Detection of tick-borne bacteria and babesia with zoonotic potential in Argas (Carios) vespertilionis (Latreille, 1802) ticks from British bats

Molecular detection of Ehrlichia Sp. in bat-associated chigger mites (trombidiformes: leeuwenhoekiidae and trombiculidae S. s.) from Brazil

Chigger mite larvae are well adapted parasites, mainly of vertebrates, and can play a role as potential vectors for pathogens, as is the case of the bacteria Orientia tsutsugamushi. In Brazil, 63 species of chiggers have been cataloged, eight of which were found parasitizing bats. Until now, no studies have monitored pathogens of bat-associated chigger species in the Americas. Here, we provide information about the detection of Ehrlichia sp. (16S rRNA gene) in Perissopalla ipeani Brennan larvae collected parasitizing the bat species Carollia perspicillata in Brazil.

Molecular Survey of Anaplasmataceae Agents, Rickettsia spp., Bartonella spp., and Piroplasmids in Ectoparasites from Cave-Dwelling Bats in Mainland Portugal

Bats and their ectoparasites play a crucial role in understanding the ecology and transmission of vector-borne pathogens, yet these dynamics remain poorly studied in Portugal. This study aimed to investigate the molecular occurrence of vector-borne bacteria (Anaplasma spp., Bartonella spp., Ehrlichia spp., and Rickettsia spp.) and protozoa (Babesia spp. and Theileria spp.) in ectoparasites of cave-dwelling bats. Bats were sampled from two caves in Portugal, and their ectoparasites included wing mites (Spinturnix myoti), ticks (Ixodes simplex), and bat flies (Penicillidia conspicua and Nycteribia schmidlii). Molecular analyses revealed the presence of Bartonella spp. in S. myoti and N. schmidlii. Phylogenetic inference based on the gltA gene positioned the detected genotypes close to those previously reported in bats and Nycteribiidae flies in Europe, Asia, and Africa. Notably, no DNA from Anaplasmataceae, Rickettsia spp., or piroplasmids was detected. The prevalence of S. myoti was high, with all examined bats being infested, showing notable differences in ectoparasite diversity concerning sex and cave-specific location. These findings suggest that host behavior, environmental conditions, and ectoparasite lifecycles play critical roles in shaping pathogen transmission dynamics. This study advances the understanding of bat ectoparasite-pathogen interactions in a region with limited data and highlights the need for continued research to assess the zoonotic potential and ecological impacts of the Bartonella genotypes detected herein.

Zoonotic Bacteria and Vector-Borne Protozoa in Troglophilus Bat Colonies in Sicily (Southern Italy): A Biomolecular Survey

Bats, as members of the order Chiroptera, are vital to ecosystems and serve as reservoirs for numerous microorganisms, some of which can cause zoonotic diseases. Human interactions with bats are increasing due to habitat alterations, making it essential to understand their microbiota, particularly potential pathogens. This study aimed to evaluate the excretion of zoonotic bacteria and protozoa in insectivorous bats from four caves in the provinces of Ragusa, Catania, and Syracuse (Sicily, Southern Italy) using molecular biology tests for zoonotic agents, including Bartonella henselae, Borrelia, Coxiella burnetii, Leptospira, Chlamydia, Rickettsia, Anaplasma, and Piroplasmids. From December 2020 to April 2023, urine, fecal swabs, ocular conjunctival swabs, and oropharyngeal swabs were collected from 149 bats of six species, along with guano samples from the caves. Bartonella henselae DNA was detected in 3 of the 149 tested bats, one ocular conjunctival swab and two oropharyngeal swabs. Chlamydia spp. DNA was detected in a sample of guano, in feces, ocular conjunctival and oropharyngeal swabs of a bat, and in four urine samples. Piroplasmid DNA was detected in 10 of 149 fecal swabs and in 5 of 16 bat ectoparasites. No samples were positive for Leptospira spp., Borrelia spp., Coxiella burnetii, Rickettsia spp., or Anaplasma spp. These findings underscore the importance of multiple sample types in assessing bats as reservoirs for zoonotic pathogens, particularly highlighting their role in transmitting pathogens through various body habitats, including saliva, urine, and ocular excretions. This study highlights the relevance of monitoring bat populations and studying their microbiota to enhance protections for both human and animal health.

Beware with the backpack! New hosts and pathogens identified for Ixodes simplex ticks collected from bats in the Iberian Peninsula

To improve the knowledge on the role of bats in the maintenance and transmission of tick-borne pathogens, a molecular approach was used to characterize Anaplasma spp., Rickettsia spp., Coxiella burnetii, Borrelia burgdorferi s.l., piroplasmids, Hepatozoon spp., flaviviruses and nairoviruses in ticks collected from Iberian bats. A total of 732 bats from 25 species were captured at 38 sampling sites distributed in seven provinces of Spain between 2018 and 2022. Seventy-nine Ixodes simplex ticks were collected from 31 bats (Eptesicus isabellinus, Hypsugo savii, Myotis capaccini, Myotis emarginatus, Myotis myotis, Miniopterus schreibersii, Pipistrellus pipistrellus and Rhinolophus ferrumequinum). Sixty of 79 I. simplex were positive for at least one pathogen tested and were collected from 23 bats captured in southeast Spain. We detected the presence of Rickettsia slovaca in 12 ticks collected from M. emarginatus, H. savii, M. schreibersii and E. isabellinus; Rickettsia aeschlimannii in 1 tick from M. schreibersii; Anaplasma ovis in 3 ticks from H. savii and M. schreibersii; C. burnetii in 2 ticks from H. savii; Occidentia massiliensis in 1 tick from H. savii; piroplasmids in 12 ticks from H. savii, M. schreibersii and E. isabellinus; and a novel nairovirus in 1 tick from M. schreibersii. Furthermore, blood samples obtained from 14 of the 31 tick-infested bats were negative in all PCR analyses. This study describes new host and pathogen associations for the bat-specialist I. simplex, highlights the risk of spread of these pathogens, and encourages further research to understand the role of Iberian bats in the epidemiology of tick-borne pathogens.

