The association between environmental factors and tuberculosis infection among household contacts

A cross-sectional study was conducted to determine the association between environmental factors and tuberculosis infection among household contacts aged less than 15 years in Bangkok, Thailand, between May and December 2003. During the study period, 480 household contacts aged under 15 years were identified. The prevalence of tuberculosis infection among household contacts was 47.08% (95% CI = 42.60-51.56). A generalized estimating equation (GEE) indicated that the risk of positive tuberculin skin testing in household contacst was found to increase with household crowding. Children living in a crowded household were five times more likely to have tuberculosis infection (OR = 5.19, 95% CI = 2.65-8.69). The association between environmental factors and tuberculosis infection assists community tuberculosis staff in understanding the risks for tuberculosis infection in the community and planning appropriate preventive actions based on this risk.     

Immunoepidemiological studies on subclinical infection among leprosy household contacts in Thailand

Three-thousand-fourteen leprosy house-hold contacts in Thailand were surveyed by their personal history, physical examination, and immunological tests. The results were compared with those obtained from villagers in leprosy-endemic and nonendemic areas. The percentages of young people, students, children and grandchildren of the patient, the contacts of multibacillary leprosy cases, long duration of contact, BCG vaccination, FLA-ABS and Dharmendra's lepromin-positive responders were significantly higher in the household contacts than those in the villagers. The percentages of neural and dermal symptoms were not significantly different between the household contacts and the villagers in the endemic area, but the percentages were higher than those of the villagers in the nonendemic area. A PPD skin test was more frequently negative in the former two groups than in the latter. Both FLA-ABS and lepromin tests showed a significant correlation with the age of the contacts, their occupations, blood relation to the patient, the duration of contact, BCG vaccination, dermal signs such as an ill-defined plaque or macule with or without sensory loss, but did not correlate with sex, type of leprosy in the patient, or other skin diseases. The FLA-ABS test in the house-hold contacts and the villagers in an endemic area showed a significant correlation with the neural signs, such as enlargement of the peripheral nerve without sensory loss. These suspicious dermal and neural signs and symptoms were therefore considered signs of Mycobacterium leprae infection. The FLA-ABS test was sufficiently sensitive for detecting this infection and did not correlate with the lepromin or PPD skin tests. FLA-ABS-positive but lepromin-negative responders were found in 33.5% of the house-hold contacts. They were considered to be a high-risk group who may develop clinical leprosy. Nearly half of them were treated with dapsone or BCG according to the results of the PPD skin test. Follow up of these contacts, together with the remaining contacts without treatment, is in progress.     

HIV infection and risk factors among Bangkok prisoners,Thailand: a prospective cohort study

Background  

Incarceration has been associated with HIV infection among injection drug users. However, data on HIV risk factors of the inmates during incarceration are rarely reported from Thailand.     

痰涂片阳性肺结核患者成年家庭接触者患活动性结核病的风险

场所：土耳其伊斯坦布尔7个公共结核病防治所。 目的：调查伊斯坦布尔新诊断的痰涂片阳性肺结核患者成年家庭接触者（≥15岁）患活动性结核病的风险。 设计：对1997-2000年在伊斯坦布尔7家结防所登记的1570例结核病成年家庭接触者的回顾性分析。 结果：研究包括6188例家庭接触者（平均接触者／线索病例：3．9）,其中4114例（67％）大于15岁（平均接触者／线索病例：2．6）;3310例（80．5％）参加了接触者调查。平均随访时间2．2年（1～4年）;发现222例活动性结核病例（5．4％,95％可信区间5．2～5．6）,第一年发现171例。活动性结核发病率为2491／100000（15～34岁年龄组发病率3555／100000,大于35岁年龄组发病率1195／100000,P〈0．0001）。活动性结核病发病率最高的在15～24岁（8．5％）和25～34岁（6．5％）年龄组。 结论：涂片阳性肺结核患者的成年家庭接触者活动性结核发病率高。这样的高发病率说明化学预防治疗对于所有接触者,特别是年龄为15～34岁的接触者都是必要的,而不应仅仅用于儿童。     

