First detection and molecular identification of Babesia vogeli from Rhipicephalus sanguineus (Acari: Ixodidae) in Taiwan

Nationwide survey of ticks on domesticated animals in Taiwan: Revealing the hidden threat to animal and public health

Ticks are not only bloodsucking ectoparasites but also important vectors of tick-borne diseases (TBDs), posing significant threats to public and animal health. Domesticated animals serve as critical hosts for numerous ticks, highlighting the importance of understanding tick infestations in Taiwan. To address this knowledge gap, we conducted a nationwide survey to identify ticks on domesticated animals and associated environments in 2018 and 2019. A total of 6,205 ticks were collected from 1,337 host animals, revealing the presence of seven tick species, with Rhipicephalus microplus, and Rhipicephalus sanguineus being the dominant species. High infestation rates and widespread distribution of ticks were observed on domesticated animals, especially on dogs and cattle (yellow cattle and angus cattle), and the neighbouring grassland of yellow cattle. While this study has certain limitations, it provides valuable insights into the distribution and prevalence of ticks on domesticated animals in Taiwan and their implications for controlling TBDs. Further research is needed to comprehensively understand the complex interactions among ticks, hosts and pathogens.

Identification of Rhipicephalus sanguineus sensu lato infected with tick-borne pathogens from pet and stray dogs in Guangzhou, Southern China

Tick-borne diseases are of substantial concern worldwide for both humans and animals, and dogs are frequently exposed to tick infestation. The aim of this study was to examine tick infestation of pet and stray dogs in Guangzhou, Southern China, as well as tick-borne pathogens of randomly sampled ticks. Ticks were found on 118 (14.1% [95% confidence interval; CI: 13.6-14.6]) out of 836 animals in four veterinary clinics and two shelters. A total of 280 individual ticks were collected from tick-infested dogs. Rhipicephalus sanguineus sensu lato (s.l.) was identified. PCR tests were conducted to detect six tick-borne pathogens in 280 ticks. The prevalence of tick-borne pathogens was 5.3% for Babesia spp., including Babesia vogeli (5.0% [95% CI: 4.3-6.3]) and Babesia gibsoni (0.3% [95% CI: 4.3-6.3]). These results indicated that R. sanguineus s.l. was the tick species found in dogs in Guangzhou city, and that dogs were at risk to exposure to babesiosis, implying the need for surveillance for this disease in dogs in this region.

Correlation between Babesia Species Affecting Dogs in Taiwan and the Local Distribution of the Vector Ticks

The objective of our study was to survey Babesia infection rates by PCR and tick species on stray dogs to correlate the distribution of Babesia with the distribution of ticks infesting dogs in Taiwan. Three hundred eighty-eight blood samples and 3037 ticks were collected from 388 roaming, and free-ranging owned dogs at residential sites in Taiwan between January 2015 and December 2017. The prevalence of B. gibsoni and B. vogeli was 15.7% (61/388) and 9.5% (37/388), respectively. Most positive B. gibsoni dogs were found in the northern part of the country 56/61 (91.8%), whereas a few were found in the middle 5/61 (8.2%). Babesia vogeli infection rates were 10%, 3.6%, and 18.2% in the northern, central, and southern regions, respectively. Five species of ticks were found: Rhipicephalus sanguineus (throughout Taiwan), Rhipicephalus haemaphysaloides (in the north), Haemaphysalis hystricis (in the north and middle of Taiwan), and Amblyomma testidunarium and Ixodes ovatus (both in the north). None of the dogs in the south were infected with B gibsoni, which correlated with the absence of H. hystricis, a tick recently identified as the local vector for B gibsoni. Babesia vogeli was more equally distributed, coinciding with R. sanguineus, a tick that is present throughout Taiwan. Anaemia was detected in 86.9% of infected dogs; among these dogs, approximately 19.7% showed severe anaemia (HCT < 20). These findings provide useful advice for owners regarding outdoor activities with their dogs and local veterinarians with a regional differential diagnosis of babesiosis in Taiwan.

