Seroepidemiology and genotypes of hepatitis C virus in Thailand

HCV can be classified into 6 major genotypes based on the phylogenetic analysis of the genomic sequences. The 3 major genotypes found in Thailand are 3, 1 and 6, respectively. In 2004, an epidemiological survey was carried out to evaluate the seroprevalence of HCV infections among populations aged 2-60 years in four provinces of Thailand, representing the North, Northeast, Center and South of the country, respectively. One hundred and twenty five out of 5,825 serum samples (2.15%) were positive for anti-HCV by ELISA. Fifty eight out of 100 anti-HCV positive samples (58.0%) were positive by RT-PCR of the 5'UTR. The core region of 45 representative samples was sequenced allowing classification into genotype variants 1a (6.7%), 1b (26.7%), 2a (2.2%), 2c (2.2%), 3a (51.1%), 3b (2.2%) and 6 (8.9%). This information might be crucial for public health surveillance and prevention of HCV infection.     

Hepatitis D virus infection in Thailand: HDV genotyping by RT-PCR,RFLP and direct sequencing

Background: Hepatitis D virus (HDV) is a degenerate RNA virus or virusoid that requires the surface coat of hepatitis B virus (HBV), i.e. hepatitis B surface antigen (HBsAg), in order to become infectious. Three distinct genotypes of the virus have been classified. In this study, HDV genotypes were determined by restriction fragment length polymorphism (RFLP) and direct sequencing. In Thailand, simultaenous HDV/HBV infections are particularly prevalent among intravenous drug users (IVDU). Patients and Methods: A total of 743 IVDU sera were screened for HBV infection. HBsAg-positive samples were subjected to serological analysis for anti-HDV. RFLP analysis using the endonucleases Xho I and Sma I was performed on the PCR amplified HDV genome to establish the prevailing HDV genotypes. Results: 55 sera (7%) had detectable HBsAg; all 55 were subsequently subjected to serological analysis for anti-HDV, 12 (21.8%) of which were positive. Eight (66%) specimens had detectable HDV-RNA by RT-PCR. All polymorphisms were shown to be genotype I, a finding confirmed by direct sequencing. 36 HBsAg-positive sera obtained from the blood bank to serve as controls were negative for anti-HDV. Conclusion: Our data show that HDV infection is still limited among IVDU and that the pattern of polymorphism closely resembles that of the western HDV genotype I. Received: April 12, 2001 · Accepted: November 20, 2001     

Gastric volvulus caused by percutaneous endoscopic gastrostomy: a case report

Percutaneous endoscopic gastrostomy is commonly performed for enteric feeding in children with neurologic impairment because of its low rates of complication. We report a case of gastric volvulus, an unusual complication, after percutaneous endoscopic gastrostomy procedure in our institution.     

Serum hepatocyte growth factor and clinical outcome in biliary atresia

Purpose

Biliary atresia (BA) remains one of the most intractable liver diseases leading to liver fibrosis. Serum hepatocyte growth factor (HGF) has been shown to increase in cirrhotic patients. The aim of this study was to investigate the possible role of HGF in BA.

Methods

Serum levels of HGF were determined using an enzyme-linked immunosorbent assay from 28 BA patients and 25 healthy children. The patients were categorized into 3 groups according to their clinical outcomes (good, fair, and poor): group A (good), jaundice-free patients (total bilirubin [TB] < 2.0 mg%); group B (fair), patients with mild to moderate jaundice (TB, 2 to 10 mg%); and group C (poor), patients with marked jaundice (TB > 10 mg%). Unpaired t test and analysis of variance (ANOVA) with post-hoc tests were used. Data were expressed as mean and SEM.

Results

Serum HGF levels in BA patients were higher than the controls (P = .02). Subgroup analysis found that there were 12 patients in group A, 8 patients in group B, and 8 patients in group C. The mean age of patients in groups A, B, and C were 5.34 ± 0.52, 7.45 ± 1.98, and 5.49 ± 1.57 years (P > .05). Serum HGF in controls and groups A, B, and C were 0.24 ± 0.03, 0.28 ± 0.04, 0.36 ± 0.09, and 0.56 ± 0.07 ng/mL, respectively. Serum HGF levels in BA patients with poor outcome were higher than patients with good outcome (P = .02). There was no difference in serum HGF of BA patients with fair outcome compared with other groups.