Risk factors for HIV among prostitutes in Chiangmai, Thailand

The discovery of a 44% (44 out of 100) prevalence rate of HIV infection among female prostitutes working in brothels in Chiangmai in Thailand in June 1989, prompted this follow-up study in August to confirm the high prevalence rate and to look for risk factors for infection. We studied 238 female prostitutes working in 14 brothels and confirmed this high prevalence rate. Eighty-seven (36.5%) out of 238 prostitutes were found to be HIV-positive by enzyme-linked immunosorbent assay with IFA or Western blot confirmation. Logistic regressions found a significant association between HIV infection and frequency of sexual intercourse greater than 3 times per day [odds ratio (OR) = 2.82, 95% confidence interval (CI) = 1.47-5.41], sexual service charge less than 150 Baht (OR = 9.1, 95% CI = 2.9-33.3), and post sexual cleansing with water alone (OR = 3.85, 95% CI = 1.90-7.80). Of 56 women found seronegative in the June survey, 35 were re-tested in the August study. Seven (20%) of them were seropositive, giving an HIV seroconversion incidence rate of 10% per month. The findings of this study prompted intensive health education programmes among prostitutes, their customers, and owners of brothels.     

Immune correlates of acute Mycobacterium tuberculosis infection in household contacts in Kampala, Uganda

To determine immunologic and epidemiologic correlates of acute Mycobacterium tuberculosis infection in household contacts of infectious tuberculosis cases, we performed a prospective, community-based cohort study of index cases and their household contacts in Kampala, Uganda. Contacts were evaluated for tuberculin skin test (TST) conversion over two years. Interferon-gamma expression was measured using a whole blood assay after stimulating with M. tuberculosis culture-filtrate. In 222 contacts with a TST less than 5 mm at baseline, the one-year rate of TST conversion was 27%. The TST conversion was associated with the infectiousness of the index case and proximity of contact. Interferon-gamma levels at baseline were greater among TST converters compared with those who did not convert. The risk of TST conversion increased four-fold as the baseline interferon-gamma increased 10-fold, but only in contacts with BCG vaccination. In household contacts of tuberculosis, interferon-gamma responses to non-specific mycobacterial antigens may be used to make an early diagnosis of tuberculosis infection, especially in resource-limited settings where bacille Calmette-Guérin vaccination is commonly used.     

Risk factors of HIV-1 infection among female prostitutes in Khon Kaen,northeast Thailand

Summary HIV infection has increased to epidemic proportions in Thailand since 1987. There have been separate epidemics among population groups at high risk of infection and significant increases in different localities. The northeast region of Thailand has been affected by the epidemic since early 1989. The purpose of this study was to identify factors associated with HIV transmission among prostitutes during an early phase of the epidemic in the regional center of Khon Kaen. Three hundred and fifty-six prostitutes known to work in the urban area of Khon Kaen (Ampur Muang) in November 1990 were included in the study. Prostitutes were divided into two groups according to the type of place where they worked: direct prostitutes (in brothels, n=217) and indirect prostitutes (in massage parlors, n=139). The prevalence of HIV infection was found to be 12% among direct prostitutes and 2% among indirect prostitutes. Four variables were significantly associated with HIV infection after adjusting for confounders by logistic regression analysis: previous work in an area of high HIV prevalence, working in Khon Kaen less than one month, a low price charged for sex and using injectable contraceptives. Follow-up investigations are currently being carried out to explore in detail the association between the use of injectable contraceptives and HIV infection.

