, RNA interference (RNAi) has evolved as a valuable tool to study the tick gene function, screening and preliminary characterization of tick-protective antigens in a relatively short time, with a minimal use of laboratory animals before conducting expensive vaccine trials for the development of improved vaccine composition. In this process, a double-stranded RNA (dsRNA) of gene of interest is introduced into the tick system which specifically suppresses expression of a target gene. The results of RNAi-based gene silencing were interpreted by reduction in targeted gene transcript, changes in phenotypic data and anatomical/ biochemical changes in ticks; thereby, providing a clue to the probable role played by the gene in the tick biological system. Across the globe, various tick research groups applied RNAi technique for characterization and identification of new anti-tick vaccine targets. Herein, we used the RNAi tool in Hyalomma anatolicum ticks for identification and characterization of vaccine candidates.

Prevalence, Distribution, and Molecular Record of Four Hard Ticks from Livestock in the United Arab Emirates

Simple Summary

Ticks, as blood feeders and vectors of many diseases, can negatively impact livestock and human health, with potential economic impacts on the livestock industry. In this study, we documented the occurrence of four tick species (Hyalomma dromedarii, Hyalomma anatolicum, Rhipicephalus sanguineus, and Amblyomma lepidum) on camels, cows, sheep, and goats from three areas in the United Arab Emirates (UAE). Our findings indicated that H. dromedarii was the most prevalent tick species on camels. The other tick species were present at varying levels on hosts. Some of the tick species collected in this study are potential carriers of tick-borne diseases that are serious and sometimes fatal to humans and animals. Thus, there is a need for more research on ticks and tick-borne diseases in the UAE.

Abstract

Ticks are important arthropod vectors that serve as reservoirs of pathogens. Rapid urbanization and changes in animal breeding practices could be causing a rise in tick burden on animals. Studies on tick distribution on livestock and tick molecular diversity from the United Arab Emirates (UAE) are limited. The aim of this study was to (i) provide molecular and morphological identification of tick species, (ii) compare tick infestation between different hosts, (iii) compare tick infestation in relation to the sex of the host, and (iv) assess the prevalence of tick species on hosts. A total of 5950 ticks were collected from camels (4803 ticks), cows (651 ticks), goats (219 ticks), and sheep (277 ticks). Ticks were identified based on morphological characters at the species level using taxonomic keys. In addition, Polymerase Chain Reaction (PCR) amplification of the cytochrome oxidase subunit 1 (cox1) and 16S rRNA mitochondrial genes was used to identify ticks. Four species were confirmed based on molecular and morphological characterization, namely, Hyalomma dromedarii, Hyalomma anatolicum, Rhipicephalus sanguineus, and Amblyomma lepidum. Hyalomma dromedarii (94.3%) was the most abundant species, followed by H. anatolicum (32.8%). Camels were heavily infested (94%) with ticks as compared to cows (38%), sheep (37%), and goats (14%). Widespread occurrence of these four tick species in the UAE poses a risk of spreading tick-borne pathogens wherever the conditions of infection prevail.

Drop-off rhythms and survival of Hyalomma anatolicum (Acari: Ixodidae) fed on crossbred (Friesians x Zebu) calves in Sudan

