著者

Kaito Kotani Kandai Doi Nana Ushine Takuya Kato Tatsuo Sato Masaki Nonagase Shin-ichi Hayama

出版者

The Japan Society of Medical Entomology and Zoology

雑誌

衛生動物 (ISSN:04247086)

巻号頁・発行日

vol.73, no.4, pp.157-159, 2022-12-25 (Released:2022-12-25)

参考文献数

20

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An engorged ixodid tick was collected from a rescued short-tailed shearwater, Puffinus tenuirostris (Temminck), at Funabashi Sanbanse Seaside Park in Chiba Prefecture, Japan. Based on morphological features, we identified the specimen as Ixodes kerguelenensis (André and Colas-Belcour), which is a species known to infest seabirds in Oceania. To our knowledge, this is the first case report of I. kerguelenensis in Japan. The case of infestation to the shearwater suggests the possibility of the long-distance translocation of the tick in Oceanian region to Japan.

著者

Kandai Doi Fumiaki Yamasaki Takuya Kato Shin-ichi Hayama

出版者

Arachnological Society of Japan

雑誌

Acta Arachnologica (ISSN:00015202)

巻号頁・発行日

vol.70, no.1, pp.47-48, 2021-06-28 (Released:2021-07-05)

参考文献数

11

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A pseudoscorpion was found in the underfur of a feral raccoon (Procyon lotor) captured in western Tokyo in December 2019. Based on the morphological features, we identified the specimen as Haplochernes sp. This arboreal pseudoscorpion rides other arthropods and small mammals for dispersion, but little is known that the species rides medium-sized mammals such as raccoons. To our knowledge, this is the first case report of Haplochernes sp. riding a feral raccoon. Given that raccoons are an invasive species in Japan, further records of pseudoscorpions riding feral raccoons may elucidate the relationship between feral raccoons and pseudoscorpions.

著者

Natsuko SUGIURA Kandai DOI Takuya KATO Tatsushi MORITA Shin-ichi HAYAMA

出版者

JAPANESE SOCIETY OF VETERINARY SCIENCE

雑誌

Journal of Veterinary Medical Science (ISSN:09167250)

巻号頁・発行日

pp.17-0092, (Released:2018-01-19)

被引用文献数

16

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To examine outbreaks of mange in raccoon dogs (Nyctereutes procyonoides) with respect to population density, we analyzed camera trap videos, and isolated mites from raccoon dog carcasses. In a camera trapping survey, we categorized the skin condition of raccoon dogs, and used a number of independent videos to calculate the relative abundance index (RAI). The RAI of raccoon dogs with alopecia increased following an increase in the RAI of those without alopecia. Among 27 raccoon dog carcasses, 12 showed mange-compatible skin lesions. Sarcoptes scabiei was isolated from 11 of these raccoon dogs, indicating that sarcoptic mange was endemic in our study area. Therefore, a high relative population density may be a factor underlying epizootics of sarcoptic mange in raccoon dogs.

著者

Natsuko SUGIURA Kazuhiko OCHIAI Toshiaki YAMAMOTO Takuya KATO Yoshi KAWAMOTO Toshinori OMI Shin-ichi HAYAMA

出版者

JAPANESE SOCIETY OF VETERINARY SCIENCE

雑誌

Journal of Veterinary Medical Science (ISSN:09167250)

巻号頁・発行日

vol.82, no.4, pp.479-482, 2020 (Released:2020-04-09)

参考文献数

29

被引用文献数

1

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We analyzed the genotypes of three pregnant females and their litters to investigate the phenomenon of multiple paternity in wild raccoon dogs (Nyctereutes procyonoides) using 17 microsatellite markers. If a female has mated with only one male during estrus, then the maximum number of paternal alleles will not exceed two among littermates with the same father. The results revealed two out of three litters had three or four paternal alleles at one or five microsatellite loci. Therefore, the female had mated with more than one male during estrus. To the best of our knowledge, the present study is the first to report the possibility of multiple paternity in wild raccoon dogs.

著者

Shin-ichi HAYAMA Sachie NAKIRI Fumiharu KONNO

出版者

JAPANESE SOCIETY OF VETERINARY SCIENCE

雑誌

Journal of Veterinary Medical Science (ISSN:09167250)

巻号頁・発行日

vol.73, no.6, pp.809-812, 2011 (Released:2011-07-05)

参考文献数

14

被引用文献数

4 10

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This study is the first to determine the conception dates of specific individuals and estimate the pregnancy rate of a wild population in Japanese monkeys. The conception dates estimated from the embryonic ages of 37 fetuses were distributed over 128 days between September 17 and January 23, with a mean conception date of November 19 (SD=29.2 days). A comparison of the mean conception dates among age groups showed a significantly delayed conception in the subadult animals (aged 4 to 5 years; December 5, n=8) than in the adult animals (aged 6 or more years; November 15, n=29; P<0.03). The mean pregnancy rate among animals aged 4 years or more in this local population was estimated to be 48.5% (32/66).

