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EVALUATION OF AN OGAWA MYCOBACTERIUM CULTURE METHOD MODIFIED FOR HIGHER SENSITIVITY EMPLOYING CONCENTRATED SAMPLES

DAVID LUBASI ; CHARITY HABEENZU ; SATOSHI MITARAI

Tropical Medicine and Health.2004;32(1):1-4. doi:10.2149/tmh.32.1

Two egg-based culture media were evaluated for detection of mycobacteria with Löwenstein-Jensen (L-J) as a gold standard. The conventional culture method was modified to improve laboratory diagnosis of tuberculosis in resource scarce countries by employing an inexpensive but sensitive and specific culture method. Sputum samples were collected from pulmonary tuberculosis suspects who visited the chest clinic at the University Teaching Hospital in Zambia. These samples were processed using three different sample treating procedures (with or without sample concentration) and cultured on L-J and Ogawa media for mycobacteria isolation. A total of 276 sputum samples were collected from 138 pulmonary tuberculosis suspects. When the L-J result was used as a standard, the sensitivity of Ogawa and modified Ogawa was 81.7% and 90.3% respectively. Similarly, the specificities of those methods were 96.7% and 92.3% respectively. In total, 90 samples (32.6%) were smear positive and 108 (39.1%) were culture positive. The positivity of each culture method was as follows: 93 (33.7%) in L-J, 98 (35.5%) in modified Ogawa, and 82 (29.7%) in original Ogawa. The contamination rate was 1.1%, 5.1%, and 9.8% for L-J, Ogawa and modified Ogawa respectively. The Ogawa culturing method is economical, simple and quick. Its low sensitivity was overcome by employing the concentration method, the sensitivity significantly improving from 81.7% to 90.3%. Ogawa techniques are ideal in overburdened TB laboratories with poor resources in developing countries.

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IN VIVO EVALUATION OF COMBINATION EFFECTS OF CHLOROQUINE WITH CEPHARANTHIN OR MINOCYCLINE HYDROCHLORIDE AGAINST BLOOD-INDUCED CHLOROQUINE-RESISTANT PLASMODIUM BERGHEI NK 65 INFECTIONS

AKIRA ISHIH ; TOHRU SUZUKI ; TAKAKO HASEGAWA ; SHIGEO KACHI ; HWANG-HUEI WANG ; MAMORU TERADA

Tropical Medicine and Health.2004;32(1):15-19. doi:10.2149/tmh.32.15

The combination effects of chloroquine with Cepharanthin^® or minocycline hydrochloride were evaluated against a blood-induced infection with chloroquine-resistant P. berghei NK 65 in ICR mice. The infected mice in an untreated control group showed a progressively increasing parasitemia leading to mouse death. A two-day dosage of 20 mg base/kg of chloroquine alone produced little effect against P. berghei NK 65 infection, and all mice died from day 13 to 15 with an increasing parasitemia. A four-day dosage of 4 mg/kg of Cepharanthin^® alone produced no antimalarial activity, and all mice died by day 10. A four-day dosage of 50 mg/kg of minocycline hydrochloride alone produced a slight effect, but all mice died by day 18. Furthermore, mice given chloroquine in combination with Cepharanthin^® died from day 14 to 15. Mice given Cepharanthin^® plus minocycline hydrochloride also died from day 15 to 17. On the other hand, infected mice treated with chloroquine plus minocycline hydrochloride survived during the experiment. All mice treated with chloroquine alone, minocycline hydrochloride alone, chloroquine plus Cepharanthin^® or Cepharanthin^® plus minocycline hydrochloride showed low parasitemia levels during drug administration and a few subsequent days, but then malaria parasites re-increased in the bloodstream of the treated mice until death. On the other hand, malaria parasites in the mice given chloroquine plus minocycline hydrochloride decreased on day 6 and then could not be detected by microscopic examination during the observation period. This finding strongly suggests that the combination effects of chloroquine and minocycline hydrochloride are worthy of evaluation in human malaria. The results also clearly demonstrate the necessity and importance of in vivo experiments in estimating the activities of drugs.

