Lessons learned from influenza A(H1N1)pdm09 pandemic response in Thailand

In 2009, Thailand experienced rapid spread of the pandemic influenza A(H1N1)pdm09 virus. The national response came under intense public scrutiny as the number of confirmed cases and associated deaths increased. Thus, during July-December 2009, the Ministry of Public Health and the World Health Organization jointly reviewed the response efforts. The review found that the actions taken were largely appropriate and proportionate to need. However, areas needing improvement were surveillance, laboratory capacity, hospital infection control and surge capacity, coordination and monitoring of guidelines for clinical management and nonpharmaceutical interventions, risk communications, and addressing vulnerabilities of non-Thai displaced and migrant populations. The experience in Thailand may be applicable to other countries and settings, and the lessons learned may help strengthen responses to other pandemics or comparable prolonged public health emergencies.     

Methamphetamine users in northern Thailand: changing demographics and risks for HIV and STD among treatment-seeking substance abusers

Our objective was to determine sociodemographic, sexual and drug-use-related risk factors among methamphetamine (MA) users presenting for drug treatment in northern Thailand. Patients admitted for drug detoxification for MA and other drugs were studied cross-sectionally for risk factors associated with substance abuse and blood-borne and sexually transmitted pathogens. In all, 1865 (200 women) patients treated for MA, opiate, and mixed substance abuse between 1 February 1999 and 31 January 2000 completed all study procedures. Among 1865 participants, 750 (40.2%) were admitted for MA detoxification and 1115 (59.8%) for opiate (heroin, opium, or both) treatment. MA users were significantly younger, better educated, more likely to be Thai than highland ethnic minorities, and had significantly different sexual risks and sexually transmitted disease rates, including lower syphilis seropositivity and higher chlamydial prevalence, than persons admitted for opiate or mixed drug treatment. For those who reported MA use only, use by injection was rare and HIV infections significantly less common than among all other drug users. Thailand is undergoing an epidemic of MA use. These young users are a strikingly different population from opiate/heroin users in northern Thailand. MA users had higher rates of chlamydia infection than opiate users, reflecting their young age, and HIV rates in this population were lower than injecting drug users, but still elevated. MA use is a serious public health problem in Thailand and both improved prevention and treatment methodologies are urgently needed.     

The epidemiological relationship between Salmonella enterica serovar typhimurium and Salmonella enterica serovar 4,[5],12:i:- isolates from humans and swine in Thailand

A total of 138 isolates of S. Typhimurium and S. 4,[5],12:i:- from humans and swine in Thailand during 2003-2006, were evaluated for antimicrobial sensitivity by the disk diffusion method against 10 antimicrobial drugs and pulsed-field gel electrophoresis (PFGE) with endonuclease Xbal to investigate the epidemiological relationship among isolates. It was found that all isolates were classified into 27 antimicrobial resistance patterns, and 80% of S. Typhimurium and 95.4% of S. 4,[5],12:i:- isolates were resistant to three or more antimicrobial agents. By PFGE testing, the 84 PFGE patterns were categorized into A to Z patterns. Eighty percent of S. Typhimurium and 71.3% of S. 4,[5],12:i:- isolates in 7 major PFGE patterns had close clonal relationships (_85% similarity). Our studies indicate the spread of genetically identical clones of S. Typhimurium and S. 4,[5],12:i:- in humans and swine in Thailand.     

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

Design and evaluation of antiretroviral peptides corresponding to the C-terminal heptad repeat region (C-HR) of human immunodeficiency virus type 1 envelope glycoprotein gp41

Two α-helical heptad repeats, N-HR and C-HR, located in the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein gp41, play an important role in membrane fusion by forming a 6-helix bundle. C34, a peptide mimicking C-HR, inhibits the formation of the 6-helix bundle; thus, it has potential as a novel antiretroviral compound. In order to improve the inhibitory effect of C34 on HIV-1 replication, we designed new C34-derived peptides based on computational analysis of the stable conformation of the 6-helix bundle. Newly designed peptides showed a stronger inhibitory effect on the replication of recombinant viruses containing CRF01_AE, subtype B or subtype C Env than C34 or a fusion inhibitor, T-20. In addition, these peptides inhibited the replication of a T-20-resistant virus. We propose that these peptides could be applied to develop novel antiretroviral compounds to inhibit the replication of various subtypes of HIV-1 as well as of T-20-resistant variants.     

