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References to the descriptions and redescriptions of the 742 species of Ixodidae published from 1758 to December 31, 2019 are compiled, with the goal of enabling tick taxonomists to readily access this diffuse and often confusing literature. Additionally, data resulting from this effort are critically analyzed to demonstrate the problems attending correct identification of several tick species that are of medical, veterinary and/or evolutionary importance, and to highlight the need for new or enhanced diagnostic techniques. Recent morphological and molecular studies indicate that some ixodid species names represent more than one taxon; therefore, it is expected that new species will be described in the near future, based partly on material already deposited in museums around the world.

Knowledge of the tick fauna of continental Southeast Asia is either patchy or, in some cases, for example Cambodia and Myanmar, poor. Nevertheless, 97 species have been recorded from this region, making it one of the most diverse for ticks worldwide. Throughout Southeast Asia, work on tick-borne diseases of stock and companion animals, as well as of humans, is in its infancy, and the medical, veterinary and socio-economic importance of these diseases is largely unknown. Here we review current knowledge of Southeast Asian ticks and tick-borne diseases, with the aim of stimulating further research on this subject.

Zoonotic diseases are major causes of infection related morbidity and mortality worldwide. Of the various arthropods capable of transmitting pathogens that cause such diseases to humans, ticks, which are vectors of more kinds of pathogens than any other group of invertebrate, have become an increasing focus of attention. This is particularly the case in the temperate northern hemisphere where they are a significant vector of human disease. Here, we provide an overview of the complex ecological systems defining the various epidemiological cycles of tick-borne diseases. We highlight the abiotic and biotic factors influencing the establishment and persistence of tick populations and their associated pathogens. Furthermore, we emphasize the dynamic nature of such systems, especially when they are under the influence of both small and large-scale anthropogenic changes to the environment. Although a great deal of work has been done on ticks and the diseases which they transmit, the very dynamism of the system means that new factors are continually arising which shift the epidemiological pattern within specific areas. We therefore consider that more detailed, long-term (i.e. at least 10 years), multidisciplinary studies need to be carried out to define why and how these pattern shifts take place and to determine their public health significance., (Copyright © 2013 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.)

Patterns of host-parasite association are poorly understood in tropical forests. While we typically observe only snapshots of the diverse assemblages and interactions under variable conditions, there is a desire to make inferences about prevalence and host-specificity patterns. We studied the interaction of ticks with non-volant small mammals in forests of Borneo. We inferred the probability of species interactions from individual-level data in a multi-level Bayesian model that incorporated environmental covariates and advanced estimates for rarely observed species through model averaging. We estimated the likelihood of observing particular interaction frequencies under field conditions and a scenario of exhaustive sampling and examined the consequences for inferring host specificity. We recorded a total of 13 different tick species belonging to the five genera Amblyomma, Dermacentor, Haemaphysalis, Ixodes, and Rhipicephalus from a total of 37 different host species (Rodentia, Scandentia, Carnivora, Soricidae) on 237 out of 1,444 host individuals. Infestation probabilities revealed most variation across host species but less variation across tick species with three common rat and two tree shrew species being most heavily infested. Host species identity explained ca. 75 % of the variation in infestation probability and another 8-10 % was explained by local host abundance. Host traits and site-specific attributes had little explanatory power. Host specificity was estimated to be similarly low for all tick species, which were all likely to infest 34-37 host species if exhaustively sampled. By taking into consideration the hierarchical organization of individual interactions that may take place under variable conditions and that shape host-parasite networks, we can discern uncertainty and sampling bias from true interaction frequencies, whereas network attributes derived from observed values may lead to highly misleading results. Multi-level approaches may help to move this field towards inferential approaches for understanding mechanisms that shape the strength and dynamics in ecological networks.

