Feeding patterns of immature stages of Hyalomma truncatum and Hyalomma marginatum rufipes on different hosts

In this study we examine the feeding patterns of immature stages of Hyalomma truncatum and Hyalomma marginatum rufipes ticks on different hosts. Larvae of H. truncatum developed through a three-host pattern on two species of field mice, Rhabdomys pumilio and Lemniscomys rosalia. On guinea-pigs, both Hyalomma species followed a mixed two-host and three-host pattern, with the latter route being preferred, since more than 70% of the fully fed larvae dropped off from their hosts. H. truncatum was a two-host tick on rabbits. Larvae of H. marginatum rufipes did not prefer R. pumilio and L. rosalia as hosts. On guinea-pigs, H. marginatum rufipes immatures showed a mixed two-host and three-host pattern with a bias towards the three-host life cycle, since approximately 58% of the fully fed larvae dropped off. On rabbits, H. marginatum rufipes was exclusively a two-host tick. Mean engorgement weights and blood quantities ingested by H. truncatum nymphs that developed through a three-host pattern on mice were significantly higher (p<0.0001) than for those that developed through a two-host pattern on guinea-pigs and rabbits. For H.marginatum rufipes, there were no significant differences (p>0.05) between engorgement weights of nymphs that developed through two-host and three-host patterns. However, there were significant differences (p<0.0001) in blood quantities ingested by nymphs of this tick species following feeding on different hosts.     

The distribution of Hyalomma spp. ticks from domestic ruminants in Iran

The distribution of Hyalomma species on domestic animals was studied in four zoogeoghraphical zones. Nine hundred and ninety-two Hyalomma ticks were collected from sheep, goats, cattle and camels. A total of seven tick species consisting of: Hyalomma anatolicum Koch, 1844 (28.93%), H. excavatum Koch, 1844 (12.5%), H. asiaticum Schulze & Schlottke, 1930 (13.5%), H. marginatum Koch, 1844 (27.01%), H. detritum Schulze, 1919 (9.67%), H. schulzei Olenev, 1931 (4.03%) and H. dromedary Koch, 1844 (4.33%) were recorded. The results indicated that H. anatolicum, H. asiaticum, H. marginatum and H. detritum were present in all zones whereas H. excavatum was absent in Zone I. The result also showed that H. dromedari was presented in Zones III and IV whereas H. schulzei was present in Zones II and III. During this study, the tick species collected are candidates for investigation as vectors of pathogenic organisms in Iran.     

Exotic ectoparasites of ostriches recently imported into the United States

Eleven species of ectoparasitic arthropods were collected and identified from ostriches (Struthio camelus) recently imported into the United States from Africa and Europe. Four of these species are reported from ostriches for the first time. The parasites included adult hippoboscid flies (Struthiobosca struthionis) and 10 species of adult ixodid ticks (Amblyomma gemma, A. lepidum, A. variegatum, Haemaphysalis punctata, Hyalomma albiparmatum, H. luscitanicum, H. marginatum rufipes, H. truncatum, Hyalomma sp., and Rhipicephalus turanicus. As a result of these findings, the U.S. Department of Agriculture prohibited further importation into the United States of ostriches and other flightless birds on an interim basis.     

Larval identification of species and subspecies of the genus Hyalomma (Acari: Ixodidae) from Russia and neighbouring territories

