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

Bats and ectoparasites: exploring a hidden link in zoonotic disease transmission

Bats are increasingly in the focus of disease surveillance studies as they harbor pathogens that can cause severe human disease. In other host groups, ectoparasitic arthropods play an important role in transmitting pathogens to humans. Nevertheless, we currently know little about the role of bat-associated ectoparasites in pathogen transmission, not only between bats but also to humans and other species, even though some of these parasites occasionally feed on humans and harbor potentially zoonotic organisms. In this work, we summarize current knowledge on the zoonotic risks linked to bat-associated ectoparasites and provide novel risk assessment guidelines to improve targeted surveillance efforts. Additionally, we suggest research directions to help adjust surveillance strategies and to better understand the eco-epidemiological role of these parasites.

Diversity of bartonellae in mites (Acari: Mesostigmata: Macronyssidae and Spinturnicidae) of boreal forest bats: Association of host specificity of mites and habitat selection of hosts with vector potential

Research into various bacterial pathogens that can be transmitted between different animals and may have zoonotic potential has led to the discovery of different strains of Bartonella sp. in bats and their associated ectoparasites. Despite their enormous species diversity, only a few studies have focussed on the detection of bacterial pathogens in insectivorous bats of boreal forests and their associated Macronyssidae and Spinturnicidae mites. We collected and molecularly analysed mite samples from forest-dwelling bat species distributed all along the boreal belt of the Palearctic, from Central Europe to Far East. Ectoparasitic mites were pooled for DNA extraction and DNA amplification polymerase chain reaction (PCRs) were conducted to detect the presence of various bacterial (Anaplasmataceae, Bartonella sp., Rickettsia sp., Mycoplasma sp.) and protozoal (Hepatozoon sp.) pathogens. Bartonella sp. DNA was detected in four different mite species (Macronyssidae: Steatonyssus periblepharus and Spinturnicidae: Spinturnix acuminata, Sp. myoti and Sp. mystacinus), with different prevalences of the targeted gene (gltA, 16-23S ribosomal RNA intergenic spacer and ftsZ). Larger pools (>5 samples pooled) were more likely to harbour Bartonella sp. DNA, than smaller ones. In addition, cave-dwelling bat hosts and host generalist mite species are more associated with Bartonella spp. presence. Spinturnicidae mites may transmit several distinct Bartonella strains, which cluster phylogenetically close to Bartonella species known to cause diseases in humans and livestock. Mites with ubiquitous presence may facilitate the long-term maintenance (and even local recurrence) of Bartonella-infestations inside local bat populations, thus acting as continuous reservoirs for Bartonella spp in bats.

Ecology and phenology of the bat tick Argas (Carios) dewae (Acari: Argasidae)

Although 12 soft tick species (Argasidae) are native to Australia, the ecology of most is poorly known. Argas dewae parasitizes several insectivorous bat species and has been recorded on humans. Therefore, understanding its ecology is crucial for wildlife health management and public health preparedness. To address this knowledge gap, A. dewae populations were monitored from 2 bat hosts (Chalinolobus gouldii and Austronomus australis) using bat boxes at 3 sites in Victoria, Australia, for 28 months (July 2005–December 2007). A phenological profile undertaken for A. dewae revealed that tick load on bat hosts increased throughout winter and peaked in the first month of spring, before collapsing and remaining low throughout the drier late spring and summer periods. There was also further investigation of the relationship between 2 response variables (tick infestation risk and tick load) and a range of explanatory variables (body condition index, sex, age class, bioseason, site, bat density per nest box). In C. gouldii, site was the only significant predictor of A. dewae infestation risk, while load was correlated with several variables including age class, sex, bioseason, roost density and body condition index. This paper also reports the first records of A. dewae from 6 bat species in 3 bat families (Miniopteridae: Miniopterus australis; Molossidae: A. australis; Vespertilionidae: Chalinolobus morio, Myotis Macropus, Vespadelus darlingtonia, Vespadelus regulus) and a second record of A. dewae from a human. The first distribution records are presented for A. dewae in South Australia, the Australian Capital Territory and Queensland.

Bat-associated ticks as a potential link for vector-borne pathogen transmission between bats and other animals

BACKGROUND

Potentially zoonotic pathogens have been previously detected in bat-associated ticks, but their role in disease transmission and their frequency of feeding on non-bat hosts is poorly known.

