Survival benefit from non-highly active antiretroviral therapy in a resource-constrained setting

Mortality rates among HIV-1-infected patients attending a government hospital in northern Thailand were investigated to evaluate the effect of antiretroviral (ARV) drug therapy on mortality. Demographic, clinical, and laboratory data and history of ARV drug therapy were collected from all HIV-1-infected adult patients who attended the Day Care Center clinic from October 2, 1995 through October 31, 1999. The survival status of patients until October 31, 1999 was ascertained from the hospital records, mailing letters, and death certificates at the Provincial Health Office. Of 1110 patients who attended the clinic, we had data on duration of follow-up for 1081 (97%) with a total of 1175 person-years of observation; 607 (54.7%) patients died. Clinical status, CD4 group, ARV drug group, and registered year were independently associated with death. The adjusted hazard ratio of monotherapy to no therapy was 0.65 (95% CI: 0.48, 0.87; p = .001) and that of dual therapy was 0.43 (95% CI: 0.29, 0.62; p < .001). The mortality rate of patients attending a government hospital in northern Thailand is high. Suboptimum ARV drug regimens like dual therapy had a substantial survival benefit. Further cost reduction for multiple ARV drug regimens is impatiently awaited.     

HIV incidence rates among drug users in northern Thailand, 1993-7

Drug use is a major mode of HIV transmission in Thailand. This study determined HIV incidence rates among drug users in a regional drug treatment centre in northern Thailand. A retrospective cohort of repeatedly-hospitalized drug users between 1993 and 1997 was formed and HIV incidence rates were calculated. The overall incidence was 11.44 per 100 person-years of observation. Gender, age, religion, ethnicity, education, employment, income, reasons for drug use, type of drugs, mode of use, spending on drugs, and referral for treatment are associated with HIV incidence. However, there are no associations between HIV incidence and history of treatment and mode of discharge from the centre. This implies that current treatment modality has no impact on HIV infection risk and other therapeutic approaches should be explored.     

Effect of vaccination with refined components of the organism on infection of mice with Mycobacterium leprae

Only native products of Mycobacterium leprae, whether cell wall, cytosol, or membrane derived, can confer protective immunity against challenge in the mouse footpad. Previously, recombinant proteins were shown to be ineffective. The cell wall skeleton-the mycolyl-arabinogalactan-peptidoglycan complex-devoid of proteins is not protective.     

Typing of Thai clinical isolates of Mycobacterium leprae and analysis of leprosy transmission by polymorphism of tandem repeats

Mycobacterium leprae isolates from Thai leprosy patients were typed for strain differentiation and analysis of leprosy transmission using the six base tandem repeat, GACATC, in rpoT gene and TTC repeat as genetic markers. M. leprae DNA was isolated from skin biopsies of new untreated leprosy patients living in remote areas or in suburban regions of Thailand where leprosy is in low prevalence. In M. leprae strains of 100 patients, TTC alleles exhibited variations in length with 10 to 30, 33 and 35 repeats, the most common alleles being 15, 16, 17 and 19 repeats. All isolates contained three copies of the six base repeat in rpoT gene. Application of TTC repeats in tracking leprosy transmission in two families with multi-cases identified a single (but different) strain of M. leprae in each family.     

Heterosexual transmission of novel CRF01_AE and subtype B recombinant forms of HIV type 1 in northern Thailand

The increased proportion of CRFO1_AE/subtype B recombinant infections among injecting drug users raised a concern that such recombinant forms may also spread in a heterosexual population in Thailand. Using the BootScan method, we reanalyzed pol gene sequences among 114 heterosexually infected individuals in northern Thailand, who were tested for a drug-resistance genotype between July 2000 and July 2001. Two individuals were suspected of carrying a recombinant HIV-1. Thus we analyzed a nearly full-length HIV genome in the two individuals and their spouses. An identical recombinant form of CRF01_AE and subtype B was found in one couple, indicating that this recombinant virus was heterosexually transmitted. Interestingly, this recombinant form had multiple breakpoints in the core protein of Gag and both infected individuals had a high CD4+ cell count without antiretroviral therapy. CRFO1/subtype B recombinant forms exist in a heterosexual population in northern Thailand. Some recombinant virus may be associated with a slow rate of HIV disease progression.     