There are numerous discrepancies in recent published lists of the ticks of the world. Here we review the controversial names, presenting evidence for or against their validity and excluding some altogether. We also address spelling errors and present a list of 17 species described or resurrected during the years 2003-2008. We consider the following 35 tick species names to be invalid: Argas fischeri Audouin, 1826, Ornithodoros boliviensis Kohls and Clifford, 1964, Ornithodoros steini (Schulze, 1935), Amblyomma acutangulatum Neumann, 1899, Amblyomma arianae Keirans and Garris, 1986, Amblyomma bibroni (Gervais, 1842), Amblyomma colasbelcouri (Santos Dias, 1958), Amblyomma concolor Neumann, 1899, Amblyomma cooperi Nuttall and Warburton, 1908, Amblyomma curruca Schulze, 1936, Amblyomma cyprium Neumann, 1899, Amblyomma decorosum (Koch, 1867), Amblyomma nocens Robinson, 1912, Amblyomma perpunctatum (Packard, 1869), Amblyomma striatum Koch, 1844, Amblyomma superbum Santos Dias, 1953, Amblyomma testudinis (Conil, 1877), Amblyomma trinitatis Turk, 1948, Dermacentor confractus (Schulze 1933), Dermacentor daghestanicus Olenev, 1928, Haemaphysalis himalaya Hoogstraal, 1966, Haemaphysalis vietnamensis Hoogstraal and Wilson, 1966, Hyalomma detritum Schulze, 1919, Ixodes apteridis Maskell, 1897, Ixodes donarthuri Santos Dias, 1980, Ixodes kempi Nuttall, 1913, Ixodes neotomae Cooley, 1944, Ixodes rangtangensis Teng, 1973, Ixodes robertsi Camicas, Hervy, Adam and Morel, 1998, Ixodes serrafreirei Amorim, Gazetta, Bossi and Linhares, 2003, Ixodes tertiarius Scudder, 1885, Ixodes uruguayensis Kohls and Clifford, 1967, Ixodes zealandicus Dumbleton, 1961, Ixodes zumpti Arthur, 1960 and Rhipicephalus camelopardalis Walker and Wiley, 1959. We consider the following 40 names valid: Argas delicatus Neumann, 1910, Argas vulgaris Filippova, 1961, Ornithodoros aragaoi Fonseca, 1960, Ornithodoros dugesi Mazzoti, 1943, Ornithodoros knoxjonesi Jones and Clifford, 1972, Ornithodoros marocanus Velu, 1919, Ornithodoros nattereri Warburton, 1927, Amblyomma beaurepairei Vogelsang and Santos Dias, 1953, Amblyomma crassipes (Neumann, 1901), Amblyomma echidnae Roberts, 1953, Amblyomma fuscum Neumann, 1907, Amblyomma orlovi (Kolonin, 1995), Amblyomma parkeri Fonseca and Aragão, 1952, Amblyomma pseudoconcolor Aragão, 1908, Bothriocroton oudemansi (Neumann, 1910), Bothriocroton tachyglossi (Roberts, 1953), Dermacentor abaensis Teng, 1963, Dermacentor confragus (Schulze 1933), Dermacentor ushakovae Filippova and Panova, 1987, Haemaphysalis anomaloceraea Teng, 1984, Haemaphysalis filippovae Bolotin, 1979, Haemaphysalis pavlovskyi Pospelova-Shtrom, 1935, Hyalomma excavatum Koch, 1844, Hyalomma isaaci Sharif, 1928, Hyalomma rufipes Koch, 1844, Hyalomma turanicum Pomerantzev, 1946, Ixodes arabukiensis Arthur, 1959, Ixodes boliviensis Neumann, 1904, Ixodes columnae Takada and Fujita, 1992, Ixodes maslovi Emel'yanova and Kozlovskaya, 1967, Ixodes sachalinensis Filippova, 1971, Ixodes siamensis Kitaoka and Suzuki, 1983, Ixodes sigelos Keirans, Clifford and Corwin, 1976, Ixodes succineus Weidner, 1964, Rhipicephalus aurantiacus Neumann, 1907, Rhipicephalus cliffordi Morel, 1965, Rhipicephalus pilans Schulze, 1935, Rhipicephalus pseudolongus Santos Dias, 1953, Rhipicephalus serranoi Santos Dias, 1950 and Rhipicephalus tetracornus Kitaoka and Suzuki, 1983.

A total of 4803 domestic and wild animals which were presented for examination at a veterinary clinic in north Baden, Germany over a period of 1 year were examined for tick infestation. A total of 434 nymphal and adult ticks were collected from 175 hosts. Ticks found belonged to the species Ixodes ricinus (385), Ixodes hexagonus (48), and Ixodes ventalloi (one). The polymerase chain reaction was used to examine 132 I. ricinus and 21 I. hexagonus for the presence of Borrelia burgdorferi. Twenty-two per cent of adult I. ricinus were infected as were one female and one larval I. hexagonus.

