池 和憲

The genus Eumonospora Allen, 1933 (Apicomplexa: Sarcocystidae), an avian coccidia, is characterized by monosporocystic and octasporozoic oocysts without Stieda and substieda bodies. Some members of Eumonospora, which infect several raptor species, exhibit high levels of pathogenicity, making eumonosporiosis the leading cause of death in captive-bred raptors. The host specificity of these species appears to be mesostenoxenous, as evidenced by unsuccessful transmission between different orders of avian hosts. However, several studies have detected Eumonospora spp. in taxonomically distant avian hosts, indicating that some of these species may be euryxenous. In the current study, diarrheic fecal examination of a captive-bred juvenile merlin (Falconiformes: Aves) in Tokyo, Japan, was conducted, and a large number of oocysts were morphologically and molecularly identified as E. henryae (Yakimoff and Matschulsky, 1932), a coccidia species reported only in Strigiformes. This is a new recorded host for this coccidia. Phylogenetic analyses via Bayesian inference and maximum likelihood methods using concatenated genomic datasets consisting of nuclear 18S rDNA, nuclear 28S rDNA and mitochondrial cytochrome C oxidase subunit 1 gene, revealed a well-supported monophyletic clade of Eumonospora spp. belonging to the family Sarcocystidae Poche 1913, which largely corresponded to the avian host phylogram. Therefore, based on distinguishable oocyst morphology, a new subfamily, Eumonosporinae, within the family Sarcocystidae, is proposed, and a reconsideration of the definition of Sarcocystidae is suggested. Further molecular characterization of this emerging pathogen, as well as clarification of its complete life cycle, including cyst-forming ability, is required for more appropriate generic assessment.

The coccidian genus Eumonospora Allen, 1933 is re-established. Despite morphological features and host preference among species, coccidian with octasporozoic and monosporocystic oocysts are traditionally consider to belonging in the genus Caryospora Léger, 1904 (Apicomplexa: Eimeriidae). Recently, the genus Avispora Schuster et al., 2016 was proposed for above caryosporoids parasitizing birds based on combined morphological and phylogenetic analyses. However, diagnostic morphological characters of the genus Avispora, the absence of Stieda and substieda bodies, has already been mentioned in the description of the genus Eumonospora Allen, 1933 (Apicomplexa: Sarcocystidae), and thus Avispora is considered to be a junior synonym of Eumonospora. In this study, caryosporoid coccidians were detected from five owl species Bubo scandiacus, Ptilopsis leucotis, Athene noctua, Strix nebulosa, and Pulsatrix perspicillata (Strigiformes: Strigidae) and identified as Avispora henryae (Yakimoff &amp Matikaschwaili, 1932) described from Bubo bubo (Strigiformes: Strigidae). Eumonospora henryae (Yakimoff &amp Matikaschwili, 1932) comb. nov. is redescribed for this species based not only on morphological features but also on phylogenetical analyses. The key of the genus Eumonospora and a list to the species known at present are also provided.

Hepatozoon apri n. sp. is described from Japanese wild boars Sus scrofa leucomystax in Japan. The gamonts in the peripheral blood leukocytes were 11.6 ± 1.4 × 6.7 ± 1.3 μm in size. The meronts in the muscle tissues were 35.0–47.5 μm in length and 26.5–30 μm in width. A high rate (53.0%) of infection was found by nested PCR using muscle specimens from 181 wild boars captured in Tokushima, Japan. A phylogenetic analysis based on 18S rRNA gene sequences revealed that H. apri n. sp. detected in wild boars is closely related to Hepatozoon spp. isolated from carnivores. This is the first description of a species belonging to the genus Hepatozoon detected in ungulates.