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INCIDENCE OF TRAVELERS' DIARRHEA AMONG JAPANESE VISITING THAILAND

YOSHINORI MITSUI ; CHARNCHUDHI CHANYASANHA ; CHAWEEWON BOONSHUYAR ; MASAAKI SHIMADA ; KAZUHIKO MOJI

Tropical Medicine and Health.2004;32(1):21-26. doi:10.2149/tmh.32.21

A cross-sectional survey of 327 Japanese short-term travelers (≤3 weeks) arriving in Bangkok, Thailand was conducted to assess the incidence of travelers’ diarrhea (TD) as well as their symptoms and treatment-seeking behaviors. The incidence of the first episode of TD (FTD) was ascertained retrospectively by questionnaire. Reported by 69 travelers, FTD clustered within the first 8 days of arrival in Thailand, and the incidence rate varied from 2% to 8% with the highest incidence on the third day.
Cumulative probability of FTD was 19% for those arriving in Thai directly from Japan, 42 % for those arriving via Southeast Asia, and 25% for those arriving via other regions at Day 7 by the Kaplan-Meier survival analysis. Log rank test revealed a higher FTD risk for travelers arriving via other Southeast Asian countries than for those arriving directly from Japan (P < 0.005). Of all the 69 FTD episodes, 33% had classic TD defined as ≥3 unformed stools per 24 hours with at least one accompanying symptom, 49% had moderate TD defined as ≤2 unformed stools with at least one additional symptom or more unformed stools without additional symptoms, and 17% had mild TD defined as with ≤ 2 unformed stools without additional symptoms. Cumulative probability of FTD at Day 7 was 12% for classic TD, 25% for classic plus moderate TD and 30% for all the TD. More than 38% of travelers with diarrhea took medicine brought from Japan. Among travelers with classic TD, 35% bought medicine in Thailand, whereas 47-50% of travelers with moderate and mild TD took only rest without any treatment.

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CHILD DEATH AND WOMEN'S OWN EARNINGS ARE ASSOCIATED WITH CONDOM USE IN MADAGASCAR

ARMAND RANDRIANARIVO ; MAMINIRINA RAZAFINANEFA ; MONIQUE RASOLOMAHARO ; AYAKO NISHIYAMA ; TOMOHIRO SAITO ; NAOMI WAKASUGI

Tropical Medicine and Health.2004;32(1):27-30. doi:10.2149/tmh.32.27

The prevalence of human immunodeficiency virus (HIV) infection is lower in Madagascar than in continental African countries, but recently it has steadily risen. To identify factors that facilitate or deter condom use among married couples in Madagascar, a cross-sectional study was conducted by means of a questionnaire survey of 977 women attending 10 health facilities for antenatal care and child care. Information on reproductive and socioeconomic factors was obtained, and logistic regression analysis was used to identify factors contributing to condom use. Child death and women’s earnings were statistically significant factors for condom use, with an odds ratio of 2.0 (95% confidence interval (CI): 1.2-3.5) for the former and 1.6 (95% CI: 1.1-2.3) for the latter in the logistic regression analysis. The promotion of economic independence among women and the reduction of child mortality deserve greater attention in the planning of HIV prevention policy in Madagascar.

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TWO NEW SPECIES OF SIMULIUM (SIMULIUM) (DIPTERA: SIMULIIDAE) FROM THAILAND

HIROYUKI TAKAOKA ; WEJ CHOOCHOTE

Tropical Medicine and Health.2004;32(1):31-36. doi:10.2149/tmh.32.31

Two new black-fly species of the subgenus Simulium (Simulium) are described and illustrated, based on female specimens captured while approaching a human near a mountain summit in Doi Inthanon National Park, Chiang Mai Province, northern Thailand. The first species, Simulium suchariti sp. nov., is assigned to the griseifrons species-group and is distinguished from most other related species by the cibarium with tubercles near the base of its medial projection; the second, S. setsukoae sp. nov., is very similar to S. rufibasis of the tuberosum species-group but is distinguished from the latter by the shorter length of clustered stout hairs on the seventh abdominal segment and the ovipositor valve with its posteromedial corner widely bare.