The following species and subspecies of Hyalomma Koch, 1844 are recorded from Russia and neighbouring territories, including those involved in natural foci of tick-borne diseases: H. (Hyalomma) aegyptium (Linnaeus, 1758), H. (Euhyalomma) dromedarii Koch, 1844, H. (Euh.) asiaticum asiaticum Schulze et Schlottke, 1930, H. (Euh.) asiaticum caucasicum Pomerantzev, 1940, H. (Euh.) asiaticum kozlovi Olenev, 1931, H. (Euh.) anatolicum Koch, 1844, H. (Euh.) excavatum Koch, 1844, H. scupense Schulze, 1918, H. (Euh.) marginatum marginatum Koch, 1844, H. (Euh.) marginatum turanicum Pomerantzev, 1946, and H. (Euh.) marginatum rufipes Koch, 1844. The geographic distribution and host-parasite relationships of each taxon are discussed. Species characters of the larval stage, that can be distinguished using light microscopy, are found to be very few. These characters include shape of scutum, shape and rate of hypostome denticulation, shape and rate of the development of spurs on coxae I to III. Measurements of some morphological structure and their rations show statistically significant differences between some closely related species, even if qualitative discriminating characters are unknown. Only measurements and their ratios can be used for the discrimination of larval H. anatolicum from larval H. excavatum, because qualitative discriminating features have not been found for these species. The complex structure of the subspecific morhological differentiation of all parasitic stages in the polymorphic species H. asiaticum and H. marginatum is revealed. This structure probably reflects some peculiarities of the microevolutionary processes. Identification key for the larval stage of seven Hyalomma species is provided.     

Prevalence of ixodid ticks on cattle in Mazandaran province, Iran

A survey was carried out to investigate the prevalence of hard tick species (Acari: Ixodidae) on cattle in Mazandaran province, Iran. A total of 953 ticks were collected from 86 infested cattle during activating seasons of ticks during 2004-2005. Nine species were identified: Boophilus annulatus (51.3%), Rhipicephalus bursa (16.8%), Haemaphysalis punctata (6.3%), Ixodes ricinus (6.8%), Hyalomma marginatum (12.5%), Hyalomma anatolicum excavatum (5.2%), Hyalomma asiaticum (0.6%), Hyalomma detritum (0.2 %), and Dermacentor spp. (0.1%). The results show that Boophilus annulatus, Rhipicephalus bursa, and Hyalomma species are dominant tick species in the surveyed area.     

Ticks (Acari: Ixodoidea) in China: Geographical distribution,host diversity,and specificity

Ticks are obligate blood‐sucking ectoparasites, which not only directly damage through bites but also transmit many pathogens. China has a high diversity of tick species, 125 species have been reported, including 111 hard tick and 14 soft tick species. Many of the ticks are important vectors of pathogens, resulting in zoonoses. The dynamics of ticks are affected by both the host and habitat environment. However, systematic studies on the geographical distribution, host diversity, and specificity of ticks are limited in China. To achieve this goal, the relevant available data were summarized and analyzed in this study. Ticks are distributed in all parts of China and Xinjiang has the most records of ticks. The distribution of ticks in adjacent areas is similar, indicating that the habitat environment affects their distribution. Most ticks are widely distributed, whereas some species are endemic to their distributed regions. Ticks are parasitic on mammals, birds, and reptiles, of which mammals are the main host species. Overall, most ticks parasitize different hosts, only a few ticks have strict host specificity, such as ticks that are specifically parasitic on reptiles and bats. In addition, environmental changes and control efforts also influence the dynamics of ticks. These results can better reveal tick biological traits and are valuable for tick control.     

The coevolution of ixodid ticks and terrestrial vertebrates

Paleontologic and zoogeographic data speak in favour of Mesozoic origin of ixodid ticks. The absence of strict restrictions for the feeding on unusual species of hosts has caused the domination of polyphagy and oligophagy over monophagy among ixodid ticks. The same peculiarities of ixodid ecology are responsible for a restricted part or absence of phylogenetic parallelism with hosts in their evolution. Primary food relations with reptiles are, apparently, preserved only in the genus Aponomma and in many species of Amblyomma while hosts for most species of other genera are mammals and, to a lesser extent, birds. The number of potential hosts in these species can be much greater than that of real ones. Restrictions in the distribution of some species are connected rather with direct effect of unfavourable environmental factors on their nonparasitic stages of the life cycle than with the absence of suitable hosts. During the evolution of natural landscapes and at a shorter stages under the influence of successions or anthropogenic factors ixodids easily adapt themselves to feeding on new species of hosts. So the differentiation of primary and secondary hosts of these parasites is rather difficult.     

