Crimean-Congo hemorrhagic fever virus in various ixodid tick species from a highly endemic area

A New Orthonairovirus Associated with Human Febrile Illness

BACKGROUND

In June 2019, a patient presented with persistent fever and multiple organ dysfunction after a tick bite at a wetland park in Inner Mongolia. Next-generation sequencing in this patient revealed an infection with a previously unknown orthonairovirus, which we designated Wetland virus (WELV).

METHODS

We conducted active hospital-based surveillance to determine the prevalence of WELV infection among febrile patients with a history of tick bites. Epidemiologic investigation was performed. The virus was isolated, and its infectivity and pathogenicity were investigated in animal models.

RESULTS

WELV is a member of the orthonairovirus genus in the Nairoviridae family and is most closely related to the tickborne Hazara orthonairovirus genogroup. Acute WELV infection was identified in 17 patients from Inner Mongolia, Heilongjiang, Jilin, and Liaoning, China, by means of reverse-transcriptase-polymerase-chain-reaction assay. These patients presented with nonspecific symptoms, including fever, dizziness, headache, malaise, myalgia, arthritis, and back pain and less frequently with petechiae and localized lymphadenopathy. One patient had neurologic symptoms. Common laboratory findings were leukopenia, thrombocytopenia, and elevated d-dimer and lactate dehydrogenase levels. Serologic assessment of convalescent-stage samples obtained from 8 patients showed WELV-specific antibody titers that were 4 times as high as those in acute-phase samples. WELV RNA was detected in five tick species and in sheep, horses, pigs, and Transbaikal zokors (Myospalax psilurus) sampled in northeastern China. The virus that was isolated from the index patient and ticks showed cytopathic effects in human umbilical-vein endothelial cells. Intraperitoneal injection of the virus resulted in lethal infections in BALB/c, C57BL/6, and Kunming mice. The Haemaphysalis concinna tick is a possible vector that can transovarially transmit WELV.

CONCLUSIONS

A newly discovered orthonairovirus was identified and shown to be associated with human febrile illnesses in northeastern China. (Funded by the National Natural Science Foundation of China and the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences.).

Vaccine approaches and treatment aspects against Crimean Congo hemorrhagic fever

Crimean-Congo hemorrhagic fever [CCHF] is a severe infectious viral disease caused by a tick borne virus which can lead to fatal hemorrhagic disease in humans. It has been reported from some continents including Africa, Asia and Europe. Virus is transmitted to human mainly through tick bite, whose acquire infection from reservoirs wild and domesticated mammalians and ostriches. Currently no approved vaccine or drug is available for CCHF and prevention is mainly based on biosecurity measures. Ribavirin is the only approved drug that has been used in some countries to treat human disease, however some new studies did not prove the Ribavirin efficacy. Different strategies to design effective vaccines, have been conducted through years, from inactivated virus to nucleotide-based ones including DNA and mRNA vaccines. In this study we review of pioneering vaccine candidate platforms.

Perception of Ticks and Tick-Borne Diseases Worldwide

In this comprehensive review study, we addressed the challenge posed by ticks and tick-borne diseases (TBDs) with growing incidence affecting human and animal health worldwide. Data and perspectives were collected from different countries and regions worldwide, including America, Europe, Africa, Asia, and Oceania. The results updated the current situation with ticks and TBD and how it is perceived by society with information bias and gaps. The study reinforces the importance of multidisciplinary and international collaborations to advance in the surveillance, communication and proposed future directions to address these challenges.

Distribution and molecular identification of ixodid ticks infesting cattle in Kilombero and Iringa Districts, Tanzania

BACKGROUND

Hard ticks infesting cattle are vectors of Tick-borne diseases that causes major public health problems and considerable socioeconomic losses to the livestock industry in tropical and subtropical countries. A repeated cross-sectional study was carried out by collecting ticks on cattle during the wet and dry seasons from January to August 2021 in order to determine hard tick prevalence, distribution, and abundance on cattle in Kilombero and Iringa Districts of Tanzania. The collected ticks were identified morphologically using published morphological keys under a stereomicroscope and confirmed by polymerase chain reaction (PCR) and sequencing.

RESULTS

Out of 740 examined cattle, 304, (41.08%) were infested with ticks. In total, 1,780 ticks were counted on one side of the animal's body and doubled, whereby resulting in a total of 3,560 ticks were recorded. Individual tick burden ranged from n = 2 to 82 ticks per animal, with a mean tick burden of n = 11.7 ± 0.68 per animal. A total of 1,889 ticks were collected from infected cattle including 109 additional ticks observed while collecting ticks based on the animal's posture when restrained to the ground. Out of 1,889 ticks, nine species from three genera were identified morphologically: 1,377 fit in the genus Rhipicephalus, 459 to the genus of Amblyomma, and 53 to the genus Hyalomma. Rhipicephalus microplus was the most prevalent (n = 909, 48.1%), followed by Rhipicephalus evertsi (n = 310, 16.4%), Amblyomma lepidum (n = 310, 16.4%), Rhipicephalus appendiculatus (n = 140, 7.4%), Amblyomma gemma (n = 120, 6.4%), Hyalomma rufipes (n = 50, 2.6%), Amblyomma variegatum (n = 29, 1.5%), Rhipicephalus decoloratus (n = 18, 1.0%), while the least common was Hyalomma albiparmatum (n = 3, 0.2%). Tick diversity was higher in Iringa compared to Kilombero District. Tick prevalence was higher in wet season (n = 148, 41.11%). Ticks were widely distributed in different parts of the host body, with the highest distribution on zone 4 (n = 1,060, 56.11%), which includes groin, flank, abdomen, and around inner thigh of the hind legs and the lowest distribution on zone 2 (n = 14, 0.74%), which includes the back surface of the body. Both Amblyomma lepidum and Rhipicephalus microplus species were found in all the five body zones, and with the highest proportions recorded on zone 4: A. lepidum (n = 209, 67.42%) and R. microplus (n = 714, 78.55%). The nine tick species identified morphologically were also confirmed using molecular methods. However, during sequencing, two species (Rhipicephalus appendiculatus and R. decoloratus) had poor quality sequences and were excluded from the sequence analysis. Sequencing results indicated high nucleotide identity (96-100%) with sequences available in GenBank and Barcode of Life Database (BOLD). The phylogenetic analysis of partial mitochondrial COI and 16S rRNA gene sequences of ticks were used to confirm the morphological identification.

