New Records of Ticks of Genus Amblyomma Koch, 1844 (Acari: Ixodidae) for Ecuador.

PURPOSE: In Ecuador, knowledge of the diversity and geographic distribution of ticks, as well as their importance as vectors, is scarce. Within the family Ixodidae, the genus Amblyomma is the most diverse and parasitizes wild and domestic animals. This genus is represented by 19 species in Ecuador, 12 of which occur in the continental territory and 7 in the Galapagos Islands. In this way, the objective of this work was to update the diversity of ticks reported for Ecuador on wild and domestic animals. METHODS: The specimens were collected manually on mammals and birds, in four localities belonging to the Sierra and Amazon of Ecuador and were kept in tubes with 96% ethyl alcohol. After that, all specimens were separated into immatures, males and females and were identified using their morphological characters. RESULTS: This study records Amblyomma coelebs Neumann, 1899, Amblyomma longirostre (Koch, 1844) Neumann, 1905 and Amblyomma varium Koch, 1844 for the first time in Ecuador. Thus, the genus Amblyomma is currently represented by 22 species. In addition, their hosts, distribution, and importance are also discussed. CONCLUSIONS: Knowing the diversity of ticks that wildlife possesses, its interrelation with the domestic fauna, and the possible pathogens that could be transmitting could significantly contribute to wildlife's conservation.

Documentation of the Expansion of the Gulf Coast Tick (Amblyomma maculatum) and Rickettsia parkeri: First Report in Illinois.

The Gulf Coast tick, Amblyomma maculatum, is of public and veterinary health concern, as it is the primary vector of Rickettsia parkeri and Hepatozoon americanum, causative agents of Rickettsiosis and American canine hepatozoonosis. The Gulf Coast tick's range has expanded over the last 50 yr into the mid-Atlantic states, and its expansion is expected to continue northward. We are reporting the presence of A. maculatum for the first time in Illinois, including a total of 18 specimens collected at 6 different sites during surveys in 2013 and 2019. Fourteen of these specimens were screened for Rickettsia parkeri, which resulted in the detection of this bacteria in 8 samples from 4 counties. By depositing these specimens in scientific collections, we provide materialistic evidence of their establishment in 2 counties. We urge health officials to rely on and use scientific collections to document the expansion of these and other vectors across the country. Additionally, we recommend that health practitioners become aware of the clinical similarities between Rocky Mountain Spotted Fever (caused by Rickettsia rickettsii) and "tidewater" fever (caused by R. parkeri).

Data-driven predictions and novel hypotheses about zoonotic tick vectors from the genus Ixodes.

BACKGROUND: With the resurgence of tick-borne diseases such as Lyme disease and the emergence of new tick-borne pathogens such as Powassan virus, understanding what distinguishes vectors from non-vectors, and predicting undiscovered tick vectors is a crucial step towards mitigating disease risk in humans. We aimed to identify intrinsic traits that predict which Ixodes tick species are confirmed or strongly suspected to be vectors of zoonotic pathogens. METHODS: We focused on the well-studied tick genus Ixodes from which many species are known to transmit zoonotic diseases to humans. We apply generalized boosted regression to interrogate over 90 features for over 240 species of Ixodes ticks to learn what intrinsic features distinguish zoonotic vectors from non-vector species. In addition to better understanding the biological underpinnings of tick vectorial capacity, the model generates a per species probability of being a zoonotic vector on the basis of intrinsic biological similarity with known Ixodes vector species. RESULTS: Our model predicted vector status with over 91% accuracy, and identified 14 Ixodes species with high probabilities (80%) of transmitting infections from animal hosts to humans on the basis of their traits. Distinguishing characteristics of zoonotic tick vectors of Ixodes tick species include several anatomical structures that influence host seeking behavior and blood-feeding efficiency from a greater diversity of host species compared to non-vectors. CONCLUSIONS: Overall, these results suggest that zoonotic tick vectors are most likely to be those species where adult females hold a fecundity advantage by producing more eggs per clutch, which develop into larvae that feed on a greater diversity of host species compared to non-vector species. These larvae develop into nymphs whose anatomy are well suited for more efficient and longer feeding times on soft-bodied hosts compared to non-vectors, leading to larger adult females with greater fecundity. In addition to identifying novel, testable hypotheses about intrinsic features driving vectorial capacity across Ixodes tick species, our model identifies particular Ixodes species with the highest probability of carrying zoonotic diseases, offering specific targets for increased zoonotic investigation and surveillance.

