Carios kelleyi (Acari: Ixodida: Argasidae) Infected With Rickettsial Agents Documented Infesting Housing in Kansas, United States.

During September-December 2018, 25 live ticks were collected on-post at Fort Leavenworth, Kansas, in a home with a history of bat occupancy. Nine ticks were sent to the Army Public Health Center Tick-Borne Disease Laboratory and were identified as Carios kelleyi (Cooley and Kohls, 1941), a species that seldom bites humans but that may search for other sources of blood meals, including humans, when bats are removed from human dwellings. The ticks were tested for numerous agents of human disease. Rickettsia lusitaniae was identified by multilocus sequence typing to be present in two ticks, marking the first detection of this Rickettsia agent in the United States and in this species of tick. Two other Rickettsia spp. were also detected, including an endosymbiont previously associated with C. kelleyi and a possible novel Rickettsia species. The potential roles of C. kelleyi and bats in peridomestic Rickettsia transmission cycles warrant further investigation.

Nuclear (18S-28S rRNA) and mitochondrial genome markers of Carios (Carios) vespertilionis (Argasidae) support Carios Latreille, 1796 as a lineage embedded in the Ornithodorinae: re-classification of the Carios sensu Klompen and Oliver (1993) clade into its respective subgenera.

Argasid systematics remains controversial with widespread adherence to the Hoogstraal (1985) classification scheme, even though it does not reflect evolutionary relationships and results in paraphyly for the main genera of soft ticks (Argasidae), namely Argas and Ornithodoros. The alternative classification scheme, proposed by Klompen and Oliver (1993), has problems of its own: most notably paraphyly of the subgenus Pavlovskyella and the controversial grouping together of the subgenera Alectorobius, Antricola, Carios, Chiropterargas, Nothoaspis, Parantricola, Reticulinasus and Subparmatus into the genus Carios. Recent phylogenetic analyses of 18S/28S rRNA sequences and mitochondrial genomes agree with the scheme of Klompen and Oliver (1993), with regard to the paraphyly of Pavlovskyella, placement of Alveonasus, Ogadenus, Proknekalia and Secretargas in the Argasinae and placement of Carios and Chiropterargas in the Ornithodorinae (Mans et al., 2019). The Carios clade and its constituent subgenera remain controversial, since the phylogenetic position of its type species Carios (Carios) vespertilionis Latreille, 1796 (formerly Argas vespertilionis) has not been determined with confidence. The current study aimed to resolve Carios sensu lato Klompen and Oliver, 1993, and Carios sensu stricto Hoogstraal, 1985, by determining and analysing phylogenetic nuclear and mitochondrial markers for C. (C.) vespertilionis. Both the nuclear and mitochondrial markers support placement of Carios s.s. within the subfamily Ornithodorinae, but to the exclusion of the clade that includes the 6 other subgenera that are part of Carios s.l. Klompen and Oliver (1993), namely Alectorobius, Antricola, Nothoaspis, Parantricola, Reticulinasus and Subparmatus. These 6 subgenera form a monophyletic clade that might be placed as new subgenera within the genus Alectorobius, or elevated to genera. Given the substantial differences in biology among these subgenera, we propose that these 6 subgenera be elevated to genera. Thus, we propose to modify the classification scheme of Mans et al. (2019) so that the subfamily Argasinae now has six genera, Alveonasus, Argas (subgenera Argas and Persicargas), Navis, Ogadenus, Proknekalia and Secretargas, and the subfamily Ornithodorinae has nine genera, Alectorobius, Antricola (subgenera Antricola and Parantricola), Carios, Chiropterargas, Nothoaspis, Ornithodoros (subgenera Microargas, Ornamentum, Ornithodoros, Pavlovskyella and Theriodoros), Otobius, Reticulinasus and Subparmatus (genera indicated in bold).

Tick-borne pathogens in dogs, wild small mammals and their ectoparasites in the semi-arid Caatinga biome, northeastern Brazil.