Diversity and seasonal patterns of ticks parasitizing wild birds in western Portugal

The diversity and abundance of questing ticks and ticks parasitizing birds was assessed during 1?year in two recreational forests in western Portugal, a suburban forest and an enclosed game area. The aim of this study was to assess the distribution and seasonality of tick species and to understand the role of bird species as hosts for ticks. Ixodes ricinus was the most abundant questing tick collected in the enclosed game area, whereas in the suburban forest, only three ticks were collected by blanket dragging. Tick species parasitizing birds included I. ricinus, I. frontalis, I. arboricola, I. acuminatus, Haemaphysalis punctata, Hyalomma marginatum and H. lusitanicum. This is the first record of I. arboricola in Portugal. Tick prevalence and intensity of infestation differed between study areas and was higher in birds from the game area where a large population of deer and wild boar may support tick populations. Ground and shrub dwelling bird species such as Turdus merula, Erithacus rubecula and Sylvia melanocephala were the most heavily parasitized by ticks, but the importance of different bird species as hosts of larvae and nymphs of I. ricinus and I. frontalis differed. Therefore, different bird species may contribute differently for tick population maintenance.     

The effect of various host species on the feeding performance of immature stages of the tick Hyalomma truncatum (Acari: Ixodidae)

In order to determine the effect of various hosts on the feeding performance of the tick Hyalomma truncatum, we used three mammalian species as hosts. Larvae and nymphs of H. truncatum were fed, under controlled laboratory conditions, on gerbils, guinea-pigs and rabbits. The larvae fed for 4.3±1.4 days on gerbils, 5.6±1.3 days on guinea-pigs and 4.7±1.2 days on rabbits. The mean weights of the larvae which fed on the rabbits, guinea-pigs and gerbils were 0.58± 0.09, 0.46±0.04 and 0.45±0.04 mg. respectively. The feeding periods of the nymphs on gerbils, guinea-pigs and rabbits were 7.9±1.3, 8.6±1.3 and 9.6±2.2 days respectively. The mean weights of the nymphs which fed on the gerbils, guinea-pigs and rabbits were 22.5±2.8, 19.7±1.3 and 15.8±1.4 mg, respectively. Hyalomma truncatum demonstrated a life cycle of a three-host tick on gerbils and guinea-pigs and of a two-host tick on rabbits. The evolutionary advantage of a two-host cycle over a three-host cycle in metastriate ticks is discussed.     

Hyalomma (Hyalommina) arabica: nymphal and larval identity and spiny mouse hosts in Saudi Arabia (Acarina: Ixodoidea: Ixodidae)

Nymphal and larval Hyalomma (Hyalommina) arabica Pegram, Hoogstraal, and Wassef, 1982, described herein, closely resemble those of Hyalomma (Hyalommina) rhipicephaloides Neumann, differing chiefly in body size (both stages), nymphal basis capituli and scutal proportional dimensions, and distinctness of larval coxal spurs. Females of these species are also structurally similar but males differ in major critical characters. Nymphs and larvae of both species parasitize the spiny mouse (Acomys spp.), but immatures of the third African- Arabian species of this subgenus, Hyalomma (Hyalommina) punt Hoogstraal, Kaiser, and Pedersen, are unknown. Hyalomma (Hyalommina) arabica occurs in valleys and hills of western Saudi Arabia and western Yemen; H. (H.) rhipicephaloides in the Red Sea and Dead Sea areas; and H. (H.) punt in northeastern Somalia and eastern Ethiopia. The ibex (Capra ibex nubiana Cuvier) is probably the original host of adult H. (H.) arabica and H. (H.) rhipicephaloides; the related domestic goat is an important host of adults of the 3 species, which also parasitize domestic sheep. Gazelles are recorded hosts of adults of H. (H.) rhipicephaloides and H. (H.) punt and the latter is also recorded from goats, sheep, camels and cattle.     