CONCLUSION

The results showed a high burden of tick infestation on cattle, which could reduce animal production and potentially increase the risk of tick-borne diseases. Therefore, it is necessary to explore the epidemiological and molecular aspects of various tick species in other regions of Tanzania.

Arthropod vectors of disease agents: their role in public and veterinary health in Turkiye and their control measures

Mosquitoes, sandflies, and ticks are hematophagous arthropods that pose a huge threat to public and veterinary health. They are capable of serving as vectors of disease agents that can and have caused explosive epidemics affecting millions of people and animals. Several factors like climate change, urbanization, and international travel contribute substantially to the persistence and dispersal of these vectors from their established areas to newly invaded areas. Once established in their new home, they can serve as vectors for disease transmission or increase the risk of disease emergence. Turkiye is vulnerable to climate change and has experienced upward trends in annual temperatures and rising sea levels, and greater fluctuations in precipitation rates. It is a potential hotspot for important vector species because the climate in various regions is conducive for several insect and acari species and serves as a conduit for refugees and immigrants fleeing areas troubled with armed conflicts and natural disasters, which have increased substantially in recent years. These people may serve as carriers of the vectors or be infected by disease agents that require arthropod vectors for transmission. Although it cannot be supposed that every arthropod species is a competent vector, this review aims to (1)illustrate the factors that contribute to the persistence and dispersal of arthropod vectors, (2)determine the status of the established arthropod vector species in Turkiye and their capability of serving as vectors of disease agents, and (3)assess the role of newly-introduced arthropod vectors into Turkiye and how they were introduced into the country. We also provide information on important disease incidence (if there's any) and control measures applied by public health officials from different provinces.

[Crimean-Congo hemorrhagic fever]

Crimean-Congo hemorrhagic fever (CCHF) is an acute febrile illness with a high case fatality rate caused by the infection with Crimean-Congo hemorrhagic fever virus (CCHFV). The disease is endemic to a wide regions from the African continent to Asia through Europe. CCHFV is maintained in nature between Hyalomma species ticks and some species of animals. Humans are infected with CCHFV from CCHFV-positive tick bite or through a close contact with viremic animals in clucling hum am patients with CCHF. The CCHF-endemic regions depend on the distribution of the species of ticks such as Hyalomma species ticks, main vectors for CCHFV. There have been no confirmed cases of CCHF patients in Japan so far. CCHF is one of the zoonotic virus infections. Main clinical signs of the disease in humans are fever with nonspecific symptoms, and hemorrhage and deterioration in consciousness appear in severe cases. CCHF is classified in the disease category of viral hemorrhagic fevers, which include ebolavirus disease. Viral tick-borne diseases including tick-borne encephalitis, severe fever with thrombocytopenia syndrome, and Yezo virus infection, which has recently been discovered as a novel bunyavirus infection in Hokkaido, Japan, are becoming major concerns for public health in Japan. Trends of CCHF in terms of epidemiology should closely be monitored.

Detection of Crimean-Congo hemorrhagic fever virus in ticks collected from South Russia

Crimean-Congo hemorrhagic fever (CCHF) has a central role among tick-borne infections in southern Russia. Multiple cases of disease are recorded annually in most regions with the СCHF foci; moreover, an expansion of the geographic range of the disease has been noted. Since 1999, more than 2300 people have fallen ill in Russia. Ticks are the main vectors and reservoirs of the Crimean-Congo hemorrhagic fever virus (CCHFV). As it is currently known, CCHFV has been detected in ticks of 33 species. In the period 2012-2019 in the south of the European part of Russia, more than 38,000 ticks of 14 species of the genera Hyalomma, Rhipicephalus, Dermacentor, Haemaphysalis and Ixodes were tested for the presence of CCHFV. Among 4,188 tick pools studied, the virus was detected in 252 (6%). The main vector, as expected, is H. marginatum (81% of positive pools). The same species is the most numerous among the studied ticks (66%). Apart from H. marginatum, the virus was detected in the following species: H. scupense, R. rossicus, R. turanicus, R. bursa, R. annulatus, D. marginatus, Haem. punctata and Ixodes ricinus. Most of the positive results were obtained from ticks collected from vertebrate hosts. As for H. marginatum, R. rossicus, D. marginatus, and Haem. punctata, the virus was detected in questing unfed specimens collected from vegetation and soil surface, which indicates the participation of these ticks in the circulation of the virus.

Crimean-Congo Hemorrhagic Fever Virus in Asia, Africa and Europe

The global spread of ticks and various tick-borne viruses (TBVs) suggests the possibility of new tick-borne diseases emerging. Crimean-Congo hemorrhagic fever virus (CCHFV) is an emerging TBV of the Nairoviridae family that causes serious disease that can be fatal in humans. CCHFV endemic foci can be found in Africa, Asia, the Middle East, and South-Eastern Europe, and has spread to previously unaffected regions and nations, such as Spain, over the last two decades. In this review, we discuss the current situation of CCHFV in Asia, Africa and Europe based on existing knowledge, and we discuss driving factors in the distribution and transmission of the virus, such as the spread of tick vector species and host reservoirs.

Micropathogen community identification in ticks (Acari: Ixodidae) using third-generation sequencing

Ticks are important vectors that facilitate the transmission of a broad range of micropathogens to vertebrates, including humans. Because of their role in disease transmission, it has become increasingly important to identify and characterize the micropathogen profiles of tick populations. The objective of the present study was to survey the micropathogens of ticks by third-generation metagenomic sequencing using the PacBio Sequel platform. Approximately 46.481 Gbp of raw micropathogen sequence data were obtained from samples from four different regions of Heilongjiang Province, China. The clean consensus sequences were compared with host sequences and filtered at 90% similarity. Most of the identified genomes represent previously unsequenced strains. The draft genomes contain an average of 397,746 proteins predicted to be associated with micropathogens, over 30% of which do not have an adequate match in public databases. In these data, Anaplasma phagocytophilum and Coxiella burnetii were detected in all samples, while Borrelia burgdorferi was detected only in Ixodes persulcatus ticks from G1 samples. Viruses are a key component of micropathogen populations. In the present study, Simian foamy virus, Pustyn virus and Crimean-Congo haemorrhagic fever orthonairovirus were detected in different samples, and more than 10–30% of the viral community in all samples comprised unknown viruses. Deep metagenomic shotgun sequencing has emerged as a powerful tool to investigate the composition and function of complex microbial communities. Thus, our dataset substantially improves the coverage of tick micropathogen genomes in public databases and represents a valuable resource for micropathogen discovery and for studies of tick-borne diseases.