Caatinga is a biome exclusive to the semiarid zone of Brazil, where studies on ticks and tick-borne diseases are scarce. Herein, we investigated the occurrence of Rickettsia, Ehrlichia, and Coxiella in wild mammals, domestic dogs and their ectoparasites using molecular and serological techniques. During 2014-2016, blood samples and ectoparasites were collected from 70 small mammals (51 rodents, 18 marsupials, 1 wild canid) and 147 domestic dogs in three areas of the Caatinga. Through serological analyses of domestic dogs of the three areas, 8 to 11 % were seropositive for Rickettsia rickettsii, 9 to 37 % for Rickettsia amblyommatis, 61 to 75 % for Ehrlichia canis, and 0-5% for Coxiella burnetii. All wild mammals were seronegative for Rickettsia spp. and C. burnetii, except for one rodent (Wiedomys pyrrhorhinos) and one marsupial (Didelphis albiventris) that were seroreactive to C. burnetii, one wild canid (Cerdocyon thous) for R. amblyommatis, and two Rattus rattus for Rickettsia spp. Through PCR targeting DNA of Rickettsia, Ehrlichia or Coxiella, all blood samples were negative, except for the presence of Ehrlichia canis DNA in 8.8 % of the domestic dogs, and a recently reported novel agent, Ehrlichia sp. strain Natal, in one marsupial (Gracilinanus agilis). A total of 222 ticks, 84 fleas, and six lice were collected. Ticks were mostly Rhipicephalus sanguineus sensu lato, some Ixodes loricatus, Ornithodoros rietcorreai, Haemaphysalis sp., and Amblyomma spp.; fleas were Ctenocephalides felis felis, Pulex sp. and Polygenis (Polygenis) bohlsi jordani; and lice were Polyplax sp. and Gyropus sp. Through molecular detection of microorganisms, 9% of C. felis felis contained Rickettsia felis, 20 % of A. auricularium contained R. amblyommatis and 13 % of A. parvum contained 'Candidatus Rickettsia andeanae', whereas Ehrlichia canis DNA was detected in at least 6% of the R. sanguineus s.l. from one area. We report a variety of ectoparasites infesting small mammals and domestic dogs in the Caatinga biome, where these ectoparasites probably act as vectors of rickettsiae, ehrlichial agents (E. canis and Ehrlichia sp. strain Natal) and C. burnetii. Our results highlight to the potential risks of human infection by these tick-borne agents in the Caatinga biome.

Molecular detection of vector-borne bacteria in bat ticks (Acari: Ixodidae, Argasidae) from eight countries of the Old and New Worlds.

BACKGROUND: Despite the increasingly recognized eco-epidemiological significance of bats, data from molecular analyses of vector-borne bacteria in bat ectoparasites are lacking from several regions of the Old and New Worlds. METHODS: During this study, six species of ticks (630 specimens) were collected from bats in Hungary, Romania, Italy, Kenya, South Africa, China, Vietnam and Mexico. DNA was extracted from these ticks and analyzed for vector-borne bacteria with real-time PCRs (screening), as well as conventional PCRs and sequencing (for pathogen identification), based on the amplification of various genetic markers. RESULTS: In the screening assays, Rickettsia DNA was only detected in bat soft ticks, whereas Anaplasma phagocytophilum and haemoplasma DNA were present exclusively in hard ticks. Bartonella DNA was significantly more frequently amplified from hard ticks than from soft ticks of bats. In addition to Rickettsia helvetica detected by a species-specific PCR, sequencing identified four Rickettsia species in soft ticks, including a Rickettsia africae-like genotype (in association with a bat species, which is not known to migrate to Africa), three haemotropic Mycoplasma genotypes in Ixodes simplex, and Bartonella genotypes in I. ariadnae and I. vespertilionis. CONCLUSIONS: Rickettsiae (from both the spotted fever and the R. felis groups) appear to be associated with soft rather than hard ticks of bats, as opposed to bartonellae. Two tick-borne zoonotic pathogens (R. helvetica and A. phagocytophilum) have been detected for the first time in bat ticks. The present findings add Asia (China) to the geographical range of R. lusitaniae, as well as indicate the occurrence of R. hoogstraalii in South Africa. This is also the first molecular evidence for the autochthonous occurrence of a R. africae-like genotype in Europe. Bat haemoplasmas, which are closely related to haemoplasmas previously identified in bats in Spain and to "Candidatus Mycoplasma haemohominis", are reported here for the first time from Central Europe and from any bat tick.

New records of ticks infesting bats in Brazil, with observations on the first nymphal stage of Ornithodoros hasei.