Prevalence and Factors Associated with Ectoparasite Infestations in Dogs from the State of Tabasco, Mexico

This study was carried out to identify the ectoparasites that infest owned dogs in the state of Tabasco, Mexico. In total, 1,302 dogs were sampled in the 5 ecological regions of Tabasco. The dog owners were surveyed to identify the factors associated with infestations. Ectoparasites were identified using taxonomic keys. Eleven species of ectoparasites were observed. General prevalence was 26.65%. Rhipicephalus sanguineus and Ctenocephalides felis were the most prevalent and abundant ectoparasites. The most important factors associated with ectoparasite infestations in the studied dogs were living outdoors, being a non-purebred, having short hair, being dark-haired, and having a body condition <3. Ectoparasite studies such as the one presented herein generate important information to create control programs focused on decreasing infestations in companion animals and thus the likelihood of zoonotic transmission of pathogens.

Molecular detection and genetic identification of Wolbachia endosymbiont in Rhipicephalus sanguineus (Acari: Ixodidae) ticks of Taiwan

The genetic identity of Wolbachia endosymbiont in Rhipicephalus sanguineus ticks was determined for the first time in Taiwan. In total 1004 Rh. sanguineus ticks were examined for Wolbachia by polymerase chain reaction assay targeting the Wolbachia surface protein (wsp) gene. The prevalence of Wolbachia infection was detected in nymphs, females, and males with an infection rate of 55.8, 39.8, and 44%, respectively. The phylogenetic relationships were analyzed by comparing the sequences of wsp gene obtained from 60 strains of Wolbachia representing 11 strains of supergroup A and 10 strains of supergroup B. In general, seven major clades of supergroup A and six major clades of supergroup B can be easily distinguished by neighbour-joining analysis and were congruent by maximum likelihood method. All these Wolbachia strains of Taiwan were genetically affiliated to supergroups A and B with high sequence similarity of 98.3-100% and 98.6-100%, respectively. Intra- and inter-group analysis based on the genetic distance (GD) values indicated a lower level (GD < 0.017) within the group A strains of Taiwan compared with the group B (GD > 0.576) of other Wolbachia strains, as well as a lower level (GD < 0.062) within the group B strains of Taiwan compared with the group A (GD > 0.246) of other Wolbachia strains. Our results provide the first genetic identification of Wolbachia endosymbiont in Rh. sanguineus ticks collected from Taiwan, and detection of Wolbachia in male and nymphal ticks may imply the possible mechanism of transstadial transmission in Rh. sanguineus ticks.

Mitochondrial sequences of Rhipicephalus and Coxiella endosymbiont reveal evidence of lineages co-cladogenesis

Rhipicephalus ticks are competent vectors of several pathogens, such as Spotted Fever Group Rickettsiae (SFGR) and many Babesia species. Within this genus, different R. sanguineus s.l. lineages show an unequal vector competence and resistance regarding some pathogenic strains. Current literature supports that tick endosymbionts may play an essential role in the transmission ability of a vector. Indeed, the microbial community of Rhipicephalus seems to be dominated by Coxiella-like endosymbionts (CLE). Still, their co-evolutionary associations with the complicated phylogeny of Rhipicephalus lineages and their transmissible pathogens remain unclear. We performed a phylogenetic congruence analysis to address whether divergent R. sanguineus s.l. lineages had a different symbiont composition. For that, we applied a PCR based approach to screen part of the microbial community present in 279 Rhipicephalus ticks from the Iberian Peninsula and Africa. Our analyses detected several qPCR-positive signals for both SFGR and Babesia species, of which we suggest R. sanguineus-tropical lineage as a natural vector of Babesia vogeli and R. sanguineus-temperate lineage of SFGR. The acquisition of 190 CLE sequences allowed to evaluate co-phylogenetic associations between the tick and the symbiont. With this data, we observed a strong but incomplete co-cladogenesis between CLE strains and their Rhipicephalus tick lineages hosts.