Hyalomma anatolicum is one of the most economically important ticks in the Sudan. It is the main vector of tropical theileriosis in cattle and other diseases in different species. The study aims to investigate the drop-off rhythms and survival periods of tick stages fed on crossbred calves. Larvae, nymphs and adults fed on crossbred calves (male, 3–6 months old, Friesians x Zebu) kept under zero grazing system. Drop-off rhythms of engorged stages were studied under field conditions while the survival periods of unfed stages were investigated under field and laboratory conditions (27 °C and 85% R.H.). Significantly high numbers of engorged larvae dropped at night between 20H:00 and 07H:00. (March, April and August). Engorged nymphs dropped late evening and early night 16H:00–20H:00. (September), while insignificant number of engorged females dropped between 10H:00 and 14H:00 (October). Survival durations of unfed H. anatolicum stages were longer under laboratory conditions than in the field. These were 99.36 ± 1.24 and 13.12 ± 0.68 days for larvae, 63 ± 1.33 and 16 ± 0.87 days for nymphs and 90 ± 3.6 and 45 ± 2.7 days for adults, respectively. Under field condition survival studies were conducted in May, August and December 2016 for larvae, March, May, August and December 2016 for nymphs and in October 2016 for Adults. In August, 70% of unfed larvae and nymphs survived for three weeks and 2.5 weeks, respectively, in May, 16% of unfed larvae survived for one week while no unfed nymphs survived for more than 4 days. This finding may indicate that larvae are more resistant to desiccation than nymphs. The abnormal changes on the alloscutum of H. anatolicum desiccated nymphs and females were observed being shrunken and truncated posteriorly, a finding which opens new avenues for further studies. For control strategies more studies are recommended on the dropping to allow ticks drop in an area not suitable for further development as one of the control strategies and the survival studies also is exploited in rotational grazing of animals.

•

Hyalomma anatolicum larvae behaved as 3-host life cycle when fed on cross-bred calves at zero grazing system.

•

The drop-off rhythms of H. anatolicum mostly occurred at night.

•

Unfed larvae were more resistant to desiccation than unfed nymphs.

•

The ability of unfed stages to survive completes nearly ten weeks.

Four Tick-Borne Microorganisms and Their Prevalence in Hyalomma Ticks Collected from Livestock in United Arab Emirates

Ticks and associated tick-borne diseases in livestock remain a major threat to the health of animals and people worldwide. However, in the United Arab Emirates (UAE), very few studies have been conducted on tick-borne microorganisms thus far. The purpose of this cross-sectional DNA-based study was to assess the presence and prevalence of tick-borne Francisella sp., Rickettsia sp., and piroplasmids in ticks infesting livestock, and to estimate their infection rates. A total of 562 tick samples were collected from camels, cows, sheep, and goats in the Emirates of Abu Dhabi, Dubai, and Sharjah from 24 locations. DNA was extracted from ticks and PCR was conducted. We found that Hyalomma dromedarii ticks collected from camels had Francisella sp. (5.81%) and SFG Rickettsia (1.36%), which was 99% similar to Candidatus Rickettsia andeanae and uncultured Rickettsia sp. In addition, Hyalomma anatolicum ticks collected from cows were found to be positive for Theileria annulata (4.55%), whereas H. anatolicum collected from goats were positive for Theileria ovis (10%). The widespread abundance of Francisella of unknown pathogenicity and the presence of Rickettsia are a matter of concern. The discovery of T. ovis from relatively few samples from goats indicates the overall need for more surveillance. Increasing sampling efforts over a wider geographical range within the UAE could reveal the true extent of tick-borne diseases in livestock. Moreover, achieving successful tick-borne disease control requires more research and targeted studies evaluating the pathogenicity and infection rates of many microbial species.

Ivermectin resistance in the multi-host tick Hyalomma anatolicum (Acari: Ixodidae) in India

The multi-host tick, Hyalomma anatolicum is a widely distributed vector of many pathogens of veterinary and public health importance. Ivermectin (IVM), as an alternative to control pyrethroid-resistant ticks, has been used extensively for the past 4-6 years in tropical and sub-tropical countries including India resulting in declining tick control efficacy. The present study used adult immersion test (AIT) to examine the resistance status of H. anatolicum collected from three districts in the Indian state of Gujarat against ivermectin. Probit analysis was used for calculation of concentration-mortality regressions; concentrations required for 50% mortality (LC₅₀) and 95% mortality (LC₉₅), along with confidence intervals; slope of mortality; % inhibition of oviposition; and discriminating concentration (DC). The calculated LC₅₀ and LC₉₅ estimates were utilized to determine resistance ratios (RR₅₀, RR₉₅) and the resistance levels (RL) of the field ticks compared to the susceptible population. The DC (2 x LC₉₅) for IVM was calculated as 84.48 ppm, using susceptible H. anatolicum ticks (KHD). Lower estimates of the coefficient of non-determination (1-R²) for AIT ranged from 0.06 to 0.27, and the range of RR₅₀ and RR₉₅ values against IVM was estimated to be from 1.43 to 52.06 and 1.14 to 71.99, respectively, which indicated a varying degree of resistance among the field tick populations. Based on RR₅₀ values, tick populations from Danta and Palanpur showed resistance level IV and II, respectively. Another four populations (Vadgam, Kankrej, Saraswati and Sidhpur) were classified as having level I resistance status against IVM. To our knowledge, this is the first report of ivermectin resistance in H. anatolicum from Gujarat, India.