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The microbial communities from ticks were analysed by third-generation metagenomic sequencing using the PacBio Sequel platform.

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In these data, Anaplasma phagocytophilum and Coxiella burnetii were found in four groups, and Borrelia burgdorferi was detected only in Ixodes persulcatus ticks from G1 samples. Viruses are a key component of the composition of micropathogens.

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The third-generation metagenomic sequencing is far superior to second-generation sequencing in genome sequence integrity, and the similarity of the sequences obtained via third-generation metagenomic sequencing for discrimination is unmatched by other sequencing methods.

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Thus, our dataset substantially improves the coverage of tick micropathogen genomes in public databases and represents a valuable resource for micropathogen discovery and for studies of tick-borne diseases.

Prevalence and phylogenetic analysis of Crimean-Congo hemorrhagic fever virus in ticks collected from Punjab province of Pakistan

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne zoonotic disease of human that caused by CCHF virus. To study the epidemiological distribution of CCHFV, 2183 tick samples were collected from sheep, goats, cattle and buffalo of different livestock farms of ten districts of Punjab province of Pakistan. Detection of CCHFV was done using enzyme link immunosorbent assay (ELISA) after proper identification of tick samples. The partial S-segment of CCHFV from ELISA positive tick samples was amplified by PCR and sequenced to determine the genotype of CCHFV. Out of2183 collected tick samples, 1913 ticks belonged to 5 species of genus Hyalomma as H. antolicum (48%), H. marginatum (30.2%), H. rufipes (10.82%), H. impressum (5.43%) and H. dromedarii (5.27%). While 270 ticks belonged to 3 species of genus Rhipicephalus as R. microplus (44.8%), R. sanguineus (32.22%) and R. turanicus (24.8%). The overall antigenic prevalence of CCHFV was found to be 12.13% in collected tick samples and 21 tick pools were sequenced for partial S-segment of CCHFV. All of the 21 tick pools were clustered in genotype IV (Asia-1). The highest prevalence of CCHFV was found in district Chakwal (24.13%) followed by Mianwali (23.68%), Rawalpindi (23.07%), Attock (20.0%), Rajanpur (10.52%) and Lahore (8.33%). In positive tick pools, the highest prevalence of CCHFV antigen was found in H. antolicum (39.6%) followed by H. marginatum (30.18%), H. rufipes (13.2%), H. impressum (3.77%), H. dromedarii (1.88%), R. microplus (5.66%) and R. sanguineus (5.66%). The current study confirms the presence of CCHFV in the ticks population of Punjab. The CCHF virus present in Punjab belongs to Asia-1 genotype. It is important to control the tick infestation of the animals present in these areas. So that the transmission cycle of CCHF can be inhibited.

Discovery and genetic characterization of a novel orthonairovirus in Ixodes ricinus ticks from Danube Delta

Different arthropod species are vectors of a wide array of arboviruses (arthropod-borne viruses) and have likely been central to viral evolution. To better understand the extent of arthropod-borne pathogens, as well as their origin and evolutionary history, it is crucial to uncover the full range of microbial agents, including viruses associated with arthropods. In this study, a collection of ticks obtained in 2016 directly from mammal and bird hosts from several rural and natural sites of Danube Delta was subjected to transcriptome sequencing and amplification assays. Vector surveillance revealed the presence of a novel orthonairovirus species, designated Sulina virus, in Ixodes ricinus ticks. Phylogenetic clustering of each viral protein consistently placed the new virus in the Orthonairovirus genus as a new genogroup closely related to Tamdy orthonairovirus, a genogroup comprising both pathogenic and tick-associated orthonairoviruses. The serological testing of engorged ticks and blood of infected hosts, along with the inoculation of vertebrate cells and mice found no specific antibodies or viral replication, suggesting that Sulina virus is an orthonairovirus associated with the virome of Ixodes ricinus. Finally, the characterization of a novel orthonairovirus identified using high throughput sequencing will advance our knowledge of interactions between viruses and tick vectors, expanding our perspective on fundamental questions regarding orthonairovirus evolution, diversity, ecology and potential of emergence as pathogens.

Molecular characterization of Ribosomal DNA (ITS2) of hard ticks in Iran: understanding the conspecificity of Dermacentor marginatus and D. niveus

Objectives

Hard ticks (Acari: Ixodidae) are ectoparasites of medical and veterinary importance. They are obligate blood-feeding vectors with the ability to transmit a wide variety of pathogens. Standard morphological keys are normally used for the identification of tick species. However, considering the importance of accurate species identification and the determination of bio-ecological characteristics of species, relying on morphological keys alone can be questionable. In this study, two DNA fragments (ITS2 and COI) were selected for phylogenetic evaluation of Iranian hard tick species belonging to the genera Dermacentor, Hyalomma, and Rhipicephalus.

Results

1229 specimens of Dermacentor marginatus, D. niveus, Hyalomma anatolicum, Rhipicephalus bursa, and R. sanguineuss.l constituting 11 populations were collected from three different climatic and zoogeographical zones in Iran. Morphological studies revealed notable differences in important morphological characteristics between different populations of D. marginatus.

The results of ITS2 sequence analysis provided additional evidence which supports the conspecificity of D. niveus and D. marginatus. Contrary to this finding, the sequence analysis of COI and phylogeny favored the separation of the two species. Given the greater importance of COI in identifying and discriminating species, a possibility heterospecificity between the two species should be considered.

