116 research outputs found
Erratum: Correction to: The tree that hides the forest: cryptic diversity and phylogenetic relationships in the Palaearctic vector Obsoletus/Scoticus complex (Diptera: Ceratopogonidae) at the European level (Parasites Vectors (2020) 13 (265) DOI: 10.1186/s13071-020-04114-1)
No full textFollowing publication of the original article [1], the authors flagged that unfortunately there is an error with the affiliations. The affiliation of Zati Vatansever (31) is listed as Veterinary Control Central Research Institute, Ankara, Turkey. However, the correct affiliation is Faculty of Veterinary Medicine, Department of Parasitology, Kafkas University, Kars, Turkey. The authors apologize for the inconvenience caused
Different Abundances of Human-Biting Ticks in Two Neighboring Provinces in Turkey
No full textIn this study, tick samples were examined, which were obtained from humans who applied to the regional hospitals with complaints of tick bites between May and November 2007 in two neighboring provinces, Kocaeli and Sakarya, in Eastern Marmara Region of Turkey. The samples were evaluated in terms of species, developmental stage and season for each province. In the course of the study, totally 3121 ticks were collected. Of those, 1610 ticks were from Kocaeli, 1511 ticks were from Sakarya. Among the total samples Ixodes spp. (52.87%), Hyalomma spp. (41.78%), Rhipicephalus spp. (4.2%), Haemaphysalis spp. (0.7%), Dermacentor spp. (0.35%) and Argas spp. (0.003%) were identified. Additionally, it was seen that one person was bitten by male Rhipicephalus (Boophilus) annulatus and one other was bitten by nymphal stage of Otobius megnini; these species were recorded for the first time in humans in Turkey. Concerning with the incidences of tick species, majority belongs to Hyalomma spp. (60.06%) in Kocaeli and Ixodes spp. (75.65%) in Sakarya. There were somewhat differences also in incidences of other tick species between these provinces. These disparities encountered between two neighboring provinces which have adjacent coordinates and similar climates, showed that the risk of tick bites or characteristic of this risk in a region could vary distinctly in terms of sub-regions which have some specific sub-conditions
Modélisation appliquée à la fièvre hémorragique de Crimée-Congo pour tester des stratégies de maîtrise
No full textNational audienceLa Fièvre Hémorragique de Crimée-Congo est une maladie en ré-émergence, notamment en Turquie, où il a été rapporté plus de 7000 cas entre 2002 et 2012, dont 5% se sont avérés mortels. Cette maladie est due à un virus (CCHFV) principalement transmis par une tique, Hyalomma marginatum dans cette zone. Cette tique se nourrit principalement sur des hôtes rongeurs (lièvres) et des ruminants (bovins dans le cas présent). Dans le cadre d’un projet européen (EDENext – FP7), nous avons développé un modèle mathématique afin de pouvoir tester par simulation différentes stratégies de maîtrise de l’infection. Le développement d’un tel modèle résulte du couplage entre un modèle de dynamique de populations de la tique et d’un modèle de transmission du virus. Les principaux processus sont représentés dans ce modèle mécaniste dynamique qui prend en compte l’effet des conditions météorologiques et de la densité d’hôtes sur la dynamique de l’infection. Le modèle permet de simuler de manière réaliste la dynamique de populations de la tique et la prévalence de l’infection chez les bovins. Le nombre de tiques adultes infectieuses en quête d'hôtes représente le risque acarologique pour l'Homme. La dynamique de ce risque varie suivant le climat considéré, à l'échelle de la Turquie. Deux grands types de stratégie de maîtrise ont été par la suite testés par simulation : un traitement acaricide et une baisse de la densité de lièvres, hôtes des stades immatures (larve et nymphe) de la tique. Le résultat des simulations montre que si les traitements acaricides permettent de diminuer la prévalence chez les bovins, une décroissance du risque pour l’Homme serait surtout obtenue par une action sur la densité de lièvres. Les recherches actuelles portent sur l’influence du changement climatique sur la distribution de la tique H. marginatum (projet Climatick, méta-programme ACCAF, K. Chalvet-Monfray, UMR EpiA), en collaboration avec des chercheurs du CIRAD qui ont montré une installation de la tique dans le Sud de la France (Vial et al, 2016)
High prevalence and different genotypes of Crimean-Congo hemorrhagic fever virus genome in questing unfed adult Hyalomma marginatum in Thrace, Turkey
No full textCrimean-Congo hemorrhagic fever (CCHF) is a tick-borne viral disease in the old continents, in many countries south of the 50 degrees North Parallel. The agent is known to be the most prevalent and major cause of severe and fatal human hemorrhagic diseases among the tick-borne viruses, and is the second most widespread of all medically critical arboviruses following dengue. Members of the Hyalomma genus are mainly involved in the natural transmission of the CCHF virus (CCHFV); of those, H. marginatum is known to be the primary vector of the disease in the Western Palaearctic. In general, epidemiological studies have been based on serological detections in the hosts and/or virus screening of ticks collected from the hosts. To the best of our knowledge, only a few studies have been carried out to