Nested PCR assay for detection of Theileria annulata in Hyalomma anatolicum infesting cattle from coastal Odisha, India

Ticks are economically important obligatory blood feeding arthropods that have a pivotal role in transmission of infection. The present study was conducted in ixodid ticks collected from four districts of coastal Odisha, India to investigate the prevalence of Theileria annulata. Adult semi engorged Hyalomma anatolicum ticks (n = 178) were dissected, the salivary gland was isolated and DNA was extracted. A nested PCR targeting the Tams1 gene of T. annulata, utilizing two sets of primers (N516F, N517R, and Ta14136iF, Ta249R) was utilized for detection of the parasite. The PCR products were then sequenced and subjected to BLAST analysis, alignment, and phylogenetic study. Two sequences deposited in GenBank were assigned Accession No MH477290.1 and Accession No MH477291.1. The molecular investigation of T. annulata revealed an overall prevalence of 14.6% in tick vectors, and nested PCR was found to have significant (p < 0.05) higher results than primary PCR. A significant higher presence (p < 0.05) was recorded in female ticks compared with male ticks. This is the first report of detection of the parasite in tick vectors in the state of Odisha.

in Hyalomma anatolicum ticks collected in Tajikistan

The objectives of our study were to survey the prevalence of genetic markers for Rickettsia spp., Ehrlichia spp., Anaplasma spp., Babesia spp., and Theileria spp. in Hyalomma anatolicum ticks collected in southwestern Tajikistan and to perform sequencing and phylogenetic analysis of fragments of the 16S rRNA gene and groESL operon from Ehrlichia spp. and fragments of the 18S rRNA gene of Theileria spp. detected in H. anatolicum ticks. Hyalomma anatolicum ticks collected in the Tursunzade and Rudaki districts of Tajikistan were tested for DNA of Rickettsia spp., Ehrlichia spp., Anaplasma spp., Babesia spp., and Theileria spp. by PCR with specific primers. The amplified fragments were sequenced and analyzed. DNA of Ehrlichia spp. (3.3 %) and Theileria spp. (3.3 %) was detected only in H. anatolicum ticks collected from the Rudaki district, and DNA of Ehrlichia spp. (0.7 %) was found in H. anatolicum ticks from the Tursunzade district. Sequence analysis of fragments of the 16S rRNA gene and groESL operon from Ehrlichia spp. revealed high similarity to Ehrlichia spp. The Tajik isolates of Theileria spp. were genotyped as Theileria annulata based on the analysis of 18S rRNA gene sequences. The phylogenetic analysis demonstrates that Ehrlichia spp. isolates are highly similar to Ehrlichia spp. circulating in China and Brazil. The isolate Tajikistan-5 is closely related to the putative novel species Ehrlichia mineirensis. The Tajik isolates of Theileria spp. were clustered with T. annulata isolates from Turkey, Iran, Pakistan, and China by phylogenetic analyses.