Review The ecology of ticks transmitting Lyme borreliosis

The main vectors of Borrelia burgdorferi sensu lato, the cause of Lyme borreliosis, are ixodid ticks of the Ixodes persulcatus species complex. These ticks, which occur throughout the northern temperate zone, have very similar life cycles and ecological requirements. All are three-host ticks, with the immature stages mainly parasitizing small to medium-sized mammals and birds and the adult females parasitizing large mammals such as deer, cattle, sheep and hares. The host-seeking stages show a distinct seasonality, which is regulated by diapause mechanisms and there appear to be major differences in this respect between the Old World and New World species. Most cases of human borreliosis are transmitted in the summer by the nymphal stages, with the exception of the Eurasian species, I. persulcatus, in which the adult females are mainly responsible. The ticks acquire the spirochaetes from a wide variety of mammals and birds but large mammals do not seem to be infective, so that t icks that feed almost exclusively on large mammals, for example in some agricultural habitats, are rarely infected. The greatest tick infection prevalences occur in deciduous woodland harbouring a diverse mix of host species and the diversity of the different genospecies of B. burgdorferi s.l. is also greatest in such habitats. There is evidence that these genospecies have different host predilections but, apart from the fact that I. persulcatus does not seem to be infected by B. burgdorferi sensu stricto, they do not seem to be adapted to different tick strains or species. © Rapid Science Ltd. 1998     

Distribution and ecology of ticks (Acari: Ixodidae) infesting livestock in Tunisia: an overview of eighth years field collections

Ticks (Ixodidae) play a significant role as vectors of pathogens of domestic animals in Tunisia. The major losses caused by ticks are related to transmission of protozoan parasites. These include agents of tropical theileriosis and babesiosis in ruminants. Since 1991, we conducted research studies on tick population of livestock in Tunisia. This overview reports a synthesis on tick distribution, their biology and their role as vectors of pathogens in domestic animals, particularly cattle. During the whole period of the study about 15,000 tick specimens were collected from different zones of the country. A total of 14 species were identified. Hyalomma detritum detritum was the most abundant and important (vector of Theileria annulata) species infesting cattle. Hyalomma dromedarii and Hyalomma impeltatum were collected on domestic ruminants in the arid and desertic zones. Hyalomma marginatum marginatum and Hyalomma anatolicum excavatum were widespread and found on livestock hosts. Ixodes ricinus, vector of Babesia divergens and Borrelia burgdorferi sl, colonises mainly the humid zone. Boophilus annulatus and Rhipicephalus bursa infesting cattle, sheep and goats were found in the sub-humid and semi-arid zones. Haemaphysalis sulcata and Hae. punctata were collected in humid and sub-humid zones on cattle and sheep. Rhipicephalus turanicus were collected in different regions, on different animal species. Rhipicephalus sanguineus, tick of dogs, were often collected on livestock. Only few specimens of Hyalomma marginatum rufipes and Hyalomma franchinii were collected.     

Discrimination of subspecies in a polymorphic species Hyalomma marginatum (Acari, Ixodidae) based on adult stage

Morphological characteristics allowing discriminating adult stages of four subspecies of Hyalomma marginatum (H. m. marginatum, H. m. turanicum, H. m. rufipes and H. m. isaaci) are displayed. The subspecies status of all named forms is confirmed. The main discriminating characters for adults of these subspecies are peculiarities of scutal or conscutal punctations and a shape of the dorsal tale of spiracular plates (Fig. 1, 1-4; 2, 4-7; 4, 1, 2; 5, 1, 2, 6, 5-8). Nevertheless, there are a number of facts, which support only the subspecific rank of these taxa. In Turkmenistan, there is a zone inhabited by forms, adult stages of which are morphologically intermedial between H. m. marginatum and H. m. turanicum. A zone of intermedial forms between H. m. turanicum and H. m. rufipes exists in Arabian Peninsula (Hoogstraal e. a., 1981). An absence of clear discriminative characters between immatures of H. m. marginatum, H. m. turanicum and H. m. rufipes also confirms the subspecies level of these taxa. H. m. isaaci is the most differentiated subspecies. It is difficult to estimate relationships between the latter subspecies and H. m. turanicum because of a deficit of materials. However, clear morphological differences of H. m. isaaci immature stages from other subspecies were noticed (Apanaskevich, 2003). Therefore, it is quite probable that H. m. isaaci might deserve the species rank. Further analysis of relationships between subspecies of H. marginatum needs additional materials represented by all stages from zones containing intermedial forms between recently recognized subspecies.     