Human infection with Borrelia burgdorferi, the causative agent of Lyme disease, is unusually common in the "Scheelkopf" area of the town Bruchsal in north Baden (Germany), a situation which has led to considerable publicity and public concern. This study was carried out in order to clarify this situation by determining the prevalence of B. burgdorferi in both the free-living tick populations (Ixodes ricinus) and the rodent population from the "Scheelkopf" as well as from surrounding control areas. The polymerase chain reaction (PCR) was used to determine the presence of infection in whole tick preparations and in mouse bladders. The prevalence of B. burgdorferi in freeland ticks ranged from 19% to 44% and in mice from 6% to 29% depending on the area studied. The "Scheelkopf", with prevalences for ticks and mice of 33% and 10% respectively, was not significantly different from the control areas. Our results indicate that there is a high risk of human infection throughout the study area. This is probably related to the intensive use of the area for gardens and the related recreational behaviour of the human population in conjunction with the high rate of infection prevailing in I. ricinus.

A total of 1,640 stomach contents from 56 South African species of small and medium sized mammals were examined for ticks. Only six ticks were found in three specimens of the caracal Felis caracal. Although identification of the tick species was not possible owing to fragmentation and partial digestion, the genus Haemaphysalis was represented in four of these cases. We conclude that predation by small and medium sized mammals on ticks is uncommon in South Africa.

Goats acquired resistance to larvae of Amblyomma hebraeum following three repeated infestations. Resistance was associated with immediate Type I hypersensitivity reactions following intradermal skin tests using crude egg extracts. In a separate experiment, the inoculation of tick-naive goats with extracts of the larvae of A. hebraeum failed to induce observable effects on feeding larvae despite the development of anti-larval antibodies.

Three infestations of restrained Jersey and Friesland bull calves with adult Amblyomma hebraeum did not affect the rate of engorgement of female ticks and resulted in an insignificant decline in the mean engorgement weight of female ticks recovered from the Friesland group. Repeated infestations significantly affected the egg-laying capacity of engorged female ticks recovered from both groups of hosts. The Friesland calves manifested an enhanced resistance to the larvae and nymphs of Amblyomma hebraeum resulting in prolonged attachment, and a significant decline in engorgement rate of these instars compared with the Jersey group. Skin reaction tests using crude tick extracts yielded antigen-specific hypersensitivity reactions which were not related to resistance to A. hebraeum. Histological changes at the attachment site associated with tick rejection are discussed in relation to host resistance mechanisms.

The ratio of variance to mean (s2/means) of numbers of Ixodes rubicundus (males and females) per sheep was used as a measure of the dispersion pattern of this tick within a naturally infested population of sheep. Sheep were divided into two groups, one with previous contact with I. rubicundus and the other with no previous contact. Samples of 10 sheep from each group were searched for ticks on a weekly basis for 19 weeks during the winter of 1986. In each group, both male and female ticks had an s2/means ratio greater than 1 for the majority of observation periods indicating an aggregated dispersion pattern. The degree of aggregation was greater with increasing density of the ticks. The implications of these results are discussed both in relation to sampling procedures and potential control strategies.

A comparison of attachment, engorgement and moulting success of Amblyomma hebraeum larvae fed on domestic chickens and Himalayan giant white rabbits indicates that chickens are better hosts than the rabbits. Moreover the time needed for detachment of all engorged larvae is significantly less for chickens than for the rabbits. No evidence of induced immunity was found in chickens on re-infestation with larvae of A. hebraeum.

The success of natural infestations of various life history stages of Amblyomma hebraeum and Amblyomma marmoreum on the leopard tortoise, Geochelone pardalis, was compared. Success was measured by the time taken for ticks to detach, as well as the percentage of ticks engorging and subsequently either moulting to the next life history stage or laying viable eggs. Larvae of A. hebraeum were the only developmental stage not recovered. Nymphae and female A. hebraeum were less successful in moulting or laying eggs than the corresponding stages of A. marmoreum. Nevertheless, 48,7% of A. hebraeum nymphae moulted, while 1 of 6 females laid viable eggs.