Conclusions

Serum HGF is elevated in BA. Furthermore, BA patients with poor outcome have significantly elevated HGF compared with patients with good outcome. Serum HGF levels may be predictive of prognosis with respect to the progression of liver dysfunction. However, the results of HGF in patients with fair outcome are inconclusive, probably because of the small sample size. Further studies are needed to elucidate the detailed mechanisms.     

Relationship between vasoactive intestinal peptide and intrapulmonary vascular dilatation in children with various liver diseases

AIM: To evaluate the potential of vasoactive intestinal peptide (VIP) as a pathogenic factor of intrapulmonary vascular dilatation (IVD) in hepatopulmonary syndrome (HPS). BACKGROUND: HPS comprises a triad comprising liver dysfunction, IVD and hypoxaemia. Although the pathogenesis of the process has not been elucidated, many vasodilating substances, such as VIP, have been implicated in the development of pulmonary vascular abnormalities. IVD can be detected by contrast-enhanced echocardiography (CEE) before the development of abnormal gas exchange. METHODS: Forty-two children (20M, 22F; mean age 4.39 +/- 4.17 y) with various liver diseases who attended the paediatric liver clinic of King Chulalongkorn Memorial Hospital between March 2000 and February 2001 were recruited to the study. Each patient was tested for transcutaneous O2 saturation, CEE (applying the agitated normal saline technique), liver function test and serum VIP level. RESULTS: Fourteen of the 42 patients (33%) were CEE positive. Only one of the 14 patients had associated hypoxia and clinical cyanosis. The serum VIP levels of children with liver disease were significantly higher than those of the controls (60.21 +/- 35.04 pg/ml vs 43.71 +/- 34.61 pg/ml, p = 0.03). CEE-positive children tended to have higher serum VIP levels than CEE-negative children (72.65 +/- 40.31 vs 53.99 +/- 31 pg/ml, p = 0.3). The serum VIP levels of biliary atresia (BA) patients with favourable outcomes (serum bilirubin < or = 34 micromol/L) were not significantly different from those with unfavourable outcomes (serum bilirubin > 34 micromol/L) (42.95 +/- 14.53 pg/ml vs 66.07 +/- 32.17 pg/ml, p = 0.5). CONCLUSIONS: CEE is a non-invasive test for early detection of IVD in children with liver disease. VIP is not solely responsible for the pathogenesis of IVD in HPS. Further studies are required to determine which substances cause the development of IVD.     

Declining trend in the seroprevalence of infection with hepatitis A virus in Thailand

Since the mid 1970s, infection with hepatitis A virus (HAV) in Thailand has shifted from hyper-endemic to mesoendemic. In 2004, to explore this trend in prevalence further, 3997 subjects from four geographically distinct provinces of Thailand were tested, in a commercial ELISA, for antibodies to HAV. The results indicate that the seroprevalence of HAV continues to fall, almost certainly because the profound socio-economic development that has occurred over the last few decades in Thailand has brought with it significant improvements in sanitation and personal hygiene. As exposure to HAV declines, however, the risks of symptomatic and potentially severe infection in adulthood (rather than asymptomatic infection during childhood) and of epidemics of such infection, which would lead to profound economic loss, increases. Improvements in hygiene and sanitation to reduce exposure to the virus and measures to reduce the incidence of symptomatic disease in those infected, such as vaccination (which may only be cost-effective when targeted at high-risk groups), need to be carefully considered.     

Hepatitis B seroprevalence in Thailand: 12 years after hepatitis B vaccine integration into the national expanded programme on immunization