Sense organs in post-embryonic stages of Hyalomma marginatum marginatum Koch, 1844 (Acari: Ixodida: Ixodidae). I. Tarsal sensory system.

Light and scanning electron microscopic studies showed the differences in morphology and in size of Haller's organ in larvae, nymphs and adults (females and males) of Hyalomma marginatum marginatum Koch, 1844. The length of the anterior pit setae increases during post-embryonic development. The localization of these setae is the same in all stages. Six setae (one porose seta, two grooved setae, two fine setae, one conical seta) contain anterior pit of various developmental stages. In nymphs and adults more numerous pores appear on the wall surface of porose seta than in the larval stage. The structure of the capsule roof also differs in various developmental stages. Haller's organ of Hyalomma m. marginatum shows great degree of morphological development which is connected with the complicated life cycle and feeding behaviour of this tick species.     

Molecular genetic data provide support for a model of transmission dynamics in an Australian reptile tick, Bothriocroton hydrosauri

Bothriocroton hydrosauri is a three-host ixodid tick that infests large reptiles in southeastern Australia, where its most common host is a large scincid lizard Tiliqua rugosa . Based on previous ecological and behavioural studies of this system, we propose a 'ripple' model of tick population dynamics, where only a few female ticks succeed in producing surviving offspring. These females then are the centres of ripples of their progeny spreading into the broader landscape. The model predicts higher relatedness among larvae than among nymphs or adults on a host, and significant spatial autocorrelation in larvae extending further than for the later life stages. The model also predicts that adult ticks are likely to encounter related partners and that this will generate inbreeding within the population. We tested those predictions using nine polymorphic microsatellite loci on a sample of 848 ticks (464 larvae, 140 nymphs and 244 adults) collected from 98 lizard hosts from near Bundey Bore Station in South Australia. Our data support the predictions and indicate that the dynamics of transmission among hosts play an important role in parasite population structure.     

A survey of ticks (Acari: Ixodidae) on dairy cattle on the island of Menorca in Spain

A survey of ticks affecting dairy cattle under extensive management on Menorca island (off the Spanish Mediterranean coast) was performed through 1999-2000 on seven farms. The species collected were Rhipicephalus bursa, R. turanicus, Hyalomma m. marginatum, H. lusitanicum and Boophilus annulatus. The most abundant species were R. bursa and H. m. marginatum, with peaks of 10.7 (in summer) and 7.5 (in spring) ticks/cow, respectively. R. turanicus was scarcely encountered, while B. annulatus and H. lusitanicum were abundant only in a few localities. The mild climate and adequate vegetation on the island provide satisfactory habitat for extended periods of tick activity, as compared with other regions where these ticks have been collected. The competence of the ticks as vectors for pathogens and the difficulty of using acaricide treatments in the region are discussed.     