Prevalence of Crimean-Congo hemorrhagic fever virus in rural areas of Guinea

This article presents the results of a comprehensive survey of Guinea with the aim of assessing the burden of Crimean-Congo hemorrhagic fever virus (CCHFV) in rural areas of the country. Human serum samples (n = 2207) were studied using enzyme-linked immunosorbent assay (ELISA) for the presence of specific IgG against CCHFV. In addition, 4273 samples of partially- or fully-engorged ticks from several sources (cattle, domestic and roving dogs, and small mammals) were collected and studied using ELISA and RT-qPCR to detect CCHFV antigen and specific RNA. The data obtained show that 3.0 % of the population in rural Guinea was seropositive, without significant geographical or sexual differences. Seropositive individuals, however, were mainly in the 'active age' group (16-45 years old). Among ticks studied, the estimated prevalence of CCHFV was 1.3 ± 0.4 %. Five out of eight tick species studied were identified as CCHFV carriers in Guinea. Therefore, it can be assumed that the territory of Guinea is a single, continuous, natural focus of CCHFV. This identified medium intensity focus merits further study.

Investigation of Vector-Borne Viruses in Ticks, Mosquitos, and Ruminants in the Thrace District of Turkey

There is a considerable increase in vector-borne zoonotic diseases around the world, including Turkey, such as Crimean-Congo hemorrhagic fever (CCHF), tick borne encephalitis (TBE), Rift Valley fever (RVF), and West Nile fever (WNF), causing disease and death in humans and animals and significant economical losses. Hence, the aim of this study was to investigate the presence of CCHF virus (CCHFV) and TBE virus (TBEV) in ticks and RVF virus (RVFV) and WNF virus (WNV) in mosquitos, as well as in sheep and cattle, in the Thrace district of the Marmara region, which borders Bulgaria and Greece. Buffy-coat samples from 86 cattle and 81 sheep, as well as 563 ticks and 7390 mosquitos, were collected and examined by quantitative real-time RT-PCR for the presence of CCHFV, TBEV, RVFV, and WNV. All buffy-coat samples from cattle and sheep were negative for these viruses. Similarly, all tick samples were negative for CCHFV-RNA and TBEV-RNA. Among 245 pools representing 7390 mosquitos, only 1 pool sample was found to be positive for WNV-RNA and was confirmed by sequencing. Phylogenetic analysis revealed that it was WNV lineage-2. No RVFV-RNA was detected in the 245 mosquito pools. In conclusion, results of this study indicate that CCHFV, TBEV, and RVFV are not present in livestock and respective vectors in the Thrace district of Marmara region of Turkey, whereas WNV-RNA was found in mosquitos from this region.

Molecular and seroepidemiological survey on Crimean-Congo Hemorrhagic Fever Virus in Northeast of Iran

Background: Crimean-Congo hemorrhagic fever (CCHF) is a prevalent tick-borne disease in different regions of Iran. This molecular and serologic study was performed to investigate the Crimean-Congo hemorrhagic fever virus (CCHFV) in collected ticks and in blood samples of some domestic animals in North Khorasan, Northeast of Iran. Methods: In this cross sectional study, 136 blood samples from domestic animals (sheep, goats, and cows) collected in the Northeast region in Iran were examined using IgG ELISA assay. Ticks (n = 1478) were collected from sheep, goats, and cows. Out of all collected ticks, 62 specimens were investigated for CCHF virus genome using RT-PCR technique. The data were descriptively presented by median and 95% confidence interval (CI). Results: CCHFV infection rate was 8.1% in studied ticks. Two species of ticks, Hy. anatolicum (n=3; 15%, 95% CI 9.41-20.59) and Rh. sanguineus (n=2; 6.9%, 95%CI 4.33-8.58), were infected with CCHFV genome and were probable vectors of CCHF virus in the area. Infection rate was 15.4% for CCHFV in tested domestic animals. Serologic tests detected CCHFV specific IgG antibodies in 16.2% (95% CI 13.49-18.83) (99/16) and 19.2% (95% CI 13.26-25.20) (26/5) of sheep and goats, respectively. Conclusion: The present study showed that domestic animals and ticks were infected with Crimean-Congo hemorrhagic fever virus and that the disease was endemic in North Khorasan province, Iran. However, further surveillance and prevention programs are recommended.

An insight into the ecobiology, vector significance and control of Hyalomma ticks (Acari: Ixodidae): A review

Ticks (Acari:Ixodoidea) are important ectoparasites infesting livestock and human populations around the globe. Ticks can cause damage directly by affecting the site of infestation, or indirectly as vectors of a wide range of protozoa, bacteria and viruses which ultimately lead to lowered productivity of livestock populations. Hyalomma is a genus of hard ticks, having more than 30 species well-adapted to hot, humid and cold climates. Habitat diversity, vector ability, and emerging problem of acaricidal resistance in enzootic regions typify this genus in various countries around the world. This paper reviews the epidemiology, associated risk factors (temperature, climate, age, sex, breed etc.), vector role, vector-pathogen association, and reported control strategies of genus Hyalomma. The various proteins in saliva of Hyalomma secreted into the blood stream of host and the prolonged attachment are responsible for the successful engorgement of female ticks in spite of host immune defense system. The various immunological approaches that have been tried by researchers in order to cause tick rejection are also discussed. In addition, the novel biological control approaches involving the use of entomo-pathogenic nematodes and Bacillus thuringiensis (B. thuringiensis) serovar thuringiensis H14; an endotoxin, for their acaricidal effect on different species and life cycle stages of Hyalomma are also presented.

Crimean-Congo hemorrhagic fever with hepatic impairment and vaginal hemorrhage: a case report

Background

Crimean-Congo hemorrhagic fever is a tick-borne disease described in more than 30 countries in Europe, Asia, and Africa. Albania is located in the southwestern part of the Balkan Peninsula. In 1986, the first case of Crimean-Congo hemorrhagic fever was registered, and cases of patients with hemorrhagic fever are rising, and most of them present in a serious condition, when the mortality rate is very high. In districts like Mirdite, Lezhe, Gjirokaster, Skrapar, Erseke, and Kukes, there is delineated human-to-human transmission.

Case presentation

We report the case of a 32 year-old Albanian woman from a rural area of Albania. She was hospitalized at the Infectious Diseases Service, for a severe influenza-like illness of 4 days duration. Our patient had been bitten by a tick while working in her garden. She presented with nausea, vomiting, headache and muscle pain. A physical examination found a high fever of 40 °C, an enlarged liver, petechia, and vaginal bleeding; flapping tremor and fetor hepaticus were found as a sign for hepatic encephalopathy; and confusion and disorientation were observed in her neurological examination. Her platelet and white blood cell counts were very low, while her aspartate aminotransferase and alanine aminotransferase levels were very high. She was transferred to the intensive care unit because of her worsening condition. Serological and C-reactive protein test results for Crimean-Congo hemorrhagic fever were positive. She was treated with oral ribavirin and discharged with normal parameters.

