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Open access

K. Taira and Y. Saitoh

Abstract

Egg production capacity in Fasciola gigantica (Japanese strain) was estimated from egg count data obtained by the experimental infection of two goats. The goats were inoculated with a single dose of 50 metacercariae. The first goat was necropsied 132 days after infection (DAI) and the second goat 732 DAI. After patency, daily faecal production was collected and weighed and number of eggs per gram was counted. At necropsy, 23 flukes were recovered from the liver of the first goat, and five from the second goat. The mean number of eggs produced per day per worm (± 95 % confidence limits) was 9 477.9 (± 764.92) for the first goat at 106 to 132 DAI, and 8,064.1 (± 416.49) at 195 to 561 DAI for the second goat. The number of eggs produced per day per worm in F. gigantica (Japanese strain) has thus reached values ranged from approximately 8 000 to 10 000 eggs.

Open access

K. Taira, V. Šnábel, N. Okada and Y. Saitoh

Abstract

The infectivity of Toxocara cati larvae in mouse tissues, following storage at 4 °C and −25 °C, was measured using a bioassay in mice. Tissues of donor mice infected with 30-day-old T. cati larvae were stored at 4 °C for 7 and 14 days, and at −25 °C for 24 hours, then tissue larvae were inoculated into recipient mice (n = 6/group). After 15 days, larval burden in recipient mice was assessed by digestion. In the control group, a mean of 42.0 % of the inoculated larvae were established in mice. Storage of tissues at 4 °C for 7 and 14 days did not affect larval infectivity; means of 43.5 % and 37.4 % of inoculated larvae, respectively, were established in mice. Larvae exposed to −25 °C for 24 hours did not establish in mice, except for one larva recovered from a single mouse. These results may support the potential of tissue larvae in livestock animals as a causative agent of human toxocarosis.

Open access

K. Taira, Y. Une, V. Šnábel and H. Sugiyama

Abstract

The nematodes of genus Baylisascaris are common intestinal roundworms of carnivores such as raccoons, skunks, badgers, martens and bears. This report describes Baylisascaris sp. infection in a pet kinkajou Potos flavus imported into Japan from Guyana. Nematode eggs were detected in feces of the juvenile kinkajou in 2011 during a routine veterinary examination. A sequence analysis of the ITS2 nuclear target clustered the examined isolate with B. procyonis and B. columnaris, with 7.8 — 8.8 % base differences from these taxa. Eleven tandem G-A repeats identified in the polymorphic repetitive region further differentiate the kinkajou’s roundworm from recognized Baylisascaris species. This classified the studied isolate as referring to Baylisascaris sp., with its precise species delineation remaining to be determined. Given that the Baylisascaris sp. from the kinkajou is genetically closely affiliated with B. procyonis having a serious disease-producing capacity, the report appeals for precautions in informing people to avoid transmission risk.

Open access

Y. Shimono, S. Taharaguchi, K. Taira, N. Miyoshi and N. Yasuda

Abstract

Uncinaria spp. parasites were collected from two Tsushima leopard cats found on Tsushima Island, Nagasaki prefecture, Japan. One Uncinaria sp. was observed in the large intestines, and the other was observed in the small intestines. The nematode found in the large intestines was determined to be Uncinaria felidis by morphological identification. The other Uncinaria sp. found in the small intestines was morphologically different from U. felidis in the short-length of prevulvar flap. After isolation of genomic DNA of these worms, a second internal transcribed spacer (ITS2) of ribosomal DNA was amplified and sequenced using PCR techniques. The ITS2 region of U. felidis had 222 nucleotide sequences in length. The alignments of ITS2 sequence for Uncinaria felidis and Uncinaria sp. showed one nucleotide (0.45 %) replacement. These differrences may be regarded as intraspecific variation.

Open access

M. Okamoto, R. Ito, K. Taira and T. Ikeda

Summary

The novel WBN/Kob-Leprfa (fa/fa) congenic rat strain is considered a useful rat model of type 2 diabetes mellitus (T2DM). Accumulating findings suggest that low-grade inflammation is a causative factor in T2DM and that circulating levels of inflammatory cytokines are associated with insulin resistance. However, inflammatory cytokine profiles and their correlations with T2DM development/progression in fa/fa rats have not been studied. In this study, we found that the fa/fa rats had considerably high plasma levels of interleukin (IL)-1α. Abundant cecal IL-1α mRNA expression and cecal inflammation with infiltrating IL-1α-producing macrophages was observed in fa/fa rats. Bone marrow derived macrophages from fa/fa rats expressed high levels of IL-1α upon lipopolysaccharide stimulation. Furthermore, Syphacia muris infection, which delays the onset of T2DM, reduced both plasma and cecal IL-1α levels in fa/fa rats. These results suggest that macrophage infiltration and IL-1α secretion comprise an important part of T2DM development and that S. muris infection inhibits pro-inflammatory cytokine expression in fa/fa rats.

Open access

M. Okamoto, K. Taira, R. Ito and F. Asai

Summary

Syphacia muris is a ubiquitous nematode parasite and common contaminant of laboratory rats. A lthough S. muris infection is considered symptomless, it has some effects on the host’s immunity and therefore can interfere with experimental settings and interrupt final results. However, the molecular mechanisms involved in the alteration within the host’s immunity remain unclear because of the absence of information about mRNA expressed in this parasite. In this study we performed the transcriptome profiling of S. muris by next-generation sequencing. After de novo assembly and annotation, 14,821 contigs were found to have a sequence homology with any nematode sequence. Gene ontology analysis showed that the majority of the expressed genes are involved in cellular process, binding, and catalytic activity. Although the rate of expressed genes involved in the immune system was low, we found candidate genes that might be involved in the alteration within the host’s immunity by regulating the host’s innate immune response.

Open access

K. Taira, R. Yazawa, A. Watanabe, Y. Ishikawa, M. Okamoto, A. Takahashi and F. Asai

Summary

Diabetes mellitus is one of the most common endocrine disorders and its continuous global increase is due to factors as population growth, urbanization, aging, and increasing prevalence of obesity and physical inactivity. The effect of pinworm infection on the development of hyperglycemia was examined in WBN/K-Lepf (fa/fa) rats, a new model of the obese type 2 diabetes mellitus (T2DM) with pancreatitis. The rats were orally administered Syphacia muris eggs (infected group) and distilled water (control group). Hyperglycemia onset in the infected group was significantly delayed compared to the control group. Neither body weight nor intake of food and water were affected by S. muris infection. This study demonstrated that S. muris infection delayed the onset of T2DM in fa/fa rats and suggested that elucidation of the underlying mechanism and relevant pathways in the helminth-mediated protection may lead to the development of a new strategy to prevent diabetes mellitus.