A snapshot of climate drivers and temporal variation of Ixodes ovatus abundance from a giant panda living in the wild.

Ticks and tick-borne diseases have negative impacts on the health of wild animals including endangered and vulnerable species. The giant panda (Ailuropoda melanoleuca), a vulnerable and iconic flagship species, is threatened by tick infestation as well. Not only can ticks cause anemia and immunosuppression in the giant panda, but also bacterial and viral diseases. However, previous studies regarding tick infestation on giant pandas were limited in scope as case reports from sick or dead animals. In this study, an investigation focusing on the tick infestation of a reintroduced giant panda at the Daxiangling Reintroduction Base in Sichuan, China was conducted. Ticks were routinely collected and identified from the ears of the giant panda from March to September in 2021. A linear model was used to test the correlation between tick abundance and climate factors. All ticks were identified as Ixodes ovatus. Tick abundance was significantly different among months. Results from the linear model showed temperature positively correlated to tick abundance, while air pressure had a negative correlation with tick abundance. To the best of our knowledge, this study is the first reported investigation of tick species and abundance on a healthy giant panda living in the natural environment, and provides important information for the conservation of giant pandas and other species sharing the same habitat.

Complete mitochondrial genome and phylogenetic analysis of Ixodes ovatus (Acari: Ixodidae).

Ixodes ovatus is referred to as an obligatory blood-sucking ectoparasite that is capable to infest both humans and animals. In the present study, the complete mitochondrial genome of I. ovatus was sequenced and analyzed using next-generation sequencing (NGS) technology. With a size of 14,520 bp, the entire mitogenome contains 37 genes including 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), 2 ribosomal RNAs (rRNAs), and 3 control regions (D-loops). Based on the 13 PCGs nucleotide sequences, the phylogenetic relationship of I. ovatus was analyzed using Maximum-likelihood. As suggested by the results of the obtained phylogenety, I. ovatus is most closely associated with Ixodes hexagonus. This study is expected to promote further studies on the evolution of Ixodidae.

Molecular detection of Borrelia burgdorferi (sensu lato) and Rickettsia spp. in hard ticks distributed in Tokachi District, eastern Hokkaido, Japan.

Ticks transmit various pathogens, including parasites, bacteria and viruses to humans and animals. To investigate the ticks and the potentially zoonotic pathogens that they may carry, questing ticks were collected in 2017 from 7 sites in Tokachi District, eastern Hokkaido, Japan. A total of 1563 ticks including adults (male and female), nymphs and larvae were collected. Four species of ticks were identified: Ixodes ovatus, Ixodes persulcatus, Haemaphysalis japonica and Haemaphysalis megaspinosa. Of the 1563 ticks, 1155 were used for DNA extraction. In total, 527 individual tick DNA samples prepared from adults (n = 484), nymphs (n = 41) and larvae (n = 2); and 67 pooled tick DNA samples prepared from larval stages (n = 628) were examined using PCR methods and sequencing to detect Borrelia burgdorferi (sensu lato) and Rickettsia spp. The phylogenetic analysis of Borrelia spp. flaB gene sequences showed the presence of the human pathogenic B. burgdorferi (s.l.) species (Borrelia garinii, Borrelia bavariensis and Borrelia afzelii) in I. persulcatus, whereas the non-pathogenic species Borrelia japonica was found only in I. ovatus. In I. persulcatus, B. garinii and/or its closely related species B. bavariensis was detected in both adults and nymphs at a prevalence of 21.9% whereas B. afzelii was found only in adults (1.8%). The prevalence of B. japonica in adult I. ovatus was 21.8%. Rickettsia species were identified through phylogenetic analysis based on gltA, 16S rRNA, ompB and sca4 genes. Four genotypes were detected in the samples which were classified into three species. The prevalence of human pathogenic Rickettsia helvetica was 26.0% in I. persulcatus adults and nymphs, 55.6% in I. persulcatus larval pools, and 1.7% in H. megaspinosa larval pools. The prevalence of "Candidatus R. tarasevichiae" was 15.4% in I. persulcatus adults and nymphs and 33.3% in I. persulcatus larval pools. The prevalence of "Candidatus R. principis" in H. megaspinosa adults and nymphs was 11.1% whereas it was detected in 3.4% of the H. megaspinosa larval pools. These results indicate that most of the risks of Lyme borreliosis and spotted fever group rickettsiosis infection in eastern Hokkaido, Japan, are restricted to I. persulcatus.

[Effects of environmental factors on the distribution of suitable habitats of Ixodes ovatus in China].