Molecular detection of tick-borne haemopathogens in shelter dogs and Rhipicephalus sanguineus (sensu lato) ticks from Peninsular Malaysia

Ticks are important vectors in transmitting various pathogens and they could jeopardize the health and welfare of humans and animals worldwide. The present study aimed to investigate the presence of important tick-borne haemopathogens (TBH) in dogs and ticks via polymerase chain reaction (PCR) assays. A total of 220 blood samples and 140 ticks were collected from 10 animal shelters in Peninsular Malaysia. Of 220 blood samples, 77 (35 %) were positive to TBH, of which 20 % were E. canis, 12 % were A. platys, 7 % were B. gibsoni and 7 % were B. vogeli. All ticks were identified as Rhipicephalus sanguineus with five samples (3.57 %) positive with TBH. Co-infections of TBH (0.45-9.55 %) in dogs were also observed in this study.

A Retrospective Epidemiological Study: The Prevalence of Ehrlichia canis and Babesia vogeli in Dogs in the Aegean Region of Turkey

Among tick-borne diseases, Ehrlichia canis and Babesia piroplasm cause important diseases in dogs where the distributions of the pathogen, vector and host overlap. The primary aim of the present study was to detect the prevalence of Babesia spp. and E. canis using PCR and reverse line blot (RLB) hybridization assay in a total of 379 samples comprising stray and owned dogs and to compare the diagnostic sensitivity of the two tests. Overall, 41.4% of dogs were infected with B. vogeli and/or E. canis as single (35.4%) and mixed (6.1%) infections. The majority of Babesia positive dogs (74.1%) were co-infected with E. canis. PCR detected a higher (P= 0.000) number of positivity in some provinces compared to RLB. To the best of our knowledge, these findings provide the first molecular evidence for the existence of B. vogeli in the Aegean Region, Turkey. The present study pinpoints the distribution and prevalence of E. canis and B. vogeli in the Aegean region of Turkey as of 2004 and as such establishes a baseline. This is of pivotal importance for future studies aimed to demonstrate changes in the dynamics of E. canis and B. vogeli infections in the region.

First detection and genetic identification of Hepatozoon canis in Rhipicephalus sanguineus sensu lato ticks collected from dogs of Taiwan

We determined the prevalence of infection and genetic identity of Hepatozoon spp. harbored by Rhipicephalus sanguineus sensu lato ticks in Taiwan. A total of 1082 ticks were collected from dogs and DNA extraction was performed from individual tick specimens. Hepatozoon infection was detected by performing a nested-PCR assay based on the 18S small subunit ribosomal RNA (ssrRNA) gene. The genetic identity of detected Hepatozoon was identified by gene sequencing and phylogenetic analysis. Hepatozoon infection was detected in nymphs, males and females of R. sanguineus s. l. ticks with an infection rate of 20.8%, 22.8% and 29.4%, respectively. Sequence and phylogenetic analysis revealed that these Hepatozoon spp. of Taiwan were genetically affiliated to the same clade within the genospecies of H. canis and can be discriminated from other genospecies of H. americanum and H. felis. Intraspecies analysis based on the genetic distance (GD) values indicates a lower level (GD < 0.005) genetic divergence within the same genospecies of H. canis detected in Taiwan, Brazil and Spain. Interspecies analysis also reveals a higher heterogeneity of Taiwan strains distinguished from other genospecies of H. felis (GD > 0.040) and H. americanum (GD > 0.056). This study provides the first molecular evidence of H. canis detected and identified in various stages of R. sanguineus s. l. ticks in Taiwan. Detection of H. canis in unfed male ticks may imply the possible mechanism of transstadial survival in R. sanguineus s. l. ticks. Further investigations on Hepatozoon spp. harbored by various vector ticks in Taiwan may illustrate the epidemiological significance of this parasite.

