Discovery of Colpodella spp. in ticks (Hyalomma dromedarii) infesting camels in southern Egypt.

In Egypt, tick-borne diseases pose a significant threat to human and animal health, and the threat to dromedaries (Camelus dromedarius), the country's dominant camelid species, is of particular concern. These animals are frequently infested with ticks, and may thus develop tick-borne diseases or become reservoirs of tick-borne pathogens. However, there is a paucity of data on tick infestation in Egyptian camels, especially in the south of the country. Accordingly, we aimed to determine the prevalence of tick infestation in southern Egyptian camel populations (in Luxor and Aswan governorates), and identify the hemoprotozoan parasites carried by camel-infesting ticks. Camels were checked for ticks during veterinary examination at quarantine and household checks, and ticks were collected from infested camels for species identification using morphological examination and PCR analyses. Tick and hemoprotozoan species were identified using Basic Local Alignment Search Tool analysis with subsequent confirmation in phylogenetic analyses. All camel-infesting ticks belonged to the species Hyalomma dromedarii, and were clustered with ticks of this species previously found in Egypt in a phylogenetic tree based on the 16S rRNA gene. Molecular analysis targeting the 18S rRNA gene revealed the presence of hitherto undetected hemoprotozoan parasites, Colpodella spp., in 30/297 (10.1 %) camel-infesting ticks. In phylogenetic analysis, these Colpodella spp. were highly homologous (94-98.6 %) with Colpodella spp. previously deposited in GenBank with accession numbers OQ540590Q, MH208621, and GQ411073, which relate to Colpodella spp. previously detected from Haemaphysalis longicornis, Rhipicephalus haemaphysaloides, and humans in China. PCR analyses with spherical body protein-4 (SBP-4) gene-specific primers revealed Babesia bovis in 16/297 (5 %) of camel-infesting ticks, however, Babesia bigemina and Theileria annulata were not detected. Here, we report the first detection of Colpodella spp. in H. dromedarii in Egypt. Further epidemiological studies are needed to assess the risk to camels and humans, and the transmission dynamics. Based on the high tick infestation rates in Egyptian camels and the identification of previously unreported protozoan hemoparasites in ticks, we consider that the dromedary should be subject to surveillance as a sentinel species for tick-borne diseases in Egypt. Our findings underline the need for surveillance and collecting data on lesser known pathogens circulating in camel-infesting ticks, as part of a public health strategy for dealing with tick-borne diseases in Egypt.

Tissue-specific localization of tick-borne pathogens in ticks collected from camels in Kenya: insights into vector competence.

Background: Tick-borne pathogen (TBP) surveillance studies often use whole-tick homogenates when inferring tick-pathogen associations. However, localized TBP infections within tick tissues (saliva, hemolymph, salivary glands, and midgut) can inform pathogen transmission mechanisms and are key to disentangling pathogen detection from vector competence. Methods: We screened 278 camel blood samples and 504 tick tissue samples derived from 126 camel ticks sampled in two Kenyan counties (Laikipia and Marsabit) for Anaplasma, Ehrlichia, Coxiella, Rickettsia, Theileria, and Babesia by PCR-HRM analysis. Results: Candidatus Anaplasma camelii infections were common in camels (91%), but absent in all samples from Rhipicephalus pulchellus, Amblyomma gemma, Hyalomma dromedarii, and Hyalomma rufipes ticks. We detected Ehrlichia ruminantium in all tissues of the four tick species, but Rickettsia aeschlimannii was only found in Hy. rufipes (all tissues). Rickettsia africae was highest in Am. gemma (62.5%), mainly in the hemolymph (45%) and less frequently in the midgut (27.5%) and lowest in Rh. pulchellus (29.4%), where midgut and hemolymph detection rates were 17.6% and 11.8%, respectively. Similarly, in Hy. dromedarii, R. africae was mainly detected in the midgut (41.7%) but was absent in the hemolymph. Rickettsia africae was not detected in Hy. rufipes. No Coxiella, Theileria, or Babesia spp. were detected in this study. Conclusions: The tissue-specific localization of R. africae, found mainly in the hemolymph of Am. gemma, is congruent with the role of this tick species as its transmission vector. Thus, occurrence of TBPs in the hemolymph could serve as a predictor of vector competence of TBP transmission, especially in comparison to detection rates in the midgut, from which they must cross tissue barriers to effectively replicate and disseminate across tick tissues. Further studies should focus on exploring the distribution of TBPs within tick tissues to enhance knowledge of TBP epidemiology and to distinguish competent vectors from dead-end hosts.

