Seroprevalence of Hepatitis A among Thai Population Residing Near Myanmar Border.

When compared with Thailand, the seroprevalence of hepatitis A virus (HAV) is extremely high among its neighbouring countries. To investigate the seroprevalence of HAV among the Thai people residing in the border area between Thailand and Myanmar, 308 residents in Umphang, Maesod district, Tak, were recruited. Sera were tested for HAV IgG antibodies by enzyme-linked immunosorbent assay. The overall seroprevalence among the Thai people residing in the border area of Thailand was significantly higher than that among the general Thai population (71% vs 27% respectively, p<0.05). As asymptomatic or mild HAV infection typically occurs in children, the Thai people residing in the border area may receive little benefit from universal HAV vaccination. Lower protective antibodies against HAV, along with the exclusion of HAV vaccine from the Expanded Programme on Immunization, potentially increase the susceptibility to HAV among the general Thai population and may lead to more future outbreaks if HAV is introduced from the border areas. The findings suggest that HAV vaccines should be recommended to travellers before their journey to the border between Thailand and Myanmar where HAV is endemic.

Serological Analysis of Human Pandemic Influenza (H1N1) in Thailand.

The study was aimed at determining the prevalence of pandemic influenza (H1N1) 2009 among patients with respiratory tract diseases during July-December 2009 using real-time reverse transcription polymerase chain reaction. Haemagglutination inhibition (HI) assay was performed to detect antibody titres against pandemic influenza in 255 medical personnel, 307 members of the general population during the second week of December 2009 in Khon Kaen province, Thailand, and in 100 stored sera collected from people of different age-groups during 2008. The results showed that the pandemic (H1N1) 2009 had occurred during July-December 2009. The results of the HI test after the wave of this outbreak showed that 123 (48%) of the 255 sera collected from the medical personnel, 109 (36%) of the 307 sera obtained from the general population, and only two of the 100 stored sera from 2008 contained antibodies (HI titres ≥40) against pandemic influenza. Antibody against the pandemic (H1N1) 2009 was found in at least one-third of the population. In conclusion, the prevalence of virus and serological data obtained from the study can be used as the serological background level of the Thai population after the July-December pandemic. Finally, the serological data might be useful for outbreak-prevention and control strategies and for the management of vaccination for the pandemic (H1N1) 2009 in Thailand.

High prevalence of hepatitis c virus genotype 6 in Vietnam.

This study aimed to update the prevalence of the various Hepatitis C virus genotypes in Vietnamese blood donors. One hundred and three HCV antibody-positive plasma samples were collected from blood donors at the National Institute of Hematology and Blood Transfusion, Hanoi, Vietnam. All specimens were subjected to RT-PCR of the 5’ untranslated region (UTR) to confirm the presence of HCV RNA. The core and NS5B regions of the positive samples were subsequently amplified by RT-PCR followed by direct sequencing and phylogenetic analy-sis. Seventy out of 103 samples (68.0%) were RNA positive. Core and NS5B were successfully amplified and se-quences were obtained for 70 and 65 samples, respectively. Phylogenetic analysis revealed that genotype 6a was the most predominant among Vietnamese blood donors with a prevalence of 37.1% (26/70), followed by genotype 1a at 30.0% (21/70) and genotype 1b at 17.1% (12/70). The prevalence of two other genotype 6 variants, 6e and 6l was 8.6% and 1.4%, respectively. Further analysis of recent studies showed that the geographic distribution of genotype 6 covered mainly southern China and the mainland of Southeast Asia including Vietnam, Laos, Thailand, and Myanmar. The GenBank accession numbers for the sequences reported in this study are FJ768772- FJ768906.

Seroprevalence of antibodies to measles, mumps, and rubella among Thai population: evaluation of measles/MMR immunization programme.

Stored serum specimens, from four regions of Thailand, of healthy children attending well baby clinics and of healthy people with acute illnesses visiting outpatient clinics were randomly sampled and tested for IgG antibody to measles, mumps, and rubella (MMR). The immunity patterns of rubella and mumps fitted well with the history of rubella and MMR vaccination, seroprotective rates being over 85% among those aged over seven years. A high proportion of younger children acquired the infection before the age of vaccination. MMR vaccination should preferably be given to children at an earlier age. For measles, 73% seroprotective rates among children, aged 8-14 years, who should have received two doses of measles/MMR vaccine, were lower than expected. This finding was consistent with the age-group reported in outbreaks of measles in Thailand. The apparent ineffectiveness (in relation to measles) of MMR immunization of 1st grade students warrants further studies.

