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Growth variation in skull morphology of Kuril harbor seals (Phoca vitulina stejnegeri) and spotted seals (Phoca largha) in Hokkaido, Japan
2009
Nakagawa, E., Hokkaido Univ., Sapporo (Japan) | Kobayashi, M. | Suzuki, M. | Tsubota, T.
We examined morphological growth variations in skull features between the Kuril harbor seal and the spotted seal in Hokkaido, Japan. Skulls from 80 Kuril harbor seals and 41 spotted seals were collected, and we measured 29 metric and 6 non-metric cranial characteristics. Three growth classes were defined according to the postnatal developmental stage: pups (0 year), subadults (1-4 years old) and adults (more than 5 years old). We detected sexual dimorphism in Kuril harbor seal pups, subadults, and adults. Although interspecies differences were detected in each growth class, Kuril harbor seals were larger and more massive than spotted seals; this feature was already detectable in pups. We did not detect certain cranial characteristics with which to identify the two species, but it was possible to identify any unknown specimens to their species, sex, and growth class using the cranial data generated in this study. Using 6 non-metric cranial characteristics, we identified significant interspecies differences with regard to the shape of the temporozygomatic suture and the extent of the nasal-incisive suture; the shape of the temporozygomatic suture and the shape of the nares were indicators of growth class in Kuril harbor seals. Although non-metric cranial characteristics have a lower discriminating power than metric characteristics, they are easy to use in the field even by inexperienced researchers.
Show more [+] Less [-]Epizootiological survey of Trichinella spp. infection in carnivores, rodents and insectivores in Hokkaido, Japan
2007
Kanai, Y.(Hokkaido Univ., Sapporo (Japan)) | Inoue, T. | Mano, T. | Nonaka, N. | Katakura, K. | Oku, Y.
In order to evaluate the present epidemiological situation of Trichinella infection in wild animals in Hokkaido, Japan, red foxes (Vulpes vulpes), raccoon dogs (Nyctereutes procyonoides), brown bears (Ursus arctos), martens (Martes melampus), rodents and insectivores captured in Hokkaido were examined for muscle larvae by the artificial digestion method from 2000 to 2006. Foxes (44/319, 13.8%), raccoon dogs(6/77, 7.8%) and brown bears (4/126, 3.2%) were found to be infected with Trichinella larvae and all other animal species evaluated were negative. Multiplex PCR and DNA sequencing revealed that larvae from a fox captured in Otofuke, in south-eastern Hokkaido, were T. nativa, and larvae from 27 animals including 21 foxes, 2 raccoon dogs and 4 brown bears captured in western Hokkaido were Trichinella T9.
Show more [+] Less [-]Growth pattern and seasonal weight changes of the feral raccoon (Procyon lotor) in Hokkaido, Japan
2003
Asano, M. (Hokkaido Univ., Sapporo (Japan)) | Matoba, Y. | Ikeda, T. | Suzuki, M. | Asakawa, M. | Ohtaishi, N.
Polymerase chaine reaction-restriction fragment length polymorphism (PCR-RFLP) method for mtDNA typing in Hokkaido brown bear (Ursus arctos yesoensis) [Japan]
2003
Satoh, Y. (Hokkaido Univ., Sapporo (Japan)) | Mano, T. | Tsuruga, H | Masuda, R. | Matsuhashi, T. | Onuma, M. | Suzuki, M. | Ohtaishi, N.
Isolation of Pseudomonas aeruginosa from Ushubetsu River water in Hokkaido, Japan
2000
Aoi, Y. (Hokkaido Univ. of Education, Asahikawa (Japan). Asahikawa Branch) | Nakata, H. | Kida, H.
Frenkelia sp. from the red-backed vole, Clethrionomys rufocanus bedfordiae, in Hokkaido, Japan
1988
Fujita, O. (Hokkaido Univ., Sapporo (Japan). Faculty of Veterinary Medicine) | Oku, Y. | Ohbayashi, M.
Pseudoparasitism by thelastomatid nematodes in moles, Mogera spp., in Japan
1988
Yokohata, Y. (Hokkaido Univ., Sapporo (Japan). Faculty of Veterinary Medicine) | Jiang, Y.P. | Abe, H. | Ohbayashi, M.
A comparative epidemiological study of hantavirus infection in Japan and Far East Russia
2007
Kariwa, H.(Hokkaido Univ., Sapporo (Japan)) | Lokugamage, K. | Lokugamage, N. | Miyamoto, H. | Yoshii, K. | Nakauchi, M. | Yoshimatsu, K. | Arikawa, J. | Ivanov, L.I. | Iwasaki, T. | Takashima, I.