METHODOLOGY/PRINCIPAL FINDINGS

We used molecular blood meal analysis to reveal feeding patterns of the bat-associated tick species Ixodes ariadnae, I. simplex, and I. vespertilionis collected from cave and mine walls in Central and Southeastern Europe. Vertebrate DNA, predominantly from bats, was detected in 43.5% of the samples (70 of 161 ticks) but in these ticks we also detected the DNA of non-chiropteran hosts, such as dog, Canis lupus familiaris, wild boar, Sus scrofa, and horse, Equus caballus, suggesting that bat-associated ticks may exhibit a much broader host range than previously thought, including domestic and wild mammals. Furthermore, we detected the zoonotic bacteria Neoehrlichia mikurensis in bat ticks for the first time, and other bacteria, such as Bartonella and Wolbachia.

CONCLUSIONS/SIGNIFICANCE

In the light of these findings, the role of bat ticks as disease vectors should be urgently re-evaluated in more diverse host systems, as they may contribute to pathogen transmission between bats and non-chiropteran hosts.

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.

Bat Ectoparasites (Acari, Diptera, Hemiptera, Siphonaptera) in the Grand Maghreb (Algeria, Libya, Mauritania, Morocco and Tunisia): A Literature Review and New Data

BACKGROUND

Arthropods parasites of bats play a crucial role in both ecological and public health contexts, as they have the potential to transmit zoonotic agents. The study aims to identify the distribution, and host-parasite associations of bat ectoparasites in the Grand Maghreb region (Algeria, Libya, Mauritania, Morocco and Tunisia), which has been largely understudied.

METHODS

A thorough analysis of published records was conducted and we included our own field data.

RESULTS

The checklist reveals a total of 43 ectoparasite species, encompassing a range of taxa. The list comprises 9 tick species, 11 mite species (including a chigger-mite), 11 bat fly species, 3 species of bugs, and 9 species of fleas. Extensive research efforts uncovered 141 host-parasite associations. Our data presents several new country records, documenting for the first time the presence of Carios vespertilionis and Raymondia huberi in Tunisia, Ixodes simplex and Spinturnix plecotinus in Algeria.

CONCLUSION

By compiling and analysing available information, we have provided for the first time an up-to-date checklist of bat ectoparasites and their host associations in the region. This knowledge contributes to a better understanding of the epidemiological implications associated with bat ectoparasites, emphasizing their ecological and public health importance. The study's findings call for continued investigations and monitoring of bat ectoparasites to mitigate potential risks and safeguard both human and animal populations.

Season and host-community composition inside roosts may affect host-specificity of bat flies

Bat flies are one of the most abundant ectoparasites of bats, showing remarkable morphological adaptations to the parasitic habit, while the relationship with their hosts is characterized by a high level of specificity. By collecting bat flies from live hosts, our intention was to elucidate the seasonal differences in bat fly occurrence and to describe factors regulating the level of incipient host specificity. Our results indicate that the prevalence and the intensity of infestation is increasing from spring to autumn for most host species, with significant differences among different fly species. Males showed higher infestation levels than females in autumn, suggesting a non-random host choice by flies, targeting the most active host sex. Bat-bat fly host specificity shows seasonal changes and host choice of bat flies are affected by the seasonal differences in hosts' behavior and ecology, the intensity of infestation and the species composition of the local host community. Nycteribiid bat flies showed lower host specificity in the swarming (boreal autumn) period, with higher prevalence recorded on non-primary hosts. Choosing a non-primary bat host may be an adaptive choice for bat flies in the host's mating period, thus increasing their dispersive ability in a high activity phase of their hosts.

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.

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).

