[Show abstract][Hide abstract] ABSTRACT: The incidence of pneumococcal pneumonia among adults is a key driver for the cost-effectiveness of pneumococcal conjugate vaccine used among children. We sought to obtain more accurate incidence estimates among adults by including results of pneumococcal urine antigen testing (UAT) from population-based pneumonia surveillance in two Thai provinces. Active surveillance from 2006 to 2011 identified acute lower respiratory infection (ALRI)-related hospital admissions. Adult cases of pneumococcal pneumonia were defined as hospitalized ALRI patients aged ≥ 18 years with isolation of Streptococcus pneumoniae from blood or with positive UAT. Among 39,525 adult ALRI patients, we identified 481 pneumococcal pneumonia cases (105 by blood culture, 376 by UAT only). Estimated incidence of pneumococcal pneumonia hospitalizations was 30.5 cases per 100,000 person-years (2.2 and 28.3 cases per 100,000 person-years by blood culture and UAT, respectively). Incidence varied between 22.7 in 2007 and 43.5 in 2010, and increased with age to over 150 per 100,000 person-years among persons aged ≥ 70 years. Viral coinfections including influenza A/B, respiratory syncytial virus (RSV), and adenovirus occurred in 11% (44/405) of pneumococcal pneumonia cases tested. Use of UAT to identify cases of pneumococcal pneumonia among adults in rural Thailand substantially increases estimates of pneumococcal pneumonia burden, thereby informing cost-effectiveness analyses and vaccine policy decisions.
Preview · Article · Oct 2015 · The American journal of tropical medicine and hygiene
[Show abstract][Hide abstract] ABSTRACT: Background:
Few population-based estimates of the incidence of respiratory syncytial virus (RSV) infection in low- or middle-income countries are available. We describe the incidence and epidemiology of hospitalizations for RSV-associated acute lower respiratory tract infection (ALRI) detected by active population-based surveillance in 2 rural Thailand provinces during 2008-2011.
Patients hospitalized with ALRI were systematically sampled. Consenting patients provided nasopharyngeal swab specimens for RSV testing by real-time reverse-transcription polymerase chain reaction.
Of 13 982 enrolled patients hospitalized with ALRI, 1137 (8.1%) were RSV positive. After adjustment for sampling and nonenrollment, the incidence of RSV-associated ALRI hospitalization was 85 cases per 100,000 persons/year. The highest rates occurred among children aged <5 years (981 cases per 100,000 persons/year) and <1 year (1543 cases per 100,000 persons/year). Rates were low among older children and young adults but high among persons aged >65 years (130 cases per 100,000 persons/year). Eight (0.7%) RSV-infected study patients died during hospitalization. Annual RSV hospitalizations peaked during July-October with almost no documented RSV hospitalizations during January-June.
Our findings demonstrate the substantial contribution of RSV to global ALRI burden, especially in children aged <5 years and the elderly, and underscore the urgent need for effective prevention measures.
Preview · Article · Nov 2013 · The Journal of Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: Pneumonia remains a leading cause of under-five morbidity and mortality globally. Comprehensive incidence, epidemiologic, and etiologic data are needed to update prevention and control strategies.
We conducted active, population-based surveillance for hospitalized cases of acute lower respiratory infections (ALRI) among children aged <5 years in rural Thailand. ALRI cases were systematically sampled for an etiology study that tested nasopharyngeal specimens by PCR; children without ALRI were enrolled as controls from outpatient clinics.
We identified 28,543 hospitalized ALRI cases from 2005-2010. Among the 49% with chest radiographs, 76% had findings consistent with pneumonia as identified by two study radiologists. The hospitalized ALRI incidence rate (IR) was 5,772 per 100,000 child-years (95% CI 5,707, 5,837), and was higher in boys vs. girls (IR Ratio (IRR) 1.38, 95% CI 1.35, 1.41) and in children aged 6-23 months vs. other age groups (IRR 1.76, 95% CI 1.69, 1.84). Viruses most commonly detected in ALRI cases were respiratory syncytial virus (RSV, 19.5%), rhinoviruses (18.7%), bocavirus (12.8%), and influenza viruses (8%). Compared to controls, ALRI cases were more likely to test positive for RSV, influenza, adenovirus, human metapneumovirus, and parainfluenza viruses 1 and 3 (p≤0.01 for all). Bloodstream infections, most commonly Streptococcus pneumoniae and non-typhoidal Salmonella, accounted for 1.8% of cases.
Our findings underscore the high burden of hospitalization for ALRI and the importance of viral pathogens among children in Thailand. Interventions targeting viral pathogens coupled with improved diagnostic approaches, especially for bacteria, are critical for better understanding of ALRI etiology, prevention and control.
[Show abstract][Hide abstract] ABSTRACT: 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.
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.
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%).
