Pasakorn Akarasewi

Behavioral and sociodemographic risks for frequent visits to commercial sex workers among northern Thai men

Objective:The transmission of HIV-1 in Thailand has recently been attributed to exposure to infected commercial sex workers (CSW). We sought to identify risk factors for patterns of CSW visits among northern Thai men. Design:Retrospective recall of lifetime and recent CSW visits and associated risk factors were obtained by interview. Setting:Two military bases in northern Thailand. Participants:We enrolled two cohorts (n=2417) of young men, aged 19–23 years, who were conscripted into the Royal Thai Army and Air Force from six provinces in northern Thailand in May and November 1991. Main outcome measures:Frequency of self-reported lifetime and recent sex with CSW. Results:Multivariate results showed that lower socioeconomic status, early first intercourse and substance-use factors (alcohol, marijuana, other drugs, and smoking) associated with lifetime and recent sex with CSW. Sexual intercourse with other female partners, lower price paid at last CSW visit and frequency of condom use with CSW did not differentiate frequent from infrequent CSW visitors. Conclusions:Limits in the frequency of sex with CSW, improved condom practices and reduction of drinking prior to CSW visits would all appear to provide substantial protection from exposure to HIV-1 in this setting. AIDS 1993, 7:1647–1652

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 an isoniazid preventive therapy programme was shown to be feasible, further adjustments on the selection of participants, enrolment process, and follow-up system based on these findings are necessary to increase the adherence.

Was the 1988 HIV epidemic among Bangkok's injecting drug users a common source outbreak?

Objective:To describe and understand the genesis of the explosive 1988 HIV epidemic among Thai injecting drug users (IDU) in Bangkok. Design:Two cross-sectional HIV seroprevalence sample surveys (SP-1 and SP-2) of drug users, including IDU at various stages of treatment. SP-1, a 10-week estimate of prevalence, was conducted by the Bangkok Metropolitan Administration (BMA) in their detoxification clinics from 5 January to 7 March 1988. SP-2 estimated prevalence in 1 week, 12–15 September 1988, in the same 18 BMA clinics. Both surveys included an administered questionnaire that gathered demographic and behavioral information. Methods:Analysis of HIV prevalence by clinic in both SP-1 and SP-2, and the relationships between demographic data, behavioral variables, arrest history and HIV positivity in SP-1. Results:Data from individual clinics in SP-1 show significant increases in HIV prevalence among IDU sampled from early February 1988. Of IDU sampled in five ‘early’ clinics before 9 February, 2% were positive; in the 13 ‘late’ clinics sampled from 9 February until 7 March, 27% were positive. By September 1988, however, the early and late clinics were no longer heterogenous for HIV prevalence. For current IDU, HIV-positivity was associated with the sharing of injection equipment in SP-1 [odds ratio (OR), 1.82; 95% confidence limits (CL), 1.31–2.53] and recent jail or prison stay (OR, 2.15; 95% CL, 1.18–3.98). Conclusions:The behavioral factors associated with the HIV epidemic among Bangkoks IDU are similar to those described elsewhere. The monthly incidence of 5% from February to September 1988 suggests extensive needle or injection equipment sharing networks among IDU in Bangkok. Additionally, the pattern of HIV-positivity by detoxification clinic over time in early 1988, and then in September 1988 is consistent with a relationship to the prison amnesty of early December 1987. Shortly after that date, an undisclosed number of former IDU, a substantial number of whom were still injecting, and may have become HIV-positive while in custody, returned to resume injecting within existing drug-using networks throughout Bangkok and elsewhere in Thailand.

Evaluating the potential impact of the new Global Plan to Stop TB: Thailand, 2004-2005

OBJECTIVE WHOs new Global Plan to Stop TB 2006-2015 advises countries with a high burden of tuberculosis (TB) to expand case-finding in the private sector as well as services for patients with HIV and multidrug-resistant TB (MDR-TB). The objective of this study was to evaluate these strategies in Thailand using data from the Thailand TB Active Surveillance Network, a demonstration project begun in 2004. METHODS In October 2004, we began contacting public and private health-care facilities monthly to record data about people diagnosed with TB, assist with patient care, provide HIV counselling and testing, and obtain sputum samples for culture and susceptibility testing. The catchment area included 3.6 million people in four provinces. We compared results from October 2004-September 2005 (referred to as 2005) to baseline data from October 2002-September 2003 (referred to as 2003). FINDINGS In 2005, we ascertained 5841 TB cases (164/100 000), including 2320 new smear-positive cases (65/100 000). Compared with routine passive surveillance in 2003, active surveillance increased reporting of all TB cases by 19% and of new smear-positive cases by 13%. Private facilities diagnosed 634 (11%) of all TB cases. In 2005, 1392 (24%) cases were known to be HIV positive. The proportion of cases with an unknown HIV status decreased from 66% (3226/4904) in 2003 to 23% (1329/5841) in 2005 (P< 0.01). Of 4656 pulmonary cases, mycobacterial culture was performed in 3024 (65%) and MDR-TB diagnosed in 60 (1%). CONCLUSION In Thailand, piloting the new WHO strategy increased case-finding and collaboration with the private sector, and improved HIV services for TB patients and the diagnosis of MDR-TB. Further analysis of treatment outcomes and costs is needed to assess this programmes impact and cost effectiveness.