An Exotic Hitchhiker: A Case Report of Importation into Connecticut from Africa of the Human Parasitizing Tick, Hyalomma truncatum (Acari: Ixodidae).

We report the importation into Connecticut, U.S.A., of an exotic tick, Hyalomma truncatum (Koch) (Acari: Ixodidae), on a human with recent travel history to Africa. The tick was identified using key morphological characters and through DNA sequencing. This case report highlights continuing risk associated with the importation of exotic tick vectors of medical and veterinary significance on international travelers returning to the United States from abroad.

Ticks as vectors: taxonomy, biology and ecology.

Ticks are prominent parasites and competent vectors of pathogens that affect both humans and animals. This review outlines and illustrates the main features of the morphology of ticks of the families Ixodidae and Argasidae, and summarises the basic components of their life cycles. It focuses mainly on development processes and mortality among tick populations so as to provide an overview of how they are regulated in nature and how pathogens can be transmitted under such a framework. The effects of the weather on these life cycles are reviewed. The author also examines how landscape structure and biotic factors, such as the presence and abundance of hosts, may shape the density of tick populations. The uncertainty inherent in dealing with the transmission of pathogens by ticks is highlighted; this results from the sometimes complex relationships among the vectors, the climate and the presence and density of host populations. The need to obtain reliable field estimations of such relationships before drawing conclusions about the effects of the isolated components of the system is stressed. A section is devoted to addressing the expected (and not yet totally understood) effects of trends in climate on the spread of ticks, and how these can be analysed and tracked.

Histopathological study of ovaries of Rhipicephalus sanguineus (Acari: Ixodidae) exposed to different thymol concentrations.

Thymol is a monoterpene with proven acaricide action for several tick species. In addition to killing these ectoparasites, thymol can also reduce oviposition and egg hatch rate. However, the effects of thymol on the morphophysiology of tick ovaries are still unknown. Thus, the aim of this study was to evaluate the morphophysiological changes caused by this active principle in ovaries of Rhipicephalus sanguineus after a 6-day feeding period, through the application of morphohistochemical techniques. After the feeding period, a total of 50 females were divided into five groups and immersed in the following solutions: (I) distilled water (control), (II) 30% ethanol (control), (III) 1.25 mg/mL thymol, (IV) 2.5 mg/mL thymol, and (V) 5.0 mg/mL thymol. The experimental groups were kept in a climatic chamber (27 ± 1 °C; RH 80 ± 10%) for 5 days. After this period, morphological (hematoxylin/eosin) and histochemical (von Kossa) techniques were applied after remotion of the ovaries. The morphological results revealed large vacuoles in germ cells at different developmental stages and invaginations that represent deformations in the chorionic membrane. From the results obtained in this study, it was concluded that thymol interfered with the development of oocytes, which showed degeneration signs. The treatment containing 5.0 mg/mL thymol affected more accentuately the morphological development. Moreover, thymol also altered the calcium content of yolk granules, which generally showed an intense staining for this element.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry for rapid identification of tick vectors.

A method for rapid species identification of ticks may help clinicians predict the disease outcomes of patients with tick bites and may inform the decision as to whether to administer postexposure prophylactic antibiotic treatment. We aimed to establish a matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) spectrum database based on the analysis of the legs of six tick vectors: Amblyomma variegatum, Rhipicephalus sanguineus, Hyalomma marginatum rufipes, Ixodes ricinus, Dermacentor marginatus, and Dermacentor reticulatus. A blind test was performed on a trial set of ticks to identify specimens of each species. Subsequently, we used MALDI-TOF MS to identify ticks obtained from the wild or removed from patients. The latter tick samples were also identified by 12S ribosomal DNA (rDNA) sequencing and were tested for bacterial infections. Ticks obtained from the wild or removed from patients (R. sanguineus, I. ricinus, and D. marginatus) were accurately identified using MALDI-TOF MS, with the exception of those ticks for which no spectra were available in the database. Furthermore, one damaged specimen was correctly identified as I. ricinus, a vector of Lyme disease, using MALDI-TOF MS only. Six of the 14 ticks removed from patients were found to be infected by pathogens that included Rickettsia, Anaplasma, and Borrelia spp. MALDI-TOF MS appears to be an effective tool for the rapid identification of tick vectors that requires no previous expertise in tick identification. The benefits for clinicians include the more targeted surveillance of patients for symptoms of potentially transmitted diseases and the ability to make more informed decisions as to whether to administer postexposure prophylactic treatment.