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.
[Show abstract][Hide abstract] ABSTRACT: 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.
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.
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).
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.
[Show abstract][Hide abstract] ABSTRACT: Background:
Human parainfluenza viruses (HPIVs) are an important cause of acute respiratory illness in young children but little is known about their epidemiology in the tropics.
From 2003-2007, we conducted surveillance for hospitalized respiratory illness in rural Thailand. We performed reverse-transcriptase polymerase chain reaction on nasopharyngeal specimens and enzyme immunoassay on paired sera.
Of 10,097 patients enrolled, 573 (5%) of all ages and 370 (9%) of children <5 years of age had evidence of HPIV infection (HPIV1=189, HPIV2=54, HPIV3=305, untyped=27). Average adjusted annual incidence of HPIV-associated hospitalized respiratory illness was greatest in children aged <1 year (485 per 100,000 person years).
In Thailand, HPIV caused substantial illnesses requiring hospitalization in young children.
Full-text · Article · Jun 2012 · Influenza and Other Respiratory Viruses
[Show abstract][Hide abstract] ABSTRACT: Cryptococcal meningitis (CM) is a major cause of death among HIV-infected patients. Cryptococcal antigenemia (CrAg+) in the absence of CM can represent early-stage cryptococcosis during which antifungal treatment might improve outcomes. However, patients without meningitis are rarely tested for cryptococcal infection. We evaluated Cryptococcus species as a cause of acute respiratory infection in hospitalized patients in Thailand and evaluated clinical characteristics associated with CrAg+.
We tested banked serum samples from 704 human immunodeficiency virus (HIV)-infected and 730 HIV-uninfected patients hospitalized with acute respiratory infection from 2004 through 2009 in 2 rural provinces in Thailand for the presence of CrAg+. Retrospective chart reviews were conducted for CrAg+ patients to distinguish meningeal and nonmeningeal cryptococcosis and to identify clinical characteristics associated with CrAg+ in patients with and without evidence of CM.
CrAg+ was found in 92 HIV-infected patients (13.1%); only tuberculosis (19.3%) and rhinovirus (16.5%) were identified more frequently. No HIV-uninfected patients were CrAg+. Of 70 CrAg+ patients with medical charts available, 37 (52.9%) had no evidence of past or existing CM at hospitalization; 30 of those patients (42.9% of all CrAg+) had neither past nor existing CM, nor any alternate etiology of infection identified. Dyspnea was more frequent among CrAg+ patients without CM than among CrAg- patients (P = .0002).
Cryptococcus species were the most common pathogens detected in HIV-infected patients hospitalized with acute respiratory infection in Thailand. Few clinical differences were found between antigenemic and nonantigenemic HIV-infected patients. Health care providers in Thailand should evaluate HIV-infected patients hospitalized with acute respiratory infection for cryptococcal antigenemia, even in the absence of meningitis.
Full-text · Article · Dec 2011 · Clinical Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: Burkholderia pseudomallei, the causative agent of melioidosis, is endemic in northeastern Thailand. Population-based disease burden estimates are lacking and limited data on melioidosis exist from other regions of the country. Using active, population-based surveillance, we measured the incidence of bacteremic melioidosis in the provinces of Sa Kaeo (eastern Thailand) and Nakhon Phanom (northeastern Thailand) during 2006-2008. The average annual incidence in Sa Kaeo and Nakhon Phanom per 100,000 persons was 4.9 (95% confidence interval [CI] = 3.9-6.1) and 14.9 (95% CI = 13.3-16.6). The respective population mortality rates were 1.9 (95% CI = 1.3-2.8) and 4.4 (95% CI = 3.6-5.3) per 100,000. The case-fatality proportion was 36% among those with known outcome. Our findings document a high incidence and case fatality proportion of bacteremic melioidosis in Thailand, including a region not traditionally considered highly endemic, and have potential implications for clinical management and health policy.
Full-text · Article · Jul 2011 · The American journal of tropical medicine and hygiene
[Show abstract][Hide abstract] ABSTRACT: We evaluated factors associated with HIV testing history and returning for HIV test results among 2,049 Thai men who have sex with men. Of men, 50.3% reported prior HIV testing and 24.9% returned for HIV test results. Factors associated with prior HIV testing were male sex work, older age, employed, living away from the family, insertive anal sex role, history of drug use and having heard of effective HIV/AIDS treatment. Factors associated with returning for HIV test results were male sex work, older age, lack of a family confidant, history of sexually transmitted infections, and testing HIV negative in this study.
Full-text · Article · May 2011 · AIDS and Behavior
[Show abstract][Hide abstract] ABSTRACT: Population-based estimates of the incidence of invasive pneumococcal disease are unavailable for Thailand and other countries in Southeast Asia. We estimated the incidence of pneumococcal bacteremia cases requiring hospitalization in rural Thailand.
