Growth and genotypes of Echinococcus granulosus found in cattle imported from Australia and fattened in Japan.

At the abattoir on study in Miyazaki, Japan, 9537 imported cattle from Australia in average were slaughtered annually in the last 5 years (2006 to 2010) and hydatid cysts were constantly detected in about 1.8% of the cattle. In order to assess the risk of Echinococcus granulosus delivered to Japan by imported cattle, 250 cysts found in 103 cattle at the abattoir were examined for their biological characteristics and genotypes. The cattle slaughtered were imported from Australia at an age of 10-12 months old and fattened for 17-18 months in Japan. The cysts showed their size ranging from 4 to 108 mm and were mainly found in the lung. Mature protoscoleces were detected in the three largest cysts, all were of the G1 genotype. Most of the other cysts contained clear cyst fluid and had thin laminated layer with no protoscoleces. The finding implies a potential risk of E. granulosus being established in Japan, thus strict and proper meat inspection and consequent offal condemnation are requisite at abattoirs that deal with imported cattle. Genotyping based on partial fragments of mitochondrial cox1, rrnS and nad1 genes were performed on the 66 cysts, showing that most of the cysts were G1 genotype (common sheep strain). However, two and four cysts were considered as G2 (Tasmanian sheep strain) and G3 (buffalo strain) genotypes, respectively. Since it has been widely recognized that G1 is the only genotype distributing in mainland Australia and that G2 genotype has been eradicated from Tasmania, the finding of those genotypes from Australian cattle indicated that certain genotypes other than G1 genotype are distributing in mainland Australia.

Investigation of reservoir animals of Leptospira in the northern part of Miyazaki Prefecture.

We surveyed reservoir animals of leptospires in the northern part of Miyazaki Prefecture, where a cluster of human leptospirosis had occurred during the summer of 2006. Leptospira was isolated from 6 of 57 large Japanese field mice (Apodemus speciosus). The serogroups of the isolates were Autumnalis (5 strains) and Hebdomadis (1 strain) and the partial nucleotide sequences of their flaB genes suggested that the isolates belonged to L. interrogans. The human patient sera reacted specifically with the Leptospira strain isolated from the mice captured around the area where each patient occurred, suggesting that mice are the source of human infection. We also detected leptospiral DNAs by flaB-polymerase chain reaction in the kidneys of large feral animals; wild boars (positive ratio 10.3%; 4 of 39) and deer (19.2%; 10 of 52). The Leptospira spp. harbored by these animals were deduced to be L. interrogans (in 5 animals) and L. borgpetersenii (in 9 animals) by the nucleotide sequences of the amplicons. Anti-Leptospira antibodies were also detected among symptomatic hound dogs. These results suggest that these feral animals may cause leptospirosis and pose a potential risk to hunters and workers in the meat processing industry.