MRSA carriage in a tertiary governmental hospital in Thailand: emphasis on prevalence and molecular epidemiology

We investigated prevalence and risk factors for methicillin-resistant Staphylococcus aureus (MRSA) in a case-control study performed in a 900-bed tertiary governmental healthcare facility in Bangkok, Thailand. Multivariate unconditional logistic regression was used to identify risk profiles for MRSA carriage. Phage typing, pulsed-field gel electrophoresis (PFGE), polymorphisms of the coa and spa genes, hypervariable region (HVR) of SCCmec, multi-locus sequence typing (MLST), and identification of ST30/ST8 mosaic chromosome by heteroduplex-polymerase chain reaction (heteroduplex-PCR) were used to demonstrate a clonal relationship. Fifty-seven of 619 in-patients (9.2%) were positive for MRSA. Risk factors were being male, long admission, low modified McCabe score, history of MRSA infection, and use of broad spectrum cephalosporin. Molecular typing results indicated close relatedness among MRSA isolates. Successful epidemic subtypes were recovered from many different wards. However, all subtypes with different multi-locus sequence types were single locus variants (SLVs) of ST239. Heteroduplex-PCR gave two positive bands from ST8/ST30 mosaic chromosomal structures in all SLVs indicating all isolates were of the ST239 origin. The burden of MRSA nosocomial infections is high in the governmental tertiary hospital. The sole ST239 and its SLVs identified in this hospital is striking and calls for better policy for infection control and prevention.     

Effects of CCR2 and CCRS polymorphisms on HIV-1 infection in Thai females

Polymorphisms in CCR2 and CCR5 genes reportedly affect HIV-1 transmission and disease progression in HIV-1-infected individuals. In the study presented here, we examined the effects of CCR2 and CCR5 polymorphisms on HIV-1 transmission in 74 Thai females who were exposed to HIV but seronegative (ESN) and in 347 HIV-seropositive females. We found that the combination of 2 non-synonymous substitutions, CCR2 V64I and CCR5 G316A, tended to occur more frequently in ESN females (2 of 74) than in HIV-1 infected females (1 of 347) (P = 0.08). This suggested that non-synonymous substitution in the CCR5 gene also affects HIV-1 transmission in an Asian population in which the CCR5-Delta32 is very rare.     

Human disease from influenza A (H5N1), Thailand, 2004

Influenza A (H5N1) is endemic in poultry across much of Southeast Asia, but limited information exists on the distinctive features of the few human cases. In Thailand, we instituted nationwide surveillance and tested respiratory specimens by polymerase chain reaction and viral isolation. From January 1 to March 31, 2004, we reviewed 610 reports and identified 12 confirmed and 21 suspected cases. All 12 confirmed case-patients resided in villages that experienced abnormal chicken deaths, 9 lived in households whose backyard chickens died, and 8 reported direct contact with dead chickens. Seven were children <14 years of age. Fever preceded dyspnea by a median of 5 days, and lymphopenia significantly predicted acute respiratory distress syndrome development and death. Among hundreds of thousands of potential human cases of influenza A (H5N1) in Asia, a history of direct contact with sick poultry, young age, pneumonia and lymphopenia, and progression to acute respiratory distress syndrome should prompt specific laboratory testing for H5 influenza.     

Co-existence of HIV-1 subtypes B' and E infections among Thai injecting drug users

Subtypes B' and E are the two major subtypes of HIV-1 among injecting drug users (IDU) in Thailand. However, there are not many reports on subtype distribution during the early epidemic. Random blood specimens collected during 1994-2000 from 3,286 IDU at the Thanyarak Hospital were tested for HIV antibody and subtyped by using peptide binding enzyme immunoassay. The prevalence rate of HIV infection was 36.8%. All HIV-seropositive IDU were ascertained for "year of first HIV seropositivity" from their medical records. Of 1,512 HIV-seropositive samples, 1,408 (93.1%) were typeable. During 1987-1988, the proportion of subtype B' was as high as 80% but decreased rapidly to 27.6% during 1999-2000. At the same time, the proportions of subtype E increased correspondingly (Chi-square test for the trend, p < 0.05). The relatively high proportion of subtype E among IDU since an early stage of the epidemic suggests early co-existence of both subtypes and needs further investigation.     

Sexual risk behaviors of male current and ex-opiate users in Chiang Rai,Thailand

Injecting drug use and unsafe sexual practice are both considered major risk factors for HIV infection. This study reports sexual behaviors among male "current" (i.e. using heroin and/or opium at least once in the past 3 months) and "ex-" opiate users in Chiang Rai province in Northern Thailand. Between January 1999 and August 2000, 206 male opiate users were recruited by mail callback. Of the 206 drug users, 89 (43.2%) could be classified as current users. Current users did not differ from ex-users, except for educational level and ethnicity. Current and ex-opiate users showed no difference in number of regular sexual partners, proportion of having sex with commercial and non-commercial sex partners, and reported histories of sexually transmitted diseases. This study suggests that the importance of sexual risk behaviors in HIV transmission cannot be ignored in both current and ex-opiate users.