Feeding effects of Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae), on protein consumption and blood loss of their hosts.

Host blood loss by Rhipicephalus sanguineus feedings (weight/tick) ranged from 0.0179 to 0.2469 mg (0.21686 +/- 0.26785) and from 0.00103 to 0.00159 gm (0.001274 +/- 0.000204) respectively for each female and male if fed once. Results obtained herein indicated that if each sheep and or goat in production in Egypt is infested with only one pair of R. sanguines, the blood loss would reach 1084.3 kg and 867.4 kg, respectively for the population of sheep and goats. Accordingly, there was a great loss in plasma protein, about 186.5 kg and 149.2 kg respectively for the total population of sheep and goats in Egypt. The host response for tick feeding was not only by blood loss or plasma protein loss but also by protein pattern differentiation of host blood before and after tick feeding.

Eradication and control of livestock ticks: biological, economic and social perspectives.

Comparisons of successful and failed attempts to eradicate livestock ticks reveal that the social context of farming and management of the campaigns have greater influence than techniques of treatment. The biology of ticks is considered principally where it has contributed to control of ticks as practiced on farms. The timing of treatments by life cycle and season can be exploited to reduce numbers of treatments per year. Pastures can be managed to starve and desiccate vulnerable larvae questing on vegetation. Immunity to ticks acquired by hosts can be enhanced by livestock breeding. The aggregated distribution of ticks on hosts with poor immunity can be used to select animals for removal from the herd. Models of tick population dynamics required for predicting outcomes of control methods need better understanding of drivers of distribution, aggregation, stability, and density-dependent mortality. Changing social circumstances, especially of land-use, has an influence on exposure to tick-borne pathogens that can be exploited for disease control.

Travel and disease vector ticks.

There are approximately twenty species of hard (ixodid) ticks worldwide that frequently affect human populations, many of which are associated with serious, sometimes fatal disease(s). When a tick travel souvenir is presented in the clinic, the risk must be immediately assessed by identifying the tick in question, ascertaining its disease vector status and determining if there has been the opportunity for the transfer of potential pathogens. This short review on identification of disease vector ticks and aspects of blood feeding and disease transmission includes the results of an examination of 59 specimens removed from UK domestic travellers and international travellers between 2002 and 2010. Sixteen tick species belonging to six genera were recorded and almost all showed evidence of blood feeding, which appears to contradict the view that because of their size, adult ticks are found early and therefore present an insignificant risk.

[Ticks and transmission of some important diseases by ticks]. / Keneler ve Kenelerin Tasidigi Bazi Onemli Hastaliklar.

Ticks which are commonly found all around the world are ectoparasites which are obliged to suck blood from vertebrates such as mammals and birds during all of their periods of develeopment. They may cause toxicities and paralyses in the course of blood sucking through saliva injection and the attachment sites may become ports of entry for secondary agents. Healthy animals that are severely infested by ticks can show a decreased yield and anemia. Young and sick animals can even die. Besides this, ticks are both biological and mechanical vectors for viruses, bacteria, rickettsias, spirochaetas, protozoons and helminths. Ten percent of the ticks identified in the world are associated with 200 diseases. In this review the taxonomy and morphology of ticks, some of the important diseases they carry and the diagnosis and treatment of these diseases are mentioned.

Nymphs of the genus Amblyomma (Acari: Ixodidae) of Brazil: descriptions, redescriptions, and identification key.

