HIV incidence rates among drug users in northern Thailand, 1993-7

Drug use is a major mode of HIV transmission in Thailand. This study determined HIV incidence rates among drug users in a regional drug treatment centre in northern Thailand. A retrospective cohort of repeatedly-hospitalized drug users between 1993 and 1997 was formed and HIV incidence rates were calculated. The overall incidence was 11.44 per 100 person-years of observation. Gender, age, religion, ethnicity, education, employment, income, reasons for drug use, type of drugs, mode of use, spending on drugs, and referral for treatment are associated with HIV incidence. However, there are no associations between HIV incidence and history of treatment and mode of discharge from the centre. This implies that current treatment modality has no impact on HIV infection risk and other therapeutic approaches should be explored.     

Short-term effects of treatment with 300 mg oral-dose diethylcarbamazine on nocturnally periodic Wuchereria bancrofti microfilaremia and antigenemia

Seven microfilaremic Myanmar patients were treated with a single 300 mg dose of diethylcarbamazine (DEC) orally, as part of a case-finding survey in Ranong Province, Southern Thailand. This was conducted in order to evaluate the short-term effects of single-dose DEC on Wuchereria bancrofti microfilaremia and antigenemia during a 12-week course of treatment. Analysis of microfilarial periodicity on initial treatment revealed the microfilarial peak density (k) was at 52 minutes after midnight (0052). The periodicity index was then 103.26%. Single-dose DEC treatment did not affect the k values. A linear model of W. bancrofti microfilarial density reduction predicts a sharp decrease in the mean microfilarial density 2 weeks after DEC intake (Z = -2.197, p = 0.028). Over a longer period, a non-linear model predicts an increase in the mean microfilarial density to pre-treatment levels, having little or no macrofilaricidal effects. We reconfirmed the existence of nocturnally periodic W. bancrofti infection in Myanmar migrants in Ranong Province, and the short-term microfilaricidal activity of 300 mg single-dose DEC treatment used for biannual mass treatment and the DEC provocative test. Without an adequate DEC treatment dose, recrudescence can occur. A rational approach to the management of introduced nocturnally periodic W. bancrofti in Myanmar migrants, who came for short periods of stay in transmission-prone areas, is needed.     

Border and imported bancroftian filariases: baseline seroprevalence in sentinel populations exposed to infections with Wuchereria bancrofti and concomitant HIV at the start of diethylcarbamazine mass treatment in Thailand

Border bancroftian filariasis caused by Wuchereria bancrofti nocturnally subperiodic mainly exists in Karens residing alongside the Thailand-Myanmar border. Imported bancroftian filariasis caused by W. bancrofti nocturnally periodic mainly exists in cross-border Myanmar migrants. We analyzed seroprevalence data based on W. bancrofti adult worm antigen (Ag) loads and human immunodeficiency virus (HIV) immunoglobulins in the sentinel population samples which were studied prior to the start of the diethylcarbamazine (DEC) mass treatment phase in the PELF during fiscal years 2002-2006. In the Karens, the cumulative infection prevalence (36.8% serological antigen positivity or SAP) was specific for age (p < 0.001) but universal for gender (p = 0.77). The infection intensity (median Ag load = 60,827 antigen units or AU/ml) was specific for age (p = 0.031) and for males (p = 0.016). In the Myanmars, infection prevalence (24.0% SAP) was universal for age (p = 0.961) and for gender (p = 0.676). The infection intensity (median Ag load = 19,068 AU/ml) was universal for age (p = 0.433) but specific for females (p = 0.027). Overall, the Ag loads between the groups were significantly different (p = 0.014). In analysis of concomitant HIV and W. bancrofti infections, 7 (3.2%) Myanmars infected with HIV 1 and 3 (5.7%) with concomitant infections, subjected to biannual DEC treatment with 300 mg oral-dose FILADEC, were prevalent. The antigenemia clearance in the concomitant infections (r = -0.732, p = 0.039) as well as in the single W. bancrofti infection (r = -0.781, p = 0.022) was correlated with time required to clear antigenemias. We reemphasize that W. bancrofti adult worm Ag loads in the sentinel population samples would be beneficial for the PELF's implementers at the provincial level to probe the disease burdens in target areas and to evaluate and monitor the DEC treatment efficacy and effectiveness in those sentinel populations, including those with concomitant HIV eligible for the DEC mass treatment phase in the PELF.     

Potential risk factors for <Emphasis Type="Italic">Cryptosporidium</Emphasis> infection among HIV/AIDS patients in central areas of Thailand

Background  Cryptosporidiosis is very common in patients with HIV/AIDS and remains a threat to public health. A cross-sectional analytical study to determine the prevalence and identify potential risk factors associated with Cryptosporidium infection among HIV/AIDS patients was conducted. Methods  In the study of 143 HIV/AIDS adult patients with diarrhea, a total of 23 cases with Cryptosporidium infection and 120 cases with Cryptosporidium negative were reported during the study period. Results  Results revealed that the prevalence of cryptosporidiosis was 16.1%. In a stratified analysis controlling for gender, factors associated with Cryptosporidium infection were history of diarrhea >21 days, count ≤50 cells/mm³, and WBC count <4,000 cells/mm³. Conclusion  These findings confirmed that there was a strong association between cryptosporidiosis and count. Such information may provide possible recommended strategies for preventing cryptosporidiosis in HIV/AIDS persons.     

Lifestyle-related risk factors for stomach cancer in northeast Thailand.