Diversity of Ehrlichia spp., Anaplasma spp. and Neorickettsia spp. in vampire bats

Although bats (Mammalia: Chiroptera) act as natural reservoirs for many zoonotic pathogens around the world, few studies have investigated the occurrence of Anaplasmataceae agents in bats, especially vampire bats. The family Anaplasmataceae (order Rickettsiales) encompasses obligate intracellular bacteria of the genera Anaplasma, Ehrlichia, Neorickettsia, Neoehrlichia, Wolbachia, and Allocryptoplasma. The present study aimed to investigate, using molecular techniques, the presence of species of Anaplasma, Ehrlichia, and Neorickettsia in vampire bats sampled in northern Brazil. Between 2017 and 2019, spleen samples were collected from vampire bats belonging to two species, Desmodus rotundus (n = 228) from the states of Pará (n = 207), Amazonas (n = 1), Roraima (n = 18) and Amapá (n = 3), and Diaemus youngii (n = 1) from Pará. Positivity rates of 5.2% (12/229), 3% (7/229), and 10.9% (25/229) were found in PCR assays for Anaplasma spp. (16S rRNA gene), Ehrlichia spp. (dsb gene) and Neorickettsia spp. (16S rRNA gene), respectively. The present study revealed, for the first time, the occurrence of Anaplasma spp. and different genotypes of Ehrlichia spp. in vampire bats from Brazil. While phylogenetic analyses based on the dsb and ftsZ genes of Ehrlichia and 16S rRNA of Anaplasma spp. revealed phylogenetic proximity of the genotypes detected in vampire bats with Anaplasmataceae agents associated with domestic ruminants, phylogenetic inferences based on the gltA and groEL genes evidenced the occurrence of genotypes apparently exclusive to bats. Neorickettsia sp. phylogenetically associated with N. risticii was also detected in vampire bats sampled in northern Brazil.

Bat ectoparasites: chigger mites (Trombiculidae), ticks (Ixodidae and Argasidae), and bugs (Cimicidae) in the Eastern Palaearctic

Nine species-level taxa of bat ectoparasites, three chigger mites (Trombiculidae), three hard (Ixodidae), and one soft tick (Argasidae) species, as well as two bug (Cimicidae) species from nine bat species hosts were detected in the Eastern Palaearctic. Trombiculid larvae of Leptotrombidium schlugerae, Leptotrombidium album, and Ascoschoengastia latyshevi were first recorded on bats in the temperate zone of eastern Russia. L. schlugerae was more abundant than A. latyshevi in the same study sites in Eastern Siberia, and the main hosts of both chigger species were Plecotus ognevi and Eptesicus nilssonii. Ixodid ticks Dermacentor marginatus, Ixodes simplex, and Ixodes sp. were sampled from bats in Kazakhstan, the Far East, and Eastern Siberia, respectively. Phylogenetic analysis based on Cox1, 16S rDNA, and ITS2 sequences of I. simplex showed that the specimens from the Far East grouped into a clade distributed in the Eastern Palaearctic and India. In turn, the specimen of Ixodes sp. from Eastern Siberia was most closely related to Ixodes soricis and Ixodes angustus with p-distance of 9.8-10.7% (Cox1), suggesting that this tick probably belongs to a new species. Argas vespertilionis larvae were collected from three widespread bat species in Kazakhstan. Two bug species, Cimex pipistrelli and Cimex aff. lectularius, were recorded in the Far East and Eastern Siberia, respectively. Specimens from Transbaikalia were morphologically identified as Cimex lectularius. However, they differed from the latter by 12.5-12.9% of Cox1 sequences, indicating that C. aff. lectularius may be a new species.

Molecular detection of Babesia vesperuginis in bats from Lithuania

Babesia vesperuginis is an intraerythrocytic protozoan parasite that circulates among bats and ticks in many countries worldwide. However, the distribution of B. vesperuginis in the Baltic region has not been studied. A total of 86 dead bats from eight different species were collected and screened for Babesia spp. using real-time PCR. Overall, 52.3% (45/86) of the bats were found positive for Babesia spp. The prevalence of Babesia spp. in different organs varied, with the highest prevalence observed in heart tissues (37.0%) and the lowest in liver tissues (22.2%). However, the observed differences in prevalence among organs were not statistically significant. Blood samples from 125 bats of nine different species were also analyzed for Babesia spp. prevalence using real-time PCR and nested PCR. The results showed a prevalence of 35.2% and 22.4%, respectively. Moreover, 28.3% (17/60) of the examined blood samples were confirmed positive for Babesia spp. through blood smear analysis. The total of 32 partial sequences of the 18S rRNA gene derived in this study were 100% identical to B. vesperuginis sequences from GenBank. In eight species of bats, Pipistrellus nathusii, Pipistrellus pipistrellus, Pipistrellus pygmaeus, Vespertilio murinus, Eptesicus nilssonii, Eptesicus serotinus, Myotis daubentonii and Nyctalus noctula, Babesia parasites were identified. In E. nilssonii, Babesia spp. was identified for the first time.