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Risikofaktoren einer HIV-1-Infektion bei weiblichen Prostituierten in Khon Kaen, Nordost-Thailand

Zusammenfassung Seit 1987 nahm die Ausbreitung von HIV in Thailand epidemische Ausmaße an. Bevölkerungsgruppen mit hohem Infektionsrisiko wurden in den verschiedenen Regionen von zeitlich unterscheidbaren Epidemien erfaßt. Die Nordost-Region wurde vergleichsweise spät, erst 1989 betroffen. Der Zweck dieser Studie war die Identifizierung von Faktoren, die mit der übertragung von HIV bei Prostituierten in der Provinzhauptstadt Khon Kaen während der Frühphase der Epidemie assoziiert waren. 356 Prostituierte wurden im November 1990 in die Studie aufgenommen. Sie wurden gemäß ihrem Arbeitsplatz in direkte Prostituierte (in Bordellen, n=217) und indirekte Prostituierte (in Massage-Salons, n=139) gruppiert. Die HIV-Prävalenz betrug bei den direkten Prostituierten 12% und 2% bei den indirekten Prostituierten. Vier Variablen waren signifikant mit einer HIV-Infektion assoziiert, nachdem eine logistische Regressions-Analyse durchgeführt wurde: vorangegangene Tätigkeiten in einer Region mit hoher HIV-Prävalenz, Prostitution in Khon Kaen weniger als einen Monat, ein niedriger Preis, der für Sex gefordert wurde und die Anwendung injizierbarer Kontrazeptiva. Gegenwärtig werden weitere Untersuchungen durchgeführt, um den Zusammenhang zwischen der Anwendung injizierbarer Kontrazeptiva und einer HIV-Infektion im Detail zu eruieren.

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The project is commissioned by the Ministry for Economic Cooperation, Germany.     

Risk of hepatitis C virus infection among household contacts of Saudi patients with chronic liver disease

SUMMARY. To evaluate the intrafamilial transmission of heptitis C virus and related risk factors among the Saudi population, two groups were investigated: 120 index patients with chronic liver disease and their 127 family contacts, and 220 blood donors who were anti-HCV-positive but with no chronic liver disease and their 91 family contacts. After a questionnaire on the risk factors for parenteral exposure, blood samples were obtained and tested for liver biochemistry and antibody to HCV (anti-HCV) by a third-generation enzyme immunoassay (UBI HCV HA4.0). Only two spouses of 20 index patients were anti-HCV-positive while the remaining 125 family contacts were anti-HCV-negative. None of the 91 family contacts of the 20 anti-HCV-positive blood donors was anti-HCV-positive. The two spouses were wives of index patients but had a history of blood transfusion on at least two different occasions. Our results clearly indicate the intrafamilial transmission of HCV is not the route of transmission of HCV among Saudis and our results argue against sexual transmission of hepatitis C virus despite a relatively long duration of marriage.     

Risk of Mycobacterium tuberculosis infection and disease among health care workers, Chiang Rai, Thailand.

SETTING: A provincial referral hospital in northern Thailand, where a cross-sectional study during 1995-1996 reported on the occupational risk of Mycobacterium tuberculosis transmission. OBJECTIVE: To describe the effectiveness of prevention strategies for nosocomial tuberculosis (TB). DESIGN: A prospective study among health care workers (HCW) including annual tuberculin skin test (TST) screening and active TB surveillance. Following a comprehensive risk assessment, preventive interventions were implemented targeting HCWs, hospitalised patients, and the hospital environment. RESULTS: The number of pulmonary TB cases diagnosed increased steadily from 102 in 1990 to 356 in 1999. The TST conversion rate was 9.3 (95% CI 3.3-15) per 100 person-years (py) in 1995-1997, but declined steadily to 2.2 (95% CI 0.0-5.1) in 1999. HCWs first screened within 12 months of employment had higher TST conversion rates (adjusted RR = 9.5, 95% CI 1.8-49.5) compared to those employed for longer than 12 months. The annual rate of active TB per 100 000 HCWs was 536 in 1995-1999. CONCLUSION: These HCWs were exposed to active TB patients and were at risk for M. tuberculosis infection, particularly during their first 12 months of employment. Implementation of nosocomial TB control measures in 1996 was followed by declining TST conversion rates, despite increasing exposure to active TB patients.     

Infection and disease among household contacts of patients with multidrug-resistant tuberculosis.

