Clinico-epidemiology of hepatitis C viral infection in northeastern Thailand.

Hepatitis C virus (HCV) is responsible for a large number of cases of chronic liver disease worldwide. A study of clinico-epidemiology of HCV infection was conducted in 214 patients who were seropositive for antibody to HCV (anti-HCV) in Srinagarind Hospital, Khon Kaen University, northeastern Thailand, during August 1997 to December 1998. There were 199 males, 15 females and their mean age was 34.96 +/- 9.75 years with a range from 16 to 72 years. The clinical features of acute hepatitis, chronic hepatitis, liver cirrhosis, hepatocellular carcinoma (HCC) and asymptomatic HCV infection were 2, 115, 15, 2 and 80 cases. Risk factors for HCV acquisition were intravenous drug use (IVDU), tattooing and blood transfusion in 46.7, 32.2 and 18.8% of cases, respectively. 23.36% had a history of multiple risk factors while 28.9% had no history of risk factor exposure.

Clinico-epidemiology of hepatitis B viral infection in Northeastern Thailand.

Hepatitis B viral (HBV) infection is a common disease world wide. A study of clinico-epidemiology of HBV infection was conducted in 381 patients who seropositive for hepatitis B surface antigen (HBsAg) in Srinagarind Hospital, Khon Kaen University, Northeastern Thailand, during August 1997 to December 1998. 293 males, 88 females and their mean age was 30.96 +/- 12.78 years with a range from 15 to 77 years. The clinical features of acute hepatitis, chronic hepatitis, liver cirrhosis, hepatocellular carcinoma (HCC) and asymptomatic carrier were 2.36, 34.12, 4.99, 1.05 and 57.48% of cases. Possible routes for HBV transmission were family history of hepatitis, tattooing, intravenous drug addict and blood transfusion in 20.3, 11.3, 8.2 and 6.9% of cases, respectively. Signs of chronic liver disease were common in liver cirrhosis and HCC. Acute fulminating hepatitis was not found in this study.

Anti-HIV antibody titer: an alternative supplementary test for diagnosis of HIV-1 infection.

The diagnosis of HIV infection is based on screening of HIV antibodies and confirmed by a more specific supplementary test. The most common confirmation test is Western blot, which is expensive, time consuming and subject to technical skill. The present study was carried out to evaluate whether the anti-HIV-1 antibody titer is valid as a supplementary test for diagnosis of HIV-1 infection. Anti-HIV-1 antibody titers of 2,414 anti-HIV-1 positive sera determined by the particle agglutination (PA) method were analysed in comparison with the Western blot analysis. The Western blot negative result was found in 11 of 2,414 (0.46%) anti-HIV-1 positive sera, these sera also gave negative anti-HIV by ELISA. The PA titers of these sera were found in the range of 16 to 64. Seventeen samples (0.70%) with anti-HIV-1 in the titer range of 16 to 256 showed indeterminate Western blot analysis. The rest, 2,386 of these 2,414 sera (98.84%), were shown to be positive by Western blot. However, all of the 2,356 sera with antibody titers > or = 512 (97.6%) demonstrated positive Western blot results. Five cases among the 17 (29.4%) indeterminate sera were examples of early seroconversion of HIV infection, which were confirmed in follow up specimens. The results suggest that only the samples with antibody titers < 512 are required to be confirmed for HIV infection by Western blot. It is possible that early seroconversion may be inferred from anti-HIV titers. Therefore, in order to reduce time and cost, the PA anti-HIV titer can be used as an alternative supplementary test for diagnosis of HIV-1 infection in most positive screened anti-HIV samples. Western blot is needed for testing in only a few cases.

DNA typing of the HLA-A, -B and -C genes: possible MHC class I haplotypes in the northeastern-Thais.

The phenotype and gene frequencies of HLA class I were studied in the Northeastern Thai population. Blood samples were collected from 100 unrelated healthy northeastern-Thais. HLA-A, -B and -Cw alleles were determined using the polymerase chain reaction- amplification refractory mutation system (PCR-ARMS). 12 HLA-A, 20 HLA-B and 14 HLA-Cw alleles were found. Linkage disequilibrium analysis indicated the existence of 7 HLA-A-B and 19 HLA-B-Cw haplotypes. A*0207-Cw*01-B*4601 was the most common possible haplotype in this population. These results provide regional basic information for further studies in anthropology, organ transplantation and MHC disease associations in the northeastern-Thais.

Association of HCV and Treponema pallidum infection in HIV infected northeastern Thai male blood donors.

The study was performed to determine the association of seroprevalence of hepatitis C virus (HCV) and Treponema pallidum (T. pallidum) infection among HIV infected first time male blood donors (HIV group) in comparison with the HIV seronegative blood donors (control group) in the Northeast of Thailand (NET). Serum samples were collected from 10,321 first blood donation voluntary male donors. All samples were screened for anti-HIV and anti-HCV by particle agglutination test, and syphilis antibody by RPR. The anti-HIV positive sera were repeated by EIA and confirmed by western blot. The reactive anti-HCV samples were confirmed by EIA whereas reactive syphilis antibody samples were confirmed by TPPA. Fisher's exact test was used for statistical analysis. The prevalence of anti-HIV in first time male donors was 0.70 per cent (72/10,321). The age of HIV group and 10,018 male control group ranged from 17-50 years old. The prevalence of HIV among 21-40 years old age group was significantly higher than the 17-20 years old (p = 0.00003). The 17-20 years old HIV group showed significantly higher sero-prevalence of TPPA (p = 0.003). The 21-30 years old HIV group gave significantly higher sero-prevalence of anti-HCV (p = 0.0008) and TPPA (p = 0.045), but the seroprevalence of anti-HCV and TPPA among the 31-50 year old group were nonsignificantly different (p > 0.05). The concurrence of anti-HCV and TPPA in HIV groups was not found. This result indicated that HIV infection among NET voluntary male blood donors was significantly associated with T. pallidum infection in young adults and the HCV infection in mature adults.

