Molecular identification and characterization of piroplasm species in Hokkaido sika deer (Cervus nippon yesoensis), Japan

Evaluating the vector potential of deer keds Lipoptena fortisetosa for selected pathogens in Hokkaido sika deer (Cervus nippon yesoensis)

Deer keds (Lipoptena fortisetosa) are hematophagous insects that parasitize various ungulates, including Hokkaido sika deer (Cervus nippon yesoensis). Although deer keds are potential vectors for several pathogens, their role in disease transmission in Japan remains unclear. This study aimed to evaluate the potential of L. fortisetosa as a vector for selected pathogens in sika deer. Blood samples were collected from 32 sika deer and 149 deer keds (64 from deer and 85 from the environment) from the Rusha area of the Shiretoko Peninsula, Hokkaido, Japan. Nested PCRs and sequencing were performed to detect 18S rRNA gene of Theileria sp. Thrivae, 16S rRNA gene of Anaplasma sp. AP-sd (AP-sd), and flagellin B gene of Borrelia sp. in deer and deer keds. In sika deer, the infection rate was 84 % for Theileria sp. Thrivae, 75 % of AP-sd, and 3 % of Borrelia sp. The prevalence in deer keds collected from deer was 62 % for Theileria sp. Thrivae, 2 % AP-sd, and 1 % Borrelia sp. No pathogens were detected in nonparasitic deer keds captured from the environment. Notably, Theileria sp. Thrivae and AP-sd were detected in deer keds collected from PCR-negative sika deer, suggesting that deer keds acquired pathogens from a previously infested host. The absence of pathogens in non-parasitized deer keds suggests that they do not play as a biological vector for the tested pathogens. This study suggests a potential role for L. fortisetosa as a mechanical vector, emphasizing the need for additional experiments, including infection studies.

Seasonal infestation patterns of ticks on Hokkaido sika deer (Cervus nippon yesoensis)

Ticks prefer specific feeding sites on a host that are influenced by host–tick and tick–tick interactions. This study focused on the spatiotemporal distribution of ticks in Hokkaido sika deer, an important tick host in Hokkaido, Japan. Tick sampling was performed on the sika deer in the Shiretoko National Park between June and October 2022. Ticks were collected from 9 different body parts of the deer to compare their attachment site preferences. Interspecific and intraspecific relationships among ticks were examined using co-occurrence analysis. The collected ticks were nymphal and adult stages of 4 species: Ixodes ovatus, Ixodes persulcatus, Haemaphysalis japonica and Haemaphysalis megaspinosa. Seasonal variations in tick burden were observed, with I. persulcatus and I. ovatus peaking in June and declining towards October; H. japonica showing low numbers in July and August and increasing from September; and H. megaspinosa appearing from September onwards with little variation. Attachment site preferences varied among species, with a significant preference for the pinna in I. ovatus and I. persulcatus. Haemaphysalis japonica was mainly found on the body and legs between June and August, and shifted to the pinna from September. Haemaphysalis megaspinosa showed a general preference for areas other than the legs. Co-occurrence analysis revealed positive, negative and random co-occurrence patterns among the tick species. Ticks of the same genus and species exhibited positive co-occurrence patterns; I. ovatus showed negative co-occurrence patterns with Haemaphysalis spp. This study revealed the unique attachment site preferences and distinct seasonal distributions of tick species in the Hokkaido sika deer.

SPECIFIC MOLECULAR DETECTION OF PIROPLASMS AND CHARACTERIZATION OF β-TUBULIN FOR A NOVEL BABESIA SPECIES IN SIKA DEER (CERVUS NIPPON YESOENSIS)

Piroplasms, which include Babesia spp. and Theileria spp., are protozoan parasites carried by ticks and commonly cause disease in animals and humans. Those caused by Babesia spp. manifest as fever, anemia, and hemoglobinuria, while Theileria spp. can lead to high fever, diarrhea, and lymphadenopathy. Recently, Theileria capreoli and an undescribed Babesia sp. were detected for the first time in sika deer (Cervus nippon yesoensis) from Hokkaido; however, there is limited information available on their epidemiology in Japan. Here, a touchdown polymerase chain reaction and reverse line blot hybridization were used to perform an epidemiological survey of T. capreoli and Babesia sp. using blood samples from 82 sika deer in Hokkaido, Japan. This was followed by partial sequencing and phylogenetic analysis of the 18S rRNA and β-tubulin genes to characterize both piroplasm species. A total of 43 (52.4%) and 3 (3.7%) of the sika deer were positive for T. capreoli and Babesia sp., respectively. The β-tubulin gene partial sequences for Babesia sp. were distinct from those of Babesia spp. in GenBank. Phylogenetic analysis showed that the unknown Babesia sp. is more closely related to B. bigemina and B. ovata than other Babesia spp. based on the β-tubulin gene. Further studies are required to understand the ecology of these tick-borne pathogens in Japan.

