Pathom Sawanpanyalert

Human Disease from Influenza A (H5N1), Thailand, 2004

Direct contact with sick poultry, young age, pneumonia and lymphopenia, and acute respiratory distress syndrome should prompt specific laboratory testing for H5 influenza.

Human coronavirus infections in rural thailand : A comprehensive study using real-time reverse-transcription polymerase chain reaction assays

Abstract Background. We sought to determine whether infections with human coronaviruses (HCoVs) 229E, OC43, HKU1, and NL63 are associated with pneumonia and to define the epidemiology of HCoV infection in rural Thailand. Methods. We developed a real-time reverse-transcription polymerase chain reaction (RT-PCR) assay panel for the recognized HCoV types and compared HCoV infections in patients hospitalized with pneumonia, outpatients with influenza-like illness, and asymptomatic control patients between September 2003 and August 2005. Results. During study year 1, 43 (5.9%) of 734 patients with pneumonia had HCoV infections; 72.1% of the infections were with OC43. During study year 2, when control patients were available, 21 (1.8%) of 1156 patients with pneumonia, 12 (2.3%) of 513 outpatients, and 6 (2.1%) of 281 control patients had HCoV infections. Compared with infection in control patients, infection with any HCoV type or with all types combined was not associated with pneumonia (adjusted odds ratio for all HCoV types, 0.67 [95% confidence interval, 0.26–1.75]; P= .40 ). HCoV infections were detected throughout both study years; 93.6% of OC43 infections in the first year occurred from January through March. Conclusions. HCoV infections were infrequently detected in rural Thailand by use of sensitive real-time RTPCR assays. We found no association between HCoV infection and illness. However, we noted year-to-year variation in the prevalence of HCoV strains, which likely influenced our results.

Salmonella serovars from humans and other sources in Thailand, 1993-2002.

We serotyped 44,087 Salmonella isolates from humans and 26,148 from other sources from 1993 through 2002. The most common serovar causing human salmonellosis in Thailand was Salmonella enterica Weltevreden. Serovars causing human infections in Thailand differ from those in other countries and seem to be related to Salmonella serovars in different food products and reservoirs.

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 > 3 times per day [odds ratio (OR) = 2.82, 95% confidence interval (Cl) = 1.47–5.41], sexual service charge < 150 Baht (OR = 9.1, 95% Cl = 2.9–33.3), and post sexual cleansing with water alone (OR = 3.85, 95% Cl = 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.

HIV prevalence and risks among injection and noninjection drug users in northern Thailand: need for comprehensive HIV prevention programs.

The authors sought to determine sociodemographic and sexual and drug use risk factors for HIV infection among drug users in northern Thailand adjacent to the Golden Triangle. The authors enrolled patients admitted for inpatient drug detoxification at one treatment center in northern Thailand and studied HIV risks and prevalence using an interviewer-administered questionnaire and serum collection with HIV pretest and posttest counseling. Between February 1, 1999 and January 31, 2000, 1865 patients admitted for opiate and methamphetamine dependence completed study procedures. Overall HIV prevalence was 10.3%: 30.0% among 513 injection drug users (IDUs) and 2.8% among non-IDUs (OR = 14.8, 95% CI: 10.2, 21.6). HIV seroprevalence was 2.4% among exclusive methamphetamine users (98% of whom are non-IDUs) and 3.4% among opium smokers. Injection drug use was the dominant risk factor in multivariate models. Although Thailand is widely recognized as having a successful national response to the heterosexual HIV epidemic, seroprevalence in IDUs remains high. Despite a sharp increase of non-IDUs admitted to the drug treatment center, HIV infection and risks remained high among IDUs in northern Thailand. HIV prevention campaigns need to focus on IDUs and to implement harm reduction strategies to reduce transmission to IDUs and further contain the HIV epidemic in Thailand.

