Hard ticks (Acari,Ixodidae) of Croatia

The present paper is based on original and literature data. In Croatia the first studies on the occurrence of ixodid species were made about 80 years ago. The number of tick species recorded in Croatia considerably increased during the 1950s, 60s, 70s and 80s of the past century. A total of 21 species of hard tick belonging to 5 genera have been recorded in Croatia. Ixodes is the best represented genus, with seven species recorded. Haemaphysalis is represented by six species, followed by Rhipicephalus with four species. Dermacentor and Hyalomma are represented by two species each. The ticks were collected on 47 different host species. Eleven tick species were collected on Bos taurus and Ovis aries, followed by Capra hircus and Equus caballus with 8 species and Canis lupus familiaris with 6 species. On the remaining 42 host species one, two or three tick species were collected. The most widespread tick is Ixodes ricinus which was found on 25 different host species.     

Coitinuous cell lines from embryonic tissues of ticks (Acari: Ixodidae)

Summary Six new cell lines were established in continous culture from embryonic tissues of ixodid ticks. Four were fromDermacentor variabilis and two fromD. parumapertus. The cells are mostly fibroblastic and diploid. Mosquito-borne viruses (Chikungunya, O'nyong, yellow fever, and St. Louis encephalitis) as well as tick-borne ones (Langat, Powassan, Colorado tick fever, Kemerovo, and Sawgrass) replicated in certain of these cell lines, but a nonvector-borne flavivirus, Modoc, did not. An undescribed virus fromD. occidentalis ticks, which could not be isolated in Vero cells or newborn mice, was readily isolated in theD. variabilis cell line.     

Host-seeking behaviour by Australian ticks (Acari: Ixodidae) with differing host specificities

Ticks generally detach from their hosts into sites where they are later exposed to host species which may or may not be suitable for infestation. The question of how four species of ixodid ticks, with differing specificities, behave towards such potential host species was examined. Observations of the generalists,Aponomma hydrosauri andAmblyomma limbatum and the specialists,Aponomma fimbriatum andAponomma concolor, showed that the generalists were attracted to a wider range of potential host species than the specialists and that the larval stages of all tick species, regardless of specificity, contacted more potential host species than the adults. The interspecific differences may be attributed to reliance on different sets of host cues, while the intraspecific differences may reflect the developmental state of the sensory system.     

Using habitat models to map diversity: pan-African species richness of ticks (Acari: Ixodida)

Aims To show how logistic regression models for individual species can be used to produce improved estimates of species richness at a continental scale; to present these data for African ticks (Acari: Ixodida); and to address the question of whether there is a latitudinal gradient in tick species richness. Location Africa. Methods A database of 34,060 collection records for African ticks is used to produce a pan‐African map of known tick species richness at 0.25 × 0.25‐degree resolution. The likely distributions of seventy‐three species are then estimated from environmental factors using logistic regression, and localities where there is a suitably high probability of occurrence for a given species are added to the original data for that species. These augmented data are combined to produce a map of the predicted pan‐African distribution of tick species richness. The relationship of species richness to latitude is considered along a transect placed across some of the more extensively collected areas. Results Maps of known and predicted pan‐African tick species richness are presented, and deficiencies in the available data are highlighted. Correlations using both known and predicted estimates of tick species richness suggest that ticks follow similar species richness patterns to those described for African mammals and birds, with a latitudinal gradient and highest species richness in east equatorial Africa. Tick species ranges are log‐normally distributed. Main conclusions Carefully constructed probability surfaces offer a more powerful approach to mapping species ranges than simple presence‐absence maps. Such models are a useful extension to current biogeographical methods and have a wide range of potential applications in ecology, epidemiology and conservation. Tick species richness at a continental scale follows similar trends to those reported for mammals and birds.     

