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

DNA barcoding and new records of Ornithodoros yumatensis from Central Mexico

Bats represent the second order of mammals with the highest number of species worldwide with over 1,616 species, and almost 10% of them are recorded in Mexico. These mammals have a great diversity of ectoparasites, in particular soft ticks of the genus Ornithodoros. Desmodus rotundus is one of the bat species that has scarcely been studied in terms of tick species richness in Mexico, with three tick species reported in five of the 32 Mexican states. For this reason, the aim of the present work was to identify ticks associated with D. rotundus from Central Mexico. Fieldwork was undertaken in the municipality El Marqués, Ejido Atongo A, Querétaro, Mexico. Bats were captured using mist nets and were visually inspected for tick presence. The ectoparasites were identified morphologically and molecularly with the use of mitochondrial markers 16SrDNA and cytochrome oxidase subunit I (COI). A total of 30 D. rotundus (1 female, 29 males) were captured, from which 20 larvae identified as Ornithodoros yumatensis were recovered. Molecular analysis confirmed the presence of this species with identity values of 99-100% with sequences of this species from the southwestern US, and the Yucatán Peninsula, Mexico. This is the first report of ticks associated with bats for the state of Querétaro, providing the first sequences of the COI gene from Mexican populations of O. yumatensis and shows an increase in the distribution of this soft tick across Central Mexico.

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.

First Report of the Bat Tick Carios kelleyi (Acari: Ixodida: Argasidae) From Vermont, United States

The soft tick Carios kelleyi (Cooley and Kohls, 1941) is an ectoparasite of bats that can harbor bacteria known to cause disease in humans, such as Rickettsia spp., Bartonella spp., and relapsing fever Borrelia spp. Human-tick encounters may occur when bats occupy attics or similar dwellings with access points to human-inhabited areas. During May 2021, a partially engorged adult female C. kelleyi was collected from a Vermont home with an attic that was being used as a roost by big brown bats, Eptesicus fuscus (Chiroptera: Vespertilionidae). The source of the blood in the tick was the domestic dog, Canis lupus familiaris. Subsequently, eight C. kelleyi larvae were collected from a rescued E. fuscus adult. This is the first report of a soft tick species from Vermont and it is unknown how long C. kelleyi has been present in this state. Reports of C. kelleyi are on the rise across the northeastern United States but the implications for the health of humans, domestic animals, and bats in northern New England remain unclear. Bat management plans should consider the importance of bat exclusion in preventing tick encounters with members of the household and should include a tick monitoring component if bats are evicted.

Ixodes scapularis (Ixodida: Ixodidae) Parasitizing an Unlikely Host: Big Brown Bats, Eptesicus fuscus (Chiroptera: Vespertilionidae), in New York State, USA

Ixodes scapularis Say is a three-host tick that has been recorded feeding on over 150 different species of terrestrial vertebrates (mammals, birds, and reptiles). This tick is found throughout the northeastern, coastal southeastern, and upper midwestern United States and is considered the most significant vector of tick-borne pathogens to humans in North America. Despite its ubiquity and broad host range, I. scapularis previously has not been reported feeding on bats (Chiroptera). However, during 2019 and 2020, larvae and nymphs of I. scapularis were recovered from big brown bats, Eptesicus fuscus (Palisot de Beauvois), at four locations in rural New York State, USA. All Ixodes infested bats were injured and found on the ground; therefore, parasitism by I. scapularis was likely opportunistic. Nonetheless, the large number of pathogens known to be associated with bats and the frequency with which I. scapularis bites people suggest that this host-tick relationship is of at least potential epidemiological significance.

Borreliae Part 2: Borrelia Relapsing Fever Group and Unclassified Borrelia

Borreliae of the relapsing fever group (RFG) are heterogenous and can be divided mainly into three groups according to vectors, namely the soft-tick-borne relapsing fever (STBRF) Borreliae, the hard-tick-borne relapsing fever (HTBRF) Borreliae, the louse-borne relapsing fever (LBRF) Borreliae, and the avian relapsing fever ones. With respect to the geographical distribution, the STBRF Borreliae are further subdivided into Old World and New World strains. Except for the Avian relapsing fever group Borreliae, which cause avian spirochetosis, all the others share infectivity in humans. They are indeed the etiological agent of both endemic and epidemic forms of relapsing fever, causing high spirochaetemia and fever. Vectors are primarily soft ticks of Ornithodoros spp. in the STBRF group; hard ticks, notably Ixodes sp., Amblyomma sp., Dermacentor sp., and Rhipicephalus sp., in the HTBRF group; and the louse pediculus humanus humanus in the TBRF one. A recent hypothesis was supported for a common ancestor of RFG Borreliae, transmitted at the beginning by hard-body ticks. Accordingly, STBRF Borreliae switched to use soft-bodied ticks as a vector, which was followed by the use of lice by Borrelia recurrentis. There are also new candidate species of Borreliae, at present unclassified, which are also described in this review.