Bat-associated microbes: Opportunities and perils, an overview

The potential biotechnological uses of bat-associated bacteria are discussed briefly, indicating avenues for biotechnological applications of bat-associated microbes. The uniqueness of bats in terms of their lifestyle, genomes and molecular immunology may predispose bats to act as disease reservoirs. Molecular phylogenetic analysis has shown several instances of bats harbouring the ancestral lineages of bacterial (Bartonella), protozoal (Plasmodium, Trypanosoma cruzi) and viral (SARS-CoV2) pathogens infecting humans. Along with the transmission of viruses from bats, we also discuss the potential roles of bat-associated bacteria, fungi, and protozoan parasites in emerging diseases. Current evidence suggests that environmental changes and interactions between wildlife, livestock, and humans contribute to the spill-over of infectious agents from bats to other hosts. Domestic animals including livestock may act as intermediate amplifying hosts for bat-origin pathogens to transmit to humans. An increasing number of studies investigating bat pathogen diversity and infection dynamics have been published. However, whether or how these infectious agents are transmitted both within bat populations and to other hosts, including humans, often remains unknown. Metagenomic approaches are uncovering the dynamics and distribution of potential pathogens in bat microbiomes, which might improve the understanding of disease emergence and transmission. Here, we summarize the current knowledge on bat zoonoses of public health concern and flag the gaps in the knowledge to enable further research and allocation of resources for tackling future outbreaks.

Distribution of the soft tick Carios vespertilionis in lowlands and low mountain regions of Germany

In Germany, the knowledge about ticks infesting bats is limited, and is restricted only to a few studies, most of them dating back decades. To further improve our knowledge on ticks parasitising bats, healthy and sick bats in central Germany were examined for ticks. In total 519 larvae and one nymph of Carios vespertilionis were collected from nine bat species: Eptesicus nilssonii, Eptesicus serotinus, Myotis daubentonii, Myotis myotis, Nyctalus leisleri, Pipistrellus nathusii, Pipistrellus pygmaeus, Pipistrellus pipistrellus, and Vespertilio murinus. Either the presence of C. vespertilionis was new for some areas or it was confirmed in some federal states in central Germany. The infestation rate was mostly low (n = 1-5 larvae/bat). However, in two cases a high number of ticks was observed. The highest infestation of 97 C. vespertilionis larvae was recorded on one Parti-coloured bat (V. murinus).

Rickettsia and relapsing fever Borrelia in Alectorobius kelleyi (Ixodida: Argasidae) from peri domestic bats in the northeastern United States

The soft ticks (Argasidae) are known vectors of human and animal pathogens around the globe and are relatively understudied. Our aim was to assess the presence of Rickettsia and Borrelia bacteria in Alectorobius kelleyi (Argasidae) parasitizing synanthropic bats in the highly urbanized northeastern United States. By collaborating with parasitologists, bat scientists and wildlife rehabilitators we were successful in obtaining A. kelleyi from five states. Since Argasid larvae will attach to their hosts for many days, most A. kelleyi examined (92%) were larvae collected from sick or injured big brown bats, Eptesicus fuscus, undergoing care at rehabilitation centers. In addition, we obtained adult A. kelleyi captured in residential living areas and trapped in attics. An in-depth analysis of a A. kelleyi found to be infected with a spotted fever group Rickettsia (SFGR) revealed a dual infection with a R. belli-like taxon (ancestral group) as well as an SFGR closely related to R. peacockii, likely the same previously found in A. kelleyi from Iowa and Kansas. We found that 36% of the A. kelleyi tested carried the SFGR. Furthermore, we detected a relapsing fever spirochete, likely Candidatus Borrelia johnsonii, in 25% of the A. kelleyi from Pennsylvania. While it is unclear if these bacteria constitute a health risk to either bats or humans, our study indicates that human exposure to ectoparasites infesting peridomestic wildlife should be considered in the epidemiology of tick-borne diseases.

Trends in Bacterial Pathogens of Bats: Global Distribution and Knowledge Gaps

Bats have received considerable recent attention for infectious disease research because of their potential to host and transmit viruses, including Ebola, Hendra, Nipah, and multiple coronaviruses. These pathogens are occasionally transmitted from bats to wildlife, livestock, and to humans, directly or through other bridging (intermediate) hosts. Due to their public health relevance, zoonotic viruses are a primary focus of research attention. In contrast, other emerging pathogens of bats, such as bacteria, are vastly understudied despite their ubiquity and diversity. Here, we describe the currently known host ranges and geographic distributional patterns of potentially zoonotic bacterial genera in bats, using published presence-absence data of pathogen occurrence. We identify apparent gaps in our understanding of the distribution of these pathogens on a global scale. The most frequently detected bacterial genera in bats are Bartonella, Leptospira, and Mycoplasma. However, a wide variety of other potentially zoonotic bacterial genera are also occasionally found in bats, such as Anaplasma, Brucella, Borrelia, Coxiella, Ehrlichia, Francisella, Neorickettsia, and Rickettsia. The bat families Phyllostomidae, Vespertilionidae, and Pteropodidae are most frequently reported as hosts of bacterial pathogens; however, the presence of at least one bacterial genus was confirmed in all 15 bat families tested. On a spatial scale, molecular diagnostics of samples from 58 countries and four overseas departments and island states (French Guiana, Mayotte, New Caledonia, and Réunion Island) reported testing for at least one bacterial pathogen in bats. We also identified geographical areas that have been mostly neglected during bacterial pathogen research in bats, such as the Afrotropical region and Southern Asia. Current knowledge on the distribution of potentially zoonotic bacterial genera in bats is strongly biased by research effort towards certain taxonomic groups and geographic regions. Identifying these biases can guide future surveillance efforts, contributing to a better understanding of the ecoepidemiology of zoonotic pathogens in bats.