Conclusions

People in high-risk professions in the endemic areas should be informed and trained on the risk of Crimean-Congo hemorrhagic fever as a matter of urgency. Vaginal bleeding is not always a gynecological problem. In Albania, these places are the mountainous areas, so people who have traveled to these areas and who have symptoms after a tick bite are advised to contact their doctors.

Geographical distribution, climate adaptation and vector competence of the Eurasian hard tick Haemaphysalis concinna

The ixodid tick Haemaphysalis concinna Koch, 1844 is a proven vector of tick-borne encephalitis (TBE) virus and Francisella tularensis, the causative agent of tularaemia. In the present study, up-to-date maps depicting the geographical distribution and climate adaptation of H. concinna are presented. A dataset was compiled, resulting in 656 georeferenced locations in Eurasia. The distribution of H. concinna ranges from the Spanish Atlantic coast to Kamchatka, Russia, within the belt of 28-64° N latitude. H. concinna is the second most abundant tick species after Ixodes ricinus collected from birds, and third most abundant tick species flagged from vegetation in Central Europe. To investigate the climate adaptation of H. concinna, the georeferenced locations were superimposed on a high-resolution map of the Köppen-Geiger climate classification. A frequency distribution of the H. concinna occurrence under different climates shows three peaks related to the following climates: warm temperate with precipitation all year round, boreal with precipitation all year round and boreal, winter dry. Almost 87.3 % of all H. concinna locations collected are related to these climates. Thus, H. concinna prefers climates with a warm and moist summer. The remaining tick locations were characterized as cold steppes (6.2%), cold deserts (0.8%), Mediterranean climates (2.7%) or warm temperate climates with dry winter (2.9%). In those latter climates H. concinna occurs only sporadically, provided the microclimate is favourable. Beyond proven vector competence pathogen findings in questing H. concinna are compiled from the literature.

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.

Ixodoidea of the Western Palaearctic: A review of available literature for identification of species

We aim to produce a review of the most important literature references necessary for the identification of ticks of the families Ixodidae and Argasidae in Europe and northern Africa (i.e. the Western Palaearctic region). The purpose of this paper is to pinpoint a set of critically selected papers that contain reliable information on morphology, taxonomic keys, and comparative discussions which are critical for the identification of the ticks reported in the target region. When necessary, comments are provided on the systematic position of a species, or on suitable papers already addressing the issue. This review includes a list of 216 references which cover all Ixodoidea species reported as permanent residents of the Western Palaearctic, namely 28 species of the genus Ixodes, two Dermacentor, seven Haemaphysalis, nine Hyalomma, eight Rhipicephalus, five Argas and about seven species of Ornithodoros.

Seroprevalence of Crimean-Congo Hemorrhagic Fever in Turkey's Van Province

Crimean-Congo hemorrhagic fever (CCHF) is an endemic tick-borne viral disease that affects both animals and humans. This study aims to determine the seroprevalence of CCHF in Turkey's Van province using analysis of blood samples obtained from people living in the region. Blood specimens were taken from healthy subjects living in Van province and some of the surrounding villages between January and July 2012. Blood samples were initially tested using a CCHF virus (CCHFV) IgM IgG kit for anti-CCHFV IgG, followed by anti-CCHFV IgM determination of any IgG positive blood samples. IgM-positive specimens were re-confirmed using real-time polymerase chain reaction (qPCR). One hundred and 7 men and 261 women were included in the study. Fifty-three blood specimens (14.4%) were anti-CCHFV IgG positive, and 2 of these were anti-CCHFV IgM positive. Two blood samples with anti-CCHFV IgM seropositivity tested negative using qPCR, indicating chronic infections. Locality, sex, and a history of tick bites did not significantly affect anti-CCHFV IgG seropositivity. Although the incidence of anti-CCHFV IgG in blood specimens was 14.4%, no deaths have yet been reported in Turkey's Van province. It is imperative that clinical CCHFV tests be implemented for people at high risk of developing CCHFV-related complications.

Role of migratory birds in spreading Crimean-Congo hemorrhagic fever, Turkey

We investigated migratory birds’ role in spreading Crimean-Congo hemorrhagic fever virus (CCHFV) through attached ticks. We detected CCHFV RNA in ticks on migratory birds in Turkey. Two isolates showed similarity with CCHFV genotype 4, suggesting a role for ticks in CCHFV epidemics in Turkey and spread of CCHFV by birds.

Abundance and seasonal activity of Haemaphysalis concinna (Acari: Ixodidae) at the border between China and Russia in Northern Inner Mongolia, China

Background

Haemaphysalis concinna, a three-host tick vector of several pathogens, poses a high risk to the health of humans and livestock. However, knowledge of the seasonal activities, relative density and other ecological characteristics of this tick is quite limited and fragmentary. This knowledge gap represents a bottleneck in our understanding of the health risks associated with tick-borne pathogens.

Methods

We conducted a two-year study from April 2012 to March 2014 in Northern Inner Mongolia situated on the China-Russia border, China, to investigate the seasonal activities and relative density of the three developmental stages of H. concinna. During the study period, feeding ticks were removed weekly from domestic sheep and their attachment sites were recorded. Questing ticks were collected weekly from five habitats (broadleaf forest, coniferous forest, shrubs, grassland and mixed coniferous forest) using the flagging-dragging method of capture. Rodents were captured and examined on two consecutive nights each week from June to September in 2012.

Results

H. concinna ticks were found mainly in shrubs and grasslands habitats. Adults were encountered from February to October with the major peak occurring in June. Larvae, which were observed mainly from late April to late September, reached peak numbers in late July. Nymphs were observed mainly from March to October, and their numbers peaked in early July. H. concinna adults and nymphs were found attached to sheep and their most favored sites of attachment were the face and ears. H. concinna larvae were found on two rodent species, Apodemus peninsulae and Eutamias sibiricus.

Conclusion

The relative density and seasonal activities of H. concinna have been systematically reported for Northern Inner Mongolia, China. The information about the hosts infested by H. concinna and its preferred attachment sites on sheep will help efforts to control this tick and the tick-borne diseases carried by it.

