Impact of enhanced notification of tuberculosis laboratory results to minimise treatment delay, Chiang Rai Hospital, Northern Thailand.

SETTING: A provincial referral hospital in northern Thailand, where a cross-sectional study from 1995-1996 reported on the occupational risk of Mycobacterium tuberculosis transmission. OBJECTIVE: To assess the impact of acid-fast bacilli sputum smear-positive results notification to improve tuberculosis (TB) services by documenting the location of sputum collection, completing the TB register immediately, and minimising delays between hospital admission and treatment initiation. DESIGN: The cohort of smear-positive TB patients identified through laboratory microscopy record reviews from 1994-1999. Time from admission to hospital, laboratory diagnosis of TB, registration for treatment, and initiation of therapy were determined during the implementation of enhancing the laboratory results notification system. RESULTS: The number of unregistered TB patients fell from 44 cases in 1994 to none in 1999. The time elapsed from admission to treatment initiation decreased from a mean of 5.6 days in 1997 (n = 162) to 3.1 days in 1999 (n = 136) (P < 0.001). This decrease was attributed to a reduction in time between laboratory diagnosis and treatment from 2.7 days in 1997 to 0.6 days in 1999 (P < 0.001). CONCLUSION: Prompt identification, isolation and treatment of TB patients occurred through an enhanced laboratory notification system. Such systems are inexpensive, improve TB care services and may reduce nosocomial transmission of M. tuberculosis.

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.

Explosive spread and effective control of human immunodeficiency virus in northernmost Thailand: the epidemic in Chiang Rai province, 1988-99.

The human immunodeficiency virus type 1 (HIV-1) epidemic began in Asia later than most in other regions but then spread very rapidly. Upper northern Thailand was severely affected, with among the highest infection rates in Asia. The first 12 years of the HIV epidemic in Chiang Rai, Thailand's northernmost province are described. HIV infection was not reported in Chiang Rai until 1988 but, within a few years more than half of the brothel-based female sex workers and one in six of 21-year-old male Royal Thai Army conscripts from the province were HIV infected. Infection rates in Chiang Rai have since declined following an aggressive prevention campaign, but the number of AIDS cases continues to mount, along with profound demographic, social and economic effects.

Disease progression and survival with human immunodeficiency virus type 1 subtype E infection among female sex workers in Thailand.

This study describes rates and correlates of disease progression and survival among 194 female sex workers in northern Thailand who were infected with human immunodeficiency virus type 1 (HIV-1; 96% with subtype E). The median rate of CD4 T lymphocyte decline (3.9 cells/microL/month), median time from infection to <200 CD4 T lymphocytes/microL (6.9 years), and time to 25% mortality (6.0 years) were similar to those found in studies performed in Western countries before highly active antiretroviral therapy was available to populations infected with HIV-1 subtype B. Mortality rates among women with >100,000 HIV-1 RNA copies/mL were 15.4 times higher (95% confidence interval, 5.2-45.2) than among women with <10,000 copies. Initial CD4 T lymphocyte counts and serum virus load were independently strong predictors of survival. These results can help in assessing the effects of the epidemic in Thailand and in determining the prognoses for individual patients.

HIV-1 and other sexually transmitted infections in a cohort of female sex workers in Chiang Rai, Thailand.

OBJECTIVES: To determine demographic and behavioural factors and sexually transmitted infections (STIs) associated with prevalent HIV-1 infection among brothel based and other female sex workers (FSWs) in Chiang Rai, northern Thailand. METHODS: Data were collected from questionnaires, physical examinations, and laboratory evaluations on Thai FSWs enrolled in a prospective cohort study in Chiang Rai, Thailand, from 1991 to the end of 1994. RESULTS: HIV-1 seroprevalence was 32% among 500 women: 47% for 280 brothel workers and 13% for 220 other FSWs (p < 0.001); 96% of infections were due to HIV-1 subtype E. At enrolment, other STIs were common: chlamydia, 20%; gonorrhoea, 15%; active syphilis (serological diagnosis), 9%; genital ulcer, 12%; seroreactivity to Haemophilus ducreyi, 21%, and herpes simplex virus type 2 (HSV-2), 76%. On multiple logistic regression analysis, HIV-1 was associated with brothel work, birth in upper northern Thailand, initiation of commercial sex at < 15 years of age, syphilis, HSV-2 seropositivity, and genital ulcer. CONCLUSIONS: Young Thai FSWs working in brothels in northern Thailand in the early phase of the HIV epidemic have been at very high risk for HIV-1 infection and several other STIs. Programmes are needed to prevent girls and young women from entering the sex industry and to reduce the risk of infection with HIV-1 and other STIs.