In Brazil, at least 14 species of soft ticks (Argasidae) are associated with bats. While Ornithodoros hasei seems to be abundant among foliage-roosting bats, other groups of ticks are found exclusively inside caves. In this paper, noteworthy records of soft ticks infesting bats are documented in new localities from Bahia, Pernambuco, Piauí, and Rondônia states. Out of 201 bats examined, 25 were infested by 152 ticks belonging to seven taxa: Ornithodoros cavernicolous, O. hasei, Ornithodoros marinkellei, Ornithodoros cf. fonsecai, Ornithodoros cf. clarki, Antricola sp., and Nothoaspis amazoniensis. These findings provide new insights into the geographical distribution and host association of soft ticks occurring in the Neotropical region. Remarkably, morphological and biological observations about O. hasei are inferred based on the examination of on-host-collected first stage nymphs.

First report of spinose ear tick, Otobius megnini (Acari, Argasidae), in Sweden.

A dog that had travelled to Sweden was inspected by a veterinarian. In one ear canal a tick was found. It was later identified as a spinose ear tick, Otobius megnini. In this case report we also review the previously known reports of O. megnini in Europe and the recent introduction and spread in Turkey.

Ixodoidea of the Western Palaearctic: A review of available literature for identification of species.

We aim to produce a review of the most important literature references necessary for the identification of ticks of the families Ixodidae and Argasidae in Europe and northern Africa (i.e. the Western Palaearctic region). The purpose of this paper is to pinpoint a set of critically selected papers that contain reliable information on morphology, taxonomic keys, and comparative discussions which are critical for the identification of the ticks reported in the target region. When necessary, comments are provided on the systematic position of a species, or on suitable papers already addressing the issue. This review includes a list of 216 references which cover all Ixodoidea species reported as permanent residents of the Western Palaearctic, namely 28 species of the genus Ixodes, two Dermacentor, seven Haemaphysalis, nine Hyalomma, eight Rhipicephalus, five Argas and about seven species of Ornithodoros.

Life cycle of Spinose ear tick, Otobius megnini (Acari: Argasidae) infesting the race horses in Nuwara Eliya, Sri Lanka.

Otobius megnini infests mainly domesticated and wild animals and occasionally humans. It has been identified as an agent of human and horse otoacariasis in Sri Lanka. The number of nymphal stages in the life cycle of O. megnini varies from one to three in different geographic regions. The present study determined the life cycle of O. megnini infesting the racehorses in Nuwara Eliya. A tick colony was initiated from fully engorged nymphs collected from horses and maintained at 10°C, 22°C and 28°C. Immature stages were reared on New Zealand rabbits. Only the larvae weighing more than 0.9mg (84.9%) moulted to nymphs with a pre-moulting period of 5.6(±1.7) days. None of the larvae maintained at 10±1°C moulted. Larval survival was significantly higher at 28±1°C (44.2±4.3days) than at 22±1°C (35.6±9days). At 28±1°C, majority of nymphs (95.6%) weighing over 10mg moulted into adults within 12.5(±3.1) days. Nymphs kept at 10±1°C underwent diapause for 81.1(±72.0) days. Larger females (>13mg; 93.0%) laid eggs for of 44.6(±17.8) days with a mean pre-oviposition period of 10.3(±5.1) days. Females survived longer (369.8±128.3days) than males (210.4±54.1days; Student's t-test; t=5.9, p=0.001). Some females laid eggs without mating. Otobius megnini successfully completed the life cycle within 123days and has only one nymphal instar similar to the Neotropical population. Currently, O. megnini infestation is a serious problem to horses in the Nuwara Eliya racecourse and may pose a risk of spreading to dairy farms close by owing to its dynamic nature of the life cycle.

Seasonal dynamics of spinose ear tick Otobius megnini associated with horse otoacariasis in Sri Lanka.

Otobius megnini is a one host, nidicolous soft tick (Family Argasidae) whose larvae and nymphs parasitize the external ear canal of many wild and domestic animals and occasionally humans. The present study was conducted to determine the seasonal dynamics of O. megnini infesting stabled horses in Nuwara Eliya racecourses. Ticks were sampled biweekly for two years from May 2013 to May 2015 from the ear canal of seven thoroughbred male horses. Weather data: temperature, rainfall and humidity for the study period were obtained from the Meteorological Department, Colombo. A total of 23, 287 ticks of O. megnini were collected from the ear canal of horses and all of which were immature stages comprising 41.4% larvae and 59.6% nymphs. Larval counts were high during warmer months of the year with minimum numbers recording September-November. High larval abundance may be due to the high hatching rate of eggs at high temperatures. Larval abundance was significantly affected by maximum temperature, minimum relative humidity and average relative humidity (Multiple regression; r(2)=0.5, F=3.7, p=0.01). Population peaks for nymphs occurred in May, October and January. Nymph counts were low in March and April. Weather conditions did not have any correlation with the abundance of nymphs. Rainfall had no effect on both larvae and nymph counts. Even though control measures have been taken, O. megnini infestation is a serious problem for the stable owners especially because these horses are used in racing and other recreational purposes. Further, there is a high risk of spreading this tick within the country due to the presence of suitable hosts and the adaptability of the tick to survive in changing climatic conditions. Information on the seasonal dynamics of the tick population is important for employing control measures.