Diversity,ecology, and seasonality of hard ticks (Acari: Ixodidae) in eastern Croatia

The diversity of hard tick fauna was studied in different forest communities in 48 localities of eastern Croatia using the dragging‐flagging method and by hand from ten different vertebrate hosts. A total of 2,225 specimens comprising seven species in three genera were identified. Ixodes ricinus, the most abundant species (72.8% of all collected specimens) was recorded in 44 localities, followed by Dermacentor reticulatus in 19 localities, while the other five species (D. marginatus, H. concinna, H. inermis, I. canisuga, and I. hexagonus) were recorded in fewer localities. The highest ratio (67% of collected ticks) was in the adult stage with the predominance of females. The numbers of collected females, males, and nymphs of I. ricinus and H. concinna differed significantly. Ten new tick‐host associations in Croatia were recorded. Fifty‐three animals were infested with one tick species. Single species infestation with I. ricinus was found in 45.8% of animals, followed by D. reticulatus with 25.4%, D. marginatus with 10.2%, H. inermis and I. hexagonus with 3.4%, and I. canisuga with 1.7%. Coinfestation with two species of ticks were recorded in six animals. Ixodes ricinus, H. inermis, and D. reticulatus showed bimodal seasonal activity; for other species unimodal activity patterns were recorded.     

Morphological identification of ticks (Acari: Ixodidae) infesting donkeys (Equus asinus) in Maputo Province,Mozambique

Donkeys (Equus asinus) are rustic animals, but in Africa’s poorest regions, they can present multiple health problems, including tick infestation. The study’s objective was to determine the species composition of ticks that infest donkeys in Maputo Province (Mozambique). Ticks were collected in five conveniently selected southern districts of Maputo Province (Moamba, Matutuíne, Marracuene, Boane, and Matola) and were identified to species level using a stereoscopic microscope with the aid of dichotomous identification keys. In total, 500 ticks were collected from all 88 selected donkeys. Three genera of ticks were identified, namely Rhipicephalus (97.2%; 486/500), Amblyomma (2.2%; 11/500), and Hyalomma (0.6%; 3/500). Seven species were identified, of which Rhipicephalus evertsi evertsi with 50.4% (252/500) was the most prevalent, followed by Rhipicephalus appendiculatus (27.4%; 137/500), Rhipicephalus turanicus (11.6; 10/500), Rhipicephalus (boophilus) microplus (6.8; 20/500), Amblyomma hebraeum (2.2%; 11/500), Rhipicephalus sanguineus (1%; 5/500) and Hyalomma truncatum (0.6%; 3/500). Rhipicephalus evertsi evertsi occurred in all locations, whereas Hyalomma truncatum occurred only in the Boane district. Males were the most prevalent (67.2%; 336/500). The study revealed that donkeys in Maputo Province were infested with seven tick species of which R. evertsi evertsi was the main species.

     

Spirochete-like cells in a Dominican amber Ambylomma tick (Arachnida: Ixodidae)

Amber preserves microscopic, soft-bodies organisms and is a good medium in which to trace the evolution of pathogen–vector associations. Spirochetes-like cells (Spirochaetales: Spirochaetaceae) in the hemocoel and lumen of the alimentary tract of a larva tick (Amblyomma sp. Arachnida: Ixodidae) in Dominican amber are described in the collective fossil genus and species, Palaeoborrelia dominicanan. gen., n. sp. The size and shape of the fossil spirochetes closely resemble those of present-day Borrelia species. This discovery represents the first record of spirochete-like cells associated with fossil ticks.     

