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.

Hyalomma spp. ticks and associated Anaplasma spp. and Ehrlichia spp. on the Iran-Pakistan border

Background Anaplasmosis and ehrlichiosis are tick-borne diseases affecting humans and livestock, particularly in tropical and subtropical regions. Animal husbandry is the main activity of people on the borders of Iran and Pakistan, with thousands of cattle crossing the border each week. Methods PCR and sequencing of the 16S rRNA gene was used to determine the percentage and geographical distribution of the pathogens carried by Hyalomma spp. (n = 306) collected from 126 goats, cattle and camels in the region between November 2017 and late March 2018. Results In total, 1124 hard ticks including 1020 Hyalomma spp. ticks belonging to six species (Hyalomma anatolicum, Hyalomma asiaticum, Hyalomma marginatum, Hyalomma dromedarii, Hyalomma schulzei, and Hyalomma detritum) were found on the borders of Iran and Pakistan, with H. anatolicum being the most prevalent tick species. Anaplasma spp. and/or Ehrlichia spp. DNA was found in 68.3% of the engorged tick specimens (n = 256). Sequencing of a subset (12.6%) of PCR-positive samples revealed Anaplasma ovis, Anaplasma marginale, and Ehrlichia ewingii DNA in 81.8%, 9.1%, and 9.1% of the ticks, respectively. To our knowledge, this is the first report of E. ewingii, an important human pathogen, in Iran. Conclusions Based on molecular analysis, three pathogenic Anaplasmataceae were detected in six Hyalomma spp. parasitizing cattle, goats and camels, confirming the presence of these pathogens along the Iran-Pakistan border. Graphical Abstract

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.

Lack of detection of the Middle East respiratory syndrome coronavirus (MERS-CoV) nucleic acids in some Hyalomma dromedarii infesting some Camelu dromedary naturally infected with MERS-CoV

Objective The Middle East respiratory syndrome coronavirus (MERS-CoV) is one of the zoonotic coronaviruses [Hemida Peer J 7:e7556, 2019; Hemida et al. One Health 8:100102, 2019]. The dromedary camels remained the only known animal reservoir for this virus. Several aspects of the transmission cycle of the virus between animals, including arthropod-borne infection, is still largely unknown. The main objective of the current work was to study the possibility of MERS-CoV transmission through some arthropod vectors, particularly the hard ticks. To achieve this objective, we identified a positive MERS-CoV dromedary camel herd using the commercial available real-time PCR kits. We collected some arthropods, particularly the ticks from these positive animals as well as from the animal habitats. We tested these arthropods for the presence of MERS-CoV viral RNAs. Results Our results showing the absence of any detectable MERS-CoV-RNAs in these arthropods despite these animals were actively shedding the virus in their nasal secretions. Our results are confirming for the first the failure of detection of the MERS-CoV in ticks infesting dromedary camels. Failure of the detection of MERS-CoV in ticks infesting positive naturally infected MERS-CoV camels is strongly suggesting that ticks do not play roles in the transmission of the virus among the animals and close contact humans.