OBJECTIVE: To identify the environmental factors affecting the distribution of suitable habitats of Ixodes ovatus, and to examine the effects of environmental changes on the distribution of suitable habitats of I. ovatus. METHODS: Data pertaining to the distribution of I. ovatus in China were captured by literature review. The distribution of suitable habitats of I. ovatus in China was simulated using the maximum entropy model with the environmental variable data and the I. ovatus distribution data. In addition, the potential distribution of suitable habitats of I. ovatus was predicted based on the 2050 and 2070 environmental data. RESULTS: The current suitable habitats of I. ovatus cover 3.11 million km2, accounting for 32.28% of the total land area of China, and they are mainly concentrated in southwestern and northwestern China. Among the screened 16 environmental factors, the standard deviation of seasonal variation of temperature, average annual precipitation and altitude were predominant environmental factors affecting the distribution of suitable habitats of I. ovatus, and these three variables contributed 76.5% to the distribution of suitable habitats of I. ovatus in China. The suitable habitats of I. ovatus were predicted to showing a tendency towards expansion to northwestern and northeastern China in 2050 and 2070, and the proportion of highly suitable habitats of I. ovatus was predicted to increase. CONCLUSIONS: Moderate climate, adequate precipitation and high altitude are favorable for the survival of I. ovatus. Future climate changes may cause expansion of suitable habitats of I. ovatus in China.

Survey to detect tick-borne encephalitis virus from human-feeding ticks in Hokkaido, Japan.

A tick infestation is one of the most common arthropod-related skin diseases in Hokkaido, the northernmost island of Japan. Ticks also act as an infectious disease vector for humans. Tick-borne encephalitis (TBE), a highly mortal central nervous system infection caused by TBE virus (TBEV), has sporadically occurred there recently. However, there have been no epidemiological data on the current surveillance of human tick bites and the prevalence of TBEV in human-feeding ticks. This study was performed to clarify those indeterminate issues. One hundred and fifty-three ixodid ticks feeding on humans were collected from 150 outpatients in Hokkaido during the season of April to August 2018. None of the cases showed any infectious symptoms. These ticks were morphologically identified to species, and a cytopathic assay on baby hamster kidney cells was carried out to detect TBEV from each tick. The tick collection consisted of 108 Ixodes persulcatus (one nymph and 107 adult females), 44 female Ixodes ovatus, and one female Haemaphysalis japonica. No tick extracts showed positive results of the cytopathic assay, suggesting the non-existence of TBEV in the present specimens. However, the survey to detect TBEV from human-feeding ticks is still important to monitor the occurrence of TBE, because human tick bites by I. ovatus, a possible vector of TBEV, are increasing even in the northern and eastern areas of Hokkaido.

Detection of Tick-Borne Pathogens in Ticks from Dogs and Cats in the Yamagata Prefecture of Japan in 2018.

Companion animals can become infected with tick-borne diseases (TBDs) becoming a reservoir for human transfer, thereby damaging human health. To evaluate whether companion animals are infested with ticks harboring human TBD pathogens, we detected TBD pathogens in ticks collected from dogs and cats brought to animal hospitals in the Yamagata prefecture of Japan. An investigation of 164 adult ticks collected from 88 dogs and 41 cats between March and July 2018 revealed that this region was dominated by three tick species, Ixodes ovatus (n = 95, 57.9%), Ixodes nipponensis (n = 37, 22.6%) and Haemaphysalis flava (n = 10, 6.1%). To evaluate their pathogenic potential, we went on to test each tick for spotted fever group rickettsiae, Lyme disease borreliae, relapsing fever borreliae, tick-borne encephalitis virus, and Huaiyangshan banyangvirus (formerly SFTS virus). Our results identified two I. ovatus ticks infected with Borrelia miyamotoi, which causes emerging relapsing fever; several I. nipponensis ticks infected with Rickettsia monacensis, which cause rickettsiosis; and several Ixodes persulcatus ticks infected with Rickettsia helvetica, which can also cause rickettsiosis. These results suggest that dogs and cats, and veterinary professionals and pet owners, in the Yamagata prefecture have some risk of exposure to several TBDs. This means that there should be continuous monitoring and reporting of TBDs, even those known to be uncommon in Japan, in both companion animals and humans to ensure the health and safety of both humans and animals in Japan.

Isolation and molecular detection of Ehrlichia species from ticks in western, central, and eastern Japan.

Ehrlichiosis is a tick-borne bacterial disease caused by pathogens of the Ehrlichia genus. Although human ehrlichiosis has not been reported in Japan, Ehrlichia spp., which are closely related to Ehrlichia chaffeensis, were detected in several species of ixodid ticks. In this study, the presence of Ehrlichia spp. in ticks in Japan was studied by using isolation and molecular detection methods. In total, 1237 ticks were collected from vegetation in western, central, and eastern parts of Japan. The ticks were tested for detection of ehrlichial DNA with a nested polymerase chain reaction and/or isolation by inoculation of mice with the homogenate. Ehrlichial DNA was detected in 29 of these ticks. The ehrlichial DNAs, groEL and 16S rRNA genes, detected in Ixodes turdus showed a high similarity to those of E. chaffeensis with 94.7% and 99.2% identity, respectively. Ehrlichia sp. HF and Candidatus Neoehrlichia mikurensis were also detected in I. ovatus. Furthermore, Ehrlichia sp. HF was isolated from laboratory mice that were intraperitoneal inoculated with I. ovatus tick homogenate. Some ehrlichial agents detected in Ixodes ticks might be a previously unknown Ehrlichia species. In this study, Candidatus N. mikurensis was detected in I. ovatus ticks. Because I. ovatus is distributed widely and cases of its tick bite in humans are ubiquitously reported in Japan, there is a potential for ehrlichiosis to be endemic to Japan, necessitating intensive surveillance of this infectious disease.