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 (CI), 62.7–74.3] compared with 10.0% (95% CI, 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.

Performance of the BACTEC MGIT 960 compared with solid media for detection of Mycobacterium in Bangkok, Thailand.

Controlled trials have demonstrated that liquid media culture (LMC) is superior to solid media culture for diagnosis of Mycobacterium tuberculosis (MTB), but there is limited evidence about its performance in resource-limited settings. We evaluated the performance of LMC in a demonstration project in Bangkok, Thailand. Sputum specimens from persons with suspected or clinically diagnosed tuberculosis were inoculated in parallel on solid (Lowenstein-Jensen [LJ]) and liquid (mycobacterial growth indicator tube [MGIT 960]) media. Biochemical tests identified isolates as MTB or nontuberculosis mycobacteria (NTM). Of 2566 specimens received from October 2004 to September 2006, 1355 (53%) were culture positive by MGIT compared with 1013 (39%) by LJ. Median time to growth for MGIT was significantly less than LJ: 11 versus 27 days. Of 1417 isolates detected by at least 1 media, 1255 (86%) were identified as MTB and 162 (11%) NTM. MGIT improved speed and sensitivity of MTB isolation and drug susceptibility testing, regardless of HIV status.

Region-wide synchrony and traveling waves of dengue across eight countries in Southeast Asia

Significance Persons living in the tropics and subtropics are at risk for dengue fever and dengue hemorrhagic fever, and large epidemics occur unexpectedly that can overburden healthcare systems. The spatial and temporal dynamics of dengue transmission are poorly understood, limiting disease control efforts. We compiled a large-scale dataset and analyzed continental-scale patterns of dengue in Southeast Asia. Our analysis shows that periods of elevated temperatures can drive the occurrence of synchronous dengue epidemics across the region. This multicountry collaborative study improved insight that may lead to improved prediction of dengue transmission patterns and more effective disease surveillance and control efforts. Dengue is a mosquito-transmitted virus infection that causes epidemics of febrile illness and hemorrhagic fever across the tropics and subtropics worldwide. Annual epidemics are commonly observed, but there is substantial spatiotemporal heterogeneity in intensity. A better understanding of this heterogeneity in dengue transmission could lead to improved epidemic prediction and disease control. Time series decomposition methods enable the isolation and study of temporal epidemic dynamics with a specific periodicity (e.g., annual cycles related to climatic drivers and multiannual cycles caused by dynamics in population immunity). We collected and analyzed up to 18 y of monthly dengue surveillance reports on a total of 3.5 million reported dengue cases from 273 provinces in eight countries in Southeast Asia, covering ∼107 km2. We detected strong patterns of synchronous dengue transmission across the entire region, most markedly during a period of high incidence in 1997–1998, which was followed by a period of extremely low incidence in 2001–2002. This synchrony in dengue incidence coincided with elevated temperatures throughout the region in 1997–1998 and the strongest El Niño episode of the century. Multiannual dengue cycles (2–5 y) were highly coherent with the Oceanic Niño Index, and synchrony of these cycles increased with temperature. We also detected localized traveling waves of multiannual dengue epidemic cycles in Thailand, Laos, and the Philippines that were dependent on temperature. This study reveals forcing mechanisms that drive synchronization of dengue epidemics on a continental scale across Southeast Asia.

HIV-1 seroconversion rates among female commercial sex workers Chiang Mai Thailand: a multi cross-sectional study.