Cloning and catalytic profile of Hyalomma dromedarii leucine aminopeptidase.

Ticks have harmful impacts on both human and animal health and cause considerable economic losses. Leucine aminopeptidase enzymes (LAP) play important roles during tick infestation to liberate vital amino acids necessary for growth. The aim of the current study is to identify, express and characterize the LAP from the hard tick Hyalomma dromedarii and elucidate its biochemical characteristics. We cloned an open reading frame of 1560 bp encoding a protein of 519 amino acids. The LAP full-length was expressed in Escherichia coli BL21 (DE3) and purified. The recombinant enzyme (H.d rLAP- 6×His) had a predicted molecular mass of approximately 55 kDa. Purification and the enzymatic characteristics of H.d rLAP- 6×His were studied. The purified enzyme showed maximum activity at 37 °C and pH 8.0-8.5 using Leu-p-nitroanilide as a substrate. The activity of H.d rLAP- 6×His was sensitive to ß-mercaptoethanol, dl-dithiothreitol, 1,10- phenanthroline, bestatin HCl, and EDTA and completely abolished by 0.05 % SDS. In parallel, the enzymatic activity was enhanced by Ni2+, Mn2+ and Mg2+, partially inhibited by Na+, Cu2+, Ca2+ and completely inhibited by Zn2+.

Isolation, identification and antimicrobial susceptibility of the bacteria isolated from Hyalomma dromedarii infesting camels in Al-Jouf province, Saudi Arabia.

Ticks are important ectoparasites that transmit various pathogens causing morbidity and mortality in humans and animals. Saudi Arabia faces several challenges that can contribute to the emergence and spread of antimicrobial resistance (AMR) bacteria. These challenges require collaborative efforts to successfully achieve significant control of AMR in the country. The present study aims to isolate bacteria from camels' tick Hyalomma dromedarii in Al-Jouf province to identify and determine these isolates' antimicrobial susceptibilities. Forty-nine ticks were collected from dromedary camels and morphologically classified as H. dromedarii. Ticks were then homogenized and plated individually, which resulted in the isolation of 55 bacteria. The results showed that the bacterial isolates belong to 20 different species. About 71% (n = 39) of the total isolates were identified as Gram-positive bacteria comprised of 11 different species, while 29% (n = 16) of the total isolates were Gram-negative bacteria comprised of 9 different species. The most prevalent isolate within the total samples was Staphylococcus lentus (22.45%, 11/49), followed by Staphylococcus pseudintermedius (18.37%, 9/49) and Sphingomonas paucimobilis (16.33% 8/49). The antimicrobial susceptibility profile of Gram-positive bacteria showed that 100% (n = 31) were resistant to benzylpenicillin; 90.3% (n = 28) were resistant to oxacillin; 58.1% (n = 18) were resistant to clindamycin; 48.4% (n = 15) were resistant to vancomycin. In addition, 32.3% (n = 10) were resistant to trimethoprim/sulfamethoxazole and rifampicin; 25.8% (n = 8) were resistant to erythromycin; 16.1% (n = 5) were resistant to teicoplanin; 6.5% (n = 2) were resistant to tetracycline. All Gram-positive bacteria were 100% susceptible to linezolid, gentamicin, tobramycin, levofloxacin, moxifloxacin, tigecycline, and nitrofurantoin. In antimicrobial susceptibility tests for the Gram-negative bacteria, 57.14% (n = 8) of the identified bacteria were resistant to ampicillin, whereas 50% (n = 7) were resistant to cefoxitin and ceftazidime. About 28.57% (n = 4) of the Gram-negative bacteria were resistant to ceftriaxone, trimethoprim/sulfamethoxazole. In addition, 21.43% (n = 3) were resistant to amoxicillin/clavulanic acid and cephalothin; 14.29% (n = 2) were resistant to cefepime and nitrofurantoin; 7.14% (n = 1) were resistant to piperacillin/tazobactam and tigecycline. However, all Gram-negative bacteria were susceptible to other examined antimicrobials. This is the first study that investigates the role of the hard tick as a potential reservoir for AMR pathogens within our region.