Blood cultures were performed on samples from hospitalized patients in 2 rural provinces where active, population-based surveillance of community-acquired pneumonia is conducted. Blood cultures were performed at clinician discretion and were encouraged for all patients with suspected pneumonia and all children aged <5 years with suspected sepsis. Pneumococcal antigen testing was performed on positive blood culture specimens that failed to grow organisms on subculture.
From May 2005 through June 2007, 23,853 blood culture specimens were collected overall, and 7319 were collected from children aged <5 years, which represented 66% and 47% of target patients, respectively. A total of 72 culture-confirmed pneumococcal bacteremia cases requiring hospitalization were identified. An additional 44 patients had media from positive blood cultures that yielded no growth on subculture but that had positive results of pneumococcal antigen testing. Of the 116 confirmed cases of bacteremia, 27 (23%) occurred in children aged <5 years; of these, 9 (33%) were confirmed by antigen testing only. The incidence of pneumococcal bacteremia cases requiring hospitalization among children aged <5 years had a range of 10.6-28.9 cases per 100,000 persons (incidence range if cases detected by antigen are excluded, 7.5-14.0 cases per 100,000 persons).
Invasive pneumococcal disease is more common than was previously suspected in Thailand, even on the basis of estimates limited to hospitalized cases of bacteremia. These estimates, which are close to estimates of the incidence of hospitalized cases of pneumococcal bacteremia in the United States before introduction of pneumococcal conjugate vaccine, provide important data to guide public health care policy and to inform discussions about vaccine introduction in Thailand and the rest of Southeast Asia.
Full-text · Article · Mar 2009 · Clinical Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: HIV/STD risk behavior has not been examined in community samples of men who have sex with men (MSM) in Thailand. The sexually-active sample (n=927) was recruited from bars, saunas, and parks; 20% identified as bisexual and 17% tested HIV-positive. Inconsistent (<100%) condom use was reported by 45% of those with steady partners and 21% of those with casual partners in the prior three months. 21% had heard of effective HIV treatments (n=194), among whom 44% believed HIV was less serious and 36% said their risk behavior had increased after hearing about the treatments. In multivariate analysis, HIV-positive status, gay-identification, getting most HIV information from the radio, believing HIV can be transmitted by mosquito bite, and concern about acquiring an STD were associated with inconsistent condom use during anal sex; slightly older age (25-29 vs. 18-24 years) was associated with more consistent condom use. HIV/STD risk-reduction strategies for MSM in Bangkok should clearly state sexual risk to individuals in this population.
Full-text · Article · Nov 2006 · AIDS and Behavior
[Show abstract][Hide abstract] ABSTRACT: This article describes adaptation and implementation of venue-day-time (VDT) sampling to enroll Thai men who have sex with men (MSM) through bars, saunas, and parks in Bangkok for the first community-based assessment of HIV prevalence and risk behavior. VDT sampling had four phases: (1) identification and geographic mapping of venues, (2) enumerating foot traffic at a subset of venues, (3) determination of eligibility and willingness to participate at a further subset of venues, and (4) enrollment of participants at a final set of venues. Field staff included peer staff, information technologists, and lab specialists. Survey data were collected with handheld computers; oral fluid specimens were collected for HIV testing. Local stakeholders were included in the process. The VDT sampling process took 6 months to complete, with 1,121 MSM enrolled. The successful implementation of VDT sampling provides a model for adapting the method to access and assess hard-to-reach populations in other non-Western settings.
[Show abstract][Hide abstract] ABSTRACT: The HIV prevalence and associated risk behaviours in Thai men who have sex with men (MSM) are unknown. This information is crucial to inform and implement targeted preventive interventions for this population.
A cross-sectional assessment, using venue-day-time sampling, was conducted. Participants were 1121 Thai men who were 18 years or older, were residents of Bangkok, and reported anal or oral sex with a man during the past 6 months. Oral fluid specimens were tested for HIV antibody. Demographic and behavioural data were collected using an interviewer-administered Palm based automated questionnaire.
HIV prevalence was 17.3% (194 of 1121). Mean age was 26.9 years (median 25 years), and university education was completed by 42.5%. Sex with men and women during the past 6 months was reported by 22.3%; sex with a woman ever, 36%; and unprotected sexual intercourse during the past 3 months, 36.0%. Alcohol use during the past 3 months was common (73.7%); drug use was rare (2.5%). Multivariate logistic regression analyses showed lower education, recruitment from a park, self-identification as homosexual, receptive and insertive anal intercourse, more years since first anal intercourse, and more male sex partners to be significantly and independently associated with HIV prevalence.
HIV infection is common among MSM in Bangkok. HIV prevention programs are urgently needed to prevent further spread of HIV in this young and sexually active population.