Diversity of rickettsial pathogens in Columbian black‐tailed deer and their associated keds (Diptera: Hippoboscidae) and ticks (Acari: Ixodidae)

Cervids host multiple species of ixodid ticks, other ectoparasites, and a variety of rickettsiae. However, diagnostic test cross‐reactivity has precluded understanding the specific role of deer in rickettsial ecology. In our survey of 128 Columbian black‐tailed deer (Odocoileus hemionus columbianus (Richardson)) and their arthropod parasites from two northern Californian herds, combined with reports from the literature, we identified four distinct Anaplasma spp. and one Ehrlichia species. Two keds, Lipoptena depressa (Say) and Neolipoptena ferrisi Bequaert, and two ixodid ticks, Ixodes pacificus Cooley and Kohls and Dermacentor occidentalis Marx, were removed from deer. One D. occidentalis was PCR‐positive for E. chaffeensis; because it was also PCR‐positive for Anaplasma sp., this is an Anaplasma/Ehrlichia co‐infection prevalence of 4.3%. 29% of L. depressa, 23% of D. occidentalis, and 14% of deer were PCR‐positive for Anaplasma spp. DNA sequencing confirmed A. bovis and A. ovis infections in D. occidentalis, A. odocoilei in deer and keds, and Anaplasma phagocytophilum strain WI‐1 in keds and deer. This is the first report of Anaplasma spp. in a North America deer ked, and begs the question whether L. depressa may be a competent vector of Anaplasma spp. or merely acquire such bacteria while feeding on rickettsemic deer.     

Regeneration of Limbs and Sensory Organs in Ixodid Ticks (Acari,Ixodoidea, Ixodidae,and Argasidae)

We present a review of our own and literature data on reparative regeneration in ixodoid ticks (chelicerate arthropods). Ticks have a high potential for reparative regeneration and a close relationship between regeneration and development determined by similar hormonal regulatory mechanisms. These mechanisms depend on ecdysteroid hormones, which participate in the initiation of both processes, and juvenile hormones, which direct these processes either to the maintenance of larval features or to the development of nymphal and adult features. We present a detailed analysis of the regeneration of Haller's sensory organs in ixodid ticks and propose an hypothesis about the role of juvenile hormones in the modification of morphogenetic processes in this group. Furthermore, we present data on the effects of insect juvenile hormone analogs (methoprene and fenoxycarb) on the regeneration of Haller's organ, which support this hypothesis. Studies on reparative regeneration in arthropods provide a broader view of the problem of repair morphogenesis in animals.     

Regeneration of limbs and sensory organs in Ixodid ticks (Acari, Ixodeidea, Ixodidae and Argasidae)

We present a review of our own and literature data on reparative regeneration in ixodid ticks (chelicerate arthropods). Ticks have a high potential for reparative regeneration and a close relationship between regeneration and development determined by similar hormonal regulatory mechanisms. These mechanisms depend on ecdysteroid hormones, which participate in the initiation of both processes, and juvenile hormones, which direct these processes either to the maintenance of larval features or to the development of nymphal and adult features. We present a detailed analysis of the regeneration of Haller's sensory organs in ixodid ticks and propose an hypothesis about the role of juvenile hormones in the modification of morphogenetic processes in this group. Furthermore, we present data on the effects of insect juvenile hormone analogs (methoprene and fenoxycarb) on the regeneration of Haller's organ, which support this hypothesis. Studies on reparative regeneration in arthropods provide a broader view of the problem of repair morphogenesis in animals.     

Ixodid ticks feeding on humans in South Africa: with notes on preferred hosts,geographic distribution,seasonal occurrence and transmission of pathogens

This paper records the identities of 558 ixodid ticks feeding on 194 humans in South Africa. These ticks belonged to 20 species in six genera and those most frequently encountered were Amblyomma hebraeum, Haemaphysalis leachi, Hyalomma marginatum rufipes, Hyalomma truncatum, Rhipicephalus appendiculatus, Rhipicephalus gertrudae and Rhipicephalus simus. With the exception of the larvae of R. appendiculatus, the incidents of these ticks feeding on humans correlated well with their seasonal occurrences on preferred hosts. Ticks were also collected at monthly intervals, for 14 consecutive months, from the clothing of a game-guard providing protection for field-workers engaged in the collection, by means of flannel strips, of free-living ticks from the vegetation of four localities in the southern region of the Kruger National Park. In addition, with the exception of 3 months when the particular worker was absent, ticks that fed on one of the field-workers were collected over the same 14-month period. A total of 54,429 free-living ticks belonging to 14 species and six genera were collected from the vegetation at the four localities during this time and 3751 ticks belonging to 11 species and six genera from the clothing of the game-guard. The larvae of A. hebraeum and Boophilus decoloratus were the most numerous of the immature ticks, and H. leachi and R. simus of the adults on both the vegetation and the guard’s clothing. Ticks fed on the field-worker on six occasions and 14 were collected, all of which were A. hebraeum larvae. This revised version was published online in July 2006 with corrections to the Cover Date.     