MERS-CoV Found in Hyalomma dromedarii Ticks Attached to Dromedary Camels at a Livestock Market, United Arab Emirates, 2019.

The main mode of transmission of Middle East respiratory syndrome-related coronavirus (MERS-CoV) between dromedaries is likely via the respiratory route. However, there must be other modes to explain how the infection is brought to MERS-CoV-negative closed herds, such as transmission by ticks. Here, we present a study performed at three different locations in the United Arab Emirates (UAE) involving 215 dromedary camels (Camelus dromedarius) and the ticks attached to them. We tested the camels and ticks via RT-(q)PCR for the presence of MERS-CoV nucleic acids, as well as flaviviruses that may be present in the region (e.g., Alkhumra hemorrhagic fever virus). Camel sera were additionally analyzed for evidence of previous exposure to MERS-CoV. In total, 8 out of 242 tick pools were positive for MERS-CoV RNA (3.3%; Ct 34.6-38.3), 7 of which contained Hyalomma dromedarii ticks, and one contained a Hyalomma sp. tick (species not identified). All of the virus-positive ticks' host camels were also positive for MERS-CoV RNA in their nasal swab samples. Short sequences established in the N gene region from two positive tick pools were identical to viral sequences from their hosts' nasal swabs. In total, 59.3% of dromedaries at the livestock market had MERS-CoV RNA in their nasal swabs (Ct 17.7-39.5). While dromedaries at all locations were negative for MERS-CoV RNA in their serum samples, antibodies were detected in 95.2% and 98.7% of them (tested by ELISA and indirect immunofluorescence test, respectively). Given the probably transient and/or low level of MERS-CoV viremia in dromedaries and the rather high Ct values observed in the ticks, it seems unlikely that Hyalomma dromedarii is a competent vector for MERS-CoV; however, its role in mechanical or fomite transmission between camels should be investigated.

Virome diversity of Hyalomma dromedarii ticks collected from camels in the United Arab Emirates.

Background and Aim: Viruses are important components of the microbiome of ticks. Ticks are capable of transmitting several serious viral diseases to humans and animals. Hitherto, the composition of viral communities in Hyalomma dromedarii ticks associated with camels in the United Arab Emirates (UAE) remains unexplored. This study aimed to characterize the RNA virome diversity in male and female H. dromedarii ticks collected from camels in Al Ain, UAE. Materials and Methods: We collected ticks, extracted, and sequenced RNA, using Illumina (NovaSeq 6000) and Oxford Nanopore (MinION). Results: From the total generated sequencing reads, 180,559 (~0.35%) and 197,801 (~0.34%) reads were identified as virus-related reads in male and female tick samples, respectively. Taxonomic assignment of the viral sequencing reads was accomplished based on bioinformatic analyses. Further, viral reads were classified into 39 viral families. Poxiviridae, Phycodnaviridae, Phenuiviridae, Mimiviridae, and Polydnaviridae were the most abundant families in the tick viromes. Notably, we assembled the genomes of three RNA viruses, which were placed by phylogenetic analyses in clades that included the Bole tick virus. Conclusion: Overall, this study attempts to elucidate the RNA virome of ticks associated with camels in the UAE and the results obtained from this study improve the knowledge of the diversity of viruses in H. dromedarii ticks.