OBJECTIVES: To evaluate the impact of the universal hepatitis B (HB) vaccination programme on the prevalence of hepatitis B surface antigen (HBsAg) carriers and immunity to HB virus infection among children <18 years and to determine the HB seroprevalence in the Thai population. METHODS: We enrolled people in four provinces, including Chiangrai, Udon Thani, Chonburi and Nakhon Si Thammarat to geographically represent populations in the North, Northeast, Center and South of the country respectively. Serology for HBsAg, anti-hepatitis B surface (anti-HBs), and anti-hepatitis B core (anti-HBc) was tested using ELISA commercial kits. In total, 6213 subjects aged 6 months to 60 years from the four provincial hospitals and two to three district hospitals of each participating province participated. RESULTS: Overall HBsAg, anti-HBs, and anti-HBc seropositive rates amounted to 4%, 41.6% and 26.5% respectively. Of 2887 participants aged 6 months to 18 years, 2303 were born after (group I) and 584 prior to (group II) HB vaccine integration into the expanded programme on immunization of each participating province. The HBsAg seropositive rate was 0.7% among group I children and 4.3% among group II children. The prevalence rate of anti-HBc was 2.9% in group I and 15.8% in group II. In children under 18 years, the HBsAg carrier rate was 0.98% among complete vaccinees and 1.36% among participants without vaccination. CONCLUSIONS: This finding supports the efficacy of universal HB immunization in reducing the prevalence of HB infection in Thailand which is a highly endemic country.     

Persistence and immune memory to hepatitis B vaccine 20 years after primary vaccination of Thai infants, born to HBsAg and HBeAg positive mothers

This study assessed antibody persistence and immune memory to hepatitis B vaccine 20 y after priming with a recombinant hepatitis B virus (HBV) vaccine during infancy. Infants were vaccinated according to a 0, 1, 6 mo schedule with or without simultaneous administration of hepatitis B immunoglobulin (HBIg). Half of the subjects enrolled received an interim booster dose at year 5 (boosted) group, whereas the other half of the subjects enrolled did not (unboosted group). Antibody persistence was assessed until year 20. Immune memory was assessed by administration of a final HBV vaccine challenge dose at year 20 in a second study. At year 20, anti-HBs antibody concentration ≥ 10 mIU/ml rates and GMCs were higher among subjects in the boosted group (84.2% [16/19]; 95%CI: 60.4-96.6) when compared with those in the unboosted group [44.0% (11/25)]; 95% CI: 24.4-65.1). After the HBV vaccine challenge dose at year 20, anti-HBs anamnestic response for subjects in the unboosted and boosted groups was observed in 93.1% (95% CI: 77.2-99.2) and 100% (95% CI: 76.8-100) of subjects, respectively. The mean anti-HBs antibody concentration (GMC) was 562.0 mIU/ml (292.5-1079.7 mIU/ml) post administration of the challenge dose; this is a 28.5 fold increase from the pre- to post-challenge dose administration at year 20. This study demonstrates persistence of anti-HBs antibodies and presence of immune memory following hepatitis B vaccination for up to at least 20 y in Thailand. Immune memory was demonstrated for virtually all subjects, regardless whether they received they had received the additional HBV dose or not. The challenge dose at year 20 was well tolerated and a robust response was demonstrated. ClinicalTrials.gov Identifier: NCT00240526, NCT00774995.     

Serum nitric oxide in children with dengue infection

One hundred and ten patients (M/F = 67/43) from King Chulalongkorn Memorial Hospital and the provincial hospitals of Uttaradit, Ayudhaya, and Sakonnakorn, who were clinically diagnosed with dengue infection and serologically confirmed by ELISA anti-Dengue IgM and IgG were recruited. Their serum NO level was measured using commercially available assay kits to investigate its correlation with the severity of the dengue infection: dengue fever (DF), DHF I/II, and DHF III/IV or dengue shock syndrome (DSS). Serum NO levels were also measured in 38 healthy controls (M/F = 19/19). Serum NO levels in dengue patients were lower than those of the controls (control = 168.18 +/- 24.10 micromol/l, DF = 124.94 +/- 36.79 micromol/l, DHF I/II = 99.69 +/- 33.42 micromol/l, and DHF III/IV = 120.63 +/- 46.26 micromol/l; p < 0.05). Serum NO levels in patients with DHF I/II were significantly lower than in those with DHF III/IV. These preliminary data revealed that levels of serum NO in dengue patients were significantly lower than those of normal controls. Patients with DSS had higher NO levels than those with DHF I/II. The decreased NO in dengue patients could be due to endothelial damage rendering the endothelium incapable of producing NO. Endothelial function seems to play a role in the pathogenesis of dengue infection. Further studies are required to see whether serum NO levels could play a role in the course of the disease and could help predict the severity of dengue infection.