Insulin-like growth factor-1 (IGF-1) in children with postoperative biliary atresia: a cross-sectional study.

Biliary atresia is the leading cause of chronic infantile cholestasis which eventually leads to cirrhosis. Re-establishment of biliary drainage by Kasai portoenterostomy and liver transplantation for end-stage liver disease has favorably altered the clinical outcome. However, growth failure, one of the major complications of chronic liver disease, remains a major problem. The aim of the study is to evaluate growth, nutritional status and serum growth factor IGF-1 in children with biliary atresia after Kasai operation and at comparing these data between the groups with successful and unsuccessful operation. Fifty-four children with postoperative biliary atresia were evaluated for their clinical outcome, height, blood biochemistry related nutritional status and serum IGF-1. Height and serum IGF-1 were expressed as standard deviation score (SDS) to minimize the influence of age. With 44.4% of the enrolled patients the operation had been unsuccessful and jaundice persisted. The mean age of children with jaundice in comparison with the jaundice free groups was not significantly different (42.0 and 49.9 months, p = 0.458). In jaundice-free patients, hematocrit, serum albumin, calcium and phosphorus were normal and significantly higher. In the successful Kasai group, the height SDS and serum IGF-1 SDS were within the normal range and significantly higher (height SDS 0.2 +/-1.0 vs. -0.9 +/- 1.2, p < 0.01 and IGF-1 SDS 0.5 +/- 2.2 vs. -1.3 +/- 1.0, p < 0.01). The mean IGF-1 SDS in the failed Kasai group was less than -1. Children with good outcome of postoperative biliary atresia showed better growth, better nutritional status and higher serum IGF-1 levels when compared to those with unsuccessful operation.

The prevalence and persistence of human parvovirus B19 infection in thalassemic patients.

Human parvovirus B19 infection was studied in 60 thalassemic patients in Thailand. Seroprevalence, persistence of parvovirus B19 and their genotypes were identified in blood samples. Prevalence of anti-parvovirus B19 IgG and DNA found in thalassemic patients were 38% and 13%, respectively. Anti-parvovirus B19 IgM could be detected in 4% of these positive anti-parvovirus B19 IgG patients. The seroprevalence and parvovirus B19 DNA in patients with a history of blood transfusion were not significantly higher than those without such a history (44% vs. 34% and 20% vs. 9%, respectively). Phylogenetic analysis of NS1 nucleotide sequences of three parvovirus B19 samples revealed that they were parvovirus B19 genotype 1. They showed low genetic diversity from prototype (Au) strain. We concluded that acute and chronic persistent parvovirus B19 infection were found in the thalassemic Thai patients. Chronic persistence of parvovirus B19 infection might play important clinical role in thalassemic patients because of the high prevalence of parvovirus B19 DNA. Blood transfusion had no significant influence to increase the prevalence of parvovirus B19 infection in thalassemic patients.

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.

Seroprevalence of tetanus antibody in the Thai population: a national survey.

Tetanus is a disease with high mortality and the most important measure for effective prevention is vaccination. Tetanus immunization has been introduced to Thailand's national immunization program for 30 years. Yet, the coverage and seroprevalence of tetanus antibody in vast parts of the population has not been assessed. This study has been performed on 1,277 subjects aged between 6 months and 60 years or above from four geographically distinct provinces of Thailand. Tetanus antibody levels were measured using a commercially available ELISA kit. Most of the Thai population had immunity against tetanus. The level of antibodies to tetanus, as demonstrated by the geometric mean titer of antibody (GMT) (and 95% confidence interval) was 2.62 (2.34-2.91) IU/ml. The highest and lowest GMT was found in subjects aged between 5 and 9 years, and above 60 years of age with GMT (and 95% confidence intervals) of 3.64 (3.34-3.96) and 1.24 (0.67-2.29) IU/ml respectively. The minimum protective level of antitoxin (>0.01 IU/ml) was detected in 99.7 % of subjects. More than 90% of subjects displayed durable antibody protection levels (DAPL) (> or = 1.0 IU/ml), except for subjects above the age of 60 years (82%). According to this study, the majority of the population expresses tetanus antibody levels that can confer long term protection. Yet, considering the lowest GMT and the highest incidence of tetanus cases found in subjects aged above 60 years, re-immunization should be targeted at this age group especially if they had sustained any tetanus-prone injury.