Substantial viral and bacterial diversity at the bat-tick interface

Ticks harbour a high diversity of viruses, bacteria and protozoa. The soft tick Carios vespertilionis (Argasidae) is a common ectoparasite of bats in the Palearctic region and is suspected to be vector and reservoir of viruses and other microbial species in bat populations, some of which may act as zoonotic agents for human disease. The Soprano pipistrelle (Pipistrellus pygmaeus, Vespertilionidae) is widely distributed in Europe, where it can be found inside or close to human habitation. We used meta-transcriptomic sequencing to determine the RNA virome and common microbiota in blood-fed C. vespertilionis ticks collected from a Soprano pipistrelle bat roosting site in south-central Sweden. Our analyses identified 16 viruses from 11 virus families, of which 15 viruses were novel. For the first time in Sweden we identified Issuk-Kul virus, a zoonotic arthropod-borne virus previously associated with outbreaks of acute febrile illness in humans. Probable bat-associated and tick-borne viruses were classified within the families Nairoviridae, Caliciviridae and Hepeviridae, while other invertebrate-associated viruses included members of the Dicistroviridae, Iflaviridae, Nodaviridae, Partitiviridae, Permutotetraviridae, Polycipiviridae and Solemoviridae. Similarly, we found abundant bacteria in C. vespertilionis, including genera with known tick-borne bacteria, such as Coxiella spp. and Rickettsia spp. These findings demonstrate the remarkable diversity of RNA viruses and bacteria present in C. vespertilionis and highlight the importance of bat-associated ectoparasite surveillance as an effective and non-invasive means to track viruses and bacteria circulating in bats and ticks.

First Records of Possibly Human Pathogenic Rickettsia Species in Bat Ticks, Carios vespertilionis, in Sweden

The Soprano pipistrelle bat, Pipistrellus pygmaeus, is a common species in large parts of Sweden. Many of its natural habitats are near human habitations. This creates opportunities for ticks infesting these bats to encounter humans and possibly transmit zoonotic pathogens by tick bites. The bats are often infested with Carios vespertilionis, a tick species that, in addition to bats, has been recorded to bite humans on occasion. This study aimed to investigate if C. vespertilionis acts as a reservoir for Anaplasma phagocytophilum, Neoehrlichia mikurensis, Tick-borne encephalitis virus, and species of Babesia and Rickettsia and to improve currently used conventional PCR protocols for molecular species determination of Rickettsia spp. Ninety-two C. vespertilionis ticks were collected from underneath a bat-box harbouring P. pygmaeus. Pathogen-specific PCR assays showed that 58.4% were positive for Rickettsia spp. and negative for the other pathogens analysed. Phylogenetic analyses indicate that the species belong to R. parkeri, R. conorii, R. slovaca, R. sibirica subsp. mongolotimonae, R. rickettsii, and a hitherto uncultured Rickettsia sp. Several of these species are considered pathogenic to humans. Given the ecology and behaviour of C. vespertilionis, it may be a vector of these rickettsiae among bats and occasionally humans. To determine the Rickettsia species with certainty, and to determine if C. vespertilionis may be a reservoir and vector of the Rickettsia spp., further studies are needed.

One Health Approach to Tick and Tick-Borne Disease Surveillance in the United Kingdom

Where ticks are found, tick-borne diseases can present a threat to human and animal health. The aetiology of many of these important diseases, including Lyme disease, bovine babesiosis, tick-borne fever and louping ill, have been known for decades whilst others have only recently been documented in the United Kingdom (UK). Further threats such as the importation of exotic ticks through human activity or bird migration, combined with changes to either the habitat or climate could increase the risk of tick-borne disease persistence and transmission. Prevention of tick-borne diseases for the human population and animals (both livestock and companion) is dependent on a thorough understanding of where and when pathogen transmission occurs. This information can only be gained through surveillance that seeks to identify where tick populations are distributed, which pathogens are present within those populations, and the periods of the year when ticks are active. To achieve this, a variety of approaches can be applied to enhance knowledge utilising a diverse range of stakeholders (public health professionals and veterinarians through to citizen scientists). Without this information, the application of mitigation strategies to reduce pathogen transmission and impact is compromised and the ability to monitor the effects of climate change or landscape modification on the risk of tick-borne disease is more challenging. However, as with many public and animal health interventions, there needs to be a cost-benefit assessment on the most appropriate intervention applied. This review will assess the challenges of tick-borne diseases in the UK and argue for a cross-disciplinary approach to their surveillance and control.

Novel symbionts and potential human pathogens excavated from argasid tick microbiomes that are shaped by dual or single symbiosis

Research on vector-associated microbiomes has been expanding due to increasing emergence of vector-borne pathogens and awareness of the importance of symbionts in the vector physiology. However, little is known about microbiomes of argasid (or soft-bodied) ticks due to limited access to specimens. We collected four argasid species (Argas japonicus, Carios vespertilionis, Ornithodoros capensis, and Ornithodoros sawaii) from the nests or burrows of their vertebrate hosts. One laboratory-reared argasid species (Ornithodoros moubata) was also included. Attempts were then made to isolate and characterize potential symbionts/pathogens using arthropod cell lines. Microbial community structure was distinct for each tick species. Coxiella was detected as the predominant symbiont in four tick species where dual symbiosis between Coxiella and Rickettsia or Coxiella and Francisella was observed in C. vespertilionis and O. moubata, respectively. Of note, A. japonicus lacked Coxiella and instead had Occidentia massiliensis and Thiotrichales as alternative symbionts. Our study found strong correlation between tick species and life stage. We successfully isolated Oc. massiliensis and characterized potential pathogens of genera Ehrlichia and Borrelia. The results suggest that there is no consistent trend of microbiomes in relation to tick life stage that fit all tick species and that the final interpretation should be related to the balance between environmental bacterial exposure and endosymbiont ecology. Nevertheless, our findings provide insights on the ecology of tick microbiomes and basis for future investigations on the capacity of argasid ticks to carry novel pathogens with public health importance.