Detection of bacterial and protozoan pathogens in individual bats and their ectoparasites using high-throughput microfluidic real-time PCR

Among the most studied mammals in terms of their role in the spread of various pathogens with possible zoonotic effects are bats. These are animals with a very complex lifestyle, diet, and behavior. They are able to fly long distances, thus maintaining and spreading the pathogens they may be carrying. These pathogens also include vector-borne parasites and bacteria that can be spread by ectoparasites such as ticks and bat flies. In the present study, high-throughput screening was performed and we detected three bacterial pathogens: Bartonella spp., Neoehrlichia mikurensis and Mycoplasma spp., and a protozoan parasite: Theileria spp. in paired samples from bats (blood and ectoparasites). In the samples from the bat-arthropod pairs, we were able to detect Bartonella spp. and Mycoplasma spp. which also showed a high phylogenetic diversity, demonstrating the importance of these mammals and the arthropods associated with them in maintaining the spread of pathogens. Previous studies have also reported the presence of these pathogens, with one exception, Neoehrlichia mikurensis, for which phylogenetic analysis revealed less genetic divergence. High-throughput screening can detect more bacteria and parasites at once, reduce screening costs, and improve knowledge of bats as reservoirs of vector-borne pathogens. IMPORTANCE The increasing number of zoonotic pathogens is evident through extensive studies and expanded animal research. Bats, known for their role as reservoirs for various viruses, continue to be significant. However, new findings highlight the emergence of Bartonella spp., such as the human-infecting B. mayotimonensis from bats. Other pathogens like N. mikurensis, Mycoplasma spp., and Theileria spp. found in bat blood and ectoparasites raise concerns, as their impact remains uncertain. These discoveries underscore the urgency for heightened vigilance and proactive measures to understand and monitor zoonotic pathogens. By deepening our knowledge and collaboration, we can mitigate these risks, safeguarding human and animal well-being.

Tick findings from subterranean environments in the Central German Uplands and Luxembourg reveal a predominance of male Ixodes hexagonus

Questing ticks are usually collected by flagging or dragging. Mostly exophilic tick species are caught, such as Ixodes ricinus, the most common tick in Central Europe. In the present study, ticks collected from underground environments in the Grand Duchy of Luxembourg and in the Central German Uplands (Federal States of Hesse, Bavaria, Thuringia, Baden-Wuerttemberg, Rhineland-Palatinate, Saarland and Northrhine-Westphalia) were investigated. Six tick species were revealed among the 396 analyzed specimens: Ixodes ariadnae, Ixodes canisuga, Ixodes hexagonus, I. ricinus, Ixodes trianguliceps, and Dermacentor marginatus. Adults and immatures of I. hexagonus dominated the findings (57% of all specimens), especially in shelters acting as potential resting places of main hosts. Ixodes canisuga and I. trianguliceps were for the first time recorded in Luxembourg, and one nymph of the bat tick I. ariadnae represents only the second report for Germany. Collecting ticks in subterranean environments turned out to be a useful approach to increase knowledge about the occurrence of relatively rare tick species, including those that spend most of their lifetime on their hosts, but detach in such environmental settings.

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.

Worldwide host associations of the tick genus Ixodes suggest relationships based on environmental sharing rather than on co-phylogenetic events

BACKGROUND

This study aims to capture how ticks of the genus Ixodes gained their hosts using network constructs. We propose two alternative hypotheses, namely, an ecological background (ticks and hosts sharing environmentally available conditions) and a phylogenetic one, in which both partners co-evolved, adapting to existing environmental conditions after the association took place.

METHODS

We used network constructs linking all the known pairs of associations between each species and stage of ticks with families and orders of hosts. Faith's phylogenetic diversity was used to evaluate the phylogenetic distance of the hosts of each species and changes occurring in the ontogenetic switch between consecutive stages of each species (or the extent of the changes in phylogenetic diversity of hosts for consecutive stages of the same species).

RESULTS

We report highly clustered associations among Ixodes ticks and hosts, supporting the influence of the ecological adaptation and coexistence, demonstrating a lack of strict tick-host coevolution in most cases, except for a few species. Keystone hosts do not exist in the relationships between Ixodes and vertebrates because of the high redundancy of the networks, further supporting an ecological relationship between both types of partners. The ontogenetic switch of hosts is high for species with enough data, which is another potential clue supporting the ecological hypothesis. Other results suggest that the networks displaying tick-host associations are different according to the biogeographical realms. Data for the Afrotropical region reveal a lack of extensive surveys, while results for the Australasian region are suggestive of a mass extinction of vertebrates. The Palearctic network is well developed, with many links demonstrating a highly modular set of relationships.