Theileria infection with severe anemia and unhealed fracture in a sika deer Cervus nippon aplodontus (Cervidae: Cetartiodactyla)

An adult female sika deer (Cervus nippon aplodontus) inhabiting Nara Park, Nara, Japan, had broken bone injuries from a car accident. During its treatment, we found that the sika deer had severe anemia and the fracture remained unhealed throughout. Peripheral blood smear revealed piroplasms in the erythrocytes, which were identified as merozoites of undescribed Theileria species, widely found in sika deer in Japan. This is the report of a clinical case of Theileria infection, accompanied by severe anemia in a sika deer.

Detection and molecular characterization of Babesia sp. in wild boar (Sus scrofa) from western Japan

Wild animals often act as reservoirs of tick-borne Babesia and Theileria spp., which cause piroplasmosis. Therefore, epidemiological investigations about the distribution of these parasites in wild animals are important for evaluating the transmission risk to humans and livestock. In this study, we surveyed Babesia and Theileria spp. infecting wild boar (Sus scrofa) in Kagoshima and Yamaguchi prefectures and Tsushima island, which are all in western Japan, and performed molecular genetic analyses on the samples. DNA was extracted from either blood or liver samples of wild boar captured in Kagoshima prefecture in 2015, 2016, and 2018 and from blood samples from wild boar captured in Yamaguchi prefecture in 2013-2015 and Tsushima island in 2018. PCR screening for the partial 18S ribosomal RNA gene (18S rRNA) of both Babesia and Theileria spp. in wild boar revealed that 63.9 % (140 of 219 samples) were positive. Sequencing of all positive samples revealed that they were all the same Babesia species. Subsequent phylogenetic analyses showed that the parasite is closely related to Babesia sp. previously detected in the hard tick, Amblyomma testudinarium in Kagoshima, and further analyses suggested that this species is genetically related to Babesia gibsoni. On the other hand, no Theileria were detected in any of the samples. In summary, we observed a high prevalence of B. gibsoni-like Babesia sp. in wild boar in western regions of Japan. The host range, distribution, pathogenicity, and life cycle of this protozoan should be further evaluated.

Anaplasma phagocytophilum and Babesia Species of Sympatric Roe Deer (Capreolus capreolus), Fallow Deer (Dama dama), Sika Deer (Cervus nippon) and Red Deer (Cervus elaphus) in Germany

(1) Background: Wild cervids play an important role in transmission cycles of tick-borne pathogens; however, investigations of tick-borne pathogens in sika deer in Germany are lacking. (2) Methods: Spleen tissue of 74 sympatric wild cervids (30 roe deer, 7 fallow deer, 22 sika deer, 15 red deer) and of 27 red deer from a farm from southeastern Germany were analyzed by molecular methods for the presence of Anaplasma phagocytophilum and Babesia species. (3) Results: Anaplasma phagocytophilum and Babesia DNA was demonstrated in 90.5% and 47.3% of the 74 combined wild cervids and 14.8% and 18.5% of the farmed deer, respectively. Twelve 16S rRNA variants of A. phagocytophilum were delineated. While the infection rate for A. phagocytophilum among the four cervid species was similar (71.4% to 100%), it varied significantly for Babesia between roe deer (73.3%), fallow deer (14.3%), sika deer (27.3%) and red deer (40.0%). Deer ≤2 years of age tested significantly more often positive than the older deer for both A. phagocytophilum and Babesia species. (4) Conclusions: This study confirms the widespread occurrence of A. phagocytophilum and Babesia species in wild cervids and farmed red deer in Germany and documents the co-occurrence of the two tick-borne pathogens in free-ranging sika deer.

Utilizing attached hard ticks as pointers to the risk of infection by Babesia and Theileria species in sika deer (Cervus nippon yesoensis), in Japan

Ticks are hematophagous ectoparasites that have a significant impact on their animal hosts. Along with mosquitoes, they are the main arthropod vectors of disease agents in domestic animals, wildlife and humans. To investigate the occurrence and prevalence of piroplasmids in ticks, DNA was extracted from 519 hard ticks collected from 116 hunted Hokkaido sika deer (Cervus nippon yesoensis). The success of the DNA extraction was confirmed by touchdown PCR targeting the mitochondrial 16S rDNA gene of ticks. Touchdown PCR and reverse line blot (RLB) hybridization targeting the 18S rRNA gene were used to detect 14 piroplasm species. All hard ticks parasitizing Hokkaido sika deer were identified as belonging to the genera Ixodes and Haemaphysalis. In total 163 samples (31.4%) were positive for Babesia and Theileria spp. among tick species according to RLB hybridization. Tick DNA hybridized to the oligonucleotide probes of Theileria sp. Thrivae (27.0% of ticks; 140/519), Theileria capreoli (10.6%; 55/519), Babesia divergens-like (1.7%; 9/519), Babesia sp. (Bab-SD) (0.6%; 3/519), Babesia microti U.S. (0.4%; 2/519), and B. microti Hobetsu (0.4%; 2/519). The partial sequencing and phylogenetic analyses of the 18S rRNA gene confirmed the RLB hybridization results. Further investigations are needed to reveal the epidemiology and respective vectors of these pathogens.