SETTING: Urban public teaching and referral hospital in Espirito Santo, Brazil. OBJECTIVE: To assess whether rates of infection and progression to active tuberculosis (TB) differed between household contacts of patients with multidrug-resistant (MDR) and drug susceptible (DS) pulmonary tuberculosis. DESIGN: Household contacts were assessed for evidence of TB infection and disease by purified protein derivative (PPD) skin testing, physical examination, chest X-ray, and sputum smear and culture. RESULTS: Among 133 close contacts of patients with MDR-TB, 44% were PPD-positive (> or =10 mm) compared to 37% of 231 contacts of the DS-TB cases (P = 0.18, chi2 test, OR 1.2, 95%CI 0.8-2). In a multivariate logistic regression analysis, after allowance for between-household variation in PPD responses, PPD positivity among household contacts of patients with MDR-TB remained comparable to PPD positivity in contacts of patients with DS-TB (OR 2.1, 95%CI 0.7-6.5). Respectively six (4%) and 11 (4%) contacts of the MDR- and DS-TB cases were found to have active TB at the time of initial evaluation or during follow-up (P = 0.78, chi2 test). Five of six contacts of MDR-TB cases and nine of nine contacts of DS-TB cases who developed TB, and for whom drug susceptibility test results were available, had the same bacterial susceptibility profiles as their index cases. DNA fingerprinting analysis of Mycobacterium tuberculosis isolates was identical between household contacts with active TB and the index MDR or DS-TB case for all 14 pairs compared. CONCLUSION: Our data suggest that the prevalence of tuberculous infection and progression to active TB among household contacts exposed to DS and MDR-TB cases is comparable, despite a longer duration of exposure of contacts to the index case in patients with MDR-TB.     

Prevalence and risk factors of latent tuberculosis infection in close contacts with tuberculosis patients among non-resident populations in Shanghai,China

<正>Objective To investigate the prevalence of latent tuberculosis(TB)infection(LTBI),and to identify the riskfactors in close contacts of pulmonary TB patients among non-resident population in Shanghai.Methods The study subjects were the close contacts of pulmonary TB patients among non-resident populations in Xuhui,Minhang and     

Prevalence and Risk Factors for Blastocystis Infection among Children and Caregivers in a Child Care Center,Bangkok, Thailand

In September 2009, a cross-sectional study was conducted to evaluate parasitic infections in a child care center in Khlong Toei, Bangkok, Thailand. Of 503 children and staff members, 258 (51.3%) stool samples and questionnaires were obtained. The most common parasitic infection was Blastocystis sp. (13.6%). Blastocystis sp. subtype 3 was predominantly found (80.0%), followed by subtypes 2 (12.0%) and 1 (8.0%). The prevalence of Blastocystis infection varied among different age groups. The prevalence of Blastocystis infection in non-HIV-infected children aged < 10 and 10–19 years were 14.5% and 10.3%, respectively, which were not significantly different. All 31 HIV-infected children were not infected with Blastocystis sp. The most likely reason could be the result of properly using prevention measures for this specific group.     