著者

Nana Ushine Shouta MM Nakayama Mayumi Ishizuka Takuya Kato Shin-ichi Hayama

出版者

The Japanese Society of Environmental Toxicology

雑誌

環境毒性学会誌 (ISSN:13440667)

巻号頁・発行日

vol.26, pp.25-37, 2023-06-22 (Released:2023-06-22)

参考文献数

83

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Lead (Pb) is extensively used in industries and often inadvertently discharged into the environment. Despite some studies examining the effects of Pb pollution on raptors and waterfowl, its effects on other avian species have not been investigated. This study investigated the feeding selectivity of a black-headed gull (Chroicocephalus ridibundus) population using stable isotope ratios to determine the source of Pb pollution. Gulls in Tokyo and Mikawa Bay were captured from December 2016 to February 2017 and from December 2020 to March 2021, respectively. These gulls were measured 13C/12C carbon ratio (δ13C), and 15N/14N nitrogen ratio (δ15N). Blood Pb level (BLL) was measured gulls in Mikawa Bay. Based on the measurement values of δ15N, gulls were classified into two groups: primary and higher predator groups. No differences in stable isotope ratios were found between the two groups. The secondary consumers showed significantly high BLLs (P=0.002). BLLs during the wintering period were significantly higher in the primary consumer group. Our findings suggest that reducing Pb emissions, along with biological and chemical remediation of water sediment is required to prevent further Pb pollution and bioaccumulation in wild animals.

著者

Takuya KATO Yayoi ICHIDA Kazumi TEI Makoto ASANO Shin-ichi HAYAMA

出版者

JAPANESE SOCIETY OF VETERINARY SCIENCE

雑誌

Journal of Veterinary Medical Science (ISSN:09167250)

巻号頁・発行日

vol.71, no.11, pp.1473-1478, 2009 (Released:2009-12-04)

参考文献数

30

被引用文献数

5 5

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In order to examine reproductive characteristics of feral raccoons in Kamakura, 335 raccoons were collected from March 2005 to March 2007. Raccoons were classified into five age classes: Class I, less than 5 months old; Class II, 5-11 months; Class III, 12-17 months; Class IV, 18-23 months; and Class V, over 23 months old. Females were examined for their age specific pregnancy rate and litter size. To determine when raccoon births occur in the region, birth months of fetuses were estimated by the fetal growth rate, and birth months of Class I individuals were examined by tooth eruption. From fetuses of 18 pregnant females and 47 Class I individuals, it was found that the raccoon births occur from February to October. Of 163 females examined, all of Class I-II females were nulliparous. Pregnancy rate was 47.6% in Class III females, which was significantly lower than 75.0% in Class IV and 78.1% in Class V. The litter size of fetuses ranged from 2 to 5, and 3.9 on average; and that of placental scars ranged from 1 to 7, 3.8 on average. Our findings suggest that parturition of raccoons is a bimodal distribution and age at first parturition may occur between 12 and 17 months old. In order to reduce the raccoon population successfully, females of all ages should be captured throughout the year.

著者

Shin-ichi HAYAMA Yuki KAWABATA Aoi OCHI Setsuko NAKANISHI Yoshi KAWAMOTO Hideharu YAMAZAKI

出版者

JAPANESE SOCIETY OF VETERINARY SCIENCE

雑誌

Journal of Veterinary Medical Science (ISSN:09167250)

巻号頁・発行日

pp.21-0141, (Released:2021-07-06)

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The Shimokita Peninsula in Aomori Prefecture, Japan, which is inhabited by Japanese monkeys (Macaca fuscata), is the northernmost habitat for wild primates in the world. This study was the first to determine the conception dates of specific individuals and estimate the pregnancy rate of wild populations in this region. The pregnancy rate of animals aged 5 years or more at delivery was estimated to be 40.9% (27/66). Conception dates of each fetus were also estimated using a regression line of Pig-tail monkeys (Macaca nemestrina), which are taxonomically related to Japanese monkeys and have a similar physique. The conception dates were distributed across 90 days between September 24th and December 23rd, with a mean conception date of November 4th (SD=22.3 days, n=53). Using these findings, the mean birth date was estimated as April 25th, more than two weeks earlier than the mean birth date in previous research determined using direct observations carried out over the past 20 years ago. Global warming due to climate change is thought to be one of the main causes of this difference.

著者

Nana USHINE Aki TANAKA Shin-ichi HAYAMA

出版者

JAPANESE SOCIETY OF VETERINARY SCIENCE

雑誌

Journal of Veterinary Medical Science (ISSN:09167250)

巻号頁・発行日

vol.82, no.8, pp.1173-1177, 2020 (Released:2020-08-28)

参考文献数

40

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Investigating the cause of animal death is helpful to understand the reasons behind the interactions and conflicts between humans and animals. To further develop the cause of death investigation, we report a case of a Chinese spot-billed duck (Anas zonorhyncha) which hatched from a rescued duck and died 10 days after release. We inspected the duck’s cause of death using an interview of concerned people, external body examination, necropsy, and genetic examinations. Based on the fractures, the main cause of death was determined to be a traffic accident. Furthermore, molecular tests helped to detect raccoon DNA in the visible bite wounds. This case shows that molecular biological method is one of the methods of clarify the animals’ cause of death.