Establishment and Validation of Theileria annulata Sporozoite Ak-93 Infection in Laboratory-Reared Hyalomma anatolicum Tick Using In Vivo and In Vitro Assays

Background:

Tropical Theileriosis caused by Theileria annulata is a tick-borne disease which transmitted by the ixodid tick members of the genus Hyalomma. Studies on different aspects of disease require to access infective sporozoite of parasite which produced by tick vector. This study was carried out to establish of T. annulata life cycle to achieve T. annulata infected ticks.

Methods:

Laboratory rabbit and calf were used for rearing of Hyalomma anatolicum different instars. Unfed nymphs were fed on T. annulata infected calf. Clinical signs, Giemsa stained smears and Polymerase Chain Reaction (PCR) methods were used for detection of infection in blood and tick specimens. Susceptible calf was used for confirmation of sporozoites maturation and infectivity in bioassay test.

Results:

Hyalomma anatolicum two and three-host strategies of life cycle was lasted 90 and 116 days respectively. The PCR confirmed T. annulata infection in blood and tick samples. Maturation of T. annulata sporozoites was confirmed in bioassy test. First clinical symptom of disease was seen earlier in the case of transmission of disease through feeding of live ticks in comparison with blood injection method.

Conclusion:

Complete life cycle of T. annulata was done and confirmed by clinical signs, microscopic examination, molecular methods and bioassay test. According to published reports to date, this is the first report of establishment of H. anatolicum tick infection with T. annulata using susceptible calf under controlled conditions in Iran.

Molecular characterization of ticks and tick-borne piroplasms from cattle and camel in Hofuf, eastern Saudi Arabia

The aims of the present study were to characterize ticks infesting the dromedary camel and cattle in Hofuf, Eastern Saudi Arabia and to determine the piroplasms that they may harbor. DNA was extracted from ticks, collected from camels and cattle, using commercial kits and subjected to polymerase chain reaction using specific primers for the amplification of ticks and piroplasms DNA. The cytochrome oxidase subunit I mitochondrial gene (COI) was used for characterization of ticks whereas partial 18S rRNA gene (18S rRNA) was used for piroplasms characterization. Ticks were genetically identified as Hyalomma dromedarii and Hyalomma anatolicum. Both cattle and camel in Hofuf, were found to be infested with both species. Both ticks identified as H. dromedarii and H. anatolicum from camels and cows showed 100% identity to COI sequences from the same species available in GenBank. Only Theileria annulata DNA was amplified from both H. anatolicum and H. dromedarii infesting cattle. None of the ticks collected from camels revealed DNA of piroplasms. T. annulata DNA was reported for the first time from Hofuf and the role of both H. anatolicum and H. dromedarii as potential vectors for this parasite in cattle in Saudi Arabia has been documented for the first time.

Tick-Borne Pathogens Shape the Native Microbiome Within Tick Vectors

Ticks are blood-feeding arthropods and transmit a variety of medically important viral, bacterial, protozoan pathogens to animals and humans. Ticks also harbor a diverse community of microbes linked to their biological processes, such as hematophagy, and hence affect vector competence. The interactions between bacterial and/or protozoan pathogens and the tick microbiome is a black-box, and therefore we tested the hypothesis that the presence of a protozoan or bacterial pathogen will alter the microbial composition within a tick. Hence, this study was designed to define the microbial composition of two tick species, Hyalomma (H.) anatolicum and Rhipicephalus (R.) microplus. We used a combination of PCR based pathogen (Anaplasma marginale and Theileria species) and symbiont (Wolbachia species) identification followed by metagenomic sequencing and comparison of the microbial communities in PCR positive and negative ticks. A total of 1786 operational taxonomic units was identified representing 25 phyla, 50 classes, and 342 genera. The phylum Proteobacteria, Firmicutes, Actinobacteriota, and Bacteroidota were the most represented bacteria group. Alpha and beta diversity were not significantly affected in the presence or absence of Theileria sp. and A. marginale as see with H. anatolicum ticks. Interestingly, bacterial communities were significantly reduced in Theileria sp. infected R. microplus ticks, while also exhibiting a significant reduction in microbial richness and evenness. Putting these observations together, we referred to the effect the presence of Theileria sp. has on R. microplus a “pathogen-induced dysbiosis”. We also identify the presence of Plasmodium falciparum, the causative agent of human malaria from the microbiome of both H. anatolicum and R. microplus ticks. These findings support the presence of a “pathogen-induced dysbiosis” within the tick and further validation experiments are required to investigate how they are important in the vector competence of ticks. Understanding the mechanism of “pathogen-induced dysbiosis” on tick microbial composition may aid the discovery of intervention strategies for the control of emerging tick-borne infections.

