Transstadial Transmission and Long-term Association of Crimean-Congo Hemorrhagic Fever Virus in Ticks Shapes Genome Plasticity

The trade-off hypothesis, the current paradigm of arbovirus evolution, proposes that cycling between vertebrate and invertebrate hosts presents significant constraints on genetic change of arboviruses. Studying these constraints in mosquito-borne viruses has led to a new understanding of epizootics. The trade-off hypothesis is assumed to be applicable to tick-borne viruses too, although studies are lacking. Tick-borne Crimean-Congo hemorrhagic fever virus (CCHFV), a member of the family Bunyaviridae, is a major cause of severe human disease worldwide and shows an extraordinary amount of genetic diversity compared to other arboviruses, which has been linked to increased virulence and emergence in new environments. Using a transmission model for CCHFV, utilizing the main vector tick species and mice plus next generation sequencing, we detected a substantial number of consensus-level mutations in CCHFV recovered from ticks after only a single transstadial transmission, whereas none were detected in CCHFV obtained from the mammalian host. Furthermore, greater viral intra-host diversity was detected in the tick compared to the vertebrate host. Long-term association of CCHFV with its tick host for 1 year demonstrated mutations in the viral genome become fixed over time. These findings suggest that the trade-off hypothesis may not be accurate for all arboviruses

Modeling the spatial distribution of Crimean-Congo Hemorrhagic Fever outbreaks in Turkey

The more than 1100 human cases of Crimean-Congo Hemorrhagic Fever (CCHF) reported in a continuing series of outbreaks that started in 2003 in Turkey constitute the largest epidemic of the disease since CCHF was first recognized in 1944. The spatial distribution of CCHF case reporting rates in Turkey was studied to look for clusters of disease. We applied the spatial scan analysis to test the hypothesis of whether there were areas with a higher than expected number of CCHF cases. The analysis was conducted through windows of 10, 20, 40 and 80 km in diameter[SR1] to determine whether clustering of cases was dependent on the size of the scanning window. At the largest window size, consistent patterns of significantly higher than expected numbers of CCHF cases were found in a total of 40 administrative districts. A predictive model to map the habitat suitability for the vector tick was developed from satellite-based climate data and high-resolution features of the vegetation from Landsat images covering the whole country. It was found that areas of higher risk (higher CCHF reporting) were correlated (p < 0.05) with zones of high climate suitability for the tick together with a high rate of fragmentation of agricultural land interspersed between forest and shrub-type vegetation

The Effects of Nitric Oxide and Inhibitor, and Combination of Albendazole and Praziquantel On Liver in Mice Injected with Echinococcus granulosus Larvae

In this study, the role of nitric oxide (NO) in the pathogenesis of hydatidosis and the interaction with effects of anthelmintic drugs, albendazole and praziquantel, were examined in larval infection caused by protoscolices obtained from hydatid cysts of sheep liver in Albino Balb/c mice. Animals were divided into ten groups including controls and infected groups. Larval infection was established with intraperitoneal injection of protoscolices. Eight months after infection with protoscolices, the infected animals were divided into 6 groups. The infected animals were given a selective inhibitor of inducible nitric oxide synthase (iNOS) L-N6-(1-Iminoethyl) lysine-hydrochloride (L-NIL), NO donor sodium nitroprusside (SNP), albendazole and praziquantel as anthelmintic drugs for 7 days. In addition, control groups were composed of intact group, control, anthelmintic drugs + L-NIL, and anthelmintic drugs + SNP. The liver and blood samples were taken for cytological, histological, immunohistochemical and biochemical analyses 7 days after treatments at the end of experiment. The animals injected with protoscolices showed histopathological changes including inflammation areas, infiltration and accumulation of leukocytes, dilation of sinusoids, and damage in endothelial cells and hepatocytes at light microscopy. Electron microscopy were revealed severe damage in sinusoidal endothelial cells, leukocytes especially eosinophils in sinusoid lumens and disorganization in endoplasmic reticulum and nuclear membrane. Endothelial nitric oxide synthase (eNOS) and iNOS reactions were increased in the tissue. Anthelmintic drugs decreased inflammation areas and damages; however, it did not change NOS reactions in the animals given protoscolices. L-NIL and SNP diminished both iNOS and eNOS reactions. Unlike the group administered the inhibitor, SNP treated group exhibited less inflammation areas. Combination of these substances and drugs resulted in decreased inflammation areas. eNOS and iNOS reactions decreased in the drugs and SNP administered group, while only iNOS reaction was decreased in L-NIL given infection group. In addition, the infected groups which received SNP displayed expanded sinusoids and hepatocytes with vacuoles, intriguingly. While levels of serum nitrite/nitrate elevated only in the infection group given drugs and SNP, it decreased in the L-NIL administered group. Tissue level of malondialdehyde increased in infection groups with drugs and SNP. In conclusion, the results indicated that NO plays an important role in the pathogenesis of hydatidosis