Increased risk of Mycobacterium tuberculosis infection related to the occupational exposures of health care workers in Chiang Rai, Thailand.

SETTING: Chiang Rai, the northernmost province of Thailand. OBJECTIVE: To evaluate the occupational risk for tuberculous infection of health care workers (HCWs) and the utility of tuberculin skin test (TST) in a developing country setting. DESIGN: A cross-sectional TST survey, including a risk assessment questionnaire, of Chiang Rai Hospital HCWs. RESULTS: Of 911 HCWs tested, 623 (68%) had indurations of > or = 10 mm and 322 (35%) indurations of > or = 15 mm. Factors most predictive for TST positivity, using either cut-off, were employment > 1 year, frequent direct patient contact, and male sex. Moreover, having a bacillus Calmette-Guérin (BCG) scar was predictive of a > or = 10 mm, but not a > or = 15 mm, reaction. CONCLUSIONS: Chiang Rai Hospital HCWs had an increased risk for Mycobacterium tuberculosis infection, which was significantly associated with occupational exposure. Where BCG coverage is high, a TST cut-off of > or = 15 mm may correlate better with M. tuberculosis infection than does a cut-off of > or = 10 mm. Effective, affordable infection control measures are needed for health care facilities in developing countries such as Thailand, where HCWs may be at increased risk for M. tuberculosis infection from occupational exposures.

HIV-1 seroconversion in a prospective study of female sex workers in northern Thailand: continued high incidence among brothel-based women.

OBJECTIVES: To determine the incidence of HIV-1 infection, temporal trends in incidence, and risk factors for seroconversion in a cohort of female commercial sex workers (CSW) in upper northern Thailand, the region of Thailand with the highest rates of HIV-1 infection. METHODS: CSW were enrolled from 1991 through 1994 and evaluated prospectively with interviews, physical examination, testing for sexually transmitted diseases (STD), and serologic testing for HIV-1 infection. RESULTS: The incidence of HIV-1 seroconversion in the first year of follow-up was 20.3 per 100 person-years among 126 brothel-based CSW and 0.7 per 100 person-years among 159 other CSW who worked in other venues such as bars or massage parlors. Incidence remained elevated among brothel-based CSW who were enrolled later in the study compared with those who enrolled earlier. Through 1996, 30 women seroconverted. In a multivariable proportional hazards model, seroconversion was significantly associated (P < 0.05) with brothel-based sex work (adjusted risk ratio, 7.3) and Chlamydia trachomatis cervical infection (adjusted risk ratio, 3.3). CONCLUSION: Despite national HIV control efforts and declining rates of infection among young men in Thailand, brothel-based CSW may continue to be at high risk for HIV-1 infection. Additional efforts are needed to provide alternative economic choices for young women, to ensure universal condom use during commercial sex, and to develop new prevention technologies.

HIV-related risk factors of blood donors in northern Thailand before and after knowing HIV test results.

BACKGROUND: The epidemic of Human Immunodeficiency Virus (HIV) infection led blood banks to initiate donation deferral criteria based on self-reported risk factors. However little information is available on the differences in reporting risk factors before and after HIV status is known. METHODS: Between April and July 1994, blood donors in a provincial hospital in northern. Thailand were interviewed at the time of donation, about their demographic characteristics and risk factors. All donors had agreed to learn their test results and were called back for post-test counselling and reinterview. RESULTS: HIV-positive blood donors were more likely to change from 'denying' to 'acknowledging' risk factors while HIV-negatives were more likely to change from 'acknowledging' to 'denying'. The differences between risk factors obtained before and after test results were known resulted in stronger, weaker or even opposite risk measures. CONCLUSION: The study results raise questions about the impact of the differences in reporting HIV-related risk factors by the donors on how effective donation deferral criteria can be developed.

PIP: The widespread prevalence of HIV infection in countries and regions around the world has led blood banks to refuse blood donations from donors who are at high risk of being infected with HIV. Low-risk donors are instead recruited and all donors are tested for infection with HIV. The criteria for donor deferral are based mainly upon the epidemiology of HIV infection among the donors. The authors investigated the differences in reporting risk factors before and after HIV status is known. During April-July 1994, blood donors at a hospital in Chiangrai province were interviewed at the time of donation about their demographic characteristics and risk factors. 134 of the 175 HIV-positive donors returned for post-HIV-test counseling and reinterview. 423 of the 1062 HIV-negative donors returned. The donors were of median age 32 years. HIV-positive donors were more likely to change from denying to acknowledging risk factors, while HIV-seronegative donors were more likely to change from acknowledging to denying. The differences between risk factors observed before and after test results were known resulted in stronger, weaker, or even opposite risk measures.