First zootiological survey of hard ticks (Acari: Ixodidae) infesting dogs in northern Taiwan

Hard ticks infesting canine hosts were determined for the first time in northern Taiwan. Between May 2010 and April 2011, a total of 9467 ticks were collected from 2025 dogs. They were identified based on pictorial keys of their morphological characteristics. These ticks belong to three genus and six species: Rhipicephalus sanguineus, R. haemaphysaloides, Haemaphysalis hystricis, H. lagrangei, H. formosensis and Ixodes ovatus. Rhipicephalus sanguineus was the most dominant species (92.5%), followed by H. hystricis (4.6%), R. haemaphysaloides (2.3%), I. ovatus (0.54%), H. lagrangei (0.04%) and H. formosensis (0.01%). The overall density was 4.7 ticks per dog (ranging from 1.8 to 20.8) and the highest seasonal prevalence was observed in September with an average density of 8.2 ticks per dog. Our results not only provide the first survey of hard ticks infesting dogs in northern Taiwan, but also highlight the possible impact of these tick species on human health.

Hard tick (Acari: Ixodidae) species of livestock and their seasonal activity in Boyer-Ahmad and Dena cities of Kohgiluyeh and Boyer-Ahmad Province, Southwest of Iran

Aim:

The present study was carried out to identify the Ixodidae ticks fauna of livestock and their seasonal activity in the cities of Boyer-Ahmad and Dena of Kohgiluyeh Province, south-west of Iran.

Materials and Methods:

Hard ticks from sheep, goats, and cattle were collected manually, stored in 70% ethanol, and identified using morphological characters.

Results:

During the study, a total of 1273 hard ticks from four genera, including Rhipicephalus, Hyalomma, Dermacentor, and Haemaphysalis, were collected. Rhipicephalus sanguineus (s.l.) had the highest frequencies in both cities with 62.08 and 62.88% of collected specimens, followed by Hyalomma scupense with 14.36 and 13.54% in Boyer-Ahmad and Dena, respectively. Furthermore, Hyalomma marginatum with only one sample or 0.12% of collected ticks showed the lowest frequencies in the studied areas. Dermacentor marginatus with three samples or 0.37% was recorded only in Boyer-Ahmad, and Haemaphysalis sulcata with two samples or 0.43% was recorded only in Dena. In both cities, sheep were the most infested ruminant, and the ears in sheep and goats were the most affected areas. The highest activity was observed in spring, and the lowest activity was observed in winter and autumn.

Conclusion:

The results of the present study showed that Hyalomma and Rhipicephalus genera were the most widespread genera in the study areas. Regarding the importance of genera, such as Rhipicephalus, Hyalomma, and Haemaphysalis, in transmitting disease agents and the location of Kohgiloyeh and Boyer-Ahmad Province in the routes of migrant birds, further studies are required to elucidate their exact roles in human and livestock health in these areas.

Molecular Evidence for a Novel Species of Babesia in Unfed Rhipicephalus sanguineus sensu lato (Acari: Ixodidae)

This study reports a novel species of Babesia in unfed Rhipicephalus sanguineus sensu lato and its phylogenetic relationship to other species. One-hundred and forty DNA samples extracted from tick pools comprising 5,403 unfed R. sanguineus s.l. ticks were screened for Babesia. Overall Babesia infection was detected in female, male, and nymph pools with an infection rate maximum likelihood estimate (MLE) of 1.98 (CI 0.65-4.74), 0.50 (CI 0.03-2.40), and 0.07 (CI 0.01-0.21), respectively. Three adult female tick pools (MLE 1.44, CI 0.38-3.88) and one adult male pool (MLE 0.50, CI 0.03-2.40) hybridized to the catchall and Babesia genus probes but did not hybridize to any species-specific probe tested, suggesting the presence of an unidentified Babesia species. Phylogenetic analysis and sequencing revealed the newly detected Babesia isolate to form a clade distinct from fully identified canine, bovine, equine, and ovine Babesia species, with a range of 88.6-92.9% nucleotide identity.