The first clinical case due to AP92 like strain of Crimean-Congo Hemorrhagic Fever virus and a field survey

Background: Crimean-Congo Hemorrhagic Fever (CCHF) is a fatal infection, but no clinical case due to AP92 strain was reported. We described the first clinical case due to AP92 like CCHFV. Methods: A case infected by a AP92 like CCHFV was detected in Balkanian part of Turkey. Diagnosis was confirmed by RT-PCR and sequencing. A human serologic and tick survey studies were performed in the region, where the case detected. Results: Thirty eight individuals out of 741 were found to be anti CCHFV IgM positive. The attack rate for overall CCHFV was calculated as 5.2%. In univariate analyses, CCHFV IgM positivity was found to be associated with the age (p < 0.001), male gender (p = 0.001), agricultural activity (p = 0.036), and history of tick bite (p = 0.014). In multivariate analysis, older age (OR: 1.03, CI: 1.01-1.05, p < 0.001), male gender were found to be the risk factors (OR: 2.5, CI: 1.15-5.63, p = 0.020) for CCHFV infection. Conclusion: This is the first human case with AP92 like CCHFV infection. Furthermore, this is the first report of AP92 like strain in Turkey. In the region, elderly males carry the highest risk for CCHFV infection

Preferences of different tick species for human hosts in Turkey

The ticks removed from the patients who applied to the hospitals in Istanbul and neighboring cities, Turkey, with the complaint of tick bite were examined in this study, on account of their species, biological stages, attachment sites on the body, and the age of the affected patients. A total of 16,969 ticks were identified. Encountered species were as follows: 33.6 % Ixodes spp. immature, 25.3 % Hyalomma spp. immature, 24.3 % I. ricinus, 9.5 % Rhipicephalus sanguineus gr., 3.2 % R. bursa, 2.2 % Hyalomma marginatum, 1.96 % Haemaphysalis adults, 1.66 % Hyalomma aegyptium, 0.52 % Dermacentor marginatus, 0.39 % Rhipicephalus spp. nymphs, 0.12 % Dermacentor spp. nymphs, 0.11 % Haemaphysalis spp. nymphs, 0.09 % Hyalomma scupense, and 0.03 % Hyalomma excavatum. The distribution of attachment sites of the species and instars showed significant differences. Furthermore, age data of the patients also revealed that certain tick species were more common within certain age groups

Revisiting detachment techniques in human-biting ticks

Background: Early and complete removal of ticks using the right technique is important to reduce tick-transmitted diseases. Several chemical and mechanical detachment techniques have been described previously. Objective: We aimed to compare the performance of 4 tick-detachment techniques that are widely used in human beings and to determine the optimal method from these techniques. Methods: A cross-sectional study was conducted on 160 patients between April and June 2010. Patients with reported tick bite were reviewed retrospectively and divided into the following 4 groups according to the tick-detachment technique used: card detachment, lassoing, freezing, and tweezers. Performance of each technique was evaluated according to the number of fully detached, nondetached, and crushed ticks and the duration of application. Results: Of the 160 tick-bite cases assessed, we found the following efficacy rates: 82.5% (33/40), technique using tweezers; 47.5% (19/40), lassoing technique; 7.5% (3/40), card detachment; and 0% (0/40), freezing technique. The efficacy rate of the technique using tweezers was significantly higher than that of the other 3 techniques (P < .05). Limitations: This was a relatively small sample size and not designed as a randomized clinical trial. Conclusion: Tick detachment using tweezers, performed in an appropriate manner, is the easiest and most effective technique

The effects of dietary oregano essential oil on live performance, carcass yield, serum immunoglobulin G level, and oocyst count in broilers