Ticks (Acari: Ixodida) parasitizing humans in Corum and Yozgat provinces, Turkey

In order to identify ticks infesting humans in Corum and Yozgat provinces in Turkey, a total of 2110 ticks representing 14 species were collected on humans, between June and September 2009. Of those, 1551 (687♂, 450♀, 407 nymphs, 7 larvae) were collected from Corum and 559 (330♂, 180♀, 49 nymphs) were collected from Yozgat. The majority of ticks (n = 1121, 53.1 %) was Hyalomma marginatum. Other common ticks infesting humans were Dermacentor marginatus (n = 209, 9.9 %) and Rhipicephalus turanicus sensu lato (n = 145, 6.9 %) in the study area. In addition, a total of 386 immature Hyalomma were found on humans in Corum (335 nymphs, 7 larvae) and Yozgat (44 nymphs). Ixodes laguri and Haemaphysalis erinacei taurica were recorded for the first time in Corum. To the best of our knowledge, this study is the first detailed investigation on ticks infesting humans in Corum and Yozgat, except individual or incidental records. The present study provides useful information for those concerned with ticks and tick-borne diseases in Turkey.

A survey of ticks (Acari: Ixodida) infesting some wild animals from Sivas, Turkey

In order to determine the species composition of infesting ticks, between 2011 and 2012 a total of 1118 wild animals were captured from various regions of Zara, Sivas province, Turkey. A total of 138 ticks were obtained from the 58 host animals. Ticks were identified as Dermacentor marginatus (Sulzer), Haemaphysalis erinacei taurica Pospelova-Shtrom, Haemaphysalis parva (Neumann), Haemaphysalis punctata Canestrini and Fanzago, Haemaphysalis sulcata Canestrini and Fanzago, Hyalomma marginatum Koch, Ixodes laguri Olenev, Ixodes ricinus (L.), Ixodes vespertilionis Koch and Rhipicephalus turanicus Pomerantzev. To the best of our knowledge, there are several new host records for D. marginatus, H. e. taurica and I. laguri. In addition, I. vespertilionis was recorded for the first time in the Central Anatolian Region in Turkey, whereas I. laguri and H. e. taurica are firstly reported in Sivas.

First phylogenetic analysis of a Crimean-Congo hemorrhagic fever virus genome in naturally infected Rhipicephalus appendiculatus ticks (Acari: Ixodidae)

Crimean-Congo haemorrhagic fever (CCHF) is a potentially fatal systemic viral disease in many parts of the world, including Iran. The nationwide incidence of human CCHF in endemic areas was 870 confirmed cases with 126 deaths (case fatality rate, CFR = 17.6 %) in the decade leading to 2012. The detection of the CCHF virus (CCHFV) genome in tick vectors is of fundamental importance for identifying these ticks as potential reservoirs of CCHFV infection. From May to October 2013, following detection of four new clinical cases resulting in two deaths in the city of Mashhad (northeast Iran), hard ticks were recovered from infested livestock in 40 villages in Khorasan-Razavi province and examined by the microscopic method for species identification. About a quarter of the ticks were then subjected to reverse-transcription polymerase chain reaction (RT-PCR) to detect the CCHFV genome. The PCR products were then sequenced, and their phylogenetic lineages were determined. A total of 407 hard ticks were captured, representing seven different species in two distinct genera. Members of the genus Hyalomma were widely distributed in all but two of the villages studied, and this was also the most frequent (83.3 %) tick genus. Of 105 adult ticks subjected to RT-PCR, four (3.8 %) ticks were found positive for the CCHFV genome. One brown ear tick, Rhipicephalus appendiculatus, was found to be naturally infected for the first time anywhere in the world. Ticks of Hyalomma asiaticum, Hyalomma marginatum, and Rhipicephalus turanicus were also found to be naturally infected with CCHFV. CCHFV found in these four different tick species were clustered in the same lineage with the Matin and SR3 strains from Pakistan and some other strains from Iran, indicating that these tick species were naturally infected with genetically closely related CCHFV in the region. The presence of CCHFV infection in four different hard tick species was confirmed using RT-PCR in northeast Iran. Part of this infection was attributed to Rh. appendiculatus, which is thus a potential new natural vector of CCHFV in Iran. It is also confirmed by phylogenetic analysis that CCHFV in this region is genetically closely related, even in the different tick species.

Can serum ferritin level predict disease severity in patients with crimean-congo hemorrhagic Fever?

OBJECTIVE

Crimean-Congo hemorrhagic fever (CCHF) is an acute viral disease. Several factors have already been suggested to explain the pathogenesis as well as predict the disease severity. In our study we aim to investigate the role of serum ferritin level as a possible predicting factor of disease severity in these patients.

MATERIALS AND METHODS

We evaluated all patients with laboratory confirmed diagnosis of CCHF who were admitted to Boo-Ali Hospital of Zahedan from May 2011 to June 2012. Confirmation of the disease determined using the presence of anti- CCHFV IgM in the serum by enzyme-linked immunosorbent assay (ELISA) or by polymerase chain reaction(PCR). After ethical approval, patients were categorized into two groups of mild and severe disease according to disseminated intravascular coagulation (DIC) severity using the scoring system of International Society on Thrombosis and Hemostasis (ISTH). Serum ferritin levels were evaluated and compared between these two groups. Receiver operating characteristic (ROC) curve analysis was performed to assess the optimal cutoff value of serum ferritin for predicting the disease severity.

RESULTS

A total of 42 patients (36 men, 6 women, age range: 17-78 years) were included in this study, of whom 38% had Persian and 62% had Baloch ethnicity. According to DIC severity score, 54.7% of the patients had severe disease and 45.3% had mild disease. The area under the ROC curve was 0.896 and 95% CI was 0.801-0.991 (p<0.0001). A cut-off point of 1060 ng/dL, had a sensitivity of 78.9%, a specificity of 87%, a positive predictive value of 6% and a negative predictive value of 100%. Positive and negative likelihood ratios for this serum ferritin level were 6.05 and 0.24, respectively.

CONCLUSION

Increased serum ferritin level has a significant positive correlation with disease severity in patients with CCHF and can evaluate the prognosis of these patients with a high sensitivity and specificity.

