The mechanism of thrombocytopenia in dengue virus infection remains unknown. We report herein an imported case of a 21-year-old male Japanese with dengue fever caused by secondary dengue 2 virus infection. The thrombocytopenia detected around the day of defervescence was associated with an increased level of platelet-associated IgG (PAIgG). The eluate from the platelets during the acute phase of this case contained an increased activity of anti-dengue virus 2 IgG, while the eluate from platelets during the convalescent phase contained a low level of anti-dengue 2 IgG. These findings suggest the transient formation of PAIgG involving anti-dengue 2 virus IgG during the acute phase of secondary dengue 2 virus infection.
Drug susceptibility of Neisseria gonorrhoeae in the past 3 years in Lao People's Democratic Republic (Lao PDR) was examined. The organisms were collected from the patients visiting Center for Laboratory and Epidemiology, Ministry of Health, Vientiane, Lao PDR. A total of 131 isolates of N. gonorrhoeae (45 in 2000. 27 in 2001, and 59 in 2002) were collected, and the drug susceptibilities of the isolates were examined by disc method using 5 anti-microbial agents (ciprofloxacin, ceftriaxone, penicillin, spectinomycin, and tetracycline). The susceptibility was expressed as sensitive (S), intermediate (M) and resistant (R) depending on the Zone Diameter Interpretive Chart attached to the disc preparation. As the results, almost all isolates were resistant to penicillin and tetracycline, but sensitive to ceftriaxone and spectinomycin. Most of the penicillin resistant isolates were regarded as penicillinase producing N. gonorrhoeae (PPNG) depending on the effect of clavulanic acid. N. gonorrhoeae is getting resistant to ciprofloxacin in the 3-year examination period. About 10% of the isolates were resistant to ciprofloxacin in 2000, but the rate of resistant strains went up to 70% in 2002. There were very few isolates showing intermediate susceptibility.
Based on a near-complete mitochondrial DNA sequence, the phylogenetic status of a lung fluke collected in the Philippines was evaluated. The lung fluke from Leyte Island, Philippines, resembles Paragonimus westermani morphologically and is sometimes regarded as a subspecies, P westermani filipinus. In this study, all mitochondrial genes of the Leyte form were sequenced : 12 subunits of mitochondrial enzymes, 2 ribosomal RNA genes and 21 transfer RNAs. The gene order is the same as that of the previously-published P. westermani from Korea. All genes are transcribed in the same direction. The sequence from Leyte was 88.8% identical to the previously-published sequence (accession No. AF219379). This is further evidence that the Philippine form should be regarded as specifically distinct from the form in East Asia (China, Japan and Korea). This conclusion is strengthened by the observation that the molluscan host of the Philippine form is of a different family from that of the East Asian form.
The Schistosoma japonicum group and S. sinensium utilize intermediate snail hosts belonging to the genera Oncomelania and Tricula (Gastropoda : Pomatiopsidae). In the present study, partial sequences of the mitochondrial 12S rRNA gene from 7 subspecies of O. hupensis, two species of Tricula (T bollingi and T humida) and O. minima were examined to infer a phylogeny for these. Nucleotide differences among subspecies of O. hupensis were less than 6.5% and among species from different genera, 10-12%. The phylogenetic tree obtained in this study indicates that O. hupensis subspecies fell into four distinct clades ; thatis, O. h. quadrasi from the Philippines, O. h. lindoensis from Indonesia, O. h. hupensis from Yunnan, China and the remaining 5 subspecies (O. h. hupensis from other parts of China, O. h. robertsoni from China, O. h. formosana from Taiwan, O. h. chiui from Taiwan and O. h. nosophora from Japan). The phylogenetic tree also showed that O. minima was placed as sister to all of the subspecies of O. hupensis. Possible evolutionary relationships amongthe snail hosts were discussed.