Adherence to tuberculosis preventive therapy among HIV-infected persons in Chiang Rai, Thailand.

OBJECTIVE: To determine the level of and reasons associated with adherence to tuberculosis preventive therapy among asymptomatic HIV-infected individuals in northern Thailand. DESIGN: A prospective cohort study with a 9-month follow-up. METHODS: A total of 412 HIV-infected persons were enrolled in a tuberculosis preventive therapy programme in a hospital. A 9-month isoniazid regimen was prescribed. Adherence was determined by pill count. Participants who missed a scheduled appointment for more than a month were interviewed. Five focus group discussion sessions were held among those who successfully completed the therapy. RESULTS: Of the 412 participants, 69.4% (286) completed the 9-month regimen. The adherence rate, defined as the proportion of those who took more than 80% of pills, was 67.5% (n = 278). Sex, source of participants and history of physical symptoms were associated with adherence. A significant portion of defaults took place at the beginning of the therapy. Out-migration, denial of HIV status, and perceived side effects of isoniazid were frequently cited as reasons for non-adherence. For those adhering participants, the acceptance of personal HIV status, concern about children and family, and a good health provider relationship were important reasons motivating adherence. Several reminder systems were developed by the participants. CONCLUSIONS: Although a isoniazid preventive therapy programme was shown to be feasible, further adjustments on the selection of participants, enrollment process, and follow-up system based on these findings are necessary to increase the adherence.

PIP: A prospective study of 412 men and women infected with human immunodeficiency virus (HIV) who were enrolled in a hospital-based tuberculosis prevention program in Chiang Rai, Thailand, identified factors that contribute to non-adherence. Program participants were provided a 9-month supply of isoniazid, which has been shown to be effective in reducing the risk of developing clinical tuberculosis among asymptomatic HIV-infected individuals. Of the 412 individuals enrolled in the program, 286 (69.4%) completed the treatment regimen, 109 (26.5%) defaulted by failing to take the medicine for more than 60 consecutive days, and 17 (4.1%) developed acquired immunodeficiency syndrome (AIDS) or died. Among defaulters, 20 restarted the regimen and eventually complied with treatment, raising the completion rate to 74.3%. Married people, women, outpatients, surviving spouses, the self-employed, and those with no history of physical symptoms were more likely to be adherent. The primary reasons for default included outmigration for job search, denial of HIV status, perceived drug side effects, and confusion about the duration of treatment. Although this study suggests that good adherence to a tuberculosis prevention regime is possible among HIV patients, it highlights factors that should be considered (especially migration potential) in the selection of participants.

Utility of tuberculin and anergy skin testing in predicting tuberculosis infection in human immunodeficiency virus-infected persons in Thailand.

SETTING: Chiang Rai, the northernmost province of Thailand, where extensive human immunodeficiency virus (HIV) transmission has resulted in a rapid increase in tuberculosis. OBJECTIVE: To assess the utility of tuberculin and anergy skin testing to identify latent Mycobacterium tuberculosis infection in HIV-infected persons. DESIGN: A cross-sectional study and analysis were conducted to examine reactivity to tuberculin and two control antigens (mumps and candida) in HIV-negative and HIV-positive blood donors and female sex workers. RESULTS: HIV-positive persons had markedly decreased tuberculin reactivity; 14%, 19%, and 40% had an induration of > or = 10 mm, > or = 5 mm, > or = 2 mm, respectively, while 51% of 525 HIV-negative persons had an induration of > or = 10 mm (P < 0.001). Mumps and candida positivity (reactions of > or = 3 mm) were found in 94% and 78% of HIV-negative persons compared with 72% and 61% of HIV-positive persons, respectively (P < 0.001). Although HIV-positive persons had markedly less tuberculin reactivity even at higher CD4+ cell counts (> 400 cells/microL), reactivity to mumps and candida was present in more than half of HIV-positive persons with low CD4+ cell counts (< or = 200 cells/microL). Reaction to control antigens did not predict tuberculin reactivity. CONCLUSION: In this setting, tuberculin and anergy skin testing have a low predictive value in detecting M. tuberculosis infection in HIV-infected persons, and therefore such testing has a limited role in identifying HIV-infected persons who may benefit from tuberculosis preventive therapy programs.

