HIV infection among substance abusers in Thanyarak Institute On Drug Abuse, Thailand, 1987-2002.

A study of HIV infection among substance abusers from 1987 to 2002 was performed in Thanyarak Institute on Drug Abuse (TIDA). From 118,676 anti HIV tests (6,076 - 10,626 tests each year) of TIDA inpatients, 17,526 tests were positive (474 - 2,041 tests each year) In 71,403 new substance abuse cases (3,724 - 6,184 cases each year), 12,401 cases were positive (17.4%), highest in 1990 28.3% and then decreased to 8% in the last three years. In injecting drug users (IDU), the mean anti HIV positivity rate was 21.7% (range 19.2 - 29.4%) higher than those among non IDU about 8 times 2.8% (range 1.9 - 3.6%). The HIV incidence rates were from inpatients that were previously anti-HIV negative, the authors found the mean incidence rate was 7.3% per year. Anti HIV positive cases were highest in injecting heroin users (IHU) about 36.8% (range 31.5 - 46.1%). Although numbers of IHU in Thailand have decreased in the last 6 years because of changing to use methamphetamine by smoking and dying from HIV subtype B'. The authors must continue the effective preventive programs of both avoid sharing injecting equipments and promoting 100% condom program to control this reservoir of HIV infection.

Prevalence and genotypes of hepatitis C virus infection among drug addicts and blood donors in Thailand.

Hepatitis C virus (HCV) is an infectious agent that has the potential to cause chronic liver disease, cirrhosis and hepatocellular carcinoma. We determined the prevalence and genotypes of HCV infection among groups of drug addicts: intravenous drug users (n = 134), methamphetamine users (n = 100), inhaled-drugs users (n = 19) and alcoholics (n = 50); a group of blood donors acted as a control. The control group consisted of 179 randomly-selected anti-HCV positive samples: these were subjected to HCV RNA screening and genotyping. The anti-HCV test was performed by ELISA: HCV RNA screening was by nested RT-PCR that employed primers from the 5' noncoding region. The genotype assay was based upon analysis of the 5' NCR amplified sequences and RFLP. Hepatitis C virus was highly prevalent among all groups of drug addicts (12-70%). In 2000. among the new blood donors (n = 66,340) at the National Blood Center, Thai Red Cross, anti-HCV prevalence amounted to 0.98%. The HCV genotype distribution showed that the most prevalent genotype was 3a, followed by 1b and 6a. Our data demonstrated the very high prevalence of HCV infection in IVDUs, a finding that is consistent with the blood-borne nature of the virus. In order to curb HCV infection, a determined effort to educate both the general population and high-risk groups is required; such a program of education would address both general and particular methods of transmission, especially the use of non-sterile needles etc.

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.