Insects found in birds' nests from Argentina. Pseudoseisura lophotes Reichenbach, 1853 and Anumbius annumbi (Vieillot, 1817) (Aves: Furnariidae), hosts of Triatoma platensis Neiva, 1913 (Hemiptera: Reduviidae: Triatominae).

The insect fauna of the nests of Pseudoseisura lophotes (Reichenbach, 1853) (Aves: Furnariidae) from Argentina was investigated. A total of 110 species (68 identified to species, 22 identified to genus, 20 identified to family) in 40 families of 10 orders of insects was found in these nests. Triatoma platensis Neiva, 1913 (Hemiptera: Reduviidae) was found again in nests of P. lophotes, corroborating after 73 years the first observations made by Mazza in 1936. The occurrence of the insects in nests of P. lophotes is compared with the previously known insect fauna in nests of A. annumbi, Furnarius rufus (Furnariidae), and Myiopsitta monachus (Psittacidae). The insect fauna in additional nests of Anumbius annumbi from the same and/or different localities is given, and used in comparisons. The first occurrence of Cuterebridae (Diptera) in birds' nests, their pupae as the overwintering stage, and the second simultaneous infestation by two species of Philornis (Diptera: Muscidae) on the same nestlings are presented. Other simultaneous infestations of different hematophagous arthropods (Hemiptera: Cimidae; Reduviidae: Triatominae, and Acari: Argasidae) are remarked and discussed.

Immature argasid ticks: diagnosis and keys for neotropical region / Carrapatos argasídeos imaturos: diagnoses e chaves para a região neotropical

Many argasid tick species are known only through their larval descriptions, in which the chaetotaxy, together with other external morphological characteristics, has been used to separate genera and species. However, the illustrations of these features are based on optical microscopy alone and many of these features are not clearly defined. Because of the difficulties in determining the larval and nymph stages of some genera, we have prepared illustrated keys for the immature stages of argasids, including an up-to-date list of the known species of the Neotropical region. We have also included an illustrated key for larvae of the Ornithodoros species from Brazil, based on scanning electron microscopy.

Muitos carrapatos argasídeos são conhecidos somente por descrições larvais, nas quais a quetotaxia associada a outros caracteres morfológicos tem sido usada para separar gêneros e espécies. No entanto, as ilustrações sobre esses caracteres são baseadas somente em microscopia óptica e muitos deles não estão claramente definidos. Devido às dificuldades em determinar estágios larvais e ninfais de alguns gêneros, elaboramos chaves ilustradas para os estágios imaturos de argasídeos, incluindo uma lista atualizada de espécies conhecidas da região Neotropical. Incluímos também uma chave ilustrada para larvas das espécies de Ornithodoros do Brasil baseada em microscopia eletrônica de varredura.

Ornithodoros guaporensis (Acari, Ixodida: Argasidae), a new tick species from the Guapore River Basin in the Bolivian Amazon.

The soft tick Ornithodoros guaporensis n. sp. (Acari: Ixodida: Argasidae) is described from larvae and adults. Morphological analysis and 16S rDNA sequences are provided. Adults were collected from a rocky fissure inhabited by bats located in the Amazonian forest in north-eastern Bolivia (Beni Department) close to the Guapord River. Larvae were obtained from eggs laid by females collected in the field, and which were fed on rabbits in the laboratory. Larvae of O. guaporensis are morphologically closely related to Ornithodoros rioplatensis, Ornithodoros puertoricensis and Ornithodoros talaje. Larvae of O. guaporensis and O. rioplatensis can be separated from O. puertoricensis and O. talaje by the number of pairs of dorsal setae (20 in O. guaporensis and O. rioplatensis, 18 in O. puertoricensis and 17 in O. talaje). Larvae of O. guaporensis and O. rioplatensis can be differentiated by the medial dental formula (2/2 in O. guaporensis and 3/3 in O. rioplatensis) and the apex of the hypostome, which is more pointed in O. rioplatensis than in O. guaporensis. The Principal Component Analysis performed with morphometric characters of larvae showed a clear separation among O. guaporensis, O. rioplatensis, O. puertoricensis and O. talaje. Significant morphological differences among adults of these four species were not found. The analysis of the 16S rDNA sequences allowed for the differentiation between O. guaporensis and the remaining Neotropical species of the family Argasidae.

