Ticks on humans in Ankara, Turkey

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.

Detailed Infestation Spectrums About Biological Stages of Hard Ticks (Acari: Ixodida: Ixodidae) in Humans: A Systematic Review and Meta-Analysis

PURPOSE

A comprehensive systematic meta-analysis review which deals with the degrees and trends of human infestation by biological stages of ticks, the degrees and trends of human infestation by biological stages of ticks in rural and urban areas, the infestation scale of tick attachment sites in body parts of humans, and the degrees of tick infestation in human age groups is critical. Therefore, this systematic meta-analysis review summarizes the above-detailed human infestation spectrums about biological stages of hard ticks.

METHODS

After a preliminary review from 605 papers representing areas of the study objectives, 96 were selected for detailed human infestation spectrums of biological stages of hard ticks.

RESULTS

In general, the results suggest that the adult ticks, and mostly females attack humans more than larval and nymphalid ones, and adult males, respectively. Unlike the trends of human infestation by larval and nymphalid stages of ticks, and the adult, male and female ticks which exhibited approximately a sharply decreasing trend, the global trend of human infestation by hard ticks exhibited approximately a sharply increasing trend over time. Ticks attack humans more in rural area than urban area. Also, the trends of human tick infestation in rural and urban areas exhibit, respectively, a sharp increase and decrease trends over time.

CONCLUSIONS

The majority of ticks mostly attach to human body trunk and extremity than head and neck, and genital area. Ticks attack human age groups of 0-9, 20-39, and 40-59 years more than those aged between 10 and 19 or older than 60 years.

New insights about human tick infestation features: a systematic review and meta-analysis

There are many studies that provide information regarding ticks infesting humans. However, there is no a meta-analysis about the global ranks of tick infestation rates and records, global monthly tick bites and annually and periodically trends of tick infestation rates, and the global tick infestation rates among years, mounts, regions, and countries. The study provides new insights about the above objectives in a global context and therefore performed. After a preliminary review of the 610 papers representing objective areas, 241 were selected for detailed meta-analysis. In general, the global ranks of tick species were, respectively, between 0.01-85.4% and 1-53 for human infestation rates and records. Twenty-six and sixteen tick species have more than 10% and 10 records of human tick infestation rates and records, respectively. It seems these tick species tend to be more blood-feeding on humans and as a result can be more dangerous to humans. The outcome of study demonstrated that there is no difference between seasonal human tick infestation patterns in the northern and southern hemispheres. The most global monthly mean tick bites in humans were observed in June then followed in July, August, May, and September. The global annually and periodically trends of tick infestation rates in humans exhibited decreasing trends over the past decades suggesting the preventive measure to prohibit human tick infestation have been successful. It seems that the ranks of tick infestation rates and records in humans may be as two indexes to illustrate the degree of importance of tick infesting humans.

Bacterial and protozoan agents found in Hyalomma aegyptium (L., 1758) (Ixodida: Ixodidae) collected from Testudo graeca L., 1758 (Reptilia: Testudines) in Corum Province of Turkey

Hyalomma aegyptium (L., 1758) (Ixodida: Ixodidae) is a hard tick and the main host for adults are Palearctic tortoises of the genus Testudo, while larvae and nymphs are less host-specific and nymphs also attach to humans. In the present study, a total of 261 H. aegyptium ticks were removed from 26 Testudo graeca L., 1758 in Corum Province of Turkey. The most prevalent pathogens identified molecularly in the ticks were Hemolivia mauritanica (51.9 %), followed by Rickettsia aeschlimannii (32.6 %), Ehrlichia spp. (30.2 %), and Bartonella bovis (0.8 %). All samples were negative for Coxiella burnetii, Francisella tularensis, Anaplasma phagocytophilum, Babesia spp., Hepatozoon spp. and Theileria spp. Overall, 97.4 % of the examined adult ticks and 26.3 % of nymphs were infected with at least one pathogen, while 40.9 % of all ticks were infected with only one pathogen, 27.4 % with two pathogens, and 9.9 % with three pathogens, concomitantly. Overall, 80.8 % of the examined blood smears of tortoises were H. mauritanica-positive, and the mean intensity of parasitemia was 4.8 % (1-21). As a conclusion, since the examined tortoises were sampled in gardens and vineyards close to human habitation, and as a relatively large percentage of them were infested with ticks carrying pathogenic agents affecting also humans, the importance of tortoises, their ticks and pathogens in terms of the public health should be farther examined.