ObjectivesTo determine HIV seroconversion rates among female commercial sex workers (CSW) in Chiang Mai, Thailand. DesignA three-round multi cross-sectional study was used at approximately 3-month intervals. MethodsIn December 1989, 38 brothels (60%) in Chiang Mai were randomly selected. All 518 female CSW in the brothels were interviewed about their sociodemographics, sexual practices, condom use, history of sexually transmitted diseases (STD) and other risk factors. Blood was tested for Venereal Disease Research Laboratory (VDRL)-reactivity and HIV-1 antibody. The same brothels, which were all still operating, were revisited in March and July 1990 and 431 and 320 CSW, respectively, were interviewed and blood-tested. Pelvic examination, cervical, urethral and rectal cultures for gonococcus were added to the study in March 1990, although rectal culture was dropped from the study in July 1990. ResultsThere were 5.2% [95% confidence interval (Cl), 4.1–10.6] and 3.6% (95% Cl, 1.5–5.4) per woman-month HIV seroconversion rates for the December-March and March-July periods, respectively. Of the CSW, 71.6–77.0% reported histories of at least one STD. Condom-use rates among these CSW were reported to be 85.8–91.8%. High rates of positive cervical (11.2–12.3%) and urethral (8.8–11.4%) cultures for gonococcus were also found in the CSW. ConclusionsThe fact that high HIV seroconversion rates and high STD prevalence rates occur despite high rates of reported condom use suggests that more aggressive education programs are needed in Thailand.

Incidence and Epidemiology of Hospitalized Influenza Cases in Rural Thailand during the Influenza A (H1N1)pdm09 Pandemic, 2009–2010

Background Data on the burden of the 2009 influenza pandemic in Asia are limited. Influenza A(H1N1)pdm09 was first reported in Thailand in May 2009. We assessed incidence and epidemiology of influenza-associated hospitalizations during 2009–2010. Methods We conducted active, population-based surveillance for hospitalized cases of acute lower respiratory infection (ALRI) in all 20 hospitals in two rural provinces. ALRI patients were sampled 1∶2 for participation in an etiology study in which nasopharyngeal swabs were collected for influenza virus testing by PCR. Results Of 7,207 patients tested, 902 (12.5%) were influenza-positive, including 190 (7.8%) of 2,436 children aged <5 years; 86% were influenza A virus (46% A(H1N1)pdm09, 30% H3N2, 6.5% H1N1, 3.5% not subtyped) and 13% were influenza B virus. Cases of influenza A(H1N1)pdm09 first peaked in August 2009 when 17% of tested patients were positive. Subsequent peaks during 2009 and 2010 represented a mix of influenza A(H1N1)pdm09, H3N2, and influenza B viruses. The estimated annual incidence of hospitalized influenza cases was 136 per 100,000, highest in ages <5 years (477 per 100,000) and >75 years (407 per 100,000). The incidence of influenza A(H1N1)pdm09 was 62 per 100,000 (214 per 100,000 in children <5 years). Eleven influenza-infected patients required mechanical ventilation, and four patients died, all adults with influenza A(H1N1)pdm09 (1) or H3N2 (3). Conclusions Influenza-associated hospitalization rates in Thailand during 2009–10 were substantial and exceeded rates described in western countries. Influenza A(H1N1)pdm09 predominated, but H3N2 also caused notable morbidity. Expanded influenza vaccination coverage could have considerable public health impact, especially in young children.

Pneumococcal Bacteremia Requiring Hospitalization in Rural Thailand: An Update on Incidence, Clinical Characteristics, Serotype Distribution, and Antimicrobial Susceptibility, 2005–2010

Background Streptococcus pneumoniae is an important cause of morbidity and mortality in Southeast Asia, but regional data is limited. Updated burden estimates are critical as pneumococcal conjugate vaccine (PCV) is highly effective, but not yet included in the Expanded Program on Immunization of Thailand or neighboring countries. Methods We implemented automated blood culture systems in two rural Thailand provinces as part of population-based surveillance for bacteremia. Blood cultures were collected from hospitalized patients as clinically indicated. Results From May 2005– March 2010, 196 cases of pneumococcal bacteremia were confirmed in hospitalized patients. Of these, 57% had clinical pneumonia, 20% required mechanical ventilation, and 23% (n = 46) died. Antibiotic use before blood culture was confirmed in 25% of those with blood culture. Annual incidence of hospitalized pneumococcal bacteremia was 3.6 per 100,000 person-years; rates were higher among children aged <5 years at 11.7 and adults ≥65 years at 14.2, and highest among infants <1 year at 33.8. The median monthly case count was higher during December–March compared to the rest of the year 6.0 vs. 1.0 (p<0.001). The most common serotypes were 23F (16%) and 14 (14%); 61% (74% in patients <5 years) were serotypes in the 10-valent PCV (PCV 10) and 82% (92% in <5 years) in PCV 13. All isolates were sensitive to penicillin, but non-susceptibility was high for co-trimoxazole (57%), erythromycin (30%), and clindamycin (20%). Conclusions We demonstrated a high pneumococcal bacteremia burden, yet underestimated incidence because we captured only hospitalized cases, and because pre-culture antibiotics were frequently used. Our findings together with prior research indicate that PCV would likely have high serotype coverage in Thailand. These findings will complement ongoing cost effectiveness analyses and support vaccine policy evaluation in Thailand and the region.