Detection of Babesia spp. in Dogs and Their Ticks From Peninsular Malaysia: Emphasis on Babesia gibsoni and Babesia vogeli Infections in Rhipicephalus sanguineus sensu lato (Acari: Ixodidae)

Canine babesiosis is an emerging tick-borne disease with a worldwide distribution, including Malaysia. While the prevalence of Babesia has been documented from dogs in Malaysia, occurrence of Babesia has been relatively little studied in their tick vectors. Accordingly, a total of 240 dogs and 140 Rhipicephalus sanguineus sensu lato (s.l.) (Acari: Ixodidae) ticks from Malaysia were molecularly screened for the presence of Babesia protozoa in the present study. Babesia gibsoni was only detected in ticks (1.4%), whereas Babesia vogeli was detected in both ticks (1.4%) and dogs (2.1%). This study highlights the detection of B. gibsoni and B. vogeli for the first time, in both adult and nymphal stages of R. sanguineus s.l. in Malaysia, suggesting the potential role of this tick species in transmitting canine babesiosis.

Molecular evidence for the transovarial passage of Babesia gibsoni in Haemaphysalis hystricis (Acari: Ixodidae) ticks from Taiwan: a novel vector for canine babesiosis

BACKGROUND

Babesia gibsoni is the predominant tick-borne protozoan blood parasite affecting dogs throughout the Oriental region. Babesia gibsoni is transmitted by Haemaphysalis longicornis, whereas a similar role has been suggested for Rhipicephalus sanguineus. Haemaphysalis longicornis does not occur in Taiwan, but R. sanguineus is widely distributed on dogs. However, clinical cases of babesiosis are mainly restricted to the northern part of the island. The discrepancy between tick distribution and clinical cases stimulated us to investigate the tick species distribution on dogs in northern Taiwan, with the aim to identify the local vector for canine babesiosis.

METHODS

Ticks were collected from stray dogs or free ranging pet dogs in northern Taiwan between 2015 and 2017 and, after identification, were tested for the presence of tick-borne Babesia parasites using PCR and reverse line blot (RLB) hybridisation. Moreover, engorged ticks collected from the dogs were incubated at 28 °C to allow them to oviposit. Their subsequent larval progeny was also examined by PCR/RLB.

RESULTS

A total of 1085 ticks collected from 144 stray dogs at different residential areas consisted of 5 different species: H. hystricis (n = 435), R. sanguineus (n = 582), R. haemaphysaloides (n = 43), Amblyomma testudinarium (n = 14) and Ixodes ovatus (n = 11) were identified. Babesia gibsoni DNA was detected in H. hystricis females (10.3%), males (7.0%) and in 2.6% of the nymphs. One R. sanguineus female and one A. testudinarium female tick also carried B. gibsoni DNA. DNA of B. gibsoni was demonstrated in 11 out of 68 (16.2%) batches of larval ticks derived from engorged H. hystricus ticks only. Babesia vogeli DNA was detected only in R. sanguineus females (2.6%) and males (2.4%). DNA of B. vogeli was detected in 13 out of 95 (13.7%) batches of larval ticks derived from engorged R.sanguineus females.

CONCLUSIONS

Babesia gibsoni DNA was detected in the larval progeny of H. hystricis ticks only, whereas B. vogeli was restricted to the larvae of R. sanguineus. This provides evidence for transovarial passage of B. gibsoni in H. hystricis and evidence that this tick does act as the local vector for this parasite on dogs in northern Taiwan where most cases of babesiosis are reported. The vectorial capacity of R. sanguineus for babesiosis is probably restricted to the transmission of B. vogeli only.