Ticks (Ixodidae) on humans in South America

Twenty eight species of Ixodidae have been found on man in South America (21 Amblyomma, 1 Boophilus, 2 Dermacentor, 2 Haemaphysalis, 1 Ixodes and 1 Rhipicephalus species). Most of them are rarely found on man. However, three species frequently parasitize humans in restricted areas of Argentina (A. neumanni reported from 46 localities), Uruguay (A. triste from 21 sites) and Argentina–Brazil (A. parvum from 27 localities). The most widespread ticks are A. cajennense (134 localities in Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Suriname and Venezuela), A. ovale (37 localities in Argentina, Brazil, Ecuador, French Guiana, Guyana, Paraguay, Suriname and Venezuela) and A. oblongoguttatum (28 sites in Brazil, Colombia, French Guiana, Guyana, Suriname and Venezuela). Amblyomma aureolatum (18 localities in Argentina, Brazil, French Guiana and Paraguay), A. cajennense, and A. triste are vectors of rickettsioses to man in South America. A better understanding of the respective roles of these and other tick species in transmitting pathogens to humans will require further local investigations. Amblyomma ticks should be the main subjects of these studies followed by species of Boophilus, Dermacentor, Haemaphysalis and Rhipicephalus species. In contrast with North America, Europe and Asia, ticks of the genus Ixodes do not appear to be major players in transmitting diseases to human. Indeed, there is only one record of an Ixodes collected while feeding on man for all South America.     

Models of temporal variation in questing activity in individuals of Ixodes recinus (Acari: Ixodidae)

Intensive observations of the questing activity of Ixodes ricinus ticks in the field were made to provide data on the range of durations of periods of continuous questing activity, and of the variation in questing activity between individuals. Continuous periods of questing were observed to extend to a maximum of 28 hours. Substantial variation in questing activity between individuals was observed. Models fitted to the distribution of durations of bouts of questing activity provide insights into the questing ecology of I. ricinus. Results suggest that questing duration may not be solely dependent on the state of hydration of the tick. A function fitted to the frequency distribution of the proportions of active life that individuals spend on questing, provides an empirically-based model that can be used to generate a stochastic expression of variation of questing activity in individuals in a questing population.     

Three new species of Zerconidae (Acari: Mesostigmata) from Turkey

Three new species, Zercon afyonensis sp. n., Zercon karacamehmeti sp. n. and Zercon soguticus sp. n., are described and illustrated based on samples collected in the Inner Aegean Region. The similarities and differences between the related species are discussed.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:3FA1701A-A243-4E45-8AE9-FCB733CC56A6     

Optimal sampling and spatial distribution of Ixodes pacificus, Dermacentor occidentalis and Dermacentor variabilis ticks (Acari: Ixodidae)