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FURTHER EVIDENCE THAT GENOTYPE I AND GENOTYPE II OF CRYPTOSPORIDIUM PARVUM ARE DISTINCT

ZHILIANG WU ; ISAO NAGANO ; THIDARUT BOONMARS ; YUZO TAKAHASHI

Tropical Medicine and Health.2004;32(1):5-14. doi:10.2149/tmh.32.5

Three new genes of Cryptosporidium parvum were cloned, including a gene encoding methionine aminopeptidase, one encoding chaperonin containing T-complex protein 1 delta (TCP-1 delta) and one with unknown function. DNA sequence analysis indicated that these genes are quite conserved, but there were some base pair differences between genotype I and genotype II isolates. These differences were confirmed by PCR-restriction fragment length polymorphism (PCR-RFLP) analysis of the 3 genes from 41 isolates collected from different hosts and geographical origins. In brief, the band patterns generated by endonuclease Hind III or Hinf I restrictions of the gene of methionine aminopeptidase, Sac I restriction of the gene of chaperonin, or Ava II restriction of the unknown gene could differentiate the isolates of C. parvum into genotype I and genotype II. PCR primers based on these genes amplified only C. parvum genes. Even a single oocyst was detectable with these PCR primers. Thus the results provided further evidence that genotype I and genotype II are distinct, and our three new primers can be used to detect and characterize C. parvum isolates with high sensitivity.

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CHANGES IN HTLV-I POSITIVE RATES AMONG PREGNANT WOMEN IN OKINAWA PRIOR TO THE EFFECTS OF MEASURES INTRODUCED TO PREVENT VERTICAL TRANSMISSION THROUGH BREAST MILK FEEDING

YOSHIYA ANDO ; YOSHINARI MATSUMOTO ; SHIRO NAKANO ; KENSUKE SAITO ; KAZUHIRO KAKIMOTO ; TAKUO TANIGAWA ; YUTAKA EKUNI ; MOTOHIRO KAWA ; YUJI TOYAMA ; TAKENORI TOYAMA

Tropical Medicine and Health.2004;32(2):177-180. doi:10.2149/tmh.32.177

Objectives: Human T cell leukemia virus type-I (HTLV-I) is a causative agent of human T-cell leukemia and HTLV-I associated myelopathy (HAM/TSP). HTLV-I carriers are often infected vertically, especially via mother's milk. Since 1985, clinical measures have been adopted at a hospital in Okinawa to prevent vertical infections.
Methods: We examined HTLV-I antibodies in all of the women (total 11, 506) who gave birth after 24 gestational weeks at a hospital on the Okinawa main island from January 1985 to December 1999.
Results: The positive rate among all pregnant women was always higher than that among primipara alone. Both figures decreased over the period studied, but the primiparity rate (36-39%) did not change significantly. The percentage of HTLV-I positive primipara pregnant women among the HTLV-I positive total was close to the primiparity rate from 1985 to 1988, but it was considerably lower than the overall primiparity rate thereafter (22-26%).
Conclusions: Preventive measures against HTLV-I infection did not contribute to the decrease in HTLV-I positive mothers before 1999 because these measures were adopted from 1985, and so there must be other reasons for the decrease in HTLV-I positive rate. Further studies on social factors and by year of birth are needed to identify factors influencing HTLV-carrier ratios among pregnant women.