Together with the larval stage, the nymphal stage of ticks of the genus Amblyomma are the most aggressive ticks for humans entering areas inhabited by wildlife and some domestic animals in Brazil. However, due to the absence of morphological descriptions of the nymphal stage of most Brazilian Amblyomma species, plus the lack of an identification key, little or nothing is known about the life history of Amblyomma spp. nymphs in the country. In the present study, morphological description of the nymphal stage, illustrating important external characters through scanning electron microscopy, is provided for nymphs of 15 Amblyomma species that occur in Brazil, for which the nymphal stage had never been described: A. aureolatum, A. auricularium, A. calcaratum, A. coelebs, A. fuscum, A. humerale, A. incisum, A. latepunctatum, A. naponense, A. nodosum, A. ovale, A. pacae, A. pseudoconcolor, A. scalpturatum, A. varium. In addition, the nymphal stage of 12 Amblyomma species, which had been previously described, are redescribed: A. brasiliense, A. cajennense, A. dissimile, A. dubitatum, A. longirostre, A. oblongoguttatum, A. parkeri, A. parvum, A. romitii, A. rotundatum, A. tigrinum, A. triste. The descriptions and redescriptions totalized 27 species. Only 2 species (A. geayi, A. goeldii) out of the 29 Amblyomma species established in Brazil are not included in the present study. A dichotomous identification key is included to support taxonomic identification of the nymphal stage of 27 Amblyomma species established in Brazil.

[Estimation of the biological age in females of the taiga tick Ixodes persulcatus by changes in the body shape and surface of cuticle].

A method of visual estimation of the biological age of living hungry tick females by visible changes in the depth of marginal groove and the structure of the alloscutum cuticle during natural ageing is developed. In recently activated individuals, the body is convex and the marginal groove is exposed, demonstrating distinctly visible cuticular microfolds (Figs 1-4). In attenuated ticks, the body is flattened and marginal fold overlays the marginal groove, concealing cuticular microfolds (Figs 5-8).

[Characteristic features of the ranks genus and subgenus, and an intercalary rank "species complex" in ixodid ticks (Acari: Ixodidae)].

The work was carries our from the standpoint of the morphological conception of species. Vast collections of the Zoological Institute of the Russian Academy of Science testify to the existence of hiatuses in both genera and subgenera of Palearctic ixodids at all active phases of their ontogenesis. The fact that the subgenera of Palearctic genera have been well studies is notes, and composition of the subgenera is presented. The question of a taxonomic intercalary rank "species complex" is considered in detail in the context of the coevolution between some complexes of closely related species of ixodid ticks and some closely related species (genospecies, strains) of pathogens. The question of the taxonomic rank "species complex" in ixodid ticks as a phyletic species association is postulated on the basis of comparative ontogenetic data. Nomenclature status of the intercalary association "species complex" is specified in conformity with the fourth edition of the International Code of Zoological Nomenclature. Species composition of most studied complexes is presented. Some variants of morphological differentiation between species complexes within subgenus are considered. Significance of the taxonomic concept "species complex" for zoological. parasitological, and medical aspects of the ixodid ticks study was evaluated. Prognostic significance of the rank "species complex" for the study of the relationships between ixodid ticks and pathogens is discussed.

Biology of ticks.

Ticks are among the most significant blood-sucking arthropods worldwide. They transmit various pathogens that can cause disease and death in people, domesticated animals, and wildlife. Ticks have several morphologic features and physiologic mechanisms that facilitate host selection, ingestion of vertebrate blood, mating, survival, and reproduction. Although the natural history of ticks varies considerably among species, these arthropods are well-adapted to survive in tropical, temperate, and even subarctic habitats. Key factors, including the reversion of agricultural lands to forests and a close association between people and ticks, have greatly increased the risk of tick bite and human disease.

First U.S. record of the hard tick Ixodes (Pholeoixodes) gregsoni Lindquist, Wu, and Redner.

Ixodes (Pholeoixodes) gregsoni Lindquist, Wu, and Redner, a species of hard tick described in 1999 in Canada, was recovered from a harvested fisher (Martes pennanti Erxleben) and a domestic cat (Felis silvestris catus Ragni and Randi) in Vermont in 2001 and from harvested mink (Mustela vison Schreber) in Maine in 2003. These samples are the first records of this species within the United States. Although knowledge of this tick's natural history and distribution are still preliminary, these records indicate a possible greater distribution for I. gregsoni than initially perceived. Although its status as a disease vector is presently unknown, natural resource professionals should be aware of the possibility of this tick's occurrence in the northeastern United States.

[Intraspecific taxonomic differentiation in ticks (Acari: Ixodidae) in the view of the morphological conception of species].