Recent advances in research on Crimean-Congo hemorrhagic fever

Crimean-Congo hemorrhagic fever (CCHF) is an expanding tick-borne hemorrhagic disease with increasing human and animal health impact. Immense knowledge was gained over the past 10 years mainly due to advances in molecular biology, but also driven by an increased global interest in CCHFV as an emerging/re-emerging zoonotic pathogen. In the present article, we discuss the advances in research with focus on CCHF ecology, epidemiology, pathogenesis, diagnostics, prophylaxis and treatment. Despite tremendous achievements, future activities have to concentrate on the development of vaccines and antivirals/therapeutics to combat CCHF. Vector studies need to continue for better public and animal health preparedness and response. We conclude with a roadmap for future research priorities.

Crimean-Congo hemorrhagic fever virus clades V and VI (Europe 1 and 2) in ticks in Kosovo, 2012

Despite being a small country, Kosovo represents one of the few foci of Crimean-Congo hemorrhagic fever (CCHF) in Europe. The distribution of Kosovar tick vectors and the evolution of CCHF virus in ticks are both as yet unknown. A better description of the extent and the genetic diversity of CCHFV in ticks from endemic settings is essential, in order to be controlled. We investigated the 2012 distribution of Kosovar ticks alongside the prevalence and the phylogeography of tick-derived CCHFV. Hyalomma marginatum dominated in the endemic municipalities with 90.2% versus 24.3% in the non-endemic regions. Of 1,102 tested ticks, 40 (3.6%) were CCHFV-positive, belonging to H. marginatum (29), Rhipicephalus bursa (10), and Ixodes ricinus (1). The virus strains clustered with clade V and VI related sequences. They fell into two lineages: Kosovo I and II. Kosovo I comprised strains recovered exclusively from R. bursa ticks and was closely related to AP92 prototype strain. Kosovo II clustered into Kosovo IIa, including human-derived strains, and IIb including only strains detected in H. marginatum and I. ricinus. Our phylogeographic reconstruction suggests two temporally distinct CCHFV introductions: the most probable location of the most recent common ancestor of Kosovo I lineage was in Greece (63 years ago) and that of lineages IIa-b in Turkey (35 years ago). After each CCHFV introduction into Kosovo, subsequent lineage expansions suggest periods of in situ evolution. The study provides the first insight into the genetic variability and the origin of CCHFV in ticks from Kosovo. Our findings indicate the spreading of CCHFV to non-endemic areas, which underlines the importance of further studies in order to monitor and predict future CCHF outbreaks in Kosovo. The AP92-like strains appear to be more widespread than previously thought and may provide a promising target for experimental studies due to their assumed low pathogenicity.

Crimean-Congo hemorrhagic fever virus (CCHFV) is the most widespread tick-borne virus affecting humans. Its distribution coincides with that of Old World Hyalomma tick vectors. The virus circulates in an enzootic cycle, where hard ticks are both vectors and reservoirs, and mammals the amplifying hosts. Accidentally, humans become infected as dead-end hosts. One of the few CCHF-endemic European countries is Kosovo, where an annual average of ten sporadic cases, with a mean mortality rate of 18%, are reported. In this study, the tick distribution, CCHFV prevalence and the phylogeography of the tick-derived strains from 2012 were investigated. The majority of ticks belonged to Hyalomma marginatum, the main vector of CCHFV. Indeed, of 40 CCHFV-positive ticks, 29 were H. marginatum. The phylogenetic analyses revealed that 30 viral strains formed a distinct lineage within clade V (Europe 1) and were closely related to previously known strains from humans and ticks from the Balkans. However, ten isolates from Rhipicephalus bursa ticks, collected in a non-endemic region, turned out to cluster within a very divergent CCHFV clade (Europe 2), so far only known from Greece and Turkey. Since these strains presumably develop only subclinical or mild infections in humans, they might be suitable for experimental vaccine studies.

The life cycle and occurrence of Haemaphysalis concinna (Acari: Ixodidae) under field conditions

The life cycle and occurrence of Haemaphysalis concinna were investigated under field conditions from April 2012 to March 2013 in Eerguna National Natural Reserve Area situated on the China-Russia border in Inner Mongolia, China. Under natural conditions, the whole life cycle of H. concinna was allowed to complete in a natural tick habitat. With domestic rabbits supplied as hosts, the seasonal occurrence and behaviors of H. concinna were also observed in the field plot which was chosen in a natural tick habitat from April to October 2012. Results indicated that the durations of the life cycle from unfed adults to the next generation unfed adults of H. concinna ranged from 124 to 186 days (average periods of 153.1 days). The incubation time of eggs ranged from 39 to 57 days (average periods of 41.3 days), which is the longest period among the four developmental stages, followed by the premolt periods for larvae (averaged 37.7 days) and nymphs (averaged 26.0 days). The number of eggs was positively correlated with the weight of engorged females (r=0.8562, p<0.001). Eggs were laid in high amounts in the first week, subsequently, the egg amount declined gradually with small peaks occasionally observed. The female reproductive efficiency index (REI) and reproductive fitness index (RFI) was 6.2 and 4.3, respectively. Observations on the occurrence of H. concinna indicated that, in the confined plot under field conditions, larvae appeared in late May and peaked in early July, and nymphs were active during July and August. Therefore, there was an overlap in the occurrence of larvae and nymphs in both June and July.