Efficacy of pulsed dyed laser (585 nm) in the treatment of molluscum contagiosum subtype 1.

Molluscum contagiosum is a common cutaneous disease that may be difficult to treat when there are multiple lesions; especially in children. This study was conducted to determine the efficacy of pulsed dye laser (585 nm) in the treatment of molluscum contagiosum in 20 children. In the treated group, 70.5% of lesions healed after the first treatment; the remaining 10.6% after the second treatment (2 weeks later). The overall cure rate was significantly different from the control group (p< 0.01). The therapy was also well tolerated. Only mild transient hypopigmentation and erythema were observed. None encountered infectious events. In conclusion, pulsed dye laser is a good alternative treatment for molluscum contagiosum due to high efficacy and mild transient side effects.

Analysis of connective tissue growth factor promoter polymorphism in Thai children with biliary atresia.

OBJECTIVE: Connective tissue growth factor (CTGF) has been proposed to play a key role in the pathogenesis of hepatic fibrosis in biliary atresia (BA). The aim of the present study was to determine the single nucleotide polymorphism (SNP) in the promoter region of CTGF gene in a Thai population, and to investigate the possible role of CTGF promoter polymorphism in the susceptibility of BA. MATERIAL AND METHOD: Genomic DNA was obtained from 84 patients with BA and 142 healthy controls. The -447 G/C and -132 C/G in CTGF promoter were amplified and examined by amplification-refractory mutation system (ARMs) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis, respectively. The test of Hardy-Weinberg equilibrium (HWE) was performed using HWE program of SNPAnalyzer. Statistical analysis was carried out with SPSS and Epi Info. RESULT: According to the previous experiment, there were two SNPs, which were at position -447 and -132 on the promoter. However, there was only one SNP at the position -447 in the Thai population. No significant differences in genotype and allele frequency were observed between BA and controls or with BA subgroups. CONCLUSION: The present study demonstrated that CTGF polymorphism at -447 G/C was not associated with BA and the jaundice status of the postoperative BA patients.

Incidence and clinical manifestations of rotavirus infection among children with acute diarrhea admitted at Buri Ram Hospital, Thailand.

To study the incidence and clinical manifestations of rotavirus among children at Buri Ram Hospital, admitted with the diagnosis of acute diarrhea between November 2005 and February 2006. In the course of a cross sectional descriptive study, 103 stool samples obtained from inpatients below the age of 5 years were examined for rotavirus by RT- PCR. Data on clinical manifestations, complications, administration of antibiotics, length of admission and hospital cost were obtained by means of questionnaires distributed among physicians. The statistics used were presented as percentage, mean and 95% confidence interval, while chi-square and unpaired t-test were used to establish significant differences at p < 0.05. Rotavirus was detected in 45 of 103 stool samples (43.68%, 95%CI = 33.93, 53.81). No significant differences were found between clinical manifestations of children with rotavirus infection and non-rotavirus infection as both groups displayed acute watery diarrhea (p = 0.33), fever (p = 0.80), nausea or vomiting (p = 0.08), predominant lymphocytes (p = 0.54), absence of red blood cells (p = 0.63) or white blood cells (p = 0.57) in the stool examination, moderate or severe dehydration (p = 0.06), lactose intolerance (p = 0.41), hypokalemia (p = 0.55), metabolic acidosis (0.18) Administration of antibiotics was significantly reduced for treatment of rotavirus acute diarrhea (31.1% vs 63.8%, p = 0.001). Hospital cost and length of admission were significantly reduced in rotavirus acute diarrhea (1,845.04 baht vs 2,297.00 baht, p < 0.01) (2.09 days vs 2.81 days, p < 0.001). Compared to previous studies, no differences were found in the percentage of rotavirus acute diarrhea. Rotavirus infection is a major cause for hospitalization of children below the age of 5 years with acute diarrhea. Clinical characteristics of rotavirus acute diarrhea were not significantly different from those due to other etiologies. Diagnosis of rotavirus infection should be based on various clinical manifestations and specific laboratory methods. Further studies on the cost benefit of rotavirus vaccine in Thailand ought to be performed before implementing a universal vaccination program.