A common method for sampling tick populations is flagging, which is a method of dragging a white cloth over a plant substrate for a fixed distance along a transect. Flagging over rough physical surfaces or using long subtransect lengths could lead to the underestimation of tick densities. Using estimates of the drop-off rates of adult Ixodes pacificus in flag sampling, optimal sampling schemes (the length and number of subtransects) were examined using the relationships between the tick drop-off rates (c), the tick density and distribution patterns and the roughness of the sampled plant substrate. It was found that the optimal number of subtransects and Lmax, the longest subtransect length which did not significantly underestimate the tick density from c, were affected by the tick density, substrate roughness and tick distribution pattern. This study also showed that the density and distribution of I. pacificus and Dermacentor occidentalis varied greatly over time in the populations sampled, while the Dermacentor variabilis densities were low and showed no significant changes over time. Both I. pacificus and D. occidentalis had clumped distributions along trails and these clumps were aggregated. However, the clump sizes (or individual clump areas) changed significantly over time because of density fluctuation or the movement of ticks. Finally, a positive association between the number of I. pacificus and D. occidentalis adults was observed from 2 m subtransect flag collections in March 1995; no relationship was found in 1994. © Rapid Science Ltd. 1998     

Ticks (Acari: Ixodoidea: Argasidae, Ixodidae) of Chile

The tick species recorded from Chile can be listed under the following headings: (1) endemic or established: Argas keiransi Estrada-Peña, Venzal and Gonzalez-Acuña, A. neghmei Kohls and Hoogstraal; Ornithodoros amblus Chamberlin; Otobius megnini (Dugès); Amblyomma parvitarsum Neumann; A. tigrinum Koch; Ixodes auritulus Neumann; I. chilensis Kohls; I. cornuae Arthur, I. sigelos Keirans, Clifford and Corwin; I. stilesi Neumann; I. uriae White; Rhipicephalus sanguineus Koch. (2) Probably established or endemic: Argas miniatus Koch; Ornithodoros spheniscus Hoogstraal, Wassef, Hays and Keirans; Ixodes abrocomae Lahille; I. neuquenensis Ringuelet; I. pararicinus Keirans and Clifford. (3) Doubtfully established: Argas reflexus Fabricius; Ornithodoros talaje (Guérin-Méneville). (4) Exotic: Amblyomma argentinae Neumann; A. latum Koch, Rhipicephalus (=Boophilus) microplus (Canestrini). (5) Erroneously identified as present in Chile: Amblyomma americanum (Linnaeus); A. maculatum Koch; A. varium Koch; Ixodes conepati Cooley and Kohls; I. frontalis (Panzer); I. ricinus (Linnaeus); Margaropus winthemi Karsch. (6) Nomina nuda: Argas reticulatus Gervais; Amblyomma inflatum Neumann; Ixodes lagotis Gervais. Hosts and localities (including new records) are presented. Argas neghmei, O. amblus, O. megnini, I. uriae and R. sanguineus may cause severe injury to their hosts, including humans. The Chilean Ixodes fauna is unique to the Neotropical Zoogeographic Region, and additional research is needed in order to understand the biological importance of these species.This revised version was published online in May 2005 with a corrected cover date.     

Ixodid ticks on wild donkeys in a Mediterranean nature reserve (Asinara National Park): diversity and risk factors

The Sardinian coloured donkey Equus asinus (Perissodactyla: Equidae) and its albino colour morph represent the wildlife species most typical of the island of Asinara. This Mediterranean island represents a favourable context for ticks and tick‐borne diseases; however, knowledge of the tick fauna on Asinara is scarce. A total of 106 Sardinian donkeys were inspected for tick infestation from June to November 2015. All ticks found were collected, classified by stage and sex, and identified to species level. The level of infestation of each donkey was determined; both the overall tick infestation and infestations of each detected species were classified on a scale of 1–3 to give an infestation score (IS). Overall, 256 hard ticks were collected from 60 of 106 donkeys (56.6%). Rhipicephalus bursa, Haemaphysalis punctata and Hyalomma marginatum (all: Ixodida: Ixodidae) infested 26.4%, 28.3% and 6.6% of donkeys, respectively. Different variables affected the IS. With reference to overall tick infestation, a higher IS was observed in donkeys grazing on grassland and Mediterranean shrubland and in albino donkeys compared with coloured donkeys. The collected ticks included species involved in the transmission of pathogens to humans, which highlights the risks for public health in a tourist destination such as Asinara National Park.