Immature argasid ticks: diagnosis and keys for Neotropical region.

Many argasid tick species are known only through their larval descriptions, in which the chaetotaxy, together with other external morphological characteristics, has been used to separate genera and species. However, the illustrations of these features are based on optical microscopy alone and many of these features are not clearly defined. Because of the difficulties in determining the larval and nymph stages of some genera, we have prepared illustrated keys for the immature stages of argasids, including an up-to-date list of the known species of the Neotropical region. We have also included an illustrated key for larvae of the Ornithodoros species from Brazil, based on scanning electron microscopy.

Developmental changes in salivary glands of nymphs and adults of the spinose ear tick Otobius megnini.

Otobius megnini has an autogenous 1 host life cycle, where larvae and nymphs stay attached inside the ear canal for long periods, but the adult tick is free living and can lay several egg batches without feeding. In order to obtain information about anatomical structures involved in this particular life cycle, nymphs and adults of O. megnini were dissected and salivary gland images were obtained in situ with the use of scanning electronic microscopy. Measurements of salivary alveoli were obtained with the use of ImageJ 1.40 g software. In the nymphs, the Type I alveoli are relatively small (mean diameter: 19.6 µm) compared with those of the adults (mean: 43.4 µm) and other soft ticks in the literature. Type II alveoli in nymphs are similar (mean: 82.6 µm) to previously described alveoli in adult soft ticks. In contrast, the adults of O. megnini Type II alveoli are smaller (mean: 36.8 µm) and have a wrinkled surface. These findings provide more evidence that Type I alveoli take part in absorption of moisture during the free-living tick stages.

Argasid and spinturnicid mite load on swarming bats in the Tatra Mountains, Poland.

Altogether 445 bats, representing nine species, caught during swarming in the Lodowa Cave in Mount Ciemniak, Western Tatra Mountains, southern Poland, were examined for ectoparasitic mites. In total, 259 spinturnicid (Spinturnix mystacina, S. andegavinus, S. kolenatii, S. plecotinus and S. myoti) and 95 argasid (Carios vespertilionis) mites were collected from seven bat species, Myotis myotis, M. mystacinus, M. brandtii, M. daubentonii, Eptesicus nilssonii, Plecotus auritus, and Vespertilio murinus. There were sex-based differences in the prevalence of mites in some hosts but no differences in their mean intensity and there was no observed relationship between the number of mites and the condition of the bats. The prevalence of mites differed significantly between years in E. nilssonii. The results suggested a very low mite load on swarming bats that had no impact on the body condition of bats.

Developmental biology of Argas neghmei Kohls & Hoogstraal (Acari: Argasidae) under laboratory conditions.

In order to describe the developmental biology of the tick Argas neghmei Kohls & Hoogstraal under laboratory conditions, 40 females and 40 males were collected from chicken coops located in Calama (II Region, Chile). They were fed on chickens and maintained under two laboratory conditions: one group at 30 +/- 5 degrees C and 35 +/- 5 % RH and another at 27 +/- 5 degrees C and 80 +/- 5 % RH, both at 12: 12 h L:D photoperiod. The ticks were observed daily to determine larval feeding periods, preoviposition, oviposition, egg incubation as well as the frequency of egg laying, number of eggs laid, and percentage of larval hatching. Females did not lay eggs at 80 +/- 5% RH, and data on the biology of this tick was obtained only at 35 +/- 5% RH. The life cycle of A. neghmei lasted an average of 269 days. Feeding period of each nymphal stage as well as of adult females between oviposition events lasted less than a day. Females laid on average 1.8 egg batches and egg-laying period lasted on average 14 days, during which about 96 eggs were laid per female.