Background: Stomach cancer is not common in Thailand but the life styles of the Thai population are changingto become more Western so that information for planning control programme of stomach cancer is necessary.The highest incidence rates of this neoplasm are found in Eastern Asia, ranging from age-standardized rates of95.5/105 (men) and 40.1/105 (women) in Yamagata, Japan to 4.1/105 (men) and 2.1/105 (women) in Khon Kaen,Northeast of Thailand. In Thailand, the estimated age-standardized incidence rates in 1993, 1996 were 4.9/105,4.1/105 in men and 3.0/105 , 2.6/105 in women. Risk factors for stomach cancer in Thai population are unclear,but possibly include low intake of vegetables and fruits, alcohol drinking, tobacco smoking and high intake ofsalt. Objective: To investigate various aspects of dietary factors, smoking, and alcohol drinking in determiningrisk of stomach cancer in Thai population. Methods: A case-control study was conducted in Khon Kaen, Thailandduring 2002-2006, to study the role of these factors in stomach cancer. 101 stomach cancer cases and 202 matchedcontrols (case : control = 1:2) by sex, age (± 3 years) and region were recruited from Srinagarind Hospital andKhon Kaen Regional Hospital, in Khon Kaen Province. All of cases were histologically confirmed. Controls hada variety of diseases, the main ones being disease of the eye. Information on dietary habits, alcohol drinking andsmoking were collected by a structured questionnaire, blood samples were collected for further study. Results:The distribution of the general characteristics by case-control status, the distribution of age and sex were similarin cases and controls. In the final analysis, the factors that found to be higher risk but not statistically significantwere long-term filter cigarette smoking (OR=1.9, 95%CI: 0.85-4.50), long-term alcohol consumption (OR=1.2,95%CI: 0.51-2.60) and low intake of vegetables and fruits (OR=1.2, 95%CI: 0.74-1.96). A high intake of vegetableoil (OR=4.5, 95%CI: 1.00.-20.17) was found to be associated with increased risk, and similar tendencies werenoted for pork oil (OR=1.4, 95%CI: 0.63-3.01) and jeaw prik (mainly chilly with plara broth) (OR=1.2, 95%CI:0 .76- 2.01). Conclusion: Our study confirmed protective effects of a high intake of fruits and vegetables againststomach cancer development and showed a high intake of sauces to increase risk of stomach cancer as in othercountries in Asia.     

Risk factors for colorectal cancer in northeast Thailand: lifestyle related.

Background: The incidence of colorectal cancer is variable around the world. Hiroshima, Japan had the highest incidence in men in 1997 with an age-standardized rate of 86.7 per 100,000 and New Zealand had the highest, at 40.6 per 100,000, in women. The incidence of colorectal cancer in Thailand is rather low and the latest figures for Northeast of Thailand are 7.1 per 100,000 for men and 4.7 for women. The reasons for these differences between countries are possibly due to variation in dietary habits, alcohol drinking or other cofactors. Methods: A case-control study was conducted in Khon Kaen, Northeast Thailand during 2002-2006 to study risk factors for colorectal cancer in a low risk area. Totals of 253 colorectal cancer cases (males 135, females 118) and 253 age- and sex-matched controls were recruited. Information on dietary habits, alcohol drinking, smoking and other information were collected by a structured questionnaire. Blood samples were collected for further study. Both univariate and multivariate analyses were carried out. Results: In the final model of multivariate analysis, the significant risk factors for colorectal cancer were a family history of cancer (OR=1.9 95%CI=1.2-2.9) and meat consumption (OR=1.0 95%CI=1.0007-1.0026). For BMI, subjects with higher BMI unexpectedly had a lower risk of colorectal cancer (OR=0.5 95%CI=0.3-0.8). Conclusion: Our study confirmed risk factors for colorectal cancer i.e. meat consumption and cancer in the family (genetic problem). However, the results for BMI are the reverse of expected, underlining one limitation of hospital-based case-control studies, in which cases are ill and admitted to the hospital at late stage.     

Evaluation of a single oral dose of diethylcarbamazine 300 mg as provocative test and simultaneous treatment in Myanmar migrant workers with Wuchereria bancrofti infection in Thailand

We assessed the efficiency of oral diethylcarbamazine (DEC) 300 mg as a provocative test on blood examination 30 minutes after administration, while gauging the overall infection rate in Myanmar migrant workers with Wuchereria bancrofti infection who enrolled for work permits in Thailand in 2002, using circulating filarial antigens (CFA) assays, the NOW ICT Filariasis card test and the Og4C3 ELISA as reference. Overall infection rates of 0.3% (95% CI=0-0.7%), 4.2% (95% CI=1.8-6.5%) and 5.9% (95% CI=3.2-8.7%) by three diagnostic tests, respectively, were observed. Among three different location groups of Myanmar population sample tested, there were no statistically significant differences in the overall infection detection rates. When either the ICT card test or the Og4C3 ELISA was used as a reference, the specificity and positive predictive value of the DEC-provocative day test was the same, 100%. The sensitivities were 25.0% (95% CI = 0.5-49.5%) and 17.6% (95% CI = 0-35.8%) on the ICT and ELISA tests, respectively. The negative predictive values were 96.8% (95% CI = 94.8-98.9%) and 95.1% (95% CI = 92.6-97.6%), respectively. In three microfilaremic persons followed-up monitored at 8-weeks DEC post-provocation, there were 6 x 10(-1) and 7 x 10(-1) decreases in microfilaremia and antigenemia. These findings suggested that, unlike the CFA assays, the DEC-provocative day test is unsuitable for the diagnosis of active W. bancrofti infection in the population tested, and for gauging current infection prevalence. The treatment would likely be beneficial to reduce microfilaremia and antigenemia.