Purification, characterization, and enzyme kinetics of a glutathione S transferase from larvae of the camel tick Hyalomma dromedarii.

BACKGROUND: Glutathione s-transferases (GSTs) perform an essential role in detoxification of xenobiotics and endogenous compounds via their conjugation to reduce glutathione. RESULTS: A GST enzyme, designated tick larvae glutathione S transferase (TLGST), was purified from larvae of the camel tick Hyalomma dromedarii via ammonium sulfate precipitation, glutathione-Sepharose affinity column and Sephacryl S-300 chromatography. TLGST-specific activity was found to be 1.56 Umg-1 which represents 39 folds and 32.2% recovery. The molecular weight of TLGST purified from camel tick larvae was found as 42 kDa by gel filtration. TLGST has a pI value of 6.9 and was found a heterodimeric protein of 28 and 14 kDa subunits as detected on SDS-PAGE. The Lineweaver-Burk plot calculated the km for CDNB to be 0.43 mM with Vmax value of 9.2 Umg-1. TLGST exhibited its optimal activity at pH 7.9. Co2+, Ni2+ and Mn2+ increased the activity of TLGST while Ca2+, Cu2+, Fe2+ and Zn2+ inhibited it. TLGST was inhibited by cumene hydroperoxide, p-hydroxymercuribenzoate, lithocholic acid, hematin, triphenyltin chloride, p-chloromercuribenzoic acid (pCMB), N-p-Tosyl-L-phenylalanine chloromethyl ketone (TPCK), iodoacetamide, EDTA and quercetin. pCMB inhibited TLGST competitively with Ki value of 0.3 mM. CONCLUSIONS: These findings will help to understand the various physiologic conditions of ticks and targeting TLGST could be significant tool for development of prospective vaccines against ticks as a bio-control strategy to overcome the rapid grows in pesticide-resistant tick populations.

Molecular characterization of Hyalomma dromedarii and evaluation of acaricidal potential of herbal methanolic extracts against H. dromedarii larvae in comparison to synthetic acaricides.

The present study had two aims: molecular characterization of Hyalomma dromedarii infesting one-humped camels of Haryana (North India), and assessment of the acaricidal potential of herbal methanolic extracts against H. dromedarii larvae in comparison to synthetic acaricides. Phylogenetics and population neutrality indices were assessed by targeting partial amplification of mitochondrial 16S rDNA sequences. Larval packet test (LPT) was performed to evaluate the acaricidal efficacy of herbal extracts (Ferula asafoetida and Trachyspermum ammi) and synthetic acaricides (deltamethrin and fipronil). Phylogenetic studies established the collected ticks to be H. dromedarii, exhibiting a homology of 99.8-100%. However, the present study isolates formed a different sub-clade compared to H. dromedarii sequences from Egypt, Senegal, Tunisia and Saudi Arabia. Nucleotide and haplotype diversity values were indicative of demographic expansion and low gene flow. Negative values of Tajima's D (-0.612) and Fu and Li's Fst (-0.479) highlighted deviations from neutrality and emphasized recent population expansion. The median lethal concentration (LC50) values recorded for T. ammi, F. asafoetida and their combination were 3.68, 2.87 and 2.59 mg/mL, respectively, whereas the 90% lethal concentration (LC90) values were 4.09, 3.58 and 3.35 mg/mL, respectively. It was also observed that the H. dromedarii population under study was completely susceptible to both the formulated synthetic acaricides. In conclusion, combination of methanolic extracts of F. asafoetida and T. ammi could provide a potential substitute to toxic synthetic chemical acaricides and might prove a valuable component of integrated tick management strategies.