Identification and characterization of vaccine candidates against Hyalomma anatolicum-Vector of Crimean-Congo haemorrhagic fever virus

Crimean-Congo haemorrhagic fever (CCHF) is a tick borne viral disease reported from different parts of the world. The distribution of the CCHF cases are linked with the distribution of the principal vector, Hyalomma anatolicum in the ecosystem. Presently, vector control is mainly dependent on repeated application of acaricides, results in partial efficacy and generated acaricide resistant tick strains. Amongst the different components of integrated management programme, immunization of hosts is considered as one of the sustainable component. To restrict CCHF virus spreading, use of anti-Hyalomma vaccines appears as a viable solution. Accordingly, present study was under taken to characterize and evaluate vaccine potential of two conserved molecules, ferritin2 (FER2) and tropomyosin (TPM). Silencing of the genes conferred a cumulative reduction (rejection + unable to engorge) of 61.3% in FER2 and 70.2% in TPM respectively. Furthermore, 44.2% and 72.7% reduction in engorgement weight, 63.6% and 94.9% reduction in egg masses in FER2 and TPM silenced ticks in comparison to LUC-control group was recorded. The recombinant protein, rHaFER2 was characterized as 35 kDa protein with pI of 5.84 and possesses iron binding domains. While rHaTPM is a 51kDa protein with pI of 4.94 having calcium binding domains. Immunization of cross-bred calves by rHaFER2 conferred 51.7% and 51.2% protection against larvae and adults of H. anatolicum challenge infestations. While rHaTPM conferred 63.7% and 66.4% protection against larvae and adults infestations, respectively. The results were comparable with the data generated by RNAi and it clearly showed the possibility for the development of anti-hyalomma vaccine to manage CCHF virus and Theileria annulata infection in human and animals.

Hyalomma anatolicum as the Main Infesting Tick in an Important Livestock Rearing Region, Central Area of Iran

BACKGROUND

This study was carried out to determine the infestation of domestic ruminants to ticks in an important livestock-rearing region, located in central part of Iran.

METHODS

Ticks were collected from cattle, sheep, and goats and then were identified with appropriate identification keys to species level in two different ecological regions of plains and mountain in 4 seasons in 2015.

RESULTS

Totally 492 ticks from cattle, sheep, and goats in 34 herds were collected. Totally, 18.53% of domestic animals were infected by ticks. All ticks were belonged to family Ixodidae and classified into three genera and six species comprising Hyalomma anatolicum (38.83%), Hy. Asiaticum (23.37%), Hy. marginatum (2.85%), Hy. sp. (3.45%), Rhipicephalus sanguineus (14.02%) and Haemaphysalis sulcata (10.98%). Sex ratio of the collected specimens showed 241 (48.99%) male, 219 (44.51%) female and 32 (6.5%) nymph.

CONCLUSION

Studied area is important for production of livestock and dairy products. Annually, many livestock products are exported to other parts from this region; therefore, it is very important to identify the infection rate of tick-borne diseases as well as safety factors on livestock.