Microbiome analysis of the midguts of different developmental stages of Argas persicus in China

Argas persicus is an ectoparasite of poultry. The bacterial community structure and the pathogenic bacteria associated with different developmental stages of A. persicus have implications for control. Argas persicus were collected from chickens in the city of Jiuquan in Gansu, China. Bacterial DNA was extracted from the midgut contents of blood engorged larvae, nymphs and adult females. The V3-V4 hypervariable regions of 16S rRNA genes were sequenced using the IonS5™XL platform. Identification of Rickettsia spp. and detection of Coxiella burnetii were performed using PCR on target genes. The bacterial diversity within larvae was the highest and the bacterial diversity within nymphs was greater than that of adults. At different classification levels, seven bacterial phyla were common phyla, 27 genera were common genera, and 18 species were common species in the three samples. At the phylum level, Proteobacteria showed a marked predominance in all samples. Rickettsia, Stenotrophomonas, Spiroplasma, and Coxiella were the dominant bacteria at the genus level. The Rickettsia species in A. persicus was identified as Rickettsia hoogstraalii and the Coxiella species was identified as a Coxiella-like endosymbiont. Additionally, some bacterial species such as Pseudomonas geniculata, Sphingomonas koreensis, and Acinetobacter haemolyticus were reported here for the first time in A. persicus.

Infection rates, species diversity, and distribution of zoonotic Babesia parasites in ticks: a global systematic review and meta-analysis

Zoonotic Babesia species are emerging public health threats globally, and are the cause of a mild to severe malaria-like disease which may be life threatening in immunocompromised individuals. In this study, we determine the global infection rate, distribution, and the diversity of zoonotic Babesia species in tick vectors using a systematic review and meta-analysis. We used the random-effects model to pool data and determined quality of individual studies using the Joanna Briggs Institute critical appraisal instrument for prevalence studies, heterogeneity using Cochran's Q test, and across study bias using Egger's regression test. Herein, we reported a 2.16% (3915/175345, 95% CI: 1.76-2.66) global infection rate of zoonotic Babesia species (B. divergens, B. microti, and B. venatorum) in tick vectors across 36 countries and 4 continents. Sub-group infection rates ranged between 0.65% (95% CI: 0.09-4.49) and 3.70% (95% CI: 2.61-5.21). B. microti was the most prevalent (1.79%, 95% CI: 1.38-2.31) species reported in ticks, while Ixodes scapularis recorded the highest infection rate (3.92%, 95% CI: 2.55-5.99). Larvae 4.18% (95% CI: 2.15-7.97) and females 4.08% (95% CI: 2.56-6.43) were the tick stage and sex with the highest infection rates. The presence of B. divergens, B. microti, and B. venatorum in tick vectors as revealed by the present study suggests possible risk of transmission of these pathogens to humans, especially occupationally exposed population. The control of tick vectors through chemical and biological methods as well as the use of repellants and appropriate clothing by occupationally exposed population are suggested to curtail the epidemiologic, economic, and public health threats associated with this emerging public health crisis.

Identification of tick-borne pathogens using metagenomic analyses in H. longicornis feeding on humans in downtown Beijing

On August 14th, 2018, a Beijing resident living in Xicheng District found a female H. longicornis tick attached to the skin at the front of his upper shin. On examination, the patient was afebrile and appeared well. The species of the tick was identified through morphological characteristics and phylogenetic analysis based on cytochrome C oxidase subunit I. This H. longicornis tick was screened for tick-borne pathogens such as viruses, bacteria and parasites. RNA pathogens were screened by PCR and sequencing, while DNA pathogens were screened by metagenomic analyses. It was found that the tick was positive for the DNA sequences of zoonotic and animal pathogens such as A. phagocytophilum, Ehrlichia minasensis and C. burnetii. Considering the good health condition of the patient, we hypothesized that the pathogens originated from the tick specimen itself rather than host blood meal. For the first time, our study reveals the possible risk of transmission of tick-borne pathogens to human beings through tick bit in downtown Beijing. Further research is needed to screen for tick-borne pathogens among unfed ticks collected from central Beijing.

Argasid Ticks of Palearctic Bats: Distribution, Host Selection, and Zoonotic Importance

The soft ticks (Ixodida: Argasidae) are ectoparasites of terrestrial vertebrates with a wide geographic distribution, occurring on all continents. These ticks are obligate blood-feeders, most of them show high degrees of host-specialization and several species in arid and tropical regions are important parasites of livestock and men. Species commonly occurring on domestic animals and man are generally well-known, with many studies focusing on their ecology, distribution or vectorial role. However, wildlife-specialist soft ticks are less studied. Nearly half of all soft tick species are bat specialists, with five species (Carios vespertilionis, Chiropterargas boueti, Chiropterargas confusus, Reticulinasus salahi, and Secretargas transgariepinus) occurring in the Western Palearctic. There is no comprehensive study on the distribution, hosts or pathogens in these soft ticks, although most species were shown to carry several viral, bacterial, or protozoan pathogens and also to occasionally infest humans. Based on a literature survey and 1,120 distinct georeferenced records, we present here the geographical range, host selection and vectorial potential for bat-specialist soft ticks occurring in the Western Palearctic (chiefly Europe, North Africa, and the Middle East). Carios vespertilionis shows the largest distribution range and was found on most host species, being ubiquitous wherever crevice-roosting bats occur. All the other species were located only in areas with Mediterranean climate, with Ch. boueti, Chiropteraragas confusus, and R. salahi are missing entirely from Europe. These three species have a host spectrum of bats roosting primarily in caves, while S. transgariepinus and Ca. vespertilionis is feeding primarily on crevice-roosting bat species. All but one of these soft tick species are known to feed on humans and may be vectors of important disease agents (Rickettsia spp., Borrelia spp., Bartonella spp., Ehrlichia spp., Babesia spp., several nairo-, and flaviviruses). As several crevice-roosting bat species show a continuous adaptation to human-altered areas, with certain species becoming common city-dwellers in the Western Palearctic, the study of bat specialist soft ticks is also important from an epidemiologic point of view.