Tick bite-Erythema migrans.

This manuscript describes the typical presentation of erythema migrans caused by tick bite. The purposes of this article are (i) to encourage physicians to observe patients with tick bite carefully since it may cause fatal encephalitis, and (ii) to facilitate physicians, especially in endemic areas, to consider tick-borne encephalitis virus as one of the causes of encephalitis.

Tick surveillance for Borrelia miyamotoi and phylogenetic analysis of isolates in Mongolia and Japan.

Borrelia miyamotoi, recently recognized as a human pathogenic spirochete, was isolated from Ixodes persulcatus and I. ovatus in northern Mongolia and Honshu Island, a major island in Japan. Although no human B. miyamotoi infections have been reported in Mongolia, the prevalence of B. miyamotoi in ticks from Mongolia is higher than that in ticks from Hokkaido, Japan, where human cases have been reported. Moreover, the multi-locus sequence analysis of cultured isolates revealed that B. miyamotoi isolates in Mongolia belong to the Siberian type, a sequence type that was originally reported from isolates from I. persulcatus in Hokkaido. Thus, there is a possibility of unrecognized human B. miyamotoi infections in Mongolia. Moreover our data support the hypothesis of clonal expansion of the Siberian type B. miyamotoi. In contrast, although the isolates were found to belong to the Siberian type B. miyamotoi, two isolates from I. persulcatus in Honshu Island were identified to be of a different sequence type. Furthermore, B. miyamotoi isolates from I. ovatus were distinguishable from those from I. ricinus complex ticks, according to genetic analysis. In this study, we show that there may be some genetic diversity among B. miyamotoi in ticks from Honshu Island.

[Ixodes ovatus found in Huainan area in Anhui Province].

OBJECTIVE: To study the morphological characteristics of Ixodes ovatus in order to provide the evidence for future research. METHODS: A group of goats were randomly selected and checked one by one, and the ticks were collected. RESULTS: A hard tick was found on the surface of a goat, and it was identified as Ixodes ovatus. CONCLUSIONS: Ixodes ovatus has been found in Huainan area in Anhui Province, confirming that Huainan area is a new breeding place of Ixodes ovatus. This finding may contribute to the epidemiological research of tick-borne diseases.

Effects of environmental factors on the distribution of suitable habitats of Ixodes ovatus in China / 中国血吸虫病防治杂志

Objective To identify the environmental factors affecting the distribution of suitable habitats of Ixodes ovatus, and to examine the effects of environmental changes on the distribution of suitable habitats of I. ovatus. Methods Data pertaining to the distribution of I. ovatus in China were captured by literature review. The distribution of suitable habitats of I. ovatus in China was simulated using the maximum entropy model with the environmental variable data and the I. ovatus distribution data. In addition, the potential distribution of suitable habitats of I. ovatus was predicted based on the 2050 and 2070 environmental data. Results The current suitable habitats of I. ovatus cover 3.11 million km2, accounting for 32.28% of the total land area of China, and they are mainly concentrated in southwestern and northwestern China. Among the screened 16 environmental factors, the standard deviation of seasonal variation of temperature, average annual precipitation and altitude were predominant environmental factors affecting the distribution of suitable habitats of I. ovatus, and these three variables contributed 76.5% to the distribution of suitable habitats of I. ovatus in China. The suitable habitats of I. ovatus were predicted to showing a tendency towards expansion to northwestern and northeastern China in 2050 and 2070, and the proportion of highly suitable habitats of I. ovatus was predicted to increase. Conclusions Moderate climate, adequate precipitation and high altitude are favorable for the survival of I. ovatus. Future climate changes may cause expansion of suitable habitats of I. ovatus in China.

Ixodes ovatus found in Huainan area in Anhui Province / 中国血吸虫病防治杂志

Objective To study the morphological characteristics of Ixodes ovatus in order to provide the evidence for future research. Methods A group of goats were randomly selected and checked one by one,and the ticks were collected. Results A hard tick was found on the surface of a goat,and it was identified as Ixodes ovatus. Conclusions Ixodes ovatus has been found in Huainan area in Anhui Province,confirming that Huainan area is a new breeding place of Ixodes ovatus. This finding may contribute to the epidemiological research of tick-borne diseases.