Acaricide resistance and novel photosensitizing approach as alternative acaricides against the camel tick, Hyalomma dromedarii.

The control of the camel tick, Hyalomma dromedarii is very crucial. This study evaluated the novel toxicity of photosensitizers and Phoxim insecticide against H. dromedarii males using the adult immersion tests. Ticks were subjected to sunlight for 10 min post-treatment (PT). The optical characters of the applied materials were determined by UV-Vis spectroscopy (250-900 nm wavelengths). The intensity of spectra decreased as dye concentration decreased. The optical bandgap energies of the dyes at different concentrations were not changed as the concentration changed and decreased as the absorption peak of individual dyes red-shifted. The mortalities 72 h PT reached 42.2%, 44.4%, 51.1%, 71.1%, 46.7%, 48.9%, 44.4%, and 55.6% for chlorophyllin, echinochrome, field stain, methylene blue, phthalocyanine, rhodamine 6G, riboflavin, and safranin, respectively. Methylene blue recorded the highest median lethal concentration (LC50 = 127 ppm) followed by safranin, field stain, rhodamine 6G, phthalocyanine, echinochrome riboflavin, and chlorophyllin (LC50 = 209, 251, 271, 303, 324, 332, and 362 ppm, respectively, 72 h PT). Their median lethal time, LT50, values PT with 240 ppm were 45, 87, 96, 72, 129, 115, 131, and 137 h, respectively. The relative toxicities of the LC50 values 72 h PT showed that chlorophyllin, echinochrome, field stain, methylene blue, phthalocyanine, rhodamine 6G, riboflavin, and safranin were 3.2, 3.6, 4.6, 9.1, 3.8, 4.3, 3.5, and 5.6 times, respectively, more effective than Phoxim. Methylene blue, safranin, and field stain showed a broad absorbance area indicating a large photoactivity and better phototoxicity and could be used as alternative agents to synthetic acaricides.

Biochemical and functional characterization of protease inhibitors (serpins and kunitz), identified from the sialotranscriptome of Hyalomma dromedarii tick

Doenças cardiovasculares afetam o coração e as artérias sanguíneas, frequentemente surgindo a partir de disfunções relacionadas às plaquetas, desregulação da coagulação sanguínea, ou uma combinação de ambos. As glândulas salivares do carrapato são consideradas uma fonte natural atrativa de compostos antihemostáticos. Sua saliva inclui um coquetel de moléculas bioativas que atuam especificamente nos componentes distintos da coagulação sanguínea. Neste estudo, combinamos métodos computacionais e experimentais para caracterizar três serpinas, aqui chamadas de HDS1, HDS2 e HDS3, do sialotranscriptoma do carrapato do camelo, Hyalomma dromedarii. Nossos dados in silico descreveram essas serpinas como proteínas secretadas com alta semelhança com serpinas inibitórias previamente caracterizadas. As proteínas recombinantes (rHDS1, rHDS2 e rHDS3) foram expressas com sucesso usando o sistema de expressão Escherichia coli BLD21 (DE3). A rHDS1 foi obtida como um monômero bem estruturado e solúvel, enquanto rHDS2 e rHDS3 agregaram-se como corpos de inclusão. Ensaios funcionais revelaram que a rHDS1 prolongou significativamente o tempo de coagulação da via intrínseca, mirando principalmente a trombina (IC50 = 0,16 μM). A rHDS1 também foi capaz de inibir a calicreína, FXIa e um modesto efeito sobre FXIIa, exibindo impacto insignificante em outros fatores de coagulação. A rHDS1 agiu na inibição da agregação plaquetária induzida pela trombina. Por outro lado, a rHDS2 não demonstrou influência significativa no tempo de coagulação. Essas observações sobre a rHDS2 poderiam potencialmente ser atribuídas ao dobramento inadequado da proteína ou, alternativamente, ao seu impacto insignificante na hemostasia. Em conclusão, esta tese fornece insights valiosos sobre os papéis das serpinas nas glândulas salivares do carrapato do camelo. Notavelmente, a rHDS1 se destaca como a primeira serpina recombinante do gênero Hyalomma capaz de inibir a trombina tanto na coagulação sanguínea quanto na agregação plaquetária, possivelmente envolvendo a heparina como cofator. Investigações futuras são necessárias para testar a viabilidade da rHDS1 como um potencial candidato para o desenvolvimento de medicamentos visando doenças potencialmente fatais, como doenças cardíacas e derrames.