Molecular detection of apicomplexan protozoa in Hokkaido brown bears (Ursus arctos yesoensis) and Japanese black bears (Ursus thibetanus japonicus)

Many tick-borne pathogens (TBPs) are present in wildlife. The objective of this study is to reveal the role of wild bears in maintaining TBPs. A total of 49 brown bears (Ursus arctos yesoensis) from Hokkaido, and 18 Japanese black bears (Ursus thibetanus japonicus) from Tochigi, and 66 Japanese black bears from Nagano were examined by two molecular methods, reverse line blot (RLB) hybridization, and nested PCR. A total of 5 TBPs (Hepatozoon ursi, Babesia sp. UR2-like group, Cytauxzoon sp. UR1, Babesia sp. UR1, and Babesia microti) were detected from bear blood DNA samples. B. microti was detected from blood DNA samples of Japanese black bear for the first time, with the prevalence of 6.0% (5/84). Out of detected pathogens, H. ursi, Babesia sp. UR2-like pathogens, and Cytauxzoon sp. UR1 were considered as three of the most prevalent TBPs in bears. The prevalence of H. ursi were significantly higher in Japanese black bear (0% vs 96.4%) while that of Babesia sp. UR2-like group was higher in Hokkaido brown bears (89.8% vs 40.5%). The prevalence of Babesia sp. UR1 were significantly higher in Japanese black bears from Tochigi (44.4%), comparing with those from Nagano (18.2%). The prevalence of the detected TBPs were significantly higher in adult bears, comparing with those in younger bears. The present study suggests that Japanese bear species contribute in the transmission of several TBPs in Japan. The expanding distribution of bears might cause the accidental transmission of TBPs to humans and domestic animals.

Molecular detection of tick-borne protozoan parasites in sika deer (Cervus nippon) from western regions of Japan

The sika deer (Cervus nippon) is one of the most common species of wildlife in Japan. This study aimed to reveal the prevalence of tick-borne protozoan parasites in wild sika deer living in western Japan. We used nested polymerase chain reaction (PCR) to detect the 18S rRNA gene of tick-borne apicomplexan parasites (Babesia, Theileria, and Hepatozoon spp.) from 276 blood and liver samples from sika deer captured in the Yamaguchi, Oita, Kagoshima, Okayama, Ehime, Kochi, and Tokushima Prefectures. In total, 259 samples (259/276; 93.8%) tested positive in the nested PCR screening. Gene sequencing revealed that 99.6% (258/259) of positive samples contained Theileria sp. (sika 1), while Theileria sp. (sika 2), another Theileria species, was detected in only 3 samples. We also found that one sample from a sika deer captured in Kagoshima contained the gene of an unidentified Babesia sp. related to Babesia sp. Kh-Hj42, which was previously collected from tick in western Siberia. In conclusion, we found a high prevalence of piroplasms in sika deer from western Japan, and DNA analysis revealed that Theileria sp. (sika 1) had the highest infection rate.

Differential diagnosis and molecular characterization of Theileria spp. in sika deer (Cervus nippon) in Hokkaido, Japan

Sika deer (Cervus nippon) is widely distributed in Asian countries and is one of the most common wildlife animals in Hokkaido, Japan. Previous studies identified Theileria spp. in sika deer in Japan including Theileria sp. Thrivae belonging to T. cervi group and Theileria sp. sola belonging to T. capreoli group. However, the studies failed to differentiate these two species without sequencing. Therefore, epidemiological information on cervine theileriosis in Hokkaido, Japan is limited. This study differentiated the two Theileria spp. using restriction fragments length polymorphism (RFLP). Based on the PCR-RFLP, Theileria spp. were identified in 103 (88.0%) of 117 samples, and the prevalence of each parasites were 86.3% (n = 101) and 57.3% (n = 67) for Theileria sp. Thrivae and T. capreoli-like, respectively. Phylogenetic analysis based on the 18S rRNA showed a close relationship between Theileria sp. Thrivae and T. cervi in China. In addition, phylogenetic analysis of internal transcribed spacer regions also showed a close relationship between Theileria sp. Thrivae and T. cervi.