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Cryptosporidium, a waterborne protozoan parasite, has a substantial veterinary and medical impact worldwide. This parasite is more often recognized during waterborne outbreaks because of its resistance to chlorine disinfection, small size making it difficult to inactivate/eliminate through filtration, and presence in many animal species including humans. Migratory waterfowl, in addition to acting as mechanical carriers of Cryptosporidium oocysts, can also serve as natural reservoirs of infection by host-specific Cryptosporidium species. For better understanding of the extent of genetic diversity and inter-relationships among avian isolates of Cryptosporidium, 200 fecal samples of migratory ducks from the Tokachi subprefecture, Hokkaido, Japan were collected and analyzed by nested PCR (N-PCR) at the 18S rRNA gene. N-PCR revealed that 11.5% (23/200) were positive for Cryptosporidium spp. Among all samples, sequence analysis identified that 10% (20/200) were 98-100% identical to Cryptosporidium avian genotype III. On the other hand, 1.5% (3/200) were 99-100% identical to C. baileyi. This is the first molecular study reporting the prevalence of Cryptosporidium in migratory ducks in Japan. Genetic diversity among Cryptosporidium isolates from humans and birds has been reported worldwide. Nevertheless, further studies are important to assess genetic variety and to elucidate the transmission dynamics of Cryptosporidium parasites.

application/pdf, Considering the veterinary and public health significance of T. gondii infection and absence of epidemiological data in West Kordofan, and Blue Nile states in Sudan, a total of 392 serum samples from camel, cattle, sheep and goats in West Kordofan, and Blue Nile states were examined for T. gondii antibodies using Latex agglutination test. The overall seroprevalence was 22.4% (88/392). The seropositivity rate was 13.3% (6/45), 44% (33/75), 61% (22/36), 15.4% (21/136), 6% (6/100) in camels, cattle, sheep and goats and donkeys, respectively. Animal species was the only risk factor of T. gondii seropositivity. The significant higher seroprevalence of T. gondii in sheep and cattle indicates their potential role in the transmission of human toxoplasmosis in Sudan and the widespread contamination of the rural environment in Sudan with Toxoplasma oocysts. Further epidemiological studies, as well as special awareness and educational programs for toxoplasmosis are strongly suggested.

application/pdf, The present study investigated the prevalence of Toxoplasma gondii and other intestinal parasites in cats in the Tokachi subprefecture in Japan. A total of 365 household cats were included in the study, and 353 serum and 351 fecal samples were collected and analyzed. T. gondii IgG antibodies were detected in the sera of 16.14% of cats based on Latex agglutination test and ELISA. For ELISA, T. gondii RH strain tachyzoites lysate and T. gondii SAG2 recombinant protein were used as antigens. Low seropositivity was detected in cats younger than one year and older than 11 years; outdoor and hunter cats showed significantly high seropositivities. Neutering either in male or female cats, but not gender, had a considerable effect on seroprevalence. Toxoplasma gondii oocysts were detected in one fecal sample. The overall parasitic infestation in cats was 12.5%. Other detected parasites included Toxocara species, which showed the highest prevalence of 7.7%, followed by Isospora spp. (2%), Taenia spp. (1.7%), and Ancylostoma spp. (0.9%). Spirometra spp. was detected in only one sample. Outdoor cats comprised 50% of all 44 parasite-infested cats. Although T. gondii oocysts were detected in only one sample, the relatively high seroprevalence of T. gondii indicated that it can pose significant risks to the environment. Our findings highlighted the potential of outdoor cats as a source of T. gondii and other parasites. © 2018 The Japanese Society of Veterinary Science.

application/pdf, The potential contamination of Toxoplasma gondii and Neospora caninum oocysts in the human environment is a concern from the public health viewpoint. However, estimation of their seroprevalences in humans cannot be performed in a manner that distinguishes between oocysts and tissue cysts as a source of infection. Rabbits are considered popular pet animals in Japan that can acquire natural infections by the aforementioned parasites only through the ingestion of oocysts. Therefore, this study was conducted to estimate the seroprevalences of T. gondii and N. caninum in pet rabbits in Japan as an indicator of the possible oocyst contamination in the environment surrounding human beings. Serum samples of 337 rabbits were examined by different serological methods. Enzyme-linked immunosorbent assays were performed to measure the titer of IgG and IgM antibodies. Samples revealed to be seropositive by ELISA were further analyzed by a latex agglutination test, Western blotting and an indirect immunofluorescence assay. The rates of seropositivity for T. gondii were 0.89% (3/337) and 0.29% (1/337) in IgG and IgM ELISA, respectively. SAG1 and SAG2 were detected as major antigens by the positive rabbit sera in Western blotting associated with strong staining observed by IFA in T. gondii tachyzoites. Regarding N. caninum, none of the serum samples showed a specific reaction in both Western blotting and the IFA. The results of this study indicate low seroprevalences of toxoplasmosis and neosporosis in pet rabbits in Japan, suggesting low oocyst contamination in the human environment.