Morphological abnormalities in Hyalomma dromedarii and Hyalomma rufipes (Acari: Ixodidae) collected from dromedary camels (Camelus dromedarius) in Aswan, Egypt.

The present study reports anomalies in Hyalomma dromedarii and Hyalomma rufipes adults collected from dromedary camels (Camelus dromedarius) in Aswan, Egypt, between January and June 2022. A total of 52 adult ticks displayed one or several local and/or general anomalies. A wide variety of local anomalies was observed including atrophy of one or multiple legs, ectromely, absence of accessory adanal and subanal plates, fusion of adanal and accessory plates, and presence of sclerotized formation in the ventral plate, as well as abnormalities of the spiracle, anal groove, festoon, parma, and posteromedian groove. General anomalies comprised of asymmetries and gynandromorphism. Local anomalies were documented among H. dromedarii and H. rufipes, whereas general anomalies were documented only from H. dromedarii. The present work represents the first report of deuterogynander intrigue gynandromorphism in H. dromedarii, as well as the first report of morphological abnormalities in H. dromedarii and H. rufipes from Egypt.

Novel Pesticidal Efficacy of Araucaria heterophylla and Commiphora molmol Extracts against Camel and Cattle Blood-Sucking Ectoparasites.

Botanical insecticides are promising pest control agents. This research investigated the novel pesticidal efficacy of Araucaria heterophylla and Commiphora molmol extracts against four ectoparasites through treated envelopes. Seven days post-treatment (PT) with 25 mg/mL of C. molmol and A. heterophylla, complete mortality of the camel tick, Hyalomma dromedarii and cattle tick, Rhipicephalus (Boophilus) annulatus were reached. Against H. dromedarii, the median lethal concentrations (LC50s) of the methanol extracts were 1.13 and 1.04 mg/mL and those of the hexane extracts were 1.47 and 1.38 mg/mL, respectively. The LC50 values of methanol and hexane extracts against R. annulatus were 1.09 and 1.41 plus 1.55 and 1.08 mg/mL, respectively. Seven days PT with 12.5 mg/mL, extracts completely controlled Haematopinus eurysternus and Hippobosca maculata; LC50 of Ha. eurysternus were 0.56 and 0.62 mg/mL for methanol extracts and 0.55 and 1.00 mg/mL for hexane extracts, respectively, whereas those of Hi. maculata were 0.67 and 0.78 mg/mL for methanol extract and 0.68 and 0.32 mg/mL, respectively, for hexane extracts. C. molmol extracts contained sesquiterpene, fatty acid esters and phenols, whereas those of A. heterophylla possessed monoterpene, sesquiterpene, terpene alcohols, fatty acid, and phenols. Consequently, methanol extracts of C. molmol and A. heterophylla were recommended as ecofriendly pesticides.

Assessing Temporal Changes in Microbial Communities in Hyalomma dromedarii Collected From Camels in the UAE Using High-Throughput Sequencing.