CONCLUSIONS

With the obvious exceptions of Ixodes species restricted to one or a few hosts, the results point to an ecological adaptation. Even results on species linked to groups of ticks (such as Ixodes uriae and the pelagic birds or the bat-tick species) are suggestive of a previous action of environmental forces.

Parasitic fauna of bats from Costa Rica

Bats are important reservoirs and spreaders of pathogens, including those of zoonotic concern. Though Costa Rica hosts one of the highest bat species' diversity, no information is available about their parasites. In order to investigate the occurrence of vector-borne pathogens (VBPs) and gastrointestinal (GI) parasites of chiropterans from this neotropical area, ectoparasites (n = 231) and stools (n = 64) were collected from 113 bats sampled in Santa Cruz (site 1) and Talamanca (site 2). Mites, fleas and ticks were morphologically and molecularly identified, as well as pathogens transmitted by vectors (VBPs, i.e., Borrelia spp., Rickettsia spp., Bartonella spp.) and from feces, such as Giardia spp., Cryptosporidium spp. and Eimeria spp. were molecularly investigated. Overall, 21 bat species belonging to 15 genera and 5 families were identified of which 42.5% were infested by ectoparasites, with a higher percentage of mites (38.9%, i.e., Cameronieta sp. and Mitonyssoides sp.) followed by flies (2.6%, i.e., Joblingia sp.) and tick larvae (1.7%, i.e., Ornithodoros sp.). Rickettsia spp. was identified in one immature tick and phylogenetically clustered with two Rickettsia species of the Spotted Fever Group (i.e., R. massiliae and R. rhipicephali). The frequency of GI parasite infection was 14%, being 3.1% of bats infected by Giardia spp. (un-identified non-duodenalis species), 1.5% by Eimeria spp. and 9.4% by Cryptosporidium spp. (bat and rodent genotypes; one C. parvum-related human genotype). The wide range of ectoparasites collected coupled with the detection of Rickettsia sp., Giardia and Cryptosporidium in bats from Costa Rica highlight the role these mammals may play as spreaders of pathogens and the need to further investigate the pathogenic potential of these parasites.

Investigation of the Virome and Characterization of Issyk-Kul Virus from Swedish Myotis brandtii Bats

Bats are reservoirs for many different viruses, including some that can be transmitted to and cause disease in humans and/or animals. However, less is known about the bat-borne viruses circulating in Northern European countries such as in Sweden. In this study, saliva from Myotis brandtii bats, collected from south-central Sweden, was analyzed for viruses. The metagenomic analysis identified viral sequences belonging to different viral families, including, e.g., Nairoviridae, Retroviridae, Poxviridae, Herpesviridae and Siphoviridae. Interestingly, through the data analysis, the near-complete genome of Issyk-Kul virus (ISKV), a zoonotic virus within the Nairoviridae family, was obtained, showing 95-99% protein sequence identity to previously described ISKVs. This virus is believed to infect humans via an intermediate tick host or through contact with bat excrete. ISKV has previously been found in bats in Europe, but not previously in the Nordic region. In addition, near full-length genomes of two novel viruses belonging to Picornavirales order and Tymoviridae family were characterized. Taken together, our study has not only identified novel viruses, but also the presence of a zoonotic virus not previously known to circulate in this region. Thus, the results from these types of studies can help us to better understand the diversity of viruses circulating in bat populations, as well as identify viruses with zoonotic potential that could possibly be transmitted to humans.

A survey of hard ticks associated with cave dwelling mammals in Turkey

Members of the subgenus Eschatocephalus Frauenfeld, 1853 are highly specialized cave-dwelling ectoparasites of bats. We conducted a comprehensive field-based survey on bat ticks in Turkey and provided information about the phylogenetic placement of collected species. Sampling was carried out at 26 caves from 18 provinces around Turkey between 2019 and 2021. Eighty-one tick specimens collected from the cave environment or on various cave roosting bats resulted in five species: Ixodes vespertilionis, Ixodes simplex, Ixodes ariadnae, Ixodes kaiseri, and Haemaphysalis erinacei. While I. simplex was the most frequently collected species with a rate of 56.2% mainly from bats (Miniopterus schreibersii), I. vespertilionis was the most prevalent species (65.4%) and found mainly on cave walls. The first record of I. ariadnae was provided for Turkey. Phylogenetic trees were built using mt 16S rDNA and COI markers. Our results demonstrated the presence of two distinct lineages of I. vespertilionis in Turkey; one lineage grouped with European isolates, whereas three sequences clustered separately. The phylogenetic pattern of I. simplex was consistent with previous results; this clade was clustered distantly to other bat tick species. The significance of the surprising records of H. erinacei and I. kaiseri in caves is also discussed.

