Search

It has been well known that the transmission of HB virus is associated with mass inoculation and other medical procedures. In order to make clear the relation between HBV infection and the mass survey for filariasis on which sera of the examinees were drawn from their earlobes for the detecting of microfilaria with inadequately sterilized instruments, a epidemiological study was conducted in Miyako district. Okinawa prefecture, Japan, in which both HBV infection and filariasis were prevalent. A total of 2,231 inhabitants were investigated for HBV seromarkers. The over all positive rate of HBs antigen was 6.3% with the highest rate of 15.5% in the group of age 25 to 29. On the other hand, the prevalence rate of HBs antibody continued to increase along with age group, and remained to be over 60% after 30 years of age. The positive rates of both HBs antigen and antibody in the subject district were higher than those in other place of Okinawa prefecture or Japan. Comparing yearly attack rates of HBV chronologically, which were calculated from the age-specific HBV exposure rates in the district, the annual incidence of HBV infection was 6.1% (%/year) between 1954 to 1958, 5.2% (%/year) between 1959 to 1963, and then 4.4 (%/year) in the period of 1964 to 1968 in which the proportion of examinees for the survey of filariasis was the highest. In conclusion, the mass survey for filariasis was not the main factor contributing to the high prevalence of HBV infection in Miyako district.

A total of two hundreds and seventy squirrel monkeys (Saimiri sciureus) of both sexes were imported from South America through an animal dealer of the U. S. A. in eight lots from May, 1973 to July, 1974. They were investigated for the presence of the parasites for a maximum of fifteen months including nine weeks of quarantine period from the time of import. The mortality rate before or immediately after arrival at our laboratory reached 56.7% in the first two lots. This, however, could be reduced later to 4.8% by improving some conditions of transportation. Bacteriological surveys revealed no shigella or salmonella infections during the quarantine period. No tuberculin positive reactors were also detected. Filarial infestations seemed to be common in this species; about 45.5% had adult worms in the peritoneal cavity and about 65% harbored microfilaria in the peripheral blood. Acanthocephla was also found in a high rate in the lower alimentary tracts. It has been suggested that the worms disappear in fifteen months by keeping animals in the intermediate host-free circumstances. The sarcocyst was found in the femoral muscle of 7 (18.9%) of 37 animals examined histologically.