Five individuals of the domestic Java sparrows, Lonchura oryzivora (Ayes: Estrildidae), were examined for coccidian parasites. Sporulated oocysts had two sporocysts containing four sporozoites each. Sporulated oocysts (n = 30) were spherical, with a two splinter-like polar granules. Oocyst size was 22.1 x 20.7 (20.0-25.0 x 20.0-22.5) mu m. They had a thick wall that consisted of a pale yellow outer layer and a dark yellow inner layer, and lacked micropyle and residuum. Sporocysts (n = 60) were elongated ovoid 14.1 x 9.8 (12.5-15.0 x 7.5-10.0) mu m, smooth walled, and colorless, with crescent-shaped Stieda and indistinct substieda bodies. Sporocyst residuum was interspersed between sporozoites. Sporozoites were oriented transverse to the sporocyst longitudinal axis. On the basis of morphological data, the species isolated in the present study is a new species of Isospora and propose the name Isospora lunaris n. sp. (C) 2016 Elsevier Ireland Ltd. All rights reserved.

Baculovirus display systems have been utilized for cell-specific gene transfer, regenerative medicine, and as vaccine vectors. In particular, baculovirus particles displaying surface antigens have been used as vaccines against some parasites and viruses. In this study, Bombyx mori nucleopolyhedrovirus (BmNPV) particles displaying Neospora caninum antigens (NcSAG1, NcSRS2, and NcMIC3) purified from the hemolymph or fat body of silkworm larvae were prepared to vaccinate mice against N. caninum. Each antigen was expressed on the surface of BmNPV particles through glycoprotein 64 transmembrane and cytoplasmic domains. Antigen-specific antibody production was induced in mice by immunization with each recombinant BmNPV particle. NcMIC3-displaying BmNPV particles purified from the fat body induced a lower antibody titer than particles purified from the hemolymph. Antigen-specific IgG2a was predominantly produced in mice by immunization with NcSAG1-displaying BmNPV particles compared to IgG1, and induction of IFN-gamma was dominant, indicating that antigen-displaying BmNPV particles can elicit a Th1 immune response in mice. Semi-quantitative PCR analysis revealed that immunization with each antigen-displaying BmNPV particle partially protected mice from cerebral N. caninum infection. These results suggest that antigen-displaying BmNPV particles can provide an alternative method of controlling neosporosis in cattle and represent a new generation of N. caninum vaccines.

The hearts, diaphragms, hind legs, and back muscles of 64 Japanese sika deer (Cervus nippon centralis) caught in a mountainous area of Hyogo Prefecture, Japan, were examined for Sarcocystis infection by detecting sarcocysts. Sarcocysts were detected in the muscles of 52 (81.3%) individuals, and their prevalence did not differ among 1-5-year-old individuals, although no sarcocysts were detected in deer younger than 1 year old. Sarcocyst prevalence was significantly lower in the back muscles than in the other tissues. The intensity of sarcocyst infection was also significantly higher in the heart than in any other organ examined. This high prevalence of Sarcocystis infection in Japanese sika deer may be attributable to their frequent contact with the feces of the final hosts, including the hunting dogs that accompany hunters culling deer, and stray dogs, wild foxes, and raccoon dogs. The detected sarcocysts were oval to rod-like in shape and the internal section was divided by septa into many compartments. Many crescent-shaped bradyzoites were present in each compartment. The average size of 177 sarcocysts was 698.5×170.2μm. However, the measurements ranged widely, with lengths of 243.0-1,067.4μm and widths of 58.7-351.1μm. The variation of the sizes of the sarcocysts did not correlate with their shape or location of parasitization in the host.