Effects of host state and body condition on parasite infestation of bent-wing bats

BACKGROUND

Ectoparasites inhabit the body surface or outgrowths of hosts and are usually detrimental to host health and wellbeing. Hosts, however, vary in quality and may lead ectoparasites to aggregate on preferred hosts, resulting in a heterogeneous distribution of parasite load among hosts.

RESULTS

We set out to examine the effects of host individual state and body condition on the parasite load of multiple nycteribiid and streblid bat flies and Spinturnix wing mites on eastern bent-wing bats Miniopterus fuliginosus in a tropical forest in southern Taiwan. We detected a high parasite prevalence of 98.9% among the sampled bats, with nearly 75% of the bats harboring three or more species of parasites. The parasite abundance was higher in the wet season from mid spring to early fall, coinciding with the breeding period of female bats, than in the dry winter season. In both seasonal periods, the overall parasite abundance of adult females was higher than that of adult males. Among the bats, reproductive females, particularly lactating females, exhibited a higher body condition and were generally most infested. The Penicillidia jenynsii and Nycteribia parvula bat flies showed a consistent female-biased infection pattern. The N. allotopa and Ascodipteron speiserianum flies, however, showed a tendency towards bats of a moderate to higher body condition, particularly reproductive females and adult males.

CONCLUSIONS

We found an overall positive correlation between parasite abundance and reproductive state and body condition of the host and female-biased parasitism for M. fuliginosus bats. However, the effects of body condition and female-biased infestation appear to be parasite species specific, and suggest that the mobility, life history, and potential inter-species interactions of the parasites may all play important roles.

Focus on Hyperparasites: Biotic and Abiotic Traits Affecting the Prevalence of Parasitic Microfungi on Bat Ectoparasites

The tritrophic association of bats, bat flies, and Laboulbeniales microfungi is a remarkably understudied system that may reveal patterns applicable to community ecology theory of (hyper)parasites. Laboulbeniales are biotrophic microfungi, exclusively associated with arthropods, with several species that are specialized on bat flies, which themselves are permanent ectoparasites of bats. Several hypotheses were tested on biotic and abiotic traits that may influence the presence and prevalence of hyperparasitic Laboulbeniales fungi on bat flies, based on southeastern European data. We found a wide distribution of fungal infection on bat flies, with underground-dwelling bats hosting more Laboulbeniales-infected flies compared to crevice-dwelling species. Bat host behavior, sociality, roost selection (underground versus crevice), bat fly sex, and season all have significant effects on the prevalence of fungal infection. Laboulbeniales infections are more common on bat flies that are infecting bat species with dense and long-lasting colonies (Miniopterus schreibersii, Myotis myotis, Myotis blythii), which roost primarily in underground sites. Inside these sites, elevated temperature and humidity may enhance the development and transmission of Laboulbeniales fungi. Sexual differences in bat hosts’ behavior also have an effect on fungal infection risk, with densely roosting female bat hosts harboring more Laboulbeniales-infected bat flies.

Characterization of Keterah orthonairovirus and evaluation of therapeutic candidates against Keterah orthonairovirus infectious disease