Influenza viruses in Thailand: 7 years of sentinel surveillance data, 2004-2010

Please cite this paper as: Chittaganpitch et al. (2012) Influenza viruses in Thailand: 7 years of sentinel surveillance data, 2004–2010. Influenza and Other Respiratory Viruses 6(4), 276–283. Background The re‐emergence of avian influenza A (H5N1) in 2004 and the pandemic of influenza A (H1N1) in 2009 highlight the need for routine surveillance systems to monitor influenza viruses, particularly in Southeast Asia where H5N1 is endemic in poultry. In 2004, the Thai National Institute of Health, in collaboration with the US Centers for Disease Control and Prevention, established influenza sentinel surveillance throughout Thailand. Objectives To review routine epidemiologic and virologic surveillance for influenza viruses for public health action. Methods Throat swabs from persons with influenza‐like illness and severe acute respiratory illness were collected at 11 sentinel sites during 2004–2010. Influenza viruses were identified using the standard protocol for polymerase chain reaction. Viruses were cultured and identified by immunofluorescence assay; strains were identified by hemagglutination inhibition assay. Data were analyzed to describe frequency, seasonality, and distribution of circulating strains. Results Of the 19 457 throat swabs, 3967 (20%) were positive for influenza viruses: 2663 (67%) were influenza A and able to be subtyped [21% H1N1, 25% H3N2, 21% pandemic (pdm) H1N1] and 1304 (33%) were influenza B. During 2009–2010, the surveillance system detected three waves of pdm H1N1. Influenza annually presents two peaks, a major peak during the rainy season (June–August) and a minor peak in winter (October–February). Conclusions These data suggest that March–April may be the most appropriate months for seasonal influenza vaccination in Thailand. This system provides a robust profile of the epidemiology of influenza viruses in Thailand and has proven useful for public health planning.     

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.     

The impact of antigenic drift of influenza A virus on human herd immunity: Sero-epidemiological study of H1N1 in healthy Thai population in 2009

To examine the effect of the antigenic drift of H1N1 influenza viruses on herd immunity, neutralization antibodies from 744 sera from Thai healthy volunteers in 2008–2009, who had not been vaccinated for at least the last 5 years, were investigated by microneutralization (MN) and hemagglutination inhibition (HI) assays. Significantly higher MN titers were observed for the H1N1 Thai isolate in 2006 than in 2008. The results indicate that the antigenically drifted virus effectively escaped herd immunity. Since the low neutralization activity of herd immunity against drifted viruses is an important factor for viruses to spread efficiently, continuous sero-epidemiological study is required for public health.     

Full‐length sequence of genotype 3 hepatitis E virus derived from a pig in Thailand

Hepatitis E virus (HEV) infection in pigs was investigated in two principal swine farming areas in Thailand. Anti‐HEV antibodies and HEV RNA in sera were examined in 258 pigs reared on five commercial farms from age 1 to 6.5 months and sows. Overall, 167 of 258 (64.7%) pigs were positive for anti‐HEV IgG, while 20 of 258 (7.75%) had detectable HEV RNA. Sequence analysis of 20 HEV isolates obtained from viremic pigs revealed that they were 92.3–100% identical to each other and had 82.2–88.2% nucleotide similarity to other reported genotype 3 isolates in 415 nucleotide sequences within ORF2 region. Further characterization by sequencing the complete genome of the Thai swine HEV isolate (named Thai‐swHEV07) and phylogenetic analysis showed that Thai‐swHEV07 segregated into a cluster consisting of swine isolates from Japan, Mongolia, and Kyrgyzstan within the HEV genotype 3. The Thai‐swHEV07 had a genomic length of 7,229 nt excluding the polyadenylated region at 3′ terminus of the genome. Comparison of Thai‐swHEV07 and 27 reported strains of genotype 3 revealed 80.4–85.9% nucleotide identity, with the highest identity of 85.9% to the novel swHEV strain from Mongolia. These findings suggest that genotype 3 HEV isolates are markedly heterogeneous. J. Med. Virol. 81:657–664, 2009 © 2009 Wiley‐Liss, Inc.