The present study was designed to evaluate the effect of dietary oregano essential oil on the live performance, carcass yield, and serum IgG levels of broilers and to examine its anticoccidial effect. In a completely randomized design, 1,200 straight-run Ross 308 broilers were allocated into 3 experimental groups, each consisting of 5 replicates. The first group received a basal diet with an anticoccidial (Cygro) at a level of 100 mg/kg of the feed. The second group received diets supplemented with oregano essential oil (Orego-Stim) at a level of 300 mg/kg of the feed, whereas the third group received neither the coccidiostat nor oregano oil (negative control). Throughout the experimental period of 42 d, individual BW and pen feed intake were recorded weekly, and FCR were calculated. Blood samples were collected on d 1 and 42 to determine serum IgG levels. Oocyst counts were determined in excreta samples taken at 10-d intervals from each replication. Results indicated that dietary oregano essential oil and anticoccidial supplementation improved the FCR significantly (P 0.05) at 42 d. Although not significant, there was a slight increase in the serum IgG levels of broilers fed the oregano oil diet. Although the dietary oregano oil significantly (P < 0.05) lowered the excreta oocyst counts compared with those of birds fed the negative control diet, its anticoccidial effect was significantly less than the effects in birds fed the diet with the anticoccidial. In conclusion, oregano essential oil may provide an alternative to conventional anticoccidial additives in broiler feeds

The role of ticks in the maintenance and transmission of Crimean-Congo hemorrhagic fever virus: A review of published field and laboratory studies

This manuscript is part of a series of reviews that aim to cover published research on Crimean-Congo hemorrhagic fever (CCHF) and its etiological agent, CCHF virus (CCHFV). The virus is maintained and transmitted in a vertical and horizontal transmission cycle involving a variety of wild and domestic vertebrate species that act as amplification hosts, without showing signs of illness. These vertebrates have traditionally been considered reservoirs of CCHFV, but in fact they develop only a transient viremia, while the virus can persist in ticks for their entire lifespan, and can also be transmitted vertically to the next generation. As a result, ticks are now considered to be both the vector and the reservoir for the virus. CCHFV has been detected in a wide range of tick species, but only a few have been proven to be vectors and reservoirs, mainly because most published studies have been performed under a broad variety of conditions, precluding definitive characterization. This article reviews the published literature, summarizes current knowledge of the role of ticks in CCHFV maintenance and transmission and provides guidance for how to fill the knowledge gaps. Special focus is given to existing data on tick species in which vertical passage has been demonstrated under natural or experimental conditions. At the same time, we identify earlier reports that used unreliable methods and perceptions to ascribe a vector role to some species of ticks, and have contributed to confusion regarding viral transmission. We also examine epidemiological pathways of CCHFV circulation and discuss priority areas for future research. (C) 2017 Elsevier B.V. All rights reserved

Rickettsia Species in Ticks Removed from Humans in Istanbul, Turkey

A total of 167 ticks collected from humans in Istanbul (Turkey) in 2006 were screened for Rickettsia species, and nested PCRs targeting gltA and ompA rickettsial fragment genes were carried out. Rickettsia monacensis (51), R. aeschlimannii (8), R. conorii subsp. conorii (3), R. helvetica (2), R. raoultii (1), R. africae (1), R. felis (1), and other Rickettsia spp. (2), were detected. To our knowledge, these Rickettsia species (except R. conorii) had never been reported in ticks removed from humans in Turkey. The presence of R. africae also had not been previously described, either in Hyalomma ticks or in any European tick species. In addition, R. aeschlimannii and R. felis had not been found associated with Rhipicephalus bursa specimens. The presence of human pathogenic Rickettsia in ticks removed from humans provides information about the risk of tick-borne rickettsioses in Turkey

Interactions of Human Dermal Dendritic Cells and Langerhans Cells Treated with Hyalomma Tick Saliva with Crimean-Congo Hemorrhagic Fever Virus

Crimean-Congo hemorrhagic fever virus is one the most important and wide spread tick-borne viruses. Very little is known about the transmission from the tick and the early aspects of pathogenesis. Here, we generate human cutaneous antigen presenting cells-dermal dendritic cells and Langerhans cells-from umbilical cord progenitor cells. In order to mimic the environment created during tick feeding, tick salivary gland extract was generated from semi-engorged Hyalomma marginatum ticks. Our findings indicate that human dermal dendritic cells and Langerhans cells are susceptible and permissive to Crimean-Congo hemorrhagic fever virus infection, however, to different degrees. Infection leads to cell activation and cytokine/chemokine secretion, although these responses vary between the different cell types. Hyalomma marginatum salivary gland extract had minimal effect on cell responses, with some synergy with viral infection with respect to cytokine secretion. However, salivary gland extract appeared to inhibit antigen presenting cells (APCs) migration. Based on the findings here we hypothesize that human dermal dendritic cells and Langerhans cells serve as early target cells. Rather affecting Crimean-Congo hemorrhagic fever virus replication, tick saliva likely immunomodulates and inhibits migration of these APCs from the feeding site