The species Keterah orthonairovirus is a member of the genus Orthonairovirus. Few studies have focused on this species, and there remains no treatment for Issyk-Kul fever, an infectious disease caused by a Keterah orthonairovirus. This study was performed to characterize this species using two viruses, Issyk-Kul virus (ISKV) and Soft tick bunyavirus (STBV), in cell culture and type I interferon receptor knockout (IFNAR-/-) mice and to evaluate the efficacy of serum transfusion using a mouse model of ISKV infection. The two viruses replicated in many kinds of mammal- and tick-derived cell lines but showed few different characteristics in tropism and antigenicity against anti-viral sera in cell culture. Neither virus caused clinical signs in wild-type mice, but both caused lethal infection in IFNAR-/- mice. ISKV caused more acute death than STBV in IFNAR-/- mice. In both viral infections in IFNAR-/- mice, macroscopic abnormalities were prominent in the liver. Similar levels of viral genome between ISKV- and STBV-infected IFNAR-/- mice were observed in blood, liver, lymphoid tissues and adrenal gland at moribund stages. Hematologic abnormalities in IFNAR-/- mice infected with these viruses, including leukopenia and thrombocytopenia, and biochemical abnormalities indicating liver damage were prominent. In addition, blood levels of many kinds of cytokines and chemokines such as granulocyte colony-stimulating factor, interleukin-6, tumor necrosis factor-α, interferon gamma-induced protein 10 and monocyte chemoattractant protein-1 were elevated. ISKV-immunized serum transfusion after infection delayed the time to death of IFNAR-/- mice. Thus, the present study showed that the species Keterah orthonairovirus could proliferate in most mammal-derived cell lines and cause severe liver lesions and death in IFNAR-/- mice and that serum transfusion might be effective in treatment against Issyk-Kul fever.

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 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.

Rickettsia spp. in bats of Romania: high prevalence of Rickettsia monacensis in two insectivorous bat species

Background

Spotted fever group rickettsiae represent one of the most diverse groups of vector-borne bacteria, with several human pathogenic species showing an emerging trend worldwide. Most species are vectored by ticks (Ixodidae), with many zoonotic reservoir species among most terrestrial vertebrate groups. While the reservoir competence of many different vertebrate species is well known (e.g. birds, rodents and dogs), studies on insectivorous bats have been rarely performed despite their high species diversity, ubiquitous urban presence and importance in harboring zoonotic disease agents. Romania has a high diversity and ubiquity of bats. Moreover, seven out of eight SFG rickettsiae species with zoonotic potential were previously reported in Romania. Based on this, the aim of this study was to detect Rickettsia species in tissue samples in bats.

Methods

Here we report a large-scale study (322 bats belonging to 20 species) on the presence of Rickettsia spp. in Romanian bat species. Tissue samples from insectivorous bats were tested for the presence of Rickettsia DNA using PCR detection amplifying a 381 bp fragment of the gltA gene. Positive results were sequenced to confirm the results. The obtained results were statistically analyzed by chi-squared independence test.

Results

Positive results were obtained in 14.6% of bat samples. Sequence analysis confirmed the presence of R. monacensis in two bat species (Nyctalus noctula and Pipistrellus pipistrellus) in two locations.

Conclusion

This study provides the first evidence of a possible involvement of these bat species in the epidemiology of Rickettsia spp., highlighting the importance of bats in natural cycles of these vector-borne pathogens.

Wide Distribution and Diversity of Malaria-Related Haemosporidian Parasites (Polychromophilus spp.) in Bats and Their Ectoparasites in Eastern Europe

Malaria is responsible for major diseases of humans, while associated haemosporidians are important factors in regulating wildlife populations. Polychromophilus, a haemosporidian parasite of bats, is phylogenetically close to human-pathogenic Plasmodium species, and their study may provide further clues for understanding the evolutionary relationships between vertebrates and malarial parasites. Our aim was to investigate the distribution of Polychromophilus spp. in Eastern Europe and test the importance of host ecology and roost site on haemosporidian parasite infection of bats. We sampled bats and their ectoparasites at eight locations in Romania and Bulgaria. DNA was extracted from blood samples and ectoparasites and tested individually for the presence of DNA of Polychromophilus spp. using a nested PCR targeting a 705 bp fragment of cytB. Two species of Polychromophilus were identified: Po. melanipherus in Miniopterus schreibersii and associated ectoparasites and Po. murinus in rhinolophid and vespertilionid bats (6 species) and their ticks and nycteribiid flies. Only cave-dwelling bat species (and their ectoparasites) showed infections, and we found a strong correlation between infections with Polychromophilus parasites and Nycteribiidae prevalence. We report the high genetic diversity of Polychromophilus spp. in Eastern Europe, suggesting that the simultaneous presence of varied host and vector assemblages enhances bat haemosporidian parasite diversity.