Hantaviruses are causative agents of some severe human illnesses, including hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). The viruses are maintained by rodent hosts, and humans acquire infection by inhaling virus-contaminated excreta from infected animals. To examine the epidemiology of hantavirus infections in Japan and Far East Russia, we conducted epidemiological surveys in these regions. In Japan, anti-hantavirus antibodies were found in four rodent species, Clethrionomys rufocanus, Rattus norvegicus, R. rattus, and Apodemus speciosus. Although no new HFRS cases have been officially reported over the past 20 years in Japan, one member of the Japan Ground Self-Defense Force did test positive for hantavirus antibody. Repeated surveys in Far East Russia have revealed that two distinct hantavirus types cause severe HFRS in this region. Hantavirus sequences identified from A. peninsulae, fetal HFRS cases in Vladivostok, and Amur virus are highly similar to each other (92% identity) , but they are less similar (-84% identity) to the prototypical Hantaan virus, which is carried by A. agrarius. Phylogenetic analysis also indicates that Amur and A. peninsulae -associated viruses are distinct from Hantaan virus, suggesting that A. peninsulae is the reservoir animal for Amur virus, which causes severe HFRS. From HFRS patients in the Khabarovsk region, we identified viruses with nucleotide sequences that are more similar to Far East virus (96%identity) than to the Hantaan (88-89%identity) or Amur (81-83% identity) viruses. Phylogenetic analysis also indicates that the viruses from Khabarovsk HFRS patients are closely related to the Far East virus, and distinct from Amur virus.
Show more [+] Less [-]Seroepidemiological survey of morbillivirus infection in Kuril harbor seals (Phoca vitulina stejnegeri) of Hokkaido, Japan
2006
Fujii, K.(Hokkaido Univ., Sapporo (Japan)) | Sato, H. | Kakumoto, C. | Kobayashi, M. | Saito, S. | Kariya, T. | Watanabe, Y. | Sakoda, Y. | Kai, C. | Kida, H. | Suzuki, M.
Serological analysis was performed to detect morbillivirus infection in Kuril harbor seals in Hokkaido, Japan. Serum samples were collected from the seals at Nosappu (231 sera), Akkeshi (16), and Erimo (75) between 1998 and 2005. Antibodies to phocine distemper virus (PDV) were detected by ELISA in seals from Nosappu and Erimo. Antibodies to PDV were found in 56% (5/9) of the sampled seals from Nosappu in 1998, versus only 5% (3/66) for 2003, 1% (1/79) for 2004, and 1% (1/77) for 2005. These suggest epidemic caused by the virus in or before 1998. As antibody-positive seals included juvenile seals in 2003 and 2005, sporadic infections of the virus are thought to have occurred in recent years. In Erimo, antibodies to PDV were found in 50% (14/28) of sampled seals in 2004, versus only 13% (1/8) for 1999, 7% (1/15) for 2003, and 0% (0/24) for 2005. These suggest sporadic infection by the virus before 2003 and the epizootic between after autumn in 2003, when samples of 2003 were collected, and 2004. Since antibodies to canine distemper virus (CDV) were detected in one adult seal from Nosappu in each year from 2003 to 2005, sporadic infections of the virus, were suggested. There were no difference in incidence of seals with antibodies to the viruses between males and females and between juveniles and adults.
Show more [+] Less [-]Prevalence and intensity of Echinococcus multilocularis in red foxes (Vulpes vulpes schrencki) and raccoon dogs (Nyctereutes procyonoides albus) in Otaru city, Hokkaido, Japan
2002
Yimam, A.E. (Hokkaido Univ., Sapporo (Japan)) | Nonaka, N. | Oku, Y. | Kamiya, M.
A survey was done in an attempt to investigate the epidemiological status of Echinococcus multilocularis in red foxes and raccoon dogs in Otaru city from June to September 1999. Sixty-seven red foxes (Vulpes vulpes schrencki) and 13 raccoon dogs (Nyctereutesprocyonoides albus) were captured, and postmortem examinations were conducted with them. Thirty-eight red foxes (56.7%) and 3 raccoon dogs (23.1 %) were found to be infected with E. multilocularis. The total biomass ofE. multilocularis in all infected red foxes and raccoon dogs were 2,817,000 and 1,515 worms, respectively. Nine of the infected red foxes harboring more than 100,000 worms accounted for 90.6% of the total biomass. No significant differences in the prevalence were observed between male and female, and juvenile and adult. However, the worm burden was higher in juvenile than in adult foxes. In one of the infected raccoon dogs, mature worms and eggs of E. multilocularis were found in the intestine and fecal sample, respectively. This result suggested that the raccoon dogs are probably playing a small role in the egg contamination of the environment. The validity of coproantigen ELISA for diagnosis of foxes was confirmed by comparing the results of autopsy, egg examination and coproantigen ELISA using rectal fecal samples.
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