Rapid increase in HIV-related tuberculosis, Chiang Rai, Thailand, 1990-1994.

OBJECTIVE: Chiang Rai, the northernmost province of Thailand, has experienced an explosive HIV epidemic since 1989. This study assessed the impact of HIV infection on tuberculosis (TB) in the area. METHODS: We analyzed the incidence of reported TB in the province from 1982 through 1993 and TB registry data at Chiang Rai Hospital from 1985 through 1994. RESULTS: Following a steady decline in reported TB from 1982 through 1991, the incidence of TB increased sharply after 1991. TB registry data from Chiang Rai Hospital, which began confidential HIV testing in October 1989, indicated a steady and rapid increase in the number and proportion of HIV-seropositive TB patients from four (1.5% of all TB patients) in 1990 to 207 (45.5%) in 1994 (P < 0.001). Compared with HIV-negative TB patients, HIV-positive TB patients were more likely to be men, aged 20-39 years and have extrapulmonary TB (P < 0.001). Treatment completion rates were similar. Twelve months after beginning TB treatment, HIV-positive TB patients had a mortality rate of 68.6% [95% confidence interval (Cl), 62.7-74.3] compared with 10.0% (95% Cl, 8.3-12.1%) in HIV-negative patients (P < 0.001). CONCLUSION: Thailand and other Asian countries where HIV is spreading rapidly must promptly address the dual epidemic of TB and HIV in order to reduce preventable morbidity and mortality.

Donation deferral criteria for human immunodeficiency virus positivity among blood donors in northern Thailand.

BACKGROUND: The purpose of this study was to develop human immunodeficiency virus (HIV) infection donation deferral criteria for blood donors in an HIV-epidemic area of northern Thailand, where the predominant means of transmission of HIV is through heterosexual contact. STUDY DESIGN AND METHODS: In a preliminary study, 2242 blood donors were interviewed, and their blood was tested for HIV antibodies between September 1993 and April 1994. The risk factors associated with HIV positivity were identified. Criteria to identify HIV-positive persons on the basis of a logistic equation were developed and applied to another group of 5769 prospective blood donors. RESULTS: A multivariate analysis showed the following odds ratios (OR) for traits that were independently associated with HIV positivity: younger age (OR = 0.93 for each additional year of age), male gender (OR = 2.41), having no more than a primary school education (OR = 2.00), being in the military (OR = 1.78), being unsure of one's own blood safety (OR = 2.00), history of injecting drug use (OR = 5.36), diagnosis of syphilis or positive syphilis serologic test in the past 12 months (OR = 2.67), and genital ulcer in the past 12 months (OR = 4.56). On the basis of the model, with a limit of <10 percent loss of uninfected donors, predicted probabilities of HIV positivity alone or of markers of infection with HIV, hepatitis B virus, or Treponema pallidum were calculated. With a cutoff of 6.5-percent estimated probability of HIV infection, derived from the logistic equation, the donor deferral criteria have 33.6-percent sensitivity and 8.3-percent positive predictive value for HIV positivity and 15.5-percent sensitivity and 18.4-percent positive predictive value for markers of infection with one of the three pathogens. CONCLUSION: The proposed donor deferral system provides a more flexible, sensitive, and predictive tool for averting donation by those who, though HIV antibody-negative, are at a higher risk of being infected with HIV.

PIP: 2242 blood donors were interviewed and their blood tested for antibody to HIV between September 1993 and April 1994. The risk factors associated with being HIV seropositive were identified. Criteria to identify HIV-seropositive individuals on the basis of a logistic equation were then developed and applied to another group of 5769 prospective blood donors. Despite the availability of sensitive screening tests to detect HIV infection, blood donors can be infected but test seronegative if they have been infected for a period of six weeks or less. In Thailand, the rate of window-period blood donation at a university teaching hospital in Bangkok was reported to be relatively high compared with that in developed countries. The authors propose criteria capable of rooting out and excluding donations to the blood supply from people who are HIV seropositive, yet in the seronegative window period, in an HIV-epidemic area of northern Thailand, where the main mode of HIV transmission is through heterosexual contact. Younger age, being of male gender, having no more than a primary school education, being in the military, being unsure of one's own blood safety, having a history of IV drug use, diagnosis of syphilis or positive syphilis serologic test in the past 12 months, and genital ulcer in the past 12 months were each independently associated with being HIV seropositive. The proposed donor deferral system provides a more flexible, sensitive, and predictive tool for averting donation by those who, although HIV antibody-seronegative, are at comparatively greater risk of being infected with HIV.