First report of the bat fly species Basilia italica in Romania

Bat flies are haematophagous ectoparasites, highly specialised to bats and are also considered to have vectorial potential for several pathogens like Bartonella spp. or Polychromophilus spp. In Romania, past studies mostly focused on the ectoparasitic fauna of cave-dwelling bats, listing the occurrence of 10 bat fly species in the country, with only scarce information on bat flies infesting crevice-roosting bat species. Here we report the occurrence of Basiliaitalica, a rare nycteribiid species infesting primarily forest-dwelling bats. This is the first country-record for Romania and also represents the easternmost occurrence of this species. Further studies are needed to evaluate the vectorial potential of B.italica.

Host conservation through their parasites: molecular surveillance of vector-borne microorganisms in bats using ectoparasitic bat flies

Most vertebrates host a wide variety of haematophagous parasites, which may play an important role in the transmission of vector-borne microorganisms to hosts. Surveillance is usually performed by collecting blood and/or tissue samples from vertebrate hosts. There are multiple methods to obtain samples, which can be stored for decades if properly kept. However, blood sampling is considered an invasive method and may possibly be harmful to the sampled individual. In this study, we investigated the use of ectoparasites as a tool to acquire molecular information about the presence and diversity of infectious microorganism in host populations. We tested the presence of three distinct vector-borne microorganisms in both bat blood and bat flies: Bartonella bacteria, malaria-like Polychromophilus sp. (Apicomplexa), and Trypanosoma sp. (Kinetoplastea). We detected the presence of these microorganisms both in bats and in their bat flies, with the exception of Trypanosoma sp. in South African bat flies. Additionally, we found Bartonella sp. in bat flies from one population in Spain, suggesting its presence in the host population even if not detected in bats. Bartonella and Polychromophilus infection showed the highest prevalence in both bat and bat fly populations. Single, co- and triple infections were also frequently present in both. We highlight the use of haematophagous ectoparasites to study the presence of infectious microorganism in host blood and its use as an alternative, less invasive sampling method.

Human-Pathogenic Kasokero Virus in Field-Collected Ticks

Kasokero virus (KASV; genus Orthonairovirus) was first isolated in 1977 at Uganda Virus Research Institute from serum collected from Rousettus aegyptiacus bats captured at Kasokero Cave, Uganda. During virus characterization studies at the institute, 4 laboratory-associated infections resulted in mild to severe disease. Although orthonairoviruses are typically associated with vertebrate and tick hosts, a tick vector of KASV never has been reported. We tested 786 Ornithodoros (Reticulinasus) faini tick pools (3,930 ticks) for KASV. The ticks were collected from a large R. aegyptiacus bat roosting site in western Uganda. We detected KASV RNA in 43 tick pools and recovered 2 infectious isolates, 1 of which was derived from host blood–depleted ticks. Our findings suggest that KASV is maintained in an enzootic transmission cycle involving O. (R.) faini ticks and R. aegyptiacus bats and has the potential for incidental virus spillover to humans.

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.

Compositional turnover in ecto- and endoparasite assemblages of an African bat, Miniopterus natalensis (Chiroptera, Miniopteridae): effects of hierarchical scale and host sex

We studied the compositional turnover in infracommunities and component communities of ecto- and endoparasites infesting a bat, Miniopterus natalensis (Chiroptera, Miniopteridae), across seven sampling sites using the zeta diversity metric (measuring similarity between multiple communities) and calculating zeta decline and retention rate (both scales) and zeta decay (component communities). We asked whether the patterns of zeta diversity differ between (a) infracommunities and component communities; (b) ecto- and endoparasites and (c) subsets of communities infecting male and female bats. The pattern of compositional turnover differed between infracommunities and component communities in endoparasites only. The shape of zeta decline for infracommunities indicated that there were approximately equal probabilities of ecto- and endoparasitic species to occur on/in any bat individual within a site. The shape of zeta decline for component communities suggested the stochasticity of ectoparasite turnover, whereas the turnover of endoparasites was driven by niche-based processes. Compositional turnover in component communities of ectoparasites was more spatially dependent than that of endoparasites. Spatial independence of compositional turnover in endoparasites was due to subcommunities harboured by female bats. We conclude that the patterns of compositional turnover in infracommunities were similar in ecto- and endoparasites, whereas the patterns of turnover in component communities differed between these groups.