The criterions for two most used intraspecific taxonomic ranks of ticks--subspecies and morphotype, have been formulated on the basis of the study of morphological variation in the distribution range of all active ontogenetic stages of 11 polymorphic species. All these species are vectors of transmissible diseases. They have vast distribution ranges and different types of host-parasite relationships. Subspecies have the complexes of visual morphological differences expressed in one or both sexes of mature ticks more limited, than those of related species. At immature stages differences of subspecies consist more often in morphometric characters and can be established by the methods of mathematical statistics only. Morphotypes, as a rule, differ at each corresponding stage by "their own" complexes of morphometric characters. All differential parameters of studied morphotypes are overlapped, but have statistically significant differences (by the Student's test). The concrete variations of differentiation by subspecies and morphotypes have been considered. The historical factors of intraspecific differentiation have been reconstructed for each species.

[Dermacentor reticulatus (Fabricius, 1794)--distribution, biology and vector for Babesia canis in Germany]. / Dermacentor reticulatus (Fabricius, 1794)-- Verbreitung, Biologie und Vektor von Babesia canis in Deutschland.

This work deals with occurrence, distribution as well as biology and vectorial capacity of the ornate dog tick (Dermacentor (D.) reticulatus). Until 30 years ago this tick has only been described in a few natural foci in southern Germany. Its distribution has however expanded in the course of the last years. With the exception of northern Germany it is now covering large areas of Germany. This is particularly the case in the Upper Rhine Valley, Saarland and the Mark Brandenburg. However, it is endemic in many other areas of Germany as well. The transformation of agricultural land into fallow land, an increase in host reservoirs and climatic changes are discussed as main contributors to this change. Little is known about the role of this species as a vector for virus, rickettsia, bacteria and protozoa as well as its medical and veterinary importance. D. reticulatus is a vector for Babesia canis canis. It is reported here about a case of autochthonous babesiosis in a dog from Berlin/Brandenburg.

Ixodes (Ixodes) pararicinus Keirans & Clifford, 1985 (Acari: Ixodidae): description of the immature stages, distribution, hosts and medical/veterinary importance.

The immature stages of the Neotropical tick Ixodes (Ixodes) pararicinus Keirans & Clifford, 1985 are described from specimens in a laboratory colony initiated from engorged females collected on cattle and larvae fed on mice and chickens. The larva and nymph of I. pararicinus are described using SEM micrographs as well as drawings for some features of the larva. Additionally, immature stages of I. pararicinus collected on wild mice and birds in Uruguay and Argentina were compared with specimens from the laboratory colony. A taxonomic key to the nymphs of the species of the ricinus complex established in the Western Hemisphere is presented. The distribution of I. pararicinus comprises Argentina, Colombia and Uruguay, but it is also probably established in Bolivia, Brazil, Chile and Peru. Most adult ticks of this species have been found on introduced domestic artiodactyles, although Neotropical deer species must have been the ancestral host. Larvae and nymphs of I. pararicinus have also been found on sigmodontine rodents and passeriform birds. Although I. pararicinus is a member of the ricinus complex, which contains the main vectors of Borrelia burgdorferi (sensu lato), there are few studies concerning its potential for pathogen transmission.

Molecular differentiation of metastriate tick immatures.

Hard ticks, family Ixodidae, are divided into two groups, the Metastriata and the Prostriata, based on morphological differences. In the United States, there are four medically important genera of the Ixodidae: Ixodes, Amblyomma, Dermacentor, and Rhipicephalus. Ixodes is the only genus in and representative of the Prostriata, whereas the latter three genera are members of the Metastriata. All developmental stages of the Prostriata can be easily differentiated from the Metastriata using morphology. Similarly, the three Metastriate genera are highly identifiable as adults, yet as immatures, the discriminating characteristics can be difficult to use for differentiation, especially if the specimens are damaged or engorged with blood. All three Metastriate genera represent medically important vectors, thus accurate differentiation is necessary. To this end, we have developed a multiplexed-PCR diagnostic assay that, when combined with RFLP analysis will differentiate between the Metastriate genera--Amblyomma, Dermacentor, Rhipicephalus, and Haemaphysalis based on the length of the PCR amplicon and subsequent restriction digestion profile. The intended use for this diagnostic is to verify morphological identifications, especially of immatures, as well as to identify samples destroyed for molecular analysis, which will lead to more accurate field data as well as implication of vectors in disease transmission.