Epidemiological study of Japanese spotted fever and tsutsugamushi disease in Shimane Prefecture, Japan.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to Yasuhiro Yano.
Explore the source record for details and available documents.
Babesia microti protozoa were detected by light and electron microscopy in the salivary glands of field-collected Ixodes ovatus ticks; 6 of 85 adult ticks were demonstrated to be positive for B. microti DNA by polymerase chain reaction assays. In the salivary glands of unfed ticks, B. microti existed in the sporoblast stage in the granular acinus cells, and developed into the sporozoite stage during feeding on the host for 2 days. The present results indicated for the first time that I. ovatus can indeed carry B. microti and is not infected mechanically with the parasites by blood-sucking. This frequent infection of I. ovatus with B. microti demonstrates the significance of such a vector-pathogen relationship in Japan, and strongly suggests that I. ovatus is involved in the maintenance of B. microti in the fauna of Japanese rodents.
A 53-year-old man visited Mt. Arashima-dake in Fukui Prefecture, and was infested by a tick-like organism. He visited a local clinic on July 12, 2004, complaining of high fever, general fatigue and rash. After several days without definite diagnosis, he was admitted to the Fukui Prefectural Hospital, where he was treated with minocycline hydrochloride for 10 days until recovery. His clinical symptoms on admission were high fever (39.6 degrees C), erythematous eruption, eschar on the right upper arm, and regional lymphoadenopathy. The epidemiological status and some clinical findings strongly suggested spotted fever (SF), and SF was confirmed based on the finding that his sera were reactive only to antigens of the SF group rickettsiae in the indirect immunoperoxidase analysis. This case is the first official report of SF rickettsiosis in Fukui Prefecture, the northern part of central Japan.
Explore the source record for details and available documents.
A rickettsial strain IO-1 has been isolated from a tick, Ixodes ovatus, in Japan and genetically identified as Rickettsia helvetica, a member of the spotted fever group rickettsiae. Ultrastructural observations were made on the microorganism. The ultrastructure of R. helvetica IO-1 appeared to be generally the same as that previously shown for other rickettsiae of the spotted fever and typhus groups. The rickettsiae were primarily found free in the cytoplasm of L929 cultured cells. Occasionally, the rickettsiae may also invade the host cell nucleus; however, the frequency of the nuclear localization was very low.
Babesia microti-like parasites were detected for the first time in Ixodes ovatus in Hyogo Prefecture, Japan, where two reported types of B. microti-like parasites were recognized in many rodents. Of 80 adult I. ovatus ticks collected, 5 possessed the reported type and 1 possessed a new type of B. microti-like parasite.