screen the virus in unfed, questing field ticks. Nevertheless, detection of the virus in questing ticks is known to be a crucial parameter to determine the possible vector roles of the ticks and to understand the ecological dynamics of related diseases. In this study, 200 (75 males,125 females) questing H. marginatum adults collected from the field in nine villages in Thrace, located in the European part of Turkey, were screened individually for CCHFV using nested PCR. As a result, 103 (51.5 %) ticks were determined as positive with various strains of CCHFV. High positivity in questing vectors in a region where a significantly lower number of human cases have been encountered suggests that there should be some region-specific drivers that are effective in the natural dynamics of the disease. Detailed etiological and epidemiological studies are needed to reveal the possible reason for this unexpected discrepancy
External morphological anomalies in ixodid ticks from Thrace, Turkey
No full textOf 18,667 ticks examined, 33 specimens from species identified as Haemaphysalis parva, Hyalomma marginatum, Hy. scupense, Rhipicephalus bursa and Rh. turanicus were found to have external morphological anomalies. Anomalous Ha. parva, Hy. scupence and Rh. turanicus were reported in this study for the first time. General anomalies manifested as asymmetry and deformations of the idiosoma, whereas local anomalies occurred in legs, exoskeleton, spiracular, adanal, subanal and accessory plates, mouthparts and capitulum. With this study describing a gynandromorphic Hy. marginatum, the number of gynandromorphic tick cases has been raised to two in Turkey
Modeling the spatial distribution of Crimean-Congo Hemorrhagic Fever outbreaks in Turkey
No full textThe 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
Dynamic Modeling of Crimean Congo Hemorrhagic Fever Virus (CCHFV) Spread to Test Control Strategies
No full textInternational audienceCrimean Congo hemorrhagic fever is a zoonotic disease which has emerged or re-emerged recently in Eastern Europe and Turkey. The causative agent is a virus, mainly transmitted by ticks of the species Hyalomma marginatum (Koch, 1844, Ixodida, Amblyommidae). To test potential scenarios for the control of pathogen spread, a dynamic mechanistic model has been developed that takes into account the major processes involved in tick population dynamics and pathogen spread. The tick population dynamics model represents both abiotic (meteorological variables) and biotic (hare and cattle densities) factors in the determination of processes (development, host finding, and mortality). The infection model consists of an SIRS model for the host part whereas a lifelong infectiousness was considered for ticks. The model was first applied to a zone in Central Anatolia (Turkey). Simulated dynamics represent the average reported level of infection in vectors and hosts. A sensitivity analysis to parameter value has been carried out and highlighted the role of transstadial transmission as well as acquisition of the pathogen by immature stages. Applying the model to different sites of Turkey shows different patterns in the dynamics of acarological risk (number of infectious questing adults). This model was thereafter used to test control strategies. Simulation results indicate that acaricide treatments and decrease in hare density could have valuable effects when combined, either on the acarological risk or on the prevalence in cattle. The kind of model we have developed provides insight into the ability of different strategies to prevent and control disease spread
Crimean-Congo Hemorrhagic Fever Virus in Ticks Collected from Humans, Livestock, and Picnic Sites in the Hyperendemic Region of Turkey
No full textDuring June and July 2007, about 3125 adult ticks were collected from humans, animals, and vegetation in a hyperendemic region (Sivas and Tokat) of Turkey. A total of 2193 ticks were pooled in 225 pools and screened for the Crimean Congo hemorrhagic fever virus (CCHFV) presence by antigen-capture enzyme-linked immunosorbent assay. Infection rates were calculated as the maximum likelihood estimation with 95% confidence intervals (CI). The dominant tick species was found to be Hyalomma marginatum with the following infestation rates in human, cattle and sheep, respectively: 47.43%, 66.07%, and 30.12%. Maximum likelihood estimation values of CCHFV in H. marginatum ticks collected from human, cattle, and sheep were 0.91% (CI 0.05-4.42), 2.10% (CI 1.12-3.64), and 3.11% (CI 1.18-6.87), respectively. CCHFV antigens were also demonstrated in Hyalomma excavatum, Haemaphysalis parva, and Boophilus annulatus ticks collected from cattle and Rhipicephalus bursa ticks from sheep. Our results suggest that the studied area might maintain its endemic properties in the near future unless effective tick control measures are implemented.Commission (CUBAP) of Cumhuriyet University, Sivas, Turkey [SHMYO-005]This study was funded by the Presidency of Scientific Research Projects Commission (CUBAP) of Cumhuriyet University, Sivas, Turkey (SHMYO-005). The authors thank Brad Biggerstaff, who provided PooledInfRate (Version 4.0), Semra Ozcelik, Ali Fazil Yenidunya, Nergiz Hacer Turgut, Ahmet Alim, and Zubeyde Gunes for suggestions while reviewing the article and for technical support
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