We developed a transgenic potato (TrP/R7) expressing the recombinant R7 (rR7) antigen for use as an oral vaccine to protect against a chicken protozoan disease, chicken leucocytozoonosis. The TrP/R7 potato was produced by Agrobacterium tumefaciens-mediated transformation and regeneration, and the R7 gene insertion into potato chromosomes was confirmed by genomic polymerase chain reaction and Southern hybridization. rR7 antigen expression in TrP/R7 potato was also confirmed by sandwich enzyme-linked immunosorbent assay and western blotting using an antibody against the second-generation schizont of Leucocytozoon caulleryi. A transgenic potato clone with the highest rR7 antigen expression (3 μg rR7 antigen per gram of fresh-weight potato leaves) was selected, cultivated, and used in oral administration experiments to examine its ability to boost immunity. Chickens were immunized with chicken leucocytozoonosis vaccine "Hokken" by injection, and chickens that developed moderate levels of antibody titres were fed with TrP/R7 leaves. Chickens fed with TrP/R7 leaves showed increased antibody responses. In contrast, chickens fed with non-transgenic potato leaves showed a continuous decrease in antibody titres. Furthermore, chickens fed with TrP/R7 potato leaves showed strong resistance against experimental challenge with L. caulleryi infection. This study demonstrates the use of a plant-based oral vaccine to boost immunity against a protozoan disease. © 2013 Copyright Houghton Trust Ltd.

Neospora caninum is an obligate intracellular protozoan parasite that causes severe neuromuscular diseases, repeated abortion, stillbirth, and congenital infection in livestock and companion animals. The development of an effective vaccine against neosporosis in cattle is an important issue due to the significant worldwide economic impact of this disease. We evaluated the immunogenicity of four bradyzoite antigens, NcBAG1 (first described in this study), NcBSR4, NcMAG1, and NcSAG4, using an acute infection mouse model to determine synergistic effects with the tachyzoite antigen as a candidate for vaccine production. Mice were inoculated with the recombinant vaccines (r-)NcBAG1, rNcBSR4, rNcMAG1, rNcSAG4, or phosphate-buffered saline (PBS) (adjuvant control group) in an oil-in-water emulsion with bitter gourd extract, a Th1 immune stimulator, or PBS alone as the infection control group. Mice inoculated with each vaccine developed antigen-specific IgG1 and IgG2a antibodies and isolated splenocytes from mice produced high levels of interferon-gamma when infected with the N. caninum tachyzoite. The mice inoculated with rNcBAG1, rNcMAG1, or rNcSAG4 developed slight to moderate clinical symptoms but did not succumb to infection. In contrast, rNcBSR4 and both control groups developed severe disease and some mice required euthanasia. The parasitic burden in the brain tissues of vaccinated mice was assessed by N. caninum-specific real-time PCR at 5 weeks after infection. The parasite load in rNcBAG1-, rNcMAG1-, and rNcSAG4-inoculated mice was significantly lower than that in adjuvant and infection control mice. Therefore, these antigens may be useful for the production of a N. caninum-specific vaccination protocol.

Neosporosis, caused by an intracellular parasite, Neospora caninum, is an infectious disease primarily of cattle and dogs. It occurs worldwide and causes huge damages to dairy farms. In this study, we immunized mice with recombinant surface-associated protein 1 of N. caninum (rNcSAG1) and developed two novel monoclonal antibodies, A10 and H3, against NcSAG1 using phage-display technology. Both clones bound to purified rNcSAG1 and the half maximal inhibitory concentrations of A10 and H3 are 50 and 72 nM of rNcSAG1, respectively. In immunofluorescence assays, both A10 and H3 Fabs bound to N. caninum parasites. Direct detection of N. caninum parasites was developed firstly using an enzyme-linked immunosorbent assay (ELISA) with A10 and H3. Binding of A10 and H3 antibodies to rNcSAG1 was also inhibited by some certain anti-N. caninum antibodies in the neosporosis-positive cattle sera, suggesting they might bind to the same epitopes of NcSAG1 with those anti-N. caninum antibodies of bovine. These antibodies were demonstrated to have a potential for monitoring the N. caninum parasites in a dairy farm, which may lead to protect livestock from parasite-infection.