application/pdf, Toxoplasma gondii microneme protein 2 (TgMIC2), an apically stored adhesin, was shown to be a key participant involved in the initial attachment and invasion to a host cell. In this study, we had established the clonal line of T. gondii tachyzoites which over-expressed TgMIC2 using the tetracycline repressor (TetR)-based inducible gene expression system. The TgMIC2 over-expression significantly reduced tachyzoite propagation in vitro (p < 0.002) and significantly reduced the parasite virulence in mice (p = 0.002). The over-expression of exogenous TgMIC2 caused the increase of mRNA expression level of endogenous TgMIC2. Wild type parasites mainly expressed TgMIC2115 protein, the microneme store and the surface form of TgMIC2. Over-expression of TgMIC2 induced production of TgMIC2110, the cell surface form of TgMIC2 produced by N-terminal proteolytic processing of TgMIC2115. Some of tachyzoites became spherical shape having disordered apical complex after TgMIC2 over-expression. TgMIC2 over-expression did not effect mRNA expression level of TgMIC2-associated protein (TgM2AP), but appeared to cause the aberrance of TgM2AP protein. In conclusion, our results reveal the novel findings on the importance of the regulation of TgMIC2 transgene expression on post-translational modification of TgMIC2 and TgM2AP, and parasite’s morphology and propagation, with all together impacting the outcome of infection.

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application/pdf, A combination of antigenic regions of microneme proteins have been previously reported as being protective against chronic toxoplasmosis. In this work, we evaluated immune responses induced by immunizing BALB/c and C57BL/6 mice intradermally with plasmid DNA encoding the protein sequences of Toxoplasma gondii AMA1, MIC2, M2AP and BAG1. Mice immunized with the AMA1 gene developed high levels of serum IgG2a and c antibodies as well as cellular immune responses associated with IFN-γ synthesis suggesting a modulated Th1 type of response. Immunization with the AMA1 gene resulted in a partial but significant protection against the acute phase of toxoplasmosis compared to MIC2, M2AP and BAG1 genes. Therefore, the AMA1 gene appears to generate a strong specific immune response and also provides effective protection against toxoplasmosis more than the MIC2, M2AP and BAG1 genes.

application/pdf, Neospora caninum infection is an important disease affecting bovine and canine populations worldwide. The dense granule antigen 7 of N. caninum (NcGRA7) is considered to be an immunodominant antigen. In the present study, the gene encoding truncated NcGRA7 (NcGRA7t) lacking an N-terminal signal peptide was expressed in Escherichia coli, and its diagnostic potential in an enzyme-linked immunosorbent assay (ELISA) was evaluated. The ELISA could clearly discriminate between known N. caninum-positive and -negative sera from dogs. Serum samples randomly collected from dogs in Japan and China were examined for the diagnosis of neosporosis using the ELISA. Twenty-three of 135 samples (17.03%) and 9 of 95 (9.47%) samples from Japan and China, respectively, were positive for antibodies to N. caninum. Of the 32 ELISA-positive samples, 29 (90.62%) were confirmed as positive by Western blot analysis with whole tachyzoite antigens. These results indicate that the recombinant NcGRA7t would be a reliable antigen in ELISA for the diagnosis of canine neosporosis.

Oxgen isotope ratio and chemistry profiles were compared to find the corresponding interstadials during the Wisconsin Ice Age between the GRIP (Greenland) and Dome Fuji (Antarctica) deep ice core data for the past one hundred and sixty thousand years. Eight interstadials in GRIPδ^O profile were found to correspond to those in Dome Fuji δ^O profile. Eleven interstadials in GRIPδ^O profile were found to correspond to those in Dome Fuji chemistry (calcium, nitrate and sulfate) profile, which is better suited for the purpose of interstadial search than the δ^O profile at Dome Fuji. The Eemian interglacial period at Dome Fuji seems to be much shorter and more stable than that in the GRIP profile. Three major periods having higher contents of calcium, nitrate and sulfate appear at Dome Fuji, ranging (1) between interstadials number 1 and 8, (2) between interstadials number 17 and 19, and (3) before the Eemian, which correspond to relatively cold and stable periods in the GRIP δ^O profile. These findings promise a favorable outcome from more detailed bipolar comparison in the future for an understanding of climatic linkage conditions and the driving forces between northern and southern hemispheres., application/pdf

Surface snow observations were carried out on many glaciers in the Arctic. The observational sites were in Svalbard，Severnaya Zemlya，Greenland and arctic Canada. The seasonal variations of chemical constituents in snowfall remained in the surface snow on the central Greenland ice sheet where the effect of snowmelt was weak. Conversely, the chemical constituents in the snow layer changed with infiltration of melt water on the Svalbard glacier where strong snowmelt occurred，even in high latitudes. But in general, specific regional characteristics remained in all the glaciers. The concentrations of ions in snow were significantly decreased，because of percolation of melt water. But the ratio of NO_3 to CI still had unique regional characteristic values．, application/pdf

第4回極域科学シンポジウム横断セッション：[IC] 極域アイスコア・地形地質・モデリングから迫る古環境変動とそのメカニズム11月13日（水） 国立極地研究所 ３階 ラウンジ

第4回極域科学シンポジウム横断セッション：[IC] 極域アイスコア・地形地質・モデリングから迫る古環境変動とそのメカニズム11月12日（火） 統計数理研究所 ３階セミナー室１（D305）