Molecular and morphological identification of a human biting tick, Amblyomma testudinarium (Acari: Ixodidae), in Taiwan

Genetic identity and morphological features of a human biting tick, Amblyomma testudinarium, were determined for the first time in Taiwan. Morphological features of adult male and female ticks of Am. testudinarium were observed and photographed by a stereo- microscope. The genetic identity was analyzed by comparing the sequences of mitochondrial 16S ribosomal DNA gene obtained from 18 strains of ticks representing 10 species of Amblyomma, and four outgroup species of Dermacentor and Rhipicephalus ticks. Nine major clades could be easily distinguished by neighbour-joining analysis and were congruent by maximum-parsimony method. All these Am. testudinarium ticks collected from Taiwan and Japan were genetically affiliated to a monophyletic group with highly homogeneous sequence (99.8-100% similarity), and can be discriminated from other species of Amblyomma and other genera of ticks (Dermacentor and Rhipicephalus) with a sequence divergence ranging from 6.9 to 23.9%. Moreover, intra- and inter-species analysis based on the genetic distance (GD) values indicated a lower level (GD < 0.003) within the same lineage of Am. testudinarium ticks collected from Taiwan and Japan, as compared with other lineage groups (GD > 0.108) of Amblyomma ticks, as well as outgroup (GD > 0.172) species. Our results provide the first distinguished features of adult Am. testudinarium ticks and the first genetic identification of Am. testudinarium ticks collected from humans in Taiwan. Seasonal prevalence, host range, and vectorial capacity of this tick species in Taiwan need to be further clarified.

First detection and molecular identification of Babesia gibsoni from Rhipicephalus sanguineus ticks

Babesia gibsoni was firstly identified in Rhipicephalus sanguineus ticks infested on dogs in Asia. A total of 1195 ticks collected from veterinary practitioners and pet clinics were examined for Babesia by nested-polymerase chain reaction assay based on the 18S small subunit ribosomal RNA (ssrRNA) gene. Babesia infection was detected in nymph, male and female ticks with an infection rate of 2.42%, 0.98% and 1.97%, respectively. Sequence and phylogenetic analysis revealed that these Babesia spp. were genetically affiliated to the same clades within the genospecies of B. gibsoni and B. vogeli, and can be discriminated from other genospecies of Babesia. Intra- and inter-species analysis based on the genetic distance (GD) values indicated a lower level in B. gibsoni (GD<0.011) compared with other genospecies of Babesia (GD>0.106) and out-group protozoa (GD>0.244). This study provides the first molecular evidence of B. gibsoni identified in nymphs of R. sanguineus ticks in Asia, and further confirms the detection of B. vogeli in nymphs and adults of R. sanguineus in northern Taiwan. The epizootiological significance of canine Babesia spp. transmitted by R. sanguineus tick needs to be further identified.

Molecular analysis of Rhipicephalus sanguineus (Acari: Ixodidae), an incriminated vector tick for Babesia vogeli in Taiwan

The genetic identity of Rhipicephalus sanguineus tick was determined for the first time in Taiwan. The phylogenetic relationships were analyzed by comparing the sequences of mitochondrial 16S ribosomal DNA gene obtained from 32 strains of ticks representing six species of Rhipicephalus, two species of Dermacentor and two outgroup species (Haemaphysalis inermis and Ixodes ricinus). Seven major clades can be easily distinguished by neighbour-joining analysis and were congruent by maximum-parsimony method. All R. sanguineus ticks of Taiwan were genetically affiliated to the tropical lineage group of R. sanguineus sensu lato with highly homogeneous sequence (99.7-100% similarity), and can be discriminated from the temperate lineage group of Rhipicephalus sp. II and R. turanicus with a sequence divergence ranging from 1.7 to 5.2%. In contrast, the nucleotide variations among other Rhipicephalus spp. and other species/genus of ticks compared with the R. sanguineus ticks of Taiwan were measured from 10.6 to 25.5%. Moreover, intra- and inter-species analysis based on the genetic distance (GD) values indicated a lower level (GD < 0.003) within tropical lineage group compared with temperate lineage group (GD > 0.055) of Rhipicephalus, as well as other (GD > 0.129) and outgroup (GD > 0.236) species. Our results provide the first genetic identification of R. sanguineus ticks collected from Taiwan and demonstrate that all these R. sanguineus of Taiwan affiliated to the tropical lineage group of R. sanguineus sensu lato.