Developmental biology of Argas neghmei Kohls & Hoogstraal (Acari: Argasidae) under laboratory conditions

In order to describe the developmental biology of the tick Argas neghmei Kohls & Hoogstraal under laboratory conditions, 40 females and 40 males were collected from chicken coops located in Calama (II Region, Chile). They were fed on chickens and maintained under two laboratory conditions: one group at 30 ± 5 ºC and 35 ± 5 percent RH and another at 27 ± 5 ºC and 80 ± 5 percent RH, both at 12: 12 h L:D photoperiod. The ticks were observed daily to determine larval feeding periods, preoviposition, oviposition, egg incubation as well as the frequency of egg laying, number of eggs laid, and percentage of larval hatching. Females did not lay eggs at 80 ± 5 percent RH, and data on the biology of this tick was obtained only at 35 ± 5 percent RH. The life cycle of A. neghmei lasted an average of 269 days. Feeding period of each nymphal stage as well as of adult females between oviposition events lasted less than a day. Females laid on average 1.8 egg batches and egg-laying period lasted on average 14 days, during which about 96 eggs were laid per female.

Biological and ecological characteristics of soft ticks (Ixodida: Argasidae) and their impact for predicting tick and associated disease distribution.

As evidence of global changes is accumulating, scientists are challenged to detect distribution changes of vectors, reservoirs and pathogens caused by anthropogenic and/or environmental changes. Statistical and mathematical distribution models are emerging for ixodid hard ticks whereas no prediction has ever been developed for argasid ones. These last organisms remain unknown and under-reported; they differ from hard ticks by many structural, biological and ecological properties, which complicate direct adaptation of hard tick models. However, investigations on bibliographic resources concerning these ticks suggest that distribution modelling based on natural niche concept and using environmental factors especially climate is also possible, bearing in mind the scale of prediction and their specificities including their nidicolous lifestyle, an indiscriminate host feeding and a short bloodmeal duration, as well as a flexible development cycle through diapause periods.

Ectoparasites in an urban population of big brown bats (Eptesicus fuscus) in Colorado.

Ectoparasites of an urban population of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado, were investigated during summers 2002, 2003, and 2004. Eleven species of ectoparasites were found (the macronyssid mite Steatonyssus occidentalis, the wing mite Spinturnix bakeri, the myobiid mites Acanthophthirius caudata and Pteracarus aculeus, the chirodiscid mite Alabidocarpus eptesicus, the demodicid mite Demodex sp., the chigger Leptotrombidium myotis, the soft tick Carios kelleyi, the batfly Basilia forcipata, the batbug Cimex pilosellus, and the flea Myodopsylla borealis). Five species were analyzed by prevalence and intensity (C. pilosellus, M. borealis, L. myotis, S. bakeri, and S. occidentalis) based on 2161 counts of 1702 marked individual bats over the 3 summer study periods. We investigated 4 factors potentially influencing prevalence and intensity: age class of the host, reproductive status of adult female hosts, roosts in which the hosts were found, and abiotic conditions during the year sampled. The macronyssid mite, S. occidentalis, was the most prevalent and abundant ectoparasite. Adult big brown bats had more ectoparasites than volant juveniles for most of the species analyzed. In a sample of known age bats at 1 large colony, bats of 4 yr of age or greater had higher ectoparasite loads of S. occidentalis and S. bakeri when compared with younger bats. Lactating female bats had the highest prevalence and intensities of most ectoparasites. Annual differences in ectoparasite prevalence and intensity were related to temperature and humidity, which can affect the nidicolous species of ectoparasites. Residents of 2 buildings sprayed insecticides in response to Cimex sp., and this appeared to reduce ectoparasitism of S. occidentalis and C. pilosellus present at these buildings. Intensity of S. occidentalis had no influence on annual survival of big brown bats.

First record of hosts for tick Carios kelleyi (Acari: Ixodida: Argasidae) in Canada and Montana.

I found Carios kelleyi Cooley & Kohls (formerly Ornithodoros kelleyi) (Acari: Ixodida: Argasidae) on five species of bats (Eptesicusfuscus, Myotis lucifugus, Myotis ciliolabrum, Myotis evotis, and Myotis volans) in the prairies of southeastern Alberta and north central Montana. This is the first occurrence of ticks on bats in Canada. This is also the first record of C. kelleyi on M. evotis and M. volans. Dates of parasitization ranged from 22 May to 17 October, and the number of ticks per host ranged from 1 to 44 (median two ticks per host). Number of parasitized individuals was significantly higher in rock-roosting E. fuscus compared with building-roosting E. fuscus, rock- and building-roosting M. lucifugus, and rock-roosting M. ciliolabrum and M. evotis. A significant sex bias was noted in rock-roosting E. fuscus in 2000 with significantly more females parasitized. The number of ticks per bat host was highest in 2001, corresponding to the driest and hottest summer of the survey.