Genome-wide association studies of tuberculosis in Asians identify distinct at-risk locus for young tuberculosis

Tuberculosis (TB) is one of the most devastating chronic infectious diseases, but the role of host genetics in disease development after infection in this disease remains unidentified. Genome-wide association studies (GWASs) in Thais and Japanese were carried out and separately analyzed, attempted replication, then, combined by meta-analysis were not yielding any convincing association evidences; these results suggested that moderate to high effect-size genetic risks are not existed for TB per se. Because of failure in replication attempt of the top 50 single-nucleotide polymorphisms (SNPs) identified form meta-analysis data, we empirically split TB cases into young TB case/control data sets (GWAS-Tyoung=137/295 and GWAS-Jyoung=60/249) and old TB case/control data sets (GWAS-Told=300/295 and GWAS-Jold=123/685), re-analyzed GWAS based on age-stratified data and replicated the significant findings in two independent replication samples (young TB; Rep-Tyoung=155/249, Rep-Jyoung=41/462 and old TB; Rep-Told=212/187, Rep-Jold=71/619). GWAS and replication studies conducted in young TB identified at-risk locus in 20q12. Although the locus is located in inter-genic region, the nearest genes (HSPEP1-MAFB) from this locus are promising candidates for TB susceptibility. This locus was also associated with anti-TNF responsiveness, drug with increased susceptibility for TB. Moreover, eight SNPs in an old TB meta-analysis and six SNPs in young TB meta-analysis provided replication evidences but did not survive genome-wide significance.These findings suggest that host genetic risks for TB are affected by age at onset of TB, and this approach may accelerate the identification of the major host factors that affect TB in human populations.

Incidence of respiratory pathogens in persons hospitalized with pneumonia in two provinces in Thailand.

Although pneumonia is a leading cause of death from infectious disease worldwide, comprehensive information about its causes and incidence in low- and middle-income countries is lacking. Active surveillance of hospitalized patients with pneumonia is ongoing in Thailand. Consenting patients are tested for seven bacterial and 14 viral respiratory pathogens by PCR and viral culture on nasopharyngeal swab specimens, serology on acute/convalescent sera, sputum smears and antigen detection tests on urine. Between September 2003 and December 2005, there were 1730 episodes of radiographically confirmed pneumonia (34·6% in children aged <5 years); 66 patients (3·8%) died. A recognized pathogen was identified in 42·5% of episodes. Respiratory syncytial virus (RSV) infection was associated with 16·7% of all pneumonias, 41·2% in children. The viral pathogen with the highest incidence in children aged <5 years was RSV (417·1/100,000 per year) and in persons aged ≥50 years, influenza virus A (38·8/100,000 per year). These data can help guide health policy towards effective prevention strategies.

Integrating genome-based informatics to modernize global disease monitoring, information sharing, and response.

The rapid advancement of genome technologies holds great promise for improving the quality and speed of clinical and public health laboratory investigations and for decreasing their cost. The latest generation of genome DNA sequencers can provide highly detailed and robust information on disease-causing microbes, and in the near future these technologies will be suitable for routine use in national, regional, and global public health laboratories. With additional improvements in instrumentation, these next- or third-generation sequencers are likely to replace conventional culture-based and molecular typing methods to provide point-of-care clinical diagnosis and other essential information for quicker and better treatment of patients. Provided there is free-sharing of information by all clinical and public health laboratories, these genomic tools could spawn a global system of linked databases of pathogen genomes that would ensure more efficient detection, prevention, and control of endemic, emerging, and other infectious disease outbreaks worldwide.

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

BackgroundIncarceration 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.MethodsA prospective cohort of 689 male inmates in a Bangkok central prison was studied during 2001–2002. Follow up visits were conducted for 5 months, with testing for HIV and other infections and interviewing of demographics and risk behaviors.ResultsAmong 689 male inmates, half (50.9 %) were drug injectors. About 49% of the injectors had injection during incarceration. Most (94.9%) of the injectors had shared injection paraphernalia with others. Successful follow up rate was 98.7% after 2,581 person-months observation. HIV incidence was 4.18 per 100 person – years among all inmates, and 11.10 per 100 person – years among the injection inmates. Multivariate analysis identified variables associated with HIV prevalence: history of injection [OR = 2.30, 95%CI: 1.91–2.77], positive urine opiate test [OR = 5.04, 95%CI: 2.63–9.67], history of attendance to drug withdrawal clinics [OR = 2.00, 95%CI: 1.19–3.35] and presence of tattoos on the body [OR = 1.23, 95%CI: 1.01–1.52].ConclusionsThe main HIV risk factors of Bangkok inmates were those related to drug injection. Harm reduction measures and HIV intervention strategies should be implemented to prevent more spread of HIV among the inmates and into the community.

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.