A review of Hyalomma scupense (Acari, Ixodidae) in the Maghreb region: from biology to control

Hyalomma scupense (syn. Hyalomma detritum) is a two-host domestic endophilic tick of cattle and secondarily other ungulates in the Maghreb region (Africa). This species transmits several pathogens, among which two are major livestock diseases: Theileria annulata and Theileria equi. Various other pathogens are also transmitted by this tick species, such as Anaplasma phagocytophilum and Ehrlichia bovis. Hyalomma scupense is common in sub-humid and semi-arid areas of several regions in the world, mainly in the Maghreb region. In this region, adults attach to animals during the summer season; larvae and nymphs attach to their hosts during autumn, but there is a regional difference in H. scupense phenology. There is an overlap between immature and adult ticks, leading in some contexts to a dramatic modification of the epidemiology of tick-borne diseases. This tick species attaches preferentially to the posterior udder quarters and thighs. Tick burdens can reach 130 ticks per animal, with a mean of 60 ticks. Calves are 70 times less infested than adult cattle. The control can be implemented through six options: (i) rehabilitation of the farm buildings by roughcasting and smoothing the outer and inner surfaces of the enclosures and walls. This control option should be recommended to be combined with a thorough cleaning of the farm and its surrounding area. With regard to Theileria annulata infection, this control option is the most beneficial. (ii) Acaricide application to animals during the summer season, targeting adults. (iii) Acaricide application during the autumn period for the control of the immature stages. (iv) Acaricide application to the walls: many field veterinarians have suggested this option but it is only partially efficient since nymphs enter deep into the cracks and crevices. It should be used if there is a very high tick burden or if there is a high risk of tick-borne diseases. (v) Manual tick removal: this method is not efficient since the ticks can feed on several other animal species in the farm. This control option can lead to a reduction of the tick population, but not a decrease in tick-borne disease incidence. (vi) Vaccination: this control option consists of injecting the protein Hd86; trials have shown a partial effect on nymphs, with no effect on adult ticks. Combination of two of these control options is recommended in regions where there are high burdens of important tick vectors. Further studies are needed to improve our knowledge on this tick species in the Maghreb region, since the number of published studies on Hyalomma scupense in this region is very limited.

Seroprevalence and risk factors of Crimean-Congo hemorrhagic fever in selected seven provinces in Turkey

Turkey has been one of the most endemic regions since 2002, when Crimean-Congo hemorrhagic fever emerged worldwide. The aim of the present study was to estimate the seroprevelance of CCHF virus in humans who reside in rural and urban areas of known endemic and nonendemic selected provinces of Turkey by using commercial ELISA kit. CCHFV IgG antibodies were detected in 2.3% of the population. The most important risk factors for CCHF seropositivity, were older age, male gender, illiterate, farmer, animal husbandry, living in rural residence in adobe houses, and a previous tick bite history.

Epidemiological and behavioral factors associated with Crimean-Congo hemorrhagic fever virus infections in humans

Crimean-Congo hemorrhagic fever (CCHF), a viral disease with high fatality rate, is endemic in many countries in Europe, the Middle East, Asia and Africa. It is transmitted to humans either by tick bite or by direct contact with blood or tissues of viremic patients or livestock. Aim of the present study was to review the main epidemiological characteristics of the disease worldwide, with special attempt to show the epidemiological and behavioral factors that play a role in acquisition of the infection. It is obvious that these factors differ among countries, and the knowledge and understanding of the transmission routes in each region facilitates the implementation of proper control measures, the awareness enhancement and the prevention of the disease.

Crimean-Congo hemorrhagic fever: an overview

Crimean-Congo hemorrhagic fever (CCHF) is a zoonotic viral infection that is a serious threat to humans. The disease is widely distributed in Africa, Asia, and Europe and has developed into a serious public health concern. Humans become infected through the bites of ticks, by contact with a patient with CCHF, or by contact with blood or tissues from viremic livestock. Microvascular instability and impaired hemostasis are the hallmarks of the infection. Infection in human begins with nonspecific febrile symptoms, but may progress to a serious hemorrhagic syndrome with high mortality rates. Enzyme-linked immunoassay (ELISA) and polymerase chain reaction (PCR) are the most used and specific tests for the diagnosis. The mainstay of treatment is supportive. Although definitive studies are not available, ribavirin is suggested to be effective especially at the earlier phase of the infection. Uses of universal protective measures are the best way to avoid the infection. In this review, all aspects of CCHF are overviewed in light of the current literature.

Tick survey and detection of Crimean-Congo hemorrhagic fever virus in tick species from a non-endemic area, South Marmara region, Turkey

Crimean-Congo hemorrhagic fever (CCHF) is an increasing health concern in Turkey since 2002. There were also some recent human cases from the South Marmara region of Turkey; thus, a tick survey was performed, and possible vector tick species for the CCHF virus were determined in the region. A total of 740 adult ticks were collected from infested livestock from five locations: Çanakkale-Biga, Bursa-Orhaneli, Bursa-Keles, Balıkesir and Bilecik. Total of 11 tick species from the genera Hyalomma, Rhipicephalus, Dermacentor, Ixodes and Haemaphysalis were identified. Rhipicephalus ticks were dominant in the region; the most frequently observed tick species was R. turanicus, (53.1 %), and only 15.4 % of the identified ticks were H. marginatum. The occurrence of H. rufipes infestation in the region fort he first time. A total of 73 pools of adult ticks were tested with both an antigen-detecting ELISA and RT real-time PCR (RT rt PCR). The presence of the CCHF virus was demonstrated in 9 (12.3 %) of the tested tick pools. Although seven of the tick pools were positive for the CCHF virus with both of the methods, one pool was positive only with RT rt PCR and the other pool was only positive with the ELISA. Positive results were obtained from ticks collected from cattle, sheep and goats from two locations, Bursa-Orhaneli and Bilecik. The CCHF virus was detected in R. turanicus (n = 3), R. bursa (n = 2), H. marginatum (n = 2) and D. marginatus (n = 2) ticks. The results of this study confirm the presence of the CCHF virus and present preliminary data on the vector tick species in the southern Marmara region of Turkey.

Ticks (Acari: Ixodida) infesting humans in the provinces of Kelkit Valley, a Crimean-Congo Hemorrhagic Fever endemic region in Turkey

Ticks are mandatory blood feeding ectoparasites leading transmission of various tick-borne pathogens to human and animals. Since 2002, thousands of human tick bites and numerous Crimean-Congo Hemorrhagic Fever cases have been reported in several provinces in the Kelkit Valley region in Turkey. Despite increased cases of tick bites and tick-borne diseases, no taxonomic information is available about the tick species infesting humans in the region. In the present study, a tick survey on humans was performed to determine the species composition of ticks infesting humans in several provinces of Kelkit Valley. In the survey, 1,460 ticks (721 males, 516 females and 223 nymphs) were collected from tick-infested humans. A total of 19 tick species have been found on humans in the region, including 7 Hyalomma, 2 Argas, 2 Haemaphysalis, 2 Ixodes, Dermacentor and 3 Rhipicephalus species. Infestation of Dermacentor reticulatus on humans was documented for the first time in Turkey.