First Record of a Suspected Human-Pathogenic Borrelia Species in Populations of the Bat Tick Carios vespertilionis in Sweden

The bat tick Cariosvespertilionis has been reported from Sweden to occasionally feed on humans resulting in disease symptoms. The aim of this study was to investigate C. vespertilionis as a potential vector and reservoir of Borrelia species. In 2015 and 2018 in south-central Sweden, C. vespertilionis ticks were collected from a wooden bat box harboring Soprano pipistrelle bats, Pipistrellus pygmaeus. In addition, one C. vespertilionis tick found inside a house in southern Sweden in 2019 was collected. Ticks were screened for Borrelia spp. using a genus-specific quantitative PCR assay. The Borrelia species of the positive specimens were determined by conventional PCR followed by DNA sequencing and phylogenetic analyses. A total of 24% (22 of 92) of the analyzed C. vespertilionis ticks were Borrelia-positive. Phylogenetic analyses indicate that the bacteria belong to the relapsing fever group of borreliae; some of them appear to be identical with Borrelia sp. CPB1, a spirochete only found twice before-in the United Kingdom and in France. Our results also indicate a temporal and spatial distribution of this Borrelia species. Since C. vespertilionis occasionally bites humans, and since it exhibits a high prevalence of Borrelia bacteria, it is possible that it presents a risk of human disease. Further studies are needed to characterize Borrelia sp. CPB1 to determine if it is human-pathogenic and to determine if C. vespertilionis is a vector and/or reservoir of this agent.

First record of Ixodes simplex found on a human host, with a review of cases of human infestation by bat tick species occurring in Europe

Ixodes simplex is a bat tick species, a common parasite of the Schreibers' bent-winged bat, Miniopterus schreibersii. Its distribution is linked to the range of its host, free stages occurring exclusively inside the underground bat shelters. Here we present the first case of human infestation with I. simplex. An adult female tick was found attached to the upper limb after a visit to the underground shelter of a large bat colony. This unusual host selection is a likely consequence of the reduction of suitable hosts, as the number of bats was much lower at the time of the visit than in previous years. Bat ticks rarely feed on humans, with soft ticks (Argasidae) being more commonly involved. In the light of the potential vectorial capacity of I. simplex, the incidence and potential future risks are discussed.

Novel Genotypes of Nidicolous Argas Ticks and Their Associated Microorganisms From Spain

The knowledge of the distribution, richness and epidemiological importance of soft ticks of the genus Argas is incomplete. In Spain, five Argas species have been recorded, including three ornitophilic nidicolous ticks, but their associated microorganisms remain unknown. This study aimed to investigate ticks from bird nests and their microorganisms. Ticks were collected extensively from natural cavities and nest-boxes used by European rollers (Coracias garrulus) and little owls (Athene noctua) in Southeastern and Central Spain. Ticks were morphologically and genetically identified and corresponding DNA/RNA tick extracts were analyzed [individually (n = 150) or pooled (n = 43)] using specific PCR assays for bacteria (Anaplasmataceae, Bartonella, Borrelia, Coxiella/Rickettsiella, and Rickettsia spp.), viruses (Flaviviruses, Orthonairoviruses, and Phenuiviruses), and protozoa (Babesia/Theileria spp.). Six Argas genotypes were identified, of which only those of Argas reflexus (n = 8) were identified to the species level. Two other genotypes were closely related to each other and to Argas vulgaris (n = 83) and Argas polonicus (n = 33), respectively. These two species have not been previously reported from Western Europe. Two additional genotypes (n = 4) clustered with Argas persicus, previously reported in Spain. The remaining genotype (n = 22) showed low sequence identity with any Argas species, being most similar to the African Argas africolumbae. The microbiological screening revealed infection with a rickettsial strain belonging to Rickettsia fournieri and Candidatus Rickettsia vini group in 74.7% of ticks, mainly comprising ticks genetically related to A. vulgaris and A. polonicus. Other tick endosymbionts belonging to Coxiella, Francisella and Rickettsiella species were detected in ten, one and one tick pools, respectively. In addition, one Babesia genotype, closely related to avian Babesia species, was found in one tick pool. Lastly, Anaplasmataceae, Bartonella, Borrelia, and viruses were not detected. In conclusion, five novel Argas genotypes and their associated microorganisms with unproven pathogenicity are reported for Spain. The re-use of nests between and within years by different bird species appears to be ideal for the transmission of tick-borne microorganisms in cavity-nesting birds of semiarid areas. Further work should be performed to clarify the taxonomy and the potential role of soft Argas ticks and their microorganisms in the epidemiology of zoonoses.

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).

Rickettsia hoogstraalii and a Rickettsiella from the Bat Tick Argas transgariepinus, in Namibia

Ectoparasites were collected from Eptesicus hottentotus, the long-tailed serotine bat, caught in Namibia as part of an ecological study. Larvae of Argas transgariepinus, a blood-feeding ectoparasite of bats in Africa, were removed from 3 of 18 bats. We present scanning electron microscope images of unengorged larvae. As with other ectoparasites, this bat tick might transmit pathogens such as Borrelia and Rickettsia to their hosts as has been reported for bat ticks in Europe and North America. We screened 3 pools (25 total) of larvae of A. transgariepinus removed from the long-tailed serotine bat Eptesicus hottentotus caught in Namibia. Two microbes of unknown pathogenicity, including Rickettsia hoogstraalii, a spotted fever group pathogen, and a Rickettsiella sp. were detected by molecular techniques.