In the present talk, many great names of history in Japanese Tropical Medicine were mentioned. They were Drs. Yoshio Sawai, Manabu Sasa, Kanzen Teruya, Hachiro Sato, Yoshito Otsuji and others who worked with tropical medicine-related health problems/diseases such as, snake (Habu) bite, Tsutsugamushi disease, malaria, filariasis, schistosomiasis, paragonimiasis and other infectious or parasitic diseases. About 40 years ago, all these diseases were highly prevalent at country-wide in Japan and they were great public health problems, because of poor sanitary conditions and insufficient political atention. For example, snake (Habu) bite was one of the most serious health problem in subtropical regions of Japan, especially in Okinawa and Amami-Oshima islands. During 13 years from 1959 to 1971, 3,510 snake bite cases were reported from AmamiOshima island; the average fatality rate was 0.8% in the area. Dr. Yoshio Sawai, a microbiologist at the Institute of Medical Science at the University of Tokyo was the person who hardly worked with the Habu bite. In 1952 he was appointed as Associate Professor and chief of the newlyestablished laboratory of biological products at the Institute. Antivenin productions including these for Habu venom was one of the traditional work in the institute. Naturally Dr. Sawai tried to develop more effective and useful Habu toxoid. He frequently visited Naze Health Center, AmamiOshima island and observed there many patients suffered from serious and aggressive Habu bites with severe necrosis at the site of snake bite. He started laboratory investigations to improve the treatment of Habu bite, together with his coworkers at the Institute. Their purified and lyophilized antivenin was favorable to decrease numbers of the severe cases of Habu bites when applied clinically at Amami-Oshima island. However, yearly occurrence of severe clinical cases were still found in the area, in spite of such a Dr. Sawai's untiring efforts. After analyzing many clinical cases of Habu bites, Dr. Sawai reached to the conclusion that there might be a limitation in their serum treatment against the snake bite, because the development of local lesions by the large amount of Habu venom was too rapid for the antivenin treatment to prevent. Then, in 1963, Dr. Sawai re-
The single-step screening method (SSS) is a qualitative rapid screening test for glucose-6-phosphate dehydrogenase (G6PD) deficiency based on blue formazan formation on anion-exchanger.The reaction mixture contains equal volumes of anion exchanger, substrate mixture, coloring mixture (MTT-PMS mix) and distilled water. We assessed the stability of the reaction mixture and evaluated its reliability with two anion exchangers, DEAE-Sephadex A50™ and DEAE-Sephacel™, for applications in tests under field conditions. The reaction mixture was sufficiently stable under conditions of incubation at 70°C for 6 hours or vigorous shaking for 24 hours at room temperature. The reaction mixture could be kept at 30-35°C for 14 days under indoor conditions without shielding if it contained no MTT-PMS mix. The coloring was detectable even in diluted blood with hemoglobin concentration as low as 1.6 g/dl. Under laboratory conditions, the proportion of the samples with 10% of the normal level of activity that were diagnosed as 'low activity' was higher with DEAE-Sephacel (92%) than with DEAE-Sephadex A-50 (81%) (p=0.023). The proportion of the samples with normal activity that were diagnosed as 'normal' was 98% with DEAE-Sephacel and 100% with DEAE-Sephadex A-50. In field samples obtained in Myanmar and Indonesia, the sensitivity was lower (P=0.03 using DEAE-Sephadex and p< 0.001using DEAE-Sephacel) when we used the blue formazan spot test (BFST) as the standard. Twenty-three of 27 G6PD-deficient individuals subjected to genetic analysis were found to have mutations. All individuals who had concordant results between the SSS and the blue formazan spot test (BFST) carried molecular mutations. One case of G6PD mutation was detected among four cases diagnosed as G6PD-deficient by SSS with DEAE-Sephacel™, but diagnosed as 'normal' by BFST. The costs of one test with the DEAE-Sephadex A-50™ and the DEAE-Sephacel™ system were 0.15 US dollar and 0.30 US dollar, respectively. (297 words)
The Toxoplasma gondii number was evaluated by quantitative competitive polymerase chain reaction (QC-PCR) assay with or without sulfamethoxazole treatment in the heart, blood, brain, and small intestine of IFN-γ knockout (GKO) BALB/c (B/c) mice after peroral infection with the cyst-forming Fukaya strain. T. gondii infection was observed in the heart, blood, and brain, but not in the small intestine, of mice treated with sulfamethoxazole for 4 weeks. No correlation between T. gondii loads and sulfamethoxazole concentrations in tissues and blood was observed. T gondii was not detected in the heart and blood after continuous sulfamethoxazole treatment for two months, but a small number of parasites was demonstrated in the brain. Thus, we successfully established an animal model for evaluating chemotherapy regimens in immunocompromised hosts by using GKO B/c mice infected with T. gondii.
With the purposes of studying the recent prevalence of Wuchereria bancrofti infection in Thai-Myanmar border areas, and evaluating the usefulness of a new ELISA, which uses urine as samples (urine ELISA), 519 people in Sangkhla Buri and 84 people in Suan Phung were examined by ICT card test for filarial antigen and by urine ELISA for filaria-specific IgG4. In the former area, positive rates by ICT test and the ELISA were 16.8% and 21.2%, respectively; in the latter area, the respective rates were 10.7% and 7.1%. These figures were unexpected, because the urine ELISA used to give much higher prevalence than antigenemia tests in our previous studies. In addition, only 37 of 96 ICT positives (38.5%) were urine ELISA positive. Our previous studies showed that the sensitivity of urine ELISA among the microfilaria and/or antigen positive individuals was more than 90%. Diethylcarbamazine treatment given to the known ICT positives at 300 mg/day for 12 days reduced antigenemia rate from 100% to 32.8%, which was determined 2 months after treatment by Og4C3 ELISA. The reduction of 67.2% seemed to be unusually high. These conflicting results could be explained by possible false positive reactions produced by ICT test.
To find out the natural infection with filarial larvae, female adult black flies were collected on a human attractant in December, 2001 at Tambol Ban Laung (altitude 750 m), Doi Inthanon National Park, in northern Thailand. The total number of females collected was 823 : of which 557 (67.7%) were identified as Simulium asakoae Takaoka et Davies, 144 (17.5%) as S. nigrogilvum Summers, 97 (11.8%) as S. nakhonense Takaoka et Suzuki and 25 (3%) as other six simuliid species. By dissections, eight third-and one second-stage larvae of unidentified filarial species were found in one of 138 S. nigrogilvum and one of 484 S. asakoae, respectively. Non-filarial nematodes were found in 1.03% (5/484) of S. asakoae. This is the first report of natural infections of two black-fly species, S. nigrogilvum and S. asakoae, with a filarial larva.
