Natural larval Echinococcus multilocularis infection in a Norway rat, Rattus norvegicus, captured indoors in Hokkaido, Japan.

Natural infection with larval Echinococcus multilocularis was recognized in one of eight Norway rats, Rattus norvegicus, caught indoors in 2009 in Ebetsu, Hokkaido, northern Japan. Cystic lesions were found in the right median and lateral lobes of the liver, with numerous alveolar cysts in the periphery of the lesions. Protoscolices were formed within large cysts. The laminated layers of the cysts were positive for PAS staining. Nested PCR using the primers specific for Taenia mitochondrial 12S rDNA yielded a 250-bp product, and the sequence of the PCR product matched that of E. multilocularis isolates from Hokkaido and Germany. This is the third natural alveolar hydatidosis in R. norvegicus in Japan.

Expression and secretion of cholera toxin B subunit in lactobacilli.

Lactic acid bacteria (LAB) are used in various fields, including in food and medical supplies. There has been a great deal of research into vaccine development using LAB as carriers due to their "generally recognized as safe" status. Cholera is an infectious disease that causes diarrhea due to cholera toxin (CT) produced by Vibrio cholerae. The pentameric cholera toxin B (CTB) subunit has no toxicity, and is used as an antigen in cholera vaccines and as a delivery molecule in vaccines to various diseases. In this study, we generated recombinant LAB expressing and secreting CTB. Here, we first report that CTB expressed and secreted from LAB bound to GM1 ganglioside. The secreted CTB was purified, and its immunogenicity was determined by intranasal administration into mice. The results of the present study suggested that it may be useful as the basis of a new oral cholera vaccine combining LAB and CTB.

Phylogenetic relationships of three species within the family Heligmonellidae (Nematoda; Heligmosomoidea) from Japanese rodents and a lagomorph based on the sequences of ribosomal DNA internal transcribed spacers, ITS-1 and ITS-2.

Nematodes of the family Heligmonellidae (Heligmosomoidea; Trichostrongylina) reside in the digestive tracts of rodents and lagomorphs. Although this family contains large numbers of genera and species, genetic information on the Heligmonellidae is very limited. We collected and isolated adult worms of three species in Japan that belong to the family Heligmonellidae, namely Heligmonoides speciosus (Konno, 1963) Durette-Desset, 1970 (Hs) from Apodemus argenteus, Orientostrongylus ezoensis Tada, 1975 (Oe) from Rattus norvegicus and Lagostrongylus leporis (Schulz, 1931) (Ll) from Pentalagus furnessi, and sequenced the entire internal transcribed spacer regions, ITS-1 and ITS-2 of ribosomal DNA. ITS-1 of Hs, Oe and Ll was 426, 468 and 449 bp in length, and had a G+C content of about 41, 41 and 37 %, respectively. ITS-2 of Hs, Oe and Ll was 297, 319 and 276 bp in length and had a G+C content of about 38, 40 and 28%, respectively. The data of Hs, Oe and Ll were compared with those of two other known species within the family Heligmonellidae, Calorinensis minutus (Dujardin, 1845) (Cm) and Nippostrogylus brasiliensis (Travassos, 1914) (Nb), and with those of two species of Heligmosomidae (Heligmosomoidea), Heligmosomoides polygyrus bakeri and Ohbayashinema erbaevae. Phylogenetic analysis placed Hs, Oe and Ll in the same clade with Cm and Nb, forming a Heligmonellidae branch in both ITS-1 and ITS-2, separate from the Heligmosomoidea branch. These results demonstrated that the ITS-1 and ITS-2 sequences are useful for differentiating the Heligmonellidae nematode species. This study is the first to describe the ITS-1 and ITS-2 sequences of Hs, Oe and Ll.

Isolation of sporocyst broodsacs of the genus Leucochloridium (Leucochloridiidae: Trematoda) from the intermediate host, Succinea lauta, in Japan.

Green- or brown-striped trematode sporocyst broodsacs typical of Leucochloridium infecting the ocular tentacles of a land snail, Succinea lauta, were collected in Abashiri, Hokkaido in northern Japan (N43 degrees 59', E144 degrees 14') in June of 2000 and 2001. The metacercariae isolated from the sporocyst broodsac were morphologically identified as Leucochloridium spp. (Leucoclhoridiidae Poche). This report is the first to describe evidential specimens of the sporocyst broodsac of the genus Leucochloridium Carus, 1835, infecting the intermediate host in Japan, suggesting that Leucochloridium spp. completes their life cycle in Hokkaido, Japan.