To assess the effect of edible mushroom extracts on the induction of T-helper 1 (Th1) immunity, we examined differences in interferon-gamma (IFN-gamma) and interleukin (IL)-4 production in mice induced by hot-water extracts of 15 species of edible mushroom. Extracts from Agaricus bisporus, Flammulina velutipes, Hypsizigus marmoreus, Lentinula edodes, and Lyophyllum decastes induced both IFN-gamma and IL-4 production in mice, whereas extracts from Pleurotus ostreatus only induced IL-4. In contrast, extracts from Agaricus blazei, Grifola frondosa, Morchella esculenta, Pholiota nameko, Pleurotus citrinopileatus, and Pleurotus eryngii induced only IFN-gamma production. In particular, the extract from P. eryngii induced high levels of IFN-gamma and reduced levels of IL-4. We further investigated the use of a trial immunogen using the P. eryngii extract as a Th1 immunostimulator. An oil-in-water emulsion of the hot-water extract from P. eryngii (immunostimulator) and ovalbumin (OVA; antigen) was used as a trial immunogen. This immunogen induced strong OVA-specific IgG2a antibody production in mice compared with the negative controls. In addition, OVA-specific IgG1 antibody levels were lower than those for the negative controls. Marked increases in serum IFN-gamma levels and high-level production of IFN-gamma in the culture supernatant from the CD4(+) spleen cells in the trial immunogen group mice were observed. Our results suggested that the hot-water extract from P. eryngii induced Th1 immunity by acting as an immunostimulator.

A one-month male Greyhound dog presented with a swinging gait of the hindlimbs, and later developed muscular atrophy of the femoral region and hyperextension of hindlimbs. The dog had positive serum IFAT titers to Neospora caninum, but a negative titer in the cerebrospinal fluid (CSF). N. caninum-specific DNA was amplified from the CSF using a semi-nested polymerase chain reaction assay. Clusters of protozoa in biopsied muscle fibers were subsequently confirmed as N. caninum tachyzoites by immunohistochemical examination. Early recognition and treatment are necessary for effective recovery of clinical canine neosporosis, but antemortem diagnosis is difficult. We suggest that the detection of parasite deoxyribonucleic acid in the CSF is a useful antemortem diagnostic method in facilitating treatment of this disease.

Intestinal ciliates excreted in the feces of Asian elephants were surveyed. Fourteen species in the order Entodiniomorphida were detected. Nine Triplumaria species in the family Cycloposthiidae were found. Using the silver impregnation, two known species, T antis and T dvoinosi, were redescribed and six new species, T sukuna n. sp., T zuze n. sp., T solea n. sp., T suwakoh. sp., T. fulgora n. sp., and T harpagonis n. sp., were described. T sukuna, T zuze,T solea, and T suwako have the perivestibular polybrachykinety along the vestibular opening. The buccal infraciliary bands of T suwako are similar to those of T selenica found from elephants and the buccal infraciliary bands of T sukuna,T zuze, and T solea are similar to those of T grypoclunis described from rhinoceroses. T antis, T dvoinosi, T fulgora, and T harpagonis have the vestibular polybrachykinety extending down inside the vestibulum as found in rumen ciliates in the family Ophryoscolecidae. The caudalial ciliary zones of T. dvoinosi and T fulgora were retractable as found in rumen ophryoscolecids. Raabena bella and Pseudoentodinium elephantis showed high composition values over 30%. Ciliate densities in the three fecal samples were 0.15, 1.09, and 2.07 x 10(4)/ml. (C) 2011 Elsevier GmbH. All rights reserved.

Zinc (Zn) is an essential trace element for DNA synthesis and for cell growth and differentiation. The deficiency induces a wide range of disorders including immunodeficiency. In this study, the influence of Zn deficiency to the mice infected with Babesia microti was examined, and was compared with the influence in the rats infected with B. rodhaini previously reported. Experiments of B. microti infection were conducted using Zn-deficient (ZD; allowed to eat ad libitum on the ZD diet), Zn-adequate (ZA; allowed to eat ad libitum on the ZA diet), and diet-restricted (DR; supplied 2 g/day on the ZA diet) mice. It was suggested that the Zn deficiency exacerbated the infection dynamics of the mice with B. microti by the growth retardation, the reduction of immunity and the decrease in PCV. The results in the mice supported the consequences in the rats previously reported.