Molecular evidence of tick-borne pathogens in Hyalomma anatolicum ticks infesting cattle in Xinjiang Uygur Autonomous Region, Northwestern China

Although tick-borne pathogens have been widely reported in ticks in China, there is little information available on the prevalence of information in Hyalomma ticks from cattle. This study aims to determine the occurrence of pathogens in Hyalomma anatolicum collected from cattle in Xinjiang Uygur Autonomous Region, China, by PCR, sequencing and phylogenetic analysis. Borrelia burgdorferi s.s., Rickettsia massiliae and Anaplasma bovis were identified, whereas DNA of Ehrlichia species and an Anaplasma platys-like pathogen were also detected. Our findings highlight the risk of infection of animals and humans with these pathogens in north-western China.

Acaricidal potency of polyherbal spray against Rhipicephalus microplus and Hyalomma anatolicum infestation in cattle

Acaricidal potential of polyherbal spray (Andropogon citrates, Cymbopogon citratus, Ocimum sanctum, Pinus longifoia, Calotropis procera, Datura stramonium, Aegle marmelos, Ricinus communis, Azadirachta indica, Allium sativum, Carica papaya, Annona squamosa and Pongamia glabra) was assessed against tick infestation in cattle on the basis of measurement of tick count, complete blood count and plasma glucose, total protein, albumin and globulin before treatment and 21 days after treatment. Single application of polyherbal spray over body of 20 randomly selected tick infested cattle revealed significant reduction in mean tick count starting from 3 days post treatment till 21 days post treatment. Highly significant (P < 0.01) increase in total erythrocyte count and packed cell volume was observed in treated cows 21 days after application of spray compared to pre-treatment values indicating the reduction in blood loss due to heavy tick infestation before treatment. Plasma biochemical parameters revealed no significant changes in pre-treatment and post treatment values. The results of present study imply the clinical and haematological improvement in tick infested cattle treated with polyherbal spray and it could be potential product for use in livestock as acaricide.

Functional characterization of candidate antigens of Hyalomma anatolicum and evaluation of its cross-protective efficacy against Rhipicephalus microplus

Hyalomma anatolicum and Rhipicephalus microplus seriously affect dairy animals and immunization of host is considered as a sustainable option for the management of the tick species. Identification and validation of protective molecules are the major challenges in developing a cross-protective vaccine. The subolesin (SUB), calreticulin (CRT) and cathepsin L-like cysteine proteinase (CathL) genes of H. anatolicum were cloned, sequenced and analysed for sequence homology. Both Ha-SUB and Ha-CRT genes showed very high level of homogeneity within the species (97.6-99.4% and 98.2-99.7%) and among the tick species (77.3-99.3% and 85.1-99.7%) while for Ha-CathL the homogeneity was lower among ticks (57.5-89.5%). Besides tick species, both Ha-SUB and Ha- CRT genes showed high level of homogeneity with dipterans (47.2-53.4% and 72.0-74.4%) and nematodes (64.0% by CRT). The level of expression of the conserved genes in different stages of the tick species was studied. The differences in fold change of expression (FCE) of the targeted genes in life stages of tick were not statistically significant except Ha-SUB in eggs and in frustrated females, Ha-CRT in fed male and Ha-CathL in unfed and frustrated females where highest FCE was recorded. The functional properties of the genes were studied by RNAi technology and a significant level of gene suppression (p<0.05) resulted in very low percentage of engorgement of treated ticks viz., 3.7%, 11.1% and 30.0% in Ha-SUB, Ha-CRT and Ha-CathL respectively, in comparison to control was recorded. The recombinant proteins rHa-SUB, rHa-CRT and rHa-CathL encoded by the genes were expressed in prokaryotic expression system. They were evaluated for cross-protective efficacy and found to be respectively, 65.4%, 41.3% and 30.2% protective against H. anatolicum and 54.0%, 37.6% and 22.2%, against R. microplus infestations.