封闭社区结核病患者接触者结核感染状况预测模型

目的 通过监测封闭社区(强制隔离戒毒所)中结核病患者接触者的结核感染状况,分析影响接触者结核感染的可能因素,并构建感染预测模型。方法 采用结核菌素皮肤试验(TST),对封闭社区中2016年10月至2018年11月确诊的13例结核病患者的所有接触者,每6个月进行一次TST,至2019年7月。依据《WS 288—2017 肺结核诊断》相关标准,有卡介苗接种卡痕者硬结平均直径≥10mm、无卡痕者硬结平均直径≥5mm判断为结核病患者接触者(以下简称“接触者”)结核感染。在考虑场所特征(吸毒时间、戒毒次数、首次入本戒毒所)和不考虑场所特征情况下,分别采用Cox回归、条件logistic回归法对年龄、体质量指数(BMI)值、卡介苗接种史、既往结核病史、肺结核可疑症状、接触程度、接触患者分类因素构建感染预测模型,比较各模型对结核感染预测情况及预测值计算的ROC曲线下面积,寻找最优感染预测模型。结果 研究期间共纳入13例结核病患者,以及合格完成TST的检查对象2062名。接触者首次TST阳性而判断为结核感染者1060例,感染率为51.4%(1060/2062)。在后续2年的结核感染监测中,1002名第一次检查未感染者中有267例(26.6%,267/1002)接触者变为感染,其中173例(64.8%,173/267)是在封闭社区中出现新结核病患者后转变为结核感染;2年中社区接触者结核感染者共1327例,感染率64.4%(1327/2062)。使用logistic回归分析,在考虑场所特征情况下,纳入10个因素建立的封闭社区接触者结核感染预测模型为:结核感染=0.041×年龄+0.373×接触程度+0.046×BMI+0.028×吸毒年限-2.285;在不考虑场所特征情况下,纳入7个因素建立的预测模型为:结核感染=0.050×年龄+0.372×接触程度+0.041×BMI-2.282,ROC曲线下面积分别为0.584(95%CI:0.558~0.609)、0.625(95%CI:0.600~0.650),P值均<0.001;对结核感染预测准确率为93.6%(1242/1327)和94.1%(1249/1327)。使用Cox回归分析,在考虑场所特征情况下,建立的结核感染预测模型为:结核感染=0.020×年龄+0.133×接触程度+0.030×BMI+0.013×吸毒年限,ROC曲线下面积为0.633(95%CI:0.608~0.658),P<0.001;不考虑场所特征,建立的预测模型为:结核感染=0.025×年龄+0.135×接触程度+0.028×BMI,ROC曲线下面积为0.625(95%CI:0.600~0.650),P<0.001。结论 不考虑场所特征情况下,封闭社区结核病患者接触者结核感染预测中要考虑的因素包括年龄、BMI值、接触程度,使用两种建模方法的效果接近;如果考虑场所特征,需考虑的因素要增加吸毒年限。在能获得社区接触者随访时间的情况下,使用Cox回归预测效果更好。本研究对封闭社区接触者结核感染预测准确率较高,但尚不完善,亟需探索更多可能的影响因素。     

A study of multidrug resistant tuberculosis among symptomatic household contacts of MDR-TB patients

BackgroundDiagnosis and management of multidrug-resistant tuberculosis (MDR-TB) remains a global challenge and is associated with high morbidity and mortality. Burden of TB among symptomatic household contacts of MDR-TB is not extensively studied and screening of symptomatic contacts may provide a better opportunity for optimum management and effective TB control.MethodsThis prospective observational study was conducted in the department of Tuberculosis & Chest diseases, S.N. Medical College, Agra from February 2016 to January 2018. The study recruited 271 symptomatic household contacts of 87 index MDR-TB cases. Symptomatic contacts were screened for active disease and latent TB infection. Risk factors for the spread of disease were also looked for.ResultsOut of 271 symptomatic household contacts, 97 (35.79%) had active TB. Among 97 diseased, 62 (22.87%) had MDR-TB and 35 (12.91%) had drug-susceptible TB. 124 contacts (45%) had latent TB infection. Risk factors associated with occurrence of TB included age less than 18 years (OR = 7160, p = 0.1908, RR = 0.8082, p = 0.1887), male sex (OR = 2.3108, p = 0.0021, RR = 1.7444, p = 0.0034), Sibling as index case (OR = 0.6404, p = 0.0804, RR = 0.7520, p = 0.0806), lack of BCG vaccination (OR = 1.7763, p = 0.0271, RR = 1.4338, p = 0.0247) malnutrition (OR = 1.8980, p = 0.0138, RR = 1.5166, p = 0.0159) and lower socioeconomic status (OR = 3.2399, p < 0.0001, RR = 2.1524, p < 0.0001).ConclusionThe high case detection rate by screening symptomatic household contacts shows MDR-TB is highly transmissible and household contacts are at a higher risk of developing active disease. It provides an opportunity for early diagnosis, adequate treatment, and interrupt the chain of transmission. Identifying risk factors help prevent the progression of latent TB infection to active disease.