Zinc deficiency induces a wide range of disorders including immunodeficiency. It is known that microbial infections occur with a high frequency in the zinc-deficient hosts, but the study on the correlation between parasitic infection and zinc status ill hosts is scarcely performed. We observed that the influence of zinc deficiency to the rats infected with Babesia rodhaini. Experiments of B. rodhaini infection were conducted using zinc-deficient (ZD; eat ad libitum or 10 g/day on the ZD diet), zinc-adequate (ZA; eat ad libitum on the ZA diet), and diet-restricted (DR; eat 7 g/day on the ZA diet) rats. The Findings in this study suggested that the zinc deficiency had deleterious effects on the hemodynamics and mortality of the rats infected with A rodhaini.

Prevalence of lung worms belonging to the genus Metastrongylus was surveyed on 42 Japanese wild boars (Sus scrofa leucomystax) captured officially for wildlife damage control in the western parts of Tokyo, Japan from April 2000 to April 2001. The number of parasites was the highest in the caudal lung lobes. Four species, M. elongatus (ME), M. salmi (MS), M. asymmetricus (MA) and M. pudendotectus (MP), were identified. All the boars were infected with 2 or more species, and 64.3% of the boars had all 4 species. The composition of species, ME:MS:MA:MP=1.3:3.4:1.0:1.4, was drastically different from the previous reports. The peak of the average number of the parasites was observed in the period of January to March 2001 because of the increase of MS.

As the comparative study was carried out on the susceptibility by the pursuit of parasitemia among the Djungarian, Syrian, and Chinese hamsters as well as BALB/c mice infected with the Syrian hamster-adapted Babesia microti strain, and Djungarian hamsters showed the highest parasitemia among them. Then, the other hematological parameters were pursued in the Djungarian hamsters infected with the hamster-adapted B. micron strain. Remarkable symptoms observed were hemoglobinuria clinically, anemia hematologically, and splenomegaly macroscopically during all over the observation period for 24 weeks post infection (PI). Parasitemia began to rise at 2 weeks and peaked at 4 weeks PI. After that, parasitemia decreased gradually but was maintained with a level of about 10% on average until 24 weeks PI at the end of the experiment. A decrease in the RBC count, Hb, and PCV, and an increase in the reticulocyte and WBC counts due to the development of immature neutrophils, lymphocytes and monocytes were recognized together with a rise of parasitemia. The hamsters had macrocytic hypochromic anemia due to the increase of MCV and the decrease of MCHC in the growth phase of the parasite. It was considered that the Djungarian hamsters will be useful for the infection examination, isolation, maintenance, and passage of B. microti in laboratory.

Mice were inoculated intraperitoneally wih 34 different types of vegetable juices, and interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) were measured as markers for the induction of Th1 and Th2 cells, respectively. Serum IFN-gamma level was markedly increased in mice inoculated with bitter gourd (Momordica charantia) juice, but IL-4 levels were not increased with any of the 34 vegetable juices. Testing of the various components of bitter gourd, including peel, pulp, and seed, showed that the pulp induced the highest levels of IFN-gamma. Trial immunogen including the heat extract of the pulp induced specific IgG(2a) antibody of the mice serum inoculated with this immunogen. These results demonstrate that bitter gourd pulp induced IFN-gamma production and show its promise as a means of effective imnunostimulatory therapy specific for Th1 cells and IFN-gamma production.

Interleukin 10 (IL-10) genes of Djungarian, Chinese, and Syrian hamsters were cloned. The clones of IL-10 consisted of 537 bp nucleotides and 178 amino acids in full length, and the nucleotide and amino acid sequences exhibited a high degree of homology with those of the mouse and human. Since the number and position of signal sequences, N-glycosylations and cysteine sites in the IL-10 amino acid sequences of the hamsters were the same as those of the mouse, we suggest that the IL-10 molecular structures of the hamster are closer to that of the mouse than human.