Common features of patients with human T lymphotropic virus type I (HTLV-I) -associated myelopathy/tropical spastic paraparesis (HAM/TSP) compared to asymptomatic HTLV-I carriers include a genetically determined high cellular immune responsiveness to HTLV-I and a distributional bias of viral activation between the blood flow and central nervous system (CNS). It had been proposed that increased and altered in vitro late phase spontaneous proliferation (SP) of peripheral blood lymphocytes, which is concomitant with in vitro viral activation, is associated with the pathogenesis of HAM/TSP. To assess whether SP might epitomize the peculiar cellular inflammation in the CNS of patients with HAM/TSP, fractionated peripheral blood lymphocytes from HAM/TSP patients were employed to reconstitute this phenomenon in vitro. Although CD8+ cells had no inherent responsive potential in the absence of exogenous interleukin-2 (IL-2), the SP observed in CD4+ cell cultures was facilitated by the addition of autologous CD8+ cells to the cultures. It could be shown that proliferative responses of the CD8+ cells appeared against cultured and irradiated autologous CD4+cells but not against purified HTLV-I virions. These findings clearly demonstrate that the cellular response against the infected cells is involved and is one of the major components of the late phase SP, and support the view that this phenomenon may represent an in vitro counterpart of the susceptibility to HAM/TSP.

View full abstract

The hemolytic and antigenic activities of 36 strains of Vibrio cholerae O1 biotype El Tor, and 63 strains of Vibrio cholerae non-O1 isolated in Argentina were studied. Only 8% in stationary culture and 11% in shaking culture were hemolytic when the heart infusion broth (HIB) culture supernatants of V. cholerae O1 were examined. However, these percentages increased to 94% and 22% respectively when the strains were grown in HIB supplemented with 1% glycerol. On the other hand, most strains of V. cholerae non-O1 (97%) were hemolytic in both stationary and shaking HIB culture supernatants. The antigenic activity detected by reversed passive latex agglutination method (RPLA) varied markedly from strains and culture conditions; ranging from below the detection limit to 16, 000 ng/ml. The optimal condition of hemolysin production varied with the strain, but a stationary culture was preferable to obtain high hemolytic activity and shaking culture to obtain a large amount of hemolysin antigen. The comparison of the hemolytic and antigenic activities showed that the hemolysin is readily inactivated in the culture supernatant, especially in the case of V. cholerae O1. These findings suggested the presence of some potent inactivation factor (s) in El Tor vibrios.

View full abstract

The female and male of Simulium (Simulium) beludense sp. nov. are described based on reared adult specimens collected from Sabah, Malaysia. This new species was previously misidentified as S. (S.) nigripilosum Edwards of the melanopus-group because of a great similarity of their external morphology. The female genitalia examined in this study easily separate this new species from S. (S.) nigripilosum. It is also indicated that S. (S.) beludense sp. nov. is not assignable to the melanopus-group, but is rather closely related to S. (S.) argentipes Edwards from Peninsular Malaysia, S. (S.) bidentatum (Shiraki) from Japan and China, and S. (S.) canlaonense Delfinado from the Philippines, all of which belong to the different group so far undetermined.

View full abstract

Simulium (Byssodon) siripoomense sp. nov. is described based on two mature larval specimens collected from Thailand. This species is distinguished from the other known species of this subgenus by the pupal gill histoblast with six slender filaments. Four other simuliid species are newly recorded from this country : i.e., S. (Gomphostilbia) decuplum Takaoka and Davies, S. (G.) parahiyangum Takaoka and Sigit, S. (Simulium) brevipar Takaoka and Davies, and S. (S.) quinquestriatum (Shiraki). Two known species, which had been tentatively identified as S. (S.) sakishimaense Takaoka and S. (S.) nitidithorax Puri, are treated to be conspecific to S. (S.) fenestratum Edwards and S. (S.) tani Takaoka and Davies, respectively. Simulium (G.) sp. C, one of the five unnamed species previously reported, is found to conform to S. (G.) asakoae Takaoka and Davies.

View full abstract

Two Japanese with ovale malaria and a Cameroonian with malariae malaria were put on mefloquine and were successfully treated as long as they were observed. Two of the 3 cases entered into this study because the possibility of falciparum malaria was not excluded by the physicians who first examined their blood specimens. These case reports offer a promising alternative to chloroquine in the treatment of ovale and malariae malaria.

View full abstract

Many active flagellates were detected in stool samples of a 22-year-old Japanese male who traveled China and India. Microscopic observation showed that the organisms stained with Wright's solution were pyriform or rounded in shape, measuring 11.7-17.5 μm in length and 7.9-12.2 μm in width. The posterior end was pointed. Three free anterior flagella were located in the front end. A spherical nucleus was situated near the anterior pole. Based on these morphological features we identified the organisms as trophozoites of Chilomastix mesnili, a common intestinal protozoon. Although we examined viral, bacterial and parasitic infections other than C.mesnili, no pathogen was found. From these results obtained, it was considered to be highly probable that C.mesnili infection was the cause of the diarrhea.

View full abstract