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INHIBITION OF TRYPANOSOMA CRUZI GROWTH IN MAMMALIAN CELLS BY NIMODIPINE, WITH LOW CYTOTOXICITY TO HOST CELLS

KENICHIRO HIROTA ; AKIKO TSUBOUCHI ; JUNKO NAKAJIMA-SHIMADA ; TAKESHI NARA ; TAKASHI AOKI

Tropical Medicine and Health.2004;32(2):181-188. doi:10.2149/tmh.32.181

An in vitro infection system of Trypanosoma cruzi and HeLa cells was used to measure the anti-T. cruzi activities of various calcium antagonists classified into dihydropyridines, diphenylalkylamines, and benzothiazepines and of allopurinol and benznidazole as medium and highly effective reference compounds, respectively. Six dihydropyridines (10 μM each), i. e. nifedipine, nicardipine, nimodipine, nisoldipine, nitrendipine, and amlodipine, decreased the rates of infection of HeLa cells from 11.7% (control) to 5.8, 0.9, 1.2, 3.6, 5.9, and 1.7%, respectively. Nicardipine and amlodipine were highly toxic to HeLa cells, causing detachment of cells from coverslips. Nimodipine was thus the most effective inhibitor tested against T. cruzi infection in HeLa cells. Verapamil and gallopamil (diphenylalkylamines), diltiazem and midazolam (benzothiazepines), and allopurinol (positive control) were less effective than nimodipine. IC₅₀ values, the concentrations of compounds that elicited a 50% reduction in the infection rates of HeLa cells, were 2.5, 2.6, 1.3, 2.1, and 1.7 μM for nicardipine, nimodipine, amlodipine, verapamil, and benznidazole, respectively, while the values for nifedipine, diltiazem, and allopurinol were much higher. Nicardipine, amlodipine, and verapamil again showed significant cytotoxicities to HeLa cells. When Swiss 3T3 fibroblasts replaced HeLa cells, nimodipine markedly lowered the host-cell-infection rate, with an IC₅₀ value of 8.3 nM. Thus, nimodipine is expected to be a highly effective anti-T. cruzi lead compound, with low cytotoxicity to mammalian cells. Structural formulas of nimodipine and nicardipine in relation to their low and high cytotoxicities, respectively, against HeLa cells are discussed.

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A LIST OF AND KEYS TO BLACK FLIES (DIPTERA: SMULIIDAE) IN THAILAND

HIROYUKI TAKAOKA ; WEJ CHOOCHOTE

Tropical Medicine and Health.2004;32(2):189-197. doi:10.2149/tmh.32.189

Forty-five known species of Simulium Latreille s. l. in Thailand are listed, and keys to subgenera and species within each subgenus are provided for adults, pupae and mature larvae.

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THE USE OF TRAVEL VACCINES BY JAPANESE EXPATRIATES IN DEVELOPING COUNTRIES

ATSUO HAMADA ; YUKA UJITA ; EIICHI OKUZAWA ; TOSHIHIRO KOGA ; AKIRA UCHIKOSHI ; SHINJI FUKUSHIMA ; KIYOMI HONDO ; TETSUO NISHIKAWA ; NORIHIKO BASUGI

Tropical Medicine and Health.2004;32(2):199-202. doi:10.2149/tmh.32.199

From 1998 to 2001, using questionnaires, we surveyed the use of travel vaccines among Japanese expatriates in developing countries. The percentage of those using more than one type of travel vaccine before departure increased significantly (45.6% in 1998 to 53.4% in 2001 (p<0.001)). In regions such as tropical Africa and South Asia, vaccination rates were high. But the increase was most noticeable in East Asia, the Middle East, and Latin America. Vaccinations against hepatitis A, hepatitis B, and tetanus were high throughout the developing countries. Vaccinations against yellow fever and Japanese encephalitis were high in endemic regions. Vaccination rates were slightly higher for typhoid fever in South Asia and tropical Africa than that in other areas. Vaccination rates for cholera, however, showed yearly declines. These trends seem to reflect a growing awareness among expatriates of the benefits of travel vaccines. Even so, nearly half of those living the countries have not received sufficient vaccination, indicating a need for further education.

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