Ticks (Acari) are ectoparasites of animals that harbor communities of microbes of importance to animal and human health. Microbial communities associated with ticks exhibit temporal patterns of variation in their composition, with different genera dominating at different times of the year. In this study, molecular tools were used to assess the composition of the microbial communities associated with Hyalomma dromdarii. Adult ticks were collected every month for 1 year from 25 camels in the UAE. A total of 12 DNA pools were prepared (one pool for each month). We monitored the microbiota of ticks using high-throughput sequencing of the V3-V4 region of the bacterial 16S rRNA gene. A total of 614 operational taxonomic units were produced through de novo clustering and belonged to 17 phyla, 30 classes, 46 orders, 118 families, and 222 genera. Fifteen bacterial families were found to be the most abundant. The dominant bacterial communities associated with H. dromedarii belonged to the genera Staphylococcus, Bacillus, Francisella, and Corynebacterium, which were reported with high relative abundance from all months. No significant correlation occurred between the abundance of microbial families or genera in H. dromedarii ticks and the ambient temperature. Our findings revealed, for the first time in the UAE, temporal fluctuations of microbial communities in H. dromedarii ticks and provided key insights on the interaction between different microbial groups. Moreover, our results contribute to the current understanding of disease development and allow more investigations for potentially pathogenic microbiota.

Acaricidal Efficacy of Biosynthesized Zinc Oxide Nanoparticles Against Hyalomma dromedarii (Acari: Ixodidae) and Their Toxic Effects on Swiss Albino Mice.

PURPOSE: The current study aimed to investigate the efficacy of zinc oxide nanoparticles (ZnO NPs) synthesized by Melia azedarach aqueous extract to control Hyalomma dromedarii tick, and to evaluate their toxic effects on Swiss albino mice. METHODS: ZnO NPs were synthesized using M. azedarach aqueous extract. UV-visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive spectroscopy were used to characterize the synthesized NPs. Egg, nymph, larva, and adult immersion tests were used for bioassay of tick stages with the synthesized ZnO NP. A toxicity study was performed on Swiss albino mice after treatment with 1/10 of the oral LD50 of ZnO NPs (8437 mg/kg) for 5 successive days by oral gavage. RESULTS: The LC50 of ZnO NPs on the eggs, larvae, and nymphs was 11.6, 8.03, and 3.9 mg/ml, respectively. The reproductive performance of females treated with ZnO NPs was lower than that of untreated females. The hematological results showed an insignificant increase in the level of white blood cells with normal red blood cells, hemoglobin, in addition to normal platelet count. The biochemical analysis showed an insignificant increased level (P > 0.05) of alkaline phosphatase and alanine aminotransferase. The liver and kidney suffered few histopathological changes after oral administration of ZnO NPs. CONCLUSION: These results suggest that ZnO NPs have good acaricidal activity against eggs, larvae, and engorged nymphs of H. dromedarii. ZnO NPs minimized the number of eggs laid by engorged females and the hatchability of their eggs. ZnO NPs did not affect unfed adults. The toxicity results of the mice revealed insignificant changes in the hemogram, biochemistry, with liver and kidney suffering few histopathological changes. Future studies are needed to assess application routes (topical vs oral). Based on these findings, ZnO NPs may be incorporated in the control of camel tick H. dromedarii.

Pathogens in ticks collected in Israel: I. Bacteria and protozoa in Hyalomma aegyptium and Hyalomma dromedarii collected from tortoises and camels.

Ticks were collected from 30 Greek tortoise (Testudo graeca), and 10 Arabian camels (dromedary) (Camelus dromedarius) in Israel. All those collected from Greek tortoises belonged to Hyalomma aegyptium, while all specimens collected from the camels belonged to Hyalomma dromedarii. Out of 84 specimens of H. aegyptium, 31 pools were examined by PCR, while from 75 H. dromedarii specimens nine pools were studied. Out of 31 pools of H. aegyptium 26 were positive for pathogens or endosymbiont; 14 for one, 11 for two and one for three pathogens. Out of nine pools prepared from H. dromedarii, seven were positive for pathogens (two for C. burnetii and five for Leishmania infantum). In H. aegyptium, Rickettsia africae, Rickettsia aeschlimannii, Rickettsia endosymbiont, Coxiella burnetii, Hemolivia mauritanica, Babesia microti, Theileria sp., and Leishmania infantum was detected, while in H. dromedarii C. burnetii and L. infantum were found. None of the ticks were positive for Anaplasma/Ehrlichia, Listeria monocytogenes, Bartonella spp., Hepatozoon spp. and Toxoplasma gondii. H Rickettsia endosymbionts, C. burnetii, B. microti, Theileria sp. and L. infantum are reported for the first time in H. aegyptium, and C. burnetii and L. infantum for the first time in H. dromedarii.