First molecular detection of piroplasmids in non-hematophagous bats from Brazil, with evidence of putative novel species

Piroplasmida is an order of the phylum Apicomplexa that comprises the Babesia, Cytauxzoon, and Theileria genera. These hemoparasites infect vertebrate blood cells and may cause serious diseases in animals and humans. Even though previous studies have shown that bats are infected by different species of piroplasmids, the occurrence and diversity of these hemoparasites have not been investigated in this group of mammals in Brazil. Therefore, the present work aimed to investigate the occurrence and assess the phylogenetic placement of piroplasmids infecting bats sampled in a peri-urban area from Central-Western Brazil. Seventeen (12.6%) out of 135 animals were positive by nested PCR assay for the detection of Babesia/Theileria targeting the 18S rRNA gene. Eleven sequences of the 17 positive samples could be analyzed and showed an identity of 91.8-100% with Theileria bicornis, Babesia vogeli, a Babesia sp. identified in a small rodent (Thrichomys pachyurus) from the Brazilian Pantanal and a Babesia sp. identified in a dog from Thailand as assessed by nBLAST. A phylogenetic tree was constructed from an alignment of 1399 bp length using analyzed and known piroplasmid 18S rRNA sequences. In this tree, piroplasmid 18S rRNA sequences detected in three specimens of Phyllostomus discolor (Piroplasmid n. sp., P. discolor) were placed as a sister taxon to Theileria sensu stricto (Clade V) and Babesia sensu stricto (Clade VI). An additional phylogenetic tree was generated from a shorter alignment of 524 bp length including analyzed piroplasmid 18S rRNA sequences of bat species Artibeus planirostris and A. lituratus (Piroplasmid sp., Artibeus spp.). The two 18S rRNA sequences detected in Artibeus spp. (Piroplasmid n. sp., Artibeus spp.) were placed within Babesia sensu stricto (Clade VI) into a strongly supported clade (bootstrap: 100) that included Babesia vogeli. The two 18S rRNA sequences of Piroplasmid sp., Artibeus spp. showed a single and a two-nucleotide differences, respectively, with respect to B. vogeli in a 709 pb length alignment. For the first time, the present study shows the occurrence of putative new piroplasmid species in non-hematophagous bats from Brazil.

Baltic Group Tick-Borne Encephalitis Virus Phylogeography: Systemic Inconsistency Pattern between Genetic and Geographic Distances

Tick-Borne Encephalitis Virus (TBEV) is a dangerous arbovirus widely distributed in Northern Eurasia. The area of this pathogen changes over time. At the beginning of the 2000s, the Ixodes tick populations in Karelia increased. At the same time, the area of I. persulcatus, the main vector of the Siberian TBEV subtype, also expanded. Herein, we sequenced 10 viruses isolated from ticks collected in three locations from the Karelia region in 2008-2018. PCR positive samples were passaged in suckling mice or pig embryo kidney cells (PEK). After the second passage in suckling, mice viral RNA was isolated and E-gene fragment was sequenced. Viral sequences were expected to be similar or nearly identical. Instead, there was up to a 4.8% difference in nucleotide sequence, comparable with the most diverse viruses belonging to the Baltic subgroup in Siberian TBEV subtype (Baltic TBEV-Sib). To reveal whether this was systemic or incidental, a comprehensive phylogeographical analysis was conducted. Interestingly, viruses within each geographic region demonstrated comparable diversity to the whole Baltic TBEV-Sib. Moreover, Baltic TBEV-Sib has a distribution area limited by three ecological regions. This means that active virus mixing occurs in the vast geographic area forming one common virus pool. The most plausible explanation is the involvement of flying animals in the TBEV spread.

Zoonotic Babesia: A scoping review of the global evidence

BACKGROUND

Babesiosis is a parasitic vector-borne disease of increasing public health importance. Since the first human case was reported in 1957, zoonotic species have been reported on nearly every continent. Zoonotic Babesia is vectored by Ixodes ticks and is commonly transmitted in North America by Ixodes scapularis, the tick species responsible for transmitting the pathogens that also cause Lyme disease, Powassan virus, and anaplasmosis in humans. Predicted climate change is expected to impact the spread of vectors, which is likely to affect the distribution of vector-borne diseases including human babesiosis.

METHODS

A scoping review has been executed to characterize the global evidence on zoonotic babesiosis. Articles were compiled through a comprehensive search of relevant bibliographic databases and targeted government websites. Two reviewers screened titles and abstracts for relevance and characterized full-text articles using a relevance screening and data characterization tool developed a priori.

RESULTS

This review included 1394 articles relevant to human babesiosis and/or zoonotic Babesia species. The main zoonotic species were B. microti, B. divergens, B. duncani and B. venatorum. Articles described a variety of study designs used to study babesiosis in humans and/or zoonotic Babesia species in vectors, animal hosts, and in vitro cell cultures. Topics of study included: pathogenesis (680 articles), epidemiology (480), parasite characterization (243), diagnostic test accuracy (98), mitigation (94), treatment (65), transmission (54), surveillance (29), economic analysis (7), and societal knowledge (1). No articles reported predictive models investigating the impact of climate change on Babesia species.

CONCLUSION

Knowledge gaps in the current evidence include research on the economic burden associated with babesiosis, societal knowledge studies, surveillance of Babesia species in vectors and animal hosts, and predictive models on the impact of climate change. The scoping review results describe the current knowledge and knowledge gaps on zoonotic Babesia which can be used to inform future policy and decision making.

Bats and ticks: host selection and seasonality of bat-specialist ticks in eastern Europe

Background

Parasites may actively seek for hosts and may use a number of adaptive strategies to promote their reproductive success and host colonization. These strategies will necessarily influence their host specificity and seasonality. Ticks are important ectoparasites of vertebrates, which (in addition to directly affecting their hosts) may transmit a number of pathogens. In Europe, three hard tick species (Ixodidae: Ixodes ariadnae, I. simplex and I. vespertilionis) and at least two soft tick species (Argasidae: Argas transgariepinus and A. vespertilionis) are specialized for bats.

Methods

Here we report data on the host range of these ticks and the seasonality of tick infestation on wild caught bats in south-east Europe. We collected 1803 ticks from 30 species of bats living in underground shelters (caves and mines) from Romania and Bulgaria. On the basis of tick–host associations, we tested several hypotheses on host–parasite evolutionary adaptations regulating host specificity, seasonality and sympatric speciation.