Crimean-Congo hemorrhagic fever virus in tortoises and Hyalomma aegyptium ticks in East Thrace, Turkey: potential of a cryptic transmission cycle

Background

Recent reports have demonstrated the presence of Crimean-Congo hemorrhagic fever virus (CCHFV) genomic material in Hyalomma aegyptium ticks feeding primarily on tortoises belonging to the genus Testudo. This raises the question if these ticks and their hosts play a role in the natural transmission dynamics of CCHFV. However, the studies are limited, and assessing the relevance of H. aegyptium in perpetuating the virus in nature, and a potential spillover to humans remains unknown. This study aimed to detect CCHFV in H. aegyptium ticks and their tortoise hosts in the East Thrace region of Turkey, where H. aegyptium is the most common human-biting tick and where a high density of tortoises of the genus Testudo can be found.

Methods

During the study period, 21 blood samples from different tortoises (2 T. hermanni and 19 T. graeca), 106 tick pools (containing 448 males, 152 females, 93 nymphs and 60 larvae) collected from 65 tortoises (5 T. hermanni and 60 T. graeca), 38 adult unfed questing ticks (25 males and 13 females, screened individually) and 14 pools (containing 8 nymphs and 266 larvae) of immature unfed questing ticks collected from the ground were screened for CCHFV genome by nested PCR and partial genomes sequenced.

Results

As a result of the screening of these 179 samples, 17 (9.5%) were detected as positive as follows: 2 of 21 blood samples (9.52%), 13 (containing 18 nymphs in 3 pools, and 52 males and 8 females in 10 pools) of 106 tick pools from tortoises (12.26%), and 2 of 38 adult questing ticks (5.26%). No positive result was determined in 14 pools of immature questing ticks.

Conclusions

Previous studies have shown that reptiles can participate in the transmission of arthropod-borne viruses, but they may contribute to different aspects of the disease ecology and evolution of tick-borne viral pathogens. Our results indicate the presence of CCHFV in questing and feeding H. aegyptium ticks as well as tortoise hosts. This may indicate that CCHFV circulates in a cryptic transmission cycle in addition to the primary transmission cycle that could play a role in the natural dynamic of the virus and the transmission to humans.

Turkey tick news: A molecular investigation into the presence of tick-borne pathogens in host-seeking ticks in Anatolia; Initial evidence of putative vectors and pathogens, and footsteps of a secretly rising vector tick, Haemaphysalis parva

This Turkey-based study investigated the presence of various tick-borne microorganisms in a broad-range of host-seeking ticks (n = 1019) that exhibit both hunter and ambusher characteristics. All collected ticks were analyzed individually via PCR-sequencing, resulting in the identification of 18 different microorganisms: six Babesia spp., including one putative novel species (Ba. occultans, Ba. crassa, Ba. rossi, Babesia sp. tavsan1, Babesia sp. tavsan2, and Babesia sp. nov.); six SFG rickettsiae (Ri. aeschlimannii, Ri. s. mongolitimonae, Ri. slovaca, Ri. raoultii, Ri. monacensis, and Ri. hoogstraalii); two Borrelia burgdorferi sensu lato spp. (Bo. afzelii and Bo. lusitaniae); two unnamed Hepatozoon spp.; Theileria annulata; and Hemolivia mauritanica. This provided evidence for the natural transstadial survival of these tick-borne microorganisms in adult ticks (in addition a nymph) of Turkey. Surprisingly, this study determined the presence of five different microorganisms (Ba. crassa, Ba. rossi, Babesia sp. Ucbas, Hepatozoon sp., and Ri. hoogstraalii) in host-seeking Haemaphysalis parva adults, for which poor data exist on its vectorial competence. Therefore, this study provides important data indicating the potential vectorial capacity of Ha. parva. This study also revealed the presence of the close ecological and evolutionary relationships between two important vector ticks, Hyalomma marginatum and Hy. aegyptium and determined genetic variations (distinct phylogenetic divergences inside the main clades) in some pathogenic SFG rickettsiae that are found in these ticks. Additionally, the presence of two Babesia species described very recently in hares with unknown vectors, namely Babesia sp. tavsan1 and Babesia sp. tavsan2, were detected for the first time in ticks. Finally, two unnamed Hepatozoon spp. were detected in Haemaphysalis ticks and their phylogenetic positions were demonstrated. Consequently, this study provides important data on the diversity of tick-borne microorganisms in host-seeking ticks and on potentially novel microorganisms (Babesia and Hepatozoon species) and their possible vectors (Ha. parva, Ha. sulcata, Hy. aegyptium, Hy. marginatum, and Rh. turanicus).