Comparative study of esterases in deltamethrin and diazinon resistant Rhipicephalus microplus and Hyalomma anatolicum ticks collected from the Trans-Gangetic plains of India

A comparative analysis of esterases in susceptible and resistant ticks revealed six types of esterases (EST-1b, EST-2b, EST-3b, EST-4b, EST-5b and EST-6b) in Rhipicephalus microplus and four types (EST-1h, EST-2h, EST-3h, EST-4h) in Hyalomma anatolicum using α-naphthyl acetate substrate. Inhibition studies with eserine sulfate, p-chloromercuribenzoate, copper sulphate and phenylmethylsulfonyl fluoride revealed a marked variation in band intensity between susceptible and resistant ticks, with the latter being more intense. Qualitative expression of EST-4b along with an extra band of EST-5b and EST-6b were indicative of deltamethrin and diazinon resistance in R. microplus, whereas qualitative expression of EST-4h was probably responsible for diazinon resistance in H. anatolicum. The data suggest that increased esterase activity may represent a detoxification strategy leading to the development of resistance in these tick populations.

In vitro assessment of the acaricidal activity of Piper longum, Piper nigrum, and Zingiber officinale extracts against Hyalomma anatolicum ticks

Ticks and tick-borne diseases are a major constraint for the sustainable cattle industry in the tropical and subtropical regions including the Indian subcontinent. The development of resistance to most of the commonly used acaricides leads to an attempt to screen plant extracts and their combinations for their possible acaricidal activity to develop an eco-friendly tick control alternative. An alcoholic and various aqueous extracts of Piper longum, Piper nigrum and Zingiber officinale and their combinations were evaluated for acaricidal activity against the three-host ixodid tick, Hyalomma anatolicum by larval immersion test using 14-21 days old unfed larvae. The efficacy was assessed by measuring larval mortality (%) and the lethal concentrations for 50% (LC50) and 95% (LC95) with their 95% confidence limits (CL) values were estimated by applying regression equation analysis to the probit transformed data of mortality. A concentration-dependent mortality response was recorded in all extracts prepared from seeds of P. longum and P. nigrum and their combinations. The highest acaricidal property was exhibited by the alcoholic extract of P. longum seeds with the minimum LC50 and LC95 (95% CL) values of 0.071% (0.07-0.072) and 0.135% (0.13-0.14), respectively, followed by alcoholic combinations. Interestingly, no acaricidal activity was recorded in extracts prepared from the rhizome of Z. officinale. The results indicated that the ethanolic extracts of P. longum and P. nigrum and their combinations can be used effectively for tick control in an integrated format.

Acaricide resistance in Rhipicephalus (Boophilus) microplus and Hyalomma anatolicum collected from Haryana and Rajasthan states of India

Acaricide resistance status of Rhipicephalus (Boophilus) microplus and Hyalomma anatolicum ticks against deltamethrin and diazinon was assessed in Hisar (Haryana) and its adjoining district Churu (Rajasthan) using adult immersion test (AIT) and larval packet test (LPT). The mortality slope, LC50, LC95, 95 % confidence limit and resistance factor of field ticks were determined. Results showed that R. (B.) microplus ticks collected from Tohana (Hisar) were found resistant to both the acaricides while the ticks of Agroha (Hisar) were found to be susceptible using AIT. Similar results were observed by using standard method of LPT. Again, H. anatolicum tick isolates of Tara Nagar (Churu) were found susceptible whereas Churu tick isolates were found to be resistant using AIT for both the acaricides. LPT indicated susceptible status of H. anatolicum ticks collected from Churu as well as Tara Nagar for both the acaricides. The study warrants the need for strategic use of available acaricides to overcome the development of acaricide resistance in ticks.

(Combrataceae) against Hyalomma anatolicum (Acari: Ixodidae)