Life cycle of Amblyomma cooperi (Acari: Ixodidae) using capybaras (Hydrochaeris hydrochaeris) as hosts

The life cycle of Amblyomma cooperi was evaluated under laboratory conditions testing different host species. Larval infestations were performed on chickens (Gallus gallus) and capybaras (Hydrochaeris hydrochaeris). Nymphal infestations were performed on G. gallus, H. hydrochaeris, guinea pigs (Cavia porcellus) and wild mice (Calomys callosus). Infestations by adult ticks were performed only on capybaras. All free-living stages were observed in darkness at 27 degrees C and RH 85%. Capybaras were significantly (p < 0.05) the most suitable hosts for immature ticks, with the highest larval (63.6%) and nymphal (48%) recovery. Larval and nymphal feeding and premolt periods were significantly different (p < 0.05) between ticks fed on different host species. Male nymphs showed premolt period significantly shorter (p < 0.05) than female nymphs. The overall sex ratio of adult ticks was 0.92:1 (M:F). Infestations by adult ticks on capybaras yielded more than 76% of engorged female recovery. Only three out of 33 engorged females fed on capybaras did not lay fertile eggs. The life cycle of A. cooperi in laboratory, reported for the first time, was completed in an average period of 189.4 days. During the premolt period, all A. cooperi engorged nymphs secreted distinct blackish drops, which seem to be inherent to this species. Our results, associated data in the literature, confirm the high suitability of capybaras for the adult stage of A. cooperi and also indicate this animal species as a primary host for immature stages of A. cooperi in nature. On the other hand, the results of larval and nymphal infestation on chickens and guinea pigs suggest that birds and wild guinea pigs, which are also present in the distribution area of A. cooperi in South America, could be potentially infested by A. cooperi immature stages in nature.     

Ixodid ticks of Pavlodar Province and their participation in the circulation of tularemia infection

Investigations carried out in Pavlodar Province have shown that 7 species of ixodid ticks, Ixodes crenulatus, I. lividus, I. persulcatus, I. laguri laguri, Dermacentor marginatus, D. reticulatus, Haemaphysalis concinna, and one brought species, Hyalomma asiaticum, parasitize domestic animals and wild mammals. Maximum activity of pasture ticks of the genus Dermacentor falls on the end of April--beginning of May, that of H. concinna on the beginning of June. The growth in the abundance of pasture ticks, recorded during the last years, is favoured by the increase in the cattle live stock, its seasonal movements and pasture area reduction. Natural nidi of tularemia become more active. Since 1977 221 cultures of tularemia agent have been isolatid from pasture ticks. H. concinna takes the most active part in the infection circulation.     

Co-distribution pattern of a haemogregarine Hemolivia mauritanica (Apicomplexa: Haemogregarinidae) and its vector Hyalomma aegyptium (Metastigmata: Ixodidae)

Hyalomma aegyptium ticks were collected from tortoises, Testudo graeca, at localities in northern Africa, the Balkans, and the Near and Middle East. The intensity of infestation ranged from 1-37 ticks per tortoise. The sex ratio of feeding ticks was male-biased in all tested populations. Larger tortoises carried more ticks than did the smaller tortoises. The juveniles were either not infested, or carried only a poor tick load. Hyalomma aegyptium was absent in the western Souss Valley and Ourika Valley in Morocco, the Cyrenaica Peninsula in Libya, Jordan, and the Antilebanon Mountains in Syria. Hemolivia mauritanica, a heteroxenous apicomplexan cycling between T. graeca and H. aegyptium, was confirmed in Algeria, Romania, Turkey, Syria, Lebanon, and Iran. Its prevalence ranged from 84% in Romania (n = 45), 82% in eastern Turkey (n = 28), and 82% in the area of northwestern Syria with adjacent Turkish borderland (n = 90), to 38% in Lebanon (n = 8) and in only 1 of 16 sampled tortoises in Algeria. The intensity of parasitemia in the studied areas ranged from 0.01% up to 28.17%. The percentage of Hemolivia-infected erythrocytes was significantly higher in adults. All tortoises from Hyalomma-free areas were Hemolivia-negative. Remarkably, all 29 T. graeca from Jabal Duruz (southwestern Syria) and 36 T. graeca from the area north of Middle Atlas (Morocco) were Hemolivia-negative, despite the fact that ticks parasitized all adult tortoises in these localities. Identical host preferences of H. aegyptium and H. mauritanica suggest the occurrence of co-evolution within the Testudo-Hyalomma-Hemolivia host-parasite complex.