Seropositivity to Midichloria mitochondrii (order Rickettsiales) as a marker to determine the exposure of humans to tick bite

Ixodes ricinus is the most common tick species parasitizing humans in Europe, and the main vector of Borrelia burgdorferi sensu lato, the causative agent of Lyme disease in the continent. This tick species also harbors the endosymbiont Midichloria mitochondrii, and there is strong evidence that this bacterium is inoculated into the vertebrate host during the blood meal. A high proportion of tick bites remains unnoticed due to rarity of immediate symptoms, implying the risk of occult tick-borne infections in turn a potential risk factor for the onset of chronic-degenerative diseases. Since suitable tools to determine the previous exposure to I. ricinus bites are needed, this work investigated whether seropositivity toward a protein of M. mitochondrii (rFliD) could represent a marker for diagnosis of I. ricinus bite. We screened 274 sera collected from patients from several European countries, at different risk of tick bite, using an ELISA protocol. Our results show a clear trend indicating that positivity to rFliD is higher where the tick bite can be regarded as certain/almost certain, and lower where there is an uncertainty on the bite, with the highest positivity in Lyme patients (47.30%) and the lowest (2.00%) in negative controls. According to the obtained results, M. mitochondrii can be regarded as a useful source of antigens, with the potential to be used to assess the exposure to ticks harboring this bacterium. In prospect, additional antigens from M. mitochondrii and tick salivary glands should be investigated and incorporated in a multi-antigen test for tick bite diagnosis.

Molecular identification of tick-borne bacteria in wild animals and their ticks in Central Anatolia, Turkey

Wild animals fulfill an important mission in the ecology of tick-borne diseases as both suitable hosts to tick vectors and reservoirs of the pathogens. However, current data regarding the role of wild animals in the ecology of tick-borne pathogens is insufficient and more investigations are required. In this study, we investigated tick-borne bacterial pathogens in wild boar, hare, and fox and their ticks in Turkey. A total of 102 tick pools comprised of 445 ticks and blood samples were analyzed for the presence of bacterial DNA by PCRs targeted rickettsial gltA and ompA genes, 5S-23S rDNA gene for Borrelia spp., and msp4 gene for Anaplasma spp. As a result of PCR and sequence analyses, three pathogenic spotted fever group (SFG) rickettsiae, two SFG rickettsiae with unknown pathogenicity and one pathogenic Borrelia burgdorferi sensu lato were detected in samples obtained from wild animals. Rickettsia slovaca was detected in ticks (13.7% of tick pools) collected from wild boars and blood of a wild boar. In addition, the presences of R. hoogstraalii (19.6% of tick pools), R. aeschlimannii (5.8% of tick pools), R. sibirica subsp. mongolitimonae (1.9% of tick pools) and Candidatus R. goldwasserii (0.9% of tick pools) were detected in ticks collected from wild animals. Furthermore, B. burgdorferi sensu stricto was detected in a tick pool collected from a wild boar. This is the first report on the presence of Candidatus R. goldwasserii in Turkey. Consequently, this study shows that pathogenic Rickettsia and Borrelia species are circulating in Turkish wildlife and these pathogens can pose a threat to human health. Also, it has been determined that the investigated wild animals play a role as maintenance host for vector ticks; therefore, these animals must also be considered in the ecology of the mentioned pathogens.

Comparison of Preferred Bite Sites Between Mites and Ticks on Humans in Korea

Identification of mite and tick bite sites provides important clinical information. The predominant mite species in Korea associated with scrub typhus are Leptotrombidium pallidum and Leptotrombidium scutellare The most abundant tick species is Haemaphysalis longicornis To date, there has been no comparative study on preferred bite sites between mites and ticks in humans. This study included a review of medical records and a field study. For mite bite sites, eschars were checked on 506 patients with scrub typhus, confirmed by indirect immunofluorescence assay or nested polymerase chain reaction on the 56-kDa type-specific antigen gene of Orientia tsutsugamushi Tick bite sites were identified and marked on a diagram for 91 patients who experienced tick bites within the previous year through a field epidemiological investigation. The mite and tick bite sites in Koreans were compared. The most frequently observed mite bite sites were the anterior chest, including the axillae (29.1%) and the abdominal region, including the inguinal area (26.1%). Tick bite sites were most frequent on the lower extremities (33.0%), followed by the abdominal region, including the inguinal area (26.4%), and upper extremities (26.4%). The distribution was significantly different between mite and tick bite sites (P < 0.001). There was a statistically significant difference in the mite bite (P = 0.001), but not tick bite sites (P = 0.985), between men and women. This is the first report on the differences between tick and mite bite sites, and may help clinicians reach a rapid diagnosis of mite- or tick-borne infection.

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.

Identification of tick-borne pathogens in ticks feeding on humans in Turkey

Background

The importance of tick-borne diseases is increasing all over the world, including Turkey. The tick-borne disease outbreaks reported in recent years and the abundance of tick species and the existence of suitable habitats increase the importance of studies related to the epidemiology of ticks and tick-borne pathogens in Turkey. The aim of this study was to investigate the presence of and to determine the infection rates of some tick-borne pathogens, including Babesia spp., Borrelia burgdorferi sensu lato and spotted fever group rickettsiae in the ticks removed from humans in different parts of Ankara.