Striped mice, Rhabdomys pumilio, were trapped over a 17 month period in the Thomas Baines Nature Reserve in the eastern Cape Province of South Africa. Captured mice were placed in cages, over water, and naturally detaching ticks were collected. Only 5 larvae and 1 nymph of Amblyomma hebraeum were recovered from the mice. These represented less than 0.1% of the total number of ticks recovered. No Amblyomma marmoreum were recovered. As the vegetation and large mammals and tortoises in the Thomas Baines Nature Reserve abound in larvae of both these vectors of heartwater the low infestation rates of R. pumilio indicate that it is either unsuitable or inaccessible for these ticks. R. pumilio is therefore unlikely to play a role in the epidemiology of heartwater.

Large numbers of birds, wild mammals and domestic stock from a variety of localities within the Republic of South Africa were examined for infestation with the ixodid ticks Amblyomma hebraeum and Amblyomma marmoreum. Every warthog (Phacochoerus aethiopicus), Burchell's zebra (Equus burchelli), impala (Aepyceros melampus) and kudu (Tragelaphus strepsiceros) from the Kruger National Park in the north-eastern Transvaal Lowveld was infested with A. hebraeum. In the eastern Cape Province every helmeted guinea fowl (Numida meleagris), scrub hare (Lepus saxatilis) and kudu from the Andries Vosloo Kudu Reserve; all but 1 of the 22 domestic cattle examined on the farm "Bucklands"; and all Angora goats plus nearly all Boer goats examined on the farm "Brakhill" were infested with this tick. Most animals examined appeared to be good hosts of the immature stages, and the larger the host species the greater the chances of it harbouring large numbers of adult ticks. The largest animals examined, such as eland, buffalo, giraffe and rhinoceros, harboured very large numbers of adult A. hebraeum. No adult A. marmoreum was recovered from any host. However, 50% or more of helmeted guinea fowl and kudu from the Andries Vosloo Kudu Reserve; helmeted guinea fowl, scrub hares and eland (Taurotragus oryx) from the Mountain Zebra National Park; helmeted guinea fowl, kudu, domestic sheep, goats and cattle on the farm "Bucklands", and caracal (Felis caracal) from the Cradock and Southwell areas of the eastern Cape Province were infested with immature A. marmoreum. In the Bontebok National Park in the south-western Cape Province more than 35% of scrub hares, vaal ribbok (Pelea capreolus) and bontebok (Damaliscus dorcas dorcas) were infested with immature ticks.

The weights of feeding female Ixodes rubicundus attaching to sheep was studied in a natural focus of Karoo paralysis. The studies showed fewer females in the middle weight ranges and more in the heavier and lighter categories than would be expected if the distribution was normal. Weights were also strongly skewed towards the lighter females between 0 and 400 mg. No differences in the pattern of attachment weights occurred over the four experimental groups used, suggesting that previous contact of sheep with I. rubicundus had no effect on the ability of the tick to engorge.

The accuracy of a general and a specific method of collecting and counting ixodid ticks on live hosts was compared with that of a destructive technique which can only be applied to dead animals. Destructive sampling provided considerably more accurate results than either of the live sampling methods when applied to domestic goats (Capra hircus) and a duiker (Sylvicapra grimmia). The smaller the life stage and the tick species the less likely it is that it will be recovered by either of the live sampling techniques. Both live and destructive sampling yielded similar results for adult Amblyomma hebraeum, a large tick. A sub-sampling method, used to estimate larval numbers, was repeatable and an accurate predictor of population size for populations ranging from 50 to 1000 of unengorged A. hebraeum larvae.

Male Ixodes rubicundus were found in copula with attached females in 59% of individuals. The number of males attaching to the female integument or to the the host negligible. In laboratory experiments, males enclosed with females in a small vial had significantly longer life spans than solitary males. Paired males were found to be in copula on 20-34% of observations. Solitary males lost weight while paired males gained weight over a 2-day period. However, the specific energy content of the 2 groups remained constant.

The hosts, sites of attachment, life cycle, habitat requirements and seasonal abundance of Amblyomma astrion, Amblyomma cohaerens, Amblyomma gemma, Amblyomma hebraeum, Amblyomma lepidum, Amblyomma marmoreum, Amblyomma pomposum, Amblyomma sparsum, Amblyomma tholloni and Amblyomma variegatum, the 10 potential vectors of heartwater in Africa, are listed. Factors influencing the distribution and abundance of the ticks as well as interactions with other species and the role of predators and pathogens are discussed.