Seroepidemiology of HTLV-I infection in northeast Thailand: a four year surveillance.

The human T-lymphotropic virus type I (HTLV-I) can be transmitted through blood transfusion, sexual contact, perinataly and by breast feeding. We carried out a four years seroepidemiology surveillance study of HTLV-I infection among northeast Thai population by screening for antibodies to HTLV-I (anti-HTLV-I) in 1992, 1993, 1995 and 1997. A total of 8,323 blood samples were collected from 6,228 blood donors, 832 pregnancies, 219 multitransfused patients, 53 HIV positive intravenous drug users and 1,000 northeast-Thai workers at different periods of time. The serum samples were tested for anti-HTLV-I by particle agglutination (PA) technique and confirmed by Western blot. One sample from a multitransfused patient collected in 1992 and one sample from a blood donor collected in 1995 demonstrated positive anti-HTLV-I screening by PA but negative by Western blot. This finding indicates that at present HTLV-I is not a public health problem in the northeast of Thailand but surveillance should be continually conducted.

Distribution of HLA-A and B antigens in northeastern-Thais.

The phenotype and gene frequencies of HLA class I were studied in the Northeastern Thai population. Blood samples were collected from 100 unrelated healthy Northeastern Thais. HLA-A and B antigens were typed by using the standard microlymphocytotoxicity test. Twelve HLA-A and twenty-five HLA-B antigens were found in this population. HLA-A2, A24, A11 and the HLA-B46, B15, B22 antigens are commonly found in this group. Linkage disequilibrium analysis indicated the existence of fifteen haplotypes. The HLA-A2, B46 haplotype was the most common. These results will be useful for further studies in anthropology, organ transplantation and MHC associated disease in Northeastern Thais.

Reducing the risk of HIV transmission through blood transfusion by donor self-deferral.

A cross sectional study was conducted to evaluate the validity of implementing a blood donor self-deferral form for reducing the risk of HIV transmission through blood transfusion. The self-deferral form which was given to all blood donors, included questions about HIV risk factors in the three month period prior to blood donation. Donors were asked to declare confidentially whether their blood was safe for transfusion or not. Blood was collected and examined for HIV antigen, anti-HIV antibodies, HBsAg and syphilis antibodies. All of the serological markers detected among high risk donors and general donors were compared and analysed by Yates corrected X2 test and one-tailed Fisher's exact test with a significance level of 0.05. There were 401 self-deferred high risk donors and 15,523 general donors. The HIV antigen was found as a single marker in only one male high risk individual. The prevalence of anti-HIV antibodies, HBsAg and syphilis antibodies among the general donors was 0.61%, 5.29% and 1.17%, respectively. The anti-HIV, HBsAg and syphilis antibodies in the high risk donors were 1.99%, 7.98% and 1.25%, respectively. In comparison with the general donors, the high risk donors demonstrated statistically significant higher prevalence rates of HIV antigen (p < 0.05), anti-HIV (p < 0.005) and HBsAg (p < 0.05). In conclusion, donor self-deferral is valid for reducing the risk of HIV transmission through blood transfusion and its implementation should be encouraged when recruiting blood donors.

Preliminary survey of anti-HTLV-I in northeastern-Thais.

The anti-HTLV-I prevalence was studied by particle agglutination technique (PA) in 2,609 samples including: 403 antenatal care women from Srinagarind Hospital, Faculty of Medicine, 342 high-risk sexually transmitted disease blood donors and 1,864 randomly selected blood donors from the Blood Transfusion Centre, Faculty of Medicine, Khon Kaen University. All of the 2,609 samples gave negative anti-HTLV-I. The result revealed that HTLV-I infection is not common in northeast-Thailand. However, as the sample size from this study may be too small, further study should be carried out.

Prevalence of cytomegalovirus antibody in Thai-northeastern blood donors.

The prevalence of cytomegalovirus antibody was studied in sera of 359 Northeastern blood donors with an age range of 17-59 years by ELISA for anti-CMV total antibody (anti-CMV). Anti-CMV was detected in 93.31% (335/359) of blood donors. The prevalence in males was 91.53% (227 in 248) while female donors showed 97.30% (108 in 111) positive for anti-CMV. The results demonstrated no statistical difference between sex and age. One-hundred and eighty serum samples with positive anti-CMV were reexamined for anti-CMV IgM antibody. Only one sample was found to be positive. This study suggested that CMV seronegative blood supply was very limited. Therefore leukocyte-depleted blood should be the method of choice for prevention of post-transfusion CMV infections in high risk recipients.