Methodology/Principal Findings

A total of 169 ticks belonging to the genus Haemaphysalis, Hyalomma, Ixodes and Rhipicephalus were collected by removing from humans in different parts of Ankara. Ticks were molecularly screened for Babesia spp., Borrelia burgdorferi sensu lato and spotted fever group rickettsiae by PCR and sequencing analysis. We detected 4 Babesia spp.; B. crassa, B. major, B. occultans and B. rossi, one Borrelia spp.; B. burgdorferi sensu stricto and 3 spotted fever group rickettsiae; R. aeschlimannii, R. slovaca and R. hoogstraalii in the tick specimens analyzed. This is the report showing the presence of B. rossi in a region that is out of Africa and in the host species Ha. parva. In addition, B. crassa, for which limited information is available on its distribution and vector species, and B. occultans, for which no conclusive information is available on its presence in Turkey, were identified in Ha. parva and H. marginatum, respectively. Two human pathogenic rickettsia species (R. aeschlimannii and R. slovaca) were detected with a high prevalence in ticks. Additionally, B. burgdorferi sensu stricto was detected in unusual tick species (H. marginatum, H. excavatum, Hyalomma spp. (nymph) and Ha. parva).

Conclusions/Significance

This study investigates both the distribution of several tick-borne pathogens affecting humans and animals, and the presence of new tick-borne pathogens in Turkey. More epidemiological studies are warranted for B. rossi, which is very pathogenic for dogs, because the presented results suggest that B. rossi might have a wide distribution in Turkey. Furthermore, we recommend that tick-borne pathogens, especially R. aeschlimannii, R. slovaca, and B. burgdorferi sensu stricto, should be taken into consideration in patients who had a tick bite in Turkey.

Ticks are widespread in over all Turkey. Primary tick-borne diseases (TBDs), such as theileriosis, babesiosis, and anaplasmosis, affecting animals have been known for a long time in Turkey. However, TBDs have become a major concern in humans in recent years due to the recent Crimean-Congo hemorrhagic fever outbreak in Turkey. We know that some TBDs like CCHF, Lyme borreliosis, spotted fever group rickettsiosis, babesiosis and anaplasmosis exist in this geography. However, the other diseases except for CCHF are neglected in patients. In this study, we aimed to investigate Babesia spp., Borrelia burgdorferi sensu lato and spotted fever group rickettsiae in ticks removed from humans in different parts of Ankara by using PCR and sequencing. The result of this study showed that 4 Babesia species, one B. burgdorferi sensu lato, and 3 spotted fever group rickettsia are detected in ticks. The most striking result of this study is that B. rossi, which is very pathogenic for dogs, was reported for the first time from a region that is out of Africa and in Ha. parva. Therefore, B. rossi should be considered in dogs in Turkey. Furthermore, we propose that R. aeschlimannii, R. slovaca, and B. burgdorferi sensu stricto should be taken into consideration in patients who had a tick bite in Ankara.

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.

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.

Species distribution and detection of Crimean Congo Hemorrhagic Fever Virus (CCHFV) in field-collected ticks in Ankara Province, Central Anatolia, Turkey

Ticks may act as vectors for a number of infectious diseases including Crimean Congo Hemorrhagic Fever (CCHF). The causative agent is Crimean Congo Hemorrhagic Fever Virus (CCHFV), a member of Bunyaviridae, causing extensive ecchymosis, visceral bleeding and hepatic dysfunction with a high fatality rate in the affected individuals. CCHF was initially recognized in Turkey in 2002 and the current number of reported cases exceeds 4,400. This study was conducted to confirm the presence of tick species established as potential CCHFV vectors and investigate CCHFV activity in ticks at Ankara province, Turkey's second most-densely populated province, where CCHF cases were demonstrated. A total of 1,196 adult ticks, collected from various animals and vegetation in 12 sites located in 5 counties of Ankara during April-July 2010 were identified to species level. Twenty-two tick pools from county K2 were also evaluated for the presence of CCHFV RNA via a one-step real-time RT-PCR assay and reactive results were further confirmed by an in house nested RT-PCR assay. Nine tick species were identified: Rhipicephalus bursa (44.9%), R. sanguineus (18.9%), R. turanicus (18.1%), Haemaphysalis parva (8.3%), Hyalomma marginatum marginatum (5.4%), H. aegyptium (1.4%), H. anatolicum excavatum (1.3%), Hae. punctata (0.3%) and Dermacentor marginatus (0.2%). A total of five tick pools (22.7%) were reactive in real-time and nested RT-PCR assays. The pools included R. bursa, H. m. marginatum and Hae. parva ticks, collected from mammal hosts from two villages in one county. This is the first documentation of CCHFV activity in ticks from Ankara province, which indicates requirement for detailed surveillance to predict high risk zones in the region.