rDromaserpin: A Novel Anti-Hemostatic Serpin, from the Salivary Glands of the Hard Tick Hyalomma dromedarii.

Hemostatic disorders are caused either by platelet-related dysfunctions, defective blood coagulation, or by a combination of both, leading to an increased susceptibility to cardiovascular diseases (CVD) and other related illnesses. The unique specificity of anticoagulants from hematophagous arthropods, such as ticks, suggests that tick saliva holds great promise for discovering new treatments for these life-threatening diseases. In this study, we combined in silico and in vitro analyses to characterize the first recombinant serpin, herein called Dromaserpin, from the sialotranscriptome of the Hyalomma dromedarii tick. Our in silico data described Dromaserpin as a secreted protein of ~43 kDa with high similarities to previously characterized inhibitory serpins. The recombinant protein (rDromaserpin) was obtained as a well-structured monomer, which was tested using global blood coagulation and platelet aggregation assays. With this approach, we confirmed rDromaserpin anticoagulant activity as it significantly delayed plasma clotting in activated partial thromboplastin time and thrombin time assays. The profiling of proteolytic activity shows its capacity to inhibit thrombin in the micromolar range (0.2 to 1 µM) and in the presence of heparin this inhibition was clearly increased. It was also able to inhibit Kallikrein, FXIa and slightly FXIIa, with no significant effect on other factors. In addition, the rDromaserpin inhibited thrombin-induced platelet aggregation. Taken together, our data suggest that rDromaserpin deserves to be further investigated as a potential candidate for developing therapeutic compounds targeting disorders related to blood clotting and/or platelet aggregation.

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

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.

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.

Viral RNA Metagenomics of Hyalomma Ticks Collected from Dromedary Camels in Makkah Province, Saudi Arabia.

Arthropod-borne infections are a medical and economic threat to humans and livestock. Over the last three decades, several unprecedented viral outbreaks have been recorded in the Western part of the Arabian Peninsula. However, little is known about the circulation and diversity of arthropod-borne viruses in this region. To prepare for new outbreaks of vector-borne diseases, it is important to detect which viruses circulate in each vector population. In this study, we used a metagenomics approach to characterize the RNA virome of ticks infesting dromedary camels (Camelus dromedaries) in Makkah province, Saudi Arabia. Two hundred ticks of species Hyalomma dromedarii (n = 196) and Hyalomma impeltatum (n = 4) were collected from the Alkhurma district in Jeddah and Al-Taif city. Virome analysis showed the presence of several tick-specific viruses and tick-borne viruses associated with severe illness in humans. Some were identified for the first time in the Arabian Peninsula. The human disease-associated viruses detected included Crimean Congo Hemorrhagic fever virus and Tamdy virus (family Nairoviridae), Guertu virus (family Phenuiviridae), and a novel coltivirus that shares similarities with Tarumizu virus, Tai forest reovirus and Kundal virus (family Reoviridae). Furthermore, Alkhurma hemorrhagic virus (Flaviviridae) was detected in two tick pools by specific qPCR. In addition, tick-specific viruses in families Phenuiviridae (phleboviruses), Iflaviridae, Chuviridae, Totiviridae and Flaviviridae (Pestivirus) were detected. The presence of human pathogenetic viruses warrants further efforts in tick surveillance, xenosurveillence, vector control, and sero-epidemiological investigations in human and animal populations to predict, contain and mitigate future outbreaks in the region.

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.