The spread of avian influenza H5N1 virus; a pandemic threat to mankind.

Influenza A H5N1 virus infection presents a major public health problem in Asian and Eurasian countries. The World Health organization has voiced their concerns about a potential pandemic with the imminent threat to humankind. In 1997, an outbreak of highly pathogenic H5N1 virus emerged and caused severe systemic disease among poultry and humans in Hong Kong. This article reviews the magnitude of the 2004-2006 outbreaks in various countries and highlights the highly pathogenic avian influenza (HPAI) subtype H5N1 virus as the cause of a major epidemic with potentially vast repercussions on economics, public health and society at large. Not only has this avian influenza (AI) virus infected poultry but has also proven highly pathogenic and fatal to mammalian species including humans and felines. The present review draws a comprehensive picture encompassing epidemiology, inter-species transmission and genetic characterization of this highly virulent virus. Moreover, laboratory diagnostic techniques, vaccination strategies and antiviral therapies aimed at outbreak control and management are also discussed.

An evidence of intestinal mucosal injury in dengue infection.

The aim of this study was to determine whether there is an association between dengue infection and intestinal mucosal injury. Serum levels of intestinal fatty acid binding protein (I-FABP) were used as a specific marker for mucosal injury. The diagnosis of all patients was serologically confirmed by anti-dengue IgG or IgM. Serum I-FABP levels of 120 patients were determined and compared to those of 25 controls using ELISA. In order to investigate serum I-FABP among dengue patients, they were categorized into 5 groups according to disease severity: dengue fever (DF), dengue hemorrhagic fever (DHF) grade I through DHF grade IV. The dengue patients had higher levels of serum I-FABP compared to 25 controls (408.0 +/- 499.3 vs 124.72 +/- 147.81 pg/ml, p=0.006). The patients with DHF grade IV had the highest levels of serum I-FABP, ALT, and AST compared to the other groups. However, there were no differences in serum I-FABP, ALT, and AST levels among patients with DF, DHF grade I, grade II, and grade III. Evidence of intestinal mucosal injury in patients with dengue infection was demonstrated. Patients with DHF grade IV had high serum I-FABP levels and had associated liver injury.

Prevalence of hepatitis A virus infection in children with biliary atresia.

This study aimed at identifying the prevalence of hepatitis A virus (HAV) infection in children with biliary atresia (BA). Blood samples were collected from children with BA whom had undergone portoenterostomy and attended the pediatric liver clinic, King Chulalongkorn Memorial Hospital between May 2002 and May 2003. Seventy-seven patients, 45 females and 32 males, ages ranging from 0.2-19 years (mean +/- SD = 5.9 +/- 4.6 years) were enrolled in the study. The HAV seropositivity rate of patients aged <10 years and > or =10 years were 13.1% and 25%, respectively. The seropositivity rate of patients with favorable outcomes (total bilirubin level < or =2 mg/dl) and unfavorable outcome (total bilirubin level >2 mg/dl) were 17.5% and 13.5%, respectively, which were not statistically different (p = 0.6). Children suffering from BA with failed portoenterostomy are at risk of developing severe liver damage at an early age. In these patients a superimposed acute liver infection due to a hepatitis virus, including HAV, may affect liver function and lead to particularly severe disease. The effectiveness of HAV immunization in this particular group of children merits further study.

Prevalence of CagA and VacA genotype of Helicobacter pylori in Thai children.

Seroprevalence of Helicobacter pylori infection in children is variable according to geographical location and family sanitation. A previous study in Bangkok showed an incidence of 25.5% in 1998. The higher incidence in the urban and rural area is predicted in lower economic classes and poor sanitation. OBJECTIVE: To study the occurance of CagA and VacA genotype in Thai children using the Western blot technique. MATERIAL AND METHOD: Sera of 159 Thai native children aged 0-15 year without associated abdominal pain from different provinces in 4 parts of the Kingdom of Thailand were tested with the rapid screening test for H. pylori. The positive specimen was further tested with the Western blot technique for determination of Urea A (p