Hospitalizations for acute lower respiratory tract infection due to respiratory syncytial virus in Thailand, 2008-2011.

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. METHODS: Patients hospitalized with ALRI were systematically sampled. Consenting patients provided nasopharyngeal swab specimens for RSV testing by real-time reverse-transcription polymerase chain reaction. RESULTS: 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. CONCLUSIONS: 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.

High prevalence of cryptococcal infection among HIV-infected patients hospitalized with pneumonia in Thailand.

BACKGROUND: 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+. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Incidence and etiology of acute lower respiratory tract infections in hospitalized children younger than 5 years in rural Thailand.

BACKGROUND: 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. METHODS: We conducted active, population-based surveillance for hospitalized cases of acute lower respiratory tract infections (ALRI) among children <5 years of age in rural Thailand. ALRI cases were systematically sampled for an etiology study that tested nasopharyngeal specimens by polymerase chain reaction; children without ALRI were enrolled as controls from outpatient clinics. RESULTS: We identified 28,543 hospitalized ALRI cases from 2005 to 2010. Among the 49% with chest radiographs, 76% had findings consistent with pneumonia as identified by 2 study radiologists. The hospitalized ALRI incidence rate was 5772 per 100,000 child-years (95% confidence interval: 5707, 5837) and was higher in boys versus girls (incidence rate ratio 1.38, 95% confidence interval: 1.35-1.41) and in children 6-23 months of age versus other age groups (incidence rate ratio 1.76, 95% confidence interval: 1.69-1.84). Viruses most commonly detected in ALRI cases were respiratory syncytial virus (19.5%), rhinoviruses (18.7%), bocavirus (12.8%) and influenza viruses (8%). Compared with controls, ALRI cases were more likely to test positive for respiratory syncytial virus, influenza, adenovirus, human metapneumovirus and parainfluenza viruses 1 and 3 (P ≤ 0.01 for all). Bloodstream infections, most commonly Streptococcus pneumoniae and nontyphoidal Salmonella, accounted for 1.8% of cases. CONCLUSIONS: 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.

Rabies-related knowledge and practices among persons at risk of bat exposures in Thailand.

BACKGROUND: Rabies is a fatal encephalitis caused by lyssaviruses. Evidence of lyssavirus circulation has recently emerged in Southeast Asian bats. A cross-sectional study was conducted in Thailand to assess rabies-related knowledge and practices among persons regularly exposed to bats and bat habitats. The objectives were to identify deficiencies in rabies awareness, describe the occurrence of bat exposures, and explore factors associated with transdermal bat exposures. METHODS: A survey was administered to a convenience sample of adult guano miners, bat hunters, game wardens, and residents/personnel at Buddhist temples where mass bat roosting occurs. The questionnaire elicited information on demographics, experience with bat exposures, and rabies knowledge. Participants were also asked to describe actions they would take in response to a bat bite as well as actions for a bite from a potentially rabid animal. Bivariate analysis was used to compare responses between groups and multivariable logistic regression was used to explore factors independently associated with being bitten or scratched by a bat. FINDINGS: Of 106 people interviewed, 11 (10%) identified bats as a potential source of rabies. A history of a bat bite or scratch was reported by 29 (27%), and 38 (36%) stated either that they would do nothing or that they did not know what they would do in response to a bat bite. Guano miners were less likely than other groups to indicate animal bites as a mechanism of rabies transmission (68% vs. 90%, p=0.03) and were less likely to say they would respond appropriately to a bat bite or scratch (61% vs. 27%, p=0.003). Guano mining, bat hunting, and being in a bat cave or roost area more than 5 times a year were associated with history of a bat bite or scratch. CONCLUSIONS: These findings indicate the need for educational outreach to raise awareness of bat rabies, promote exposure prevention, and ensure appropriate health-seeking behaviors for bat-inflicted wounds, particularly among at-risk groups in Thailand.

Japanese encephalitis virus remains an important cause of encephalitis in Thailand.

BACKGROUND: Japanese encephalitis virus (JEV) is endemic in Thailand and prevention strategies include vaccination, vector control, and health education. METHODS: Between July 2003 and August 2005, we conducted hospital-based surveillance for encephalitis at seven hospitals in Bangkok and Hat Yai. Serum and cerebrospinal (CSF) specimens were tested for evidence of recent JEV infection by immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) and a plaque reduction neutralization test (PRNT). RESULTS: Of the 147 patients enrolled and tested, 24 (16%) had evidence of acute flavivirus infection: 22 (15%) with JEV and two (1%) with dengue virus. Of the 22 Japanese encephalitis (JE) cases, 10 (46%) were aged ≤ 15 years. The median length of hospital stay was 13 days; one 13-year-old child died. Ten percent of encephalitis patients enrolled in Bangkok hospitals were found to have JEV infection compared to 28% of patients enrolled in hospitals in southern Thailand (p < 0.01). Four (40%) of the 10 children with JE were reported as being vaccinated. CONCLUSIONS: JEV remains an important cause of encephalitis among hospitalized patients in Thailand. The high proportion of JE among encephalitis cases is concerning and additional public health prevention efforts or expanded vaccination may be needed.