Results

We observed significant differences in host specificity and seasonality of abundance between the morphologically different bat specialist ticks (I. simplex and I. vespertilionis) likely caused by their host choice and their respective host-seeking behavior. The two highly generalist, but morphologically similar tick species (I. ariadnae and I. vespertilionis) showed temporal differences in occurrence and activity, thus exploiting significantly different host communities while occurring in geographical sympatry.

Conclusions

We conclude that bat-specialist ticks show a wide range of adaptations to their hosts, with differences in specificity, seasonality of occurrence, the prevalence and intensity of infestation and all these contribute to a successful division of temporal niches of ticks sharing morphologically similar hosts occurring in geographical sympatry.

Diversity of Borrelia burgdorferi sensu lato species in Ixodes ticks (Acari: Ixodidae) associated with cave-dwelling bats from Poland and Romania

Bats comprise one quarter of the world's mammal species. In Europe, three nidicolous Ixodes tick species, I. vespertilionis, I. simplex and I. ariadnae are specifically associated with cave-dwelling bats, but their role as potential vectors of zoonotic agents is unknown. In this study, we used PCR-based methods to provide the first evidence of Borrelia burgdorferi sensu lato (s.l.) infections in the three bat-associated tick species collected from ten bat species sampled in Poland and Romania. B. burgdorferi s.l. was detected in 24% (64/266) of tick samples, and 40.3% (60/149) of the bats carried infected chiropterophilic ticks. In Poland, the B. burgdorferi s.l. infection prevelance of I. ariadnae ticks parasitizing Myotis species was four times higher compared to the I. vespertilionis ticks derived from Rhinolophus hipposideros bats (44.4% vs.10%, respectively). The observed differences in infection prevalence could be explained by differences in reservoir potential between bat species. Bats from the genus Myotis and Miniopterus schreibersii carried more infected ticks than R. hipposideros regardless of the tick species. Analysis of the flaB gene sequences revealed seven species from the B. burgdorferi s.l. complex (B. afzelii, B. carolinensis, B. garinii, B. lanei, B. spielmanii, B. burgdorferi s.s., and B. valaisiana), of which five are considered as human pathogens. This large diversity of Borrelia species may reflect differences in susceptibility of chiropteran hosts and/or the tick vectors. Generally, mammal-associated B. burgdorferi s.l. species were more common than bird-associated species. Our study provides evidence for new enzootic transmission cycles of B. burgdorferi s.l. spirochetes involving nidicolous Ixodes tick species and cave-dwelling bats.

Bartonella and Rickettsia Infections in Haematophagous Spinturnix myoti Mites (Acari: Mesostigmata) and their Bat Host, Myotis myotis (Yangochiroptera: Vespertilionidae), from Poland

Hematophagous Spinturnix myoti mites and their host, the greater mouse-eared bat (Myotis myotis), were tested for the presence of Bartonella spp., Rickettsia spp., and Anaplasma phagocytophilum. In total, Bartonella spp. DNA was amplified in 28% of 134 mite pools and in 25% of 59 bats tested by PCR targeting a fragment of citrate synthase gltA gen. Adult mites were at least threefold more frequently infected compared to immature stages. The overall infection prevalence among mite pools from cave-dwelling bats was higher than for those collected from attic shelters. Three distinct genotypes were detected. The most prevalent genotype in mites and bats matched closely with Candidatus Bartonella hemsundetiensis identified in bats from Finland and was relatively distant from bat-borne Bartonella strains described in the UK and France. Importantly, most sequences were close to those reported in forest workers from Poland. The presence of identical genotype among S. myoti samples and M. myotis bats suggests that bartonellae can be shared between mites and their bat hosts. In this case, wing mites could serve as vectors, whereas their hosts as reservoirs. One blood sample was positive by PCR for the msp2 gene of A. phagocytophilum. Two mite pools yielded Rickettsia spp. DNA. Both sequences were distinct from any known species but can be classified as spotted fever group Rickettsia spp. Our findings expanded our knowledge on the role of spinturnicid mites in the ecology and epidemiology of bacterial infections associated with vespertilionid bats, especially regarding the genus Bartonella.

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.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3303-4) contains supplementary material, which is available to authorized users.

Argasid and ixodid systematics: Implications for soft tick evolution and systematics, with a new argasid species list

The systematics of the genera and subgenera within the soft tick family Argasidae is not adequately resolved. Different classification schemes, reflecting diverse schools of scientific thought that elevated or downgraded groups to genera or subgenera, have been proposed. In the most recent classification scheme, Argas and Ornithodoros are paraphyletic and the placement of various subgenera remains uncertain because molecular data are lacking. Thus, reclassification of the Argasidae is required. This will enable an understanding of soft tick systematics within an evolutionary context. This study addressed that knowledge gap using mitochondrial genome and nuclear (18S and 28S ribosomal RNA) sequence data for representatives of the subgenera Alectorobius, Argas, Chiropterargas, Ogadenus, Ornamentum, Ornithodoros, Navis (subgen. nov.), Pavlovskyella, Persicargas, Proknekalia, Reticulinasus and Secretargas, from the Afrotropical, Nearctic and Palearctic regions. Hard tick species (Ixodidae) and a new representative of Nuttalliella namaqua (Nuttalliellidae), were also sequenced with a total of 83 whole mitochondrial genomes, 18S rRNA and 28S rRNA genes generated. The study confirmed the utility of next-generation sequencing to retrieve systematic markers. Paraphyly of Argas and Ornithodoros was resolved by systematic analysis and a new species list is proposed. This corresponds broadly with the morphological cladistic analysis of Klompen and Oliver (1993). Estimation of divergence times using molecular dating allowed dissection of phylogeographic patterns for argasid evolution. The discovery of cryptic species in the subgenera Chiropterargas, Ogadenus and Ornithodoros, suggests that cryptic speciation is common within the Argasidae. Cryptic speciation has implications for past biological studies of soft ticks. These are discussed in particular for the Ornithodoros (Ornithodoros) moubata and Ornithodoros (Ornithodoros) savignyi groups.