Laboratory test were carried out on eggs, larvae, nymphs and adults of Hyalomma anatolicum to determine the acaricidal activities of petroleum ether (PE) and crude ethanolic extracts (EE) from the leaves of Guiera senegalensis J.F. Gmel. (Combrataceae) using immersion method. Stock solutions, of 300 mg/ml (30%) of the each two extract, were prepared. Six two-fold serial dilutions each with three replicates were used. Both extracts, at the highest concentration 150 mg/ml (15%), induced 100% failure of hatching of the treated eggs. The concentrations of PE and EE that induced 50% inhibition of the hatchability (IC50) were 1.71 and 0.508%, respectively. In the larval immersion test (LIT), EE at 15% concentration caused complete mortality while the same concentration of PE resulted in 96% mortality. The mortalities increased with concentrations. There was a correlation between the mortalities and increased concentrations, the values of the linear correlation coefficient (r) for PE and EE were 0.93 and 0.79, and The LC50 and LC99 were 2.08 and 14.09, and 0.787 and 11.054, respectively. At the concentrations of 3.75%, 7.5% and 15%, PE inhibited the molting of the nymphs by 40, 55 and 65%, respectively, while EE induced 46.49, 64.3 and 71.4% inhibition, respectively. The effectiveness of the treatment against unfed adult females was assessed by measuring the feeding performance and egg production using adult immersion test (AIT). Although, there was no mortality in unfed adults, PE and EE inhibited feeding and egg-laying of the survived females by 35-100% and 6.16-100%, respectively. Our results indicated that G. senegalensis is a promising biocontrol candidate as an acaricidal agent against H. anatolicum.

A comparative study on cypermethrin resistance in Rhipicephalus (Boophilus) microplus and Hyalomma anatolicum from Punjab (India)

A study to evaluate cypermethrin resistance in Rhipicephalus (Boophilus) microplus and Hyalomma anatolicum collected from Muktsar and Mansa districts of Punjab state, India, was conducted by using adult immersion test (AIT). The regression graphs of probit mortality of ticks plotted against log values of concentrations of cypermethrin was utilized for the determination of slope of mortality, lethal concentration for 50% (LC50), and the resistance factor (RF). On the basis of the data generated on variables (mortality, egg mass weight, reproductive index, and percentage inhibition of oviposition), the resistance levels were categorized. Resistance to cypermethrin was categorized as level II and I in R. (B.) microplus collected from Muktsar and Mansa districts, respectively, whereas, H. anatolicum from both locations showed a susceptible status. The RF values of Muktsar and Mansa field samples of engorged R. (B.) microplus (5.48 and 2.18, respectively) were much higher as those of engorged H. anatolicum (1.12 and 0.82, respectively) indicating a lower level and slower rate of development of cypermethrin resistance in multi-host ticks. The data generated in the current study might be of immense help in formulating suitable control measures against ticks and tick-borne diseases of animals.

Morphometric Study on Male Specimens of Hyalomma anatolicum (Acari: Ixodidae) in West of Iran

BACKGROUND

Hyalomma anatolicum is the well-known hard tick, which is one of the most important livestock and human pathogens vector, wide range in host and distributed in all over the Hyalomma geographic fauna as well as in Iran. Taxonomy of the Hyalomma ssp. is debatable whereas their identification is a problematic work. The reasons for this claim is time consuming Delpy's researches in Iran also Schulze School, Feldman-Muhsam and the Russian tick workers. We would like to understand morphometric variation in the field collected H. anatolicum in Iran also validating some morphologic quantitative and qualitative characters.

METHODS

A total 247 field-collected tick specimens from different geographical regions in west of Iran includes Khuzestan and Lorestan Provinces were studied. The morphologic characters of the ticks were measured by the calibrated stereomicroscope armed scaled lens. The measurements were analyzed using SPSS for windows, version 16 on an IBM PC, so varied shapes of species in different geographic regions were drawn by the aid of a drawing tube connected to a light stereomicroscope.

RESULTS

One way ANOVA test revealed significant differences among the quantitative parameters in five zones (P < 0.001) also each zone to other zone by Post Hoc Tests e.g. LSD. No significant differences in the lateral grooves length/conscutum length ratio parameter were found.

CONCLUSION

Morphometric variation in Hyalomma spp is poorly studied. The variation in range and quantity of the morphometric parameters of H.anatolicum underlies that the correct recognition and key construction for Hyalomma species dependes on a complement morphometric study on the other species.