The biotin-avidin-peroxidase (BAP) technique for measuring serum neutralizing (NT) antibody against rabies virus in human sera was established. When the focus reduction rates with serial serum dilutions were plotted on a probit chart, a linear regression line was drawn. The slopes (b-value) of the regression lines were identical irrespective of the different test samples. The sensitivity of the BAP test for detecting NT antibody was highest when compared with that of the rapid fluorescent focus inhibition test (RFFIT) and mouse neutralization test. In addition, low level-antibody titer (< 1 : 5) which could not be detected by mouse neutralization test was detected by the BAP test and the RFFIT. Serum NT antibody response w4s easily followed by the BAP test with individuals who received 3 doses of preexposure preventive rabies vaccine. Most of the vaccinees produced a detectable amount of serum NT antibody by a single dose of vaccine and after the second vaccination, all vaccinees produced high level of the antibody and the titers increased continuously until day 21, however, the titers on day 78, two months after the last vaccination, showed a tendency of decline.

View full abstract

Goto Islands belong to Nagasaki Prefecture, and bancroftian filariasis had been endemic in these subtropical islands. For about 20 years, we have carried out the eradication program of bancroftian filariasis in two villages, Nagate and Daiho Village of Goto Islands. The eradication program was planned mainly through control of vector mosquito in Nagate Village and through treatment of persons with drug in Daiho Village. As a result of this program, no new filaria infection was found recently in these areas.
On the other hand, Goto Islands are known as endemic areas of adult-T-cell leukemia (ATL). In this time, we have carried out a seroepidemiological study, and found that the groups of persons with positive ATLA antibody had significantly higher filarial antibody titre than those of persons with negative ATLA antibody in Nagate and Daiho Village.
Thirty-four persons who were recorded as microfilaria carriers about 10 years ago showed higher positive rate of ATLA antibody than that of the others in Nagate Village.
These data suggested that the filarial antigen stimulation might act as a factor in ATLV infection and/or proliferation among inhabitants in the endemic areas of filariasis and ATL.

View full abstract

The development of thymocytotoxic autoantibodies was investigated in mice infected with Schistosoma japonicum, Schistosoma mansoni, Echinococcus multilocularis, Nematospiroides dubius, Trichinella spiralis, Trichuris muris, Hymenolepsis nana, Toxoplasma gondii, Plasmodium vinckei, Plasmodium berghei and Plasmodium chabaudi. The infections with all of these parasite species induced thymocytotoxic autoantibodies, although the levels of their cytotoxic activity were varied in different host-parasite combinations. The highest titer up to 1 : 16 was observed in the sera of mice infected with S. japonicum and S. mansoni. They have generally an optimal reactivity at 4°C but some showed greater cytotoxicity at 37°C. The cytotoxicity was completely absorbed with thymocytes. The possible mechanism (s) responsible for the production of these autoantibodies and their in vivo role were discussed.

View full abstract

We report a case of onchocercal nodule (30×20×20 mm) located at the subcutaneous tissues of the left hip of a 34-year-old Japanese who had lived in the Republic of Guinea and the Gabonese Republic for one year and a half.

View full abstract

During the period from May to November in 1980, a total of 2, 114 stool specimens were collected from individuals living in Naivasha, Kitui, Machakos, Taveta and Nandi Hills areas in Kenya, and they were examined for intestinal protozoa by formol-ether concentration method followed by idoine-staining.
Out of 2, 114 specimens 673 (31.8%) were positive for Entamoeba histolytica, 1, 105 (52.3%) for Entamoeba coli, 102 (4.8%) for Endolimax nana, 184 (8.7%) for Iodamoeba bfitschlii, 176 (8.3%) for Giardia lamblia, and 220 (10.4%) for Chilomastix mesnili. The total positive rate, which means the percentage of positive persons for any kinds of intestinal protozoa, was 75.1 per cent.

View full abstract

The stool examinations on long-term visiters to developing countries were carried out to investigate the epidemiology of parasitosis imported to Japan. The subjects of the investigation were 716 Japan Overseas Cooperation Volunteers who returned in 1981-1982. The infection rates of parasitosis among the volunteers before departure (Yamaura et al., 1981) were compared as controls of this survey. Formalin-ether sedimentation method, zinc sulfate centrifugation-flotation method and Harada & Mori's test-tube cultivation method were used for stool examination. Rizopoda was identified by Hydenhain's iron-hematoxylin staining.
The results are summarized in Table 1 and Table 2 :
1) The infection rates among returned volunteers (28.4% in 1981 and 23.2% in 1982) were much higher than the rate before departure (2.5%, 5/198) (Table 1). No relation between infection rate and sex of the volunteers was recognized.
2) The highest infection rate was found for Giardia lamblia (12.6%, 90/716). Entamoeba histolytica was observed in 2.2 per cent (16/716). High infection rate of E. histolytica was observed among the volunteers returned from Ghana (14.7%, 5/34). More than two species of parasites were found in 20.7 per cent of positive cases (Table 2).
3) The infection rates of volunteers returned from Bangradesh and from Nepal were 68.0 per cent and 56.1 per cent respectively.
These two rates were found to be significantly higher than that from other 24 countries. The ratio of helminth infection to protozoa infection in African and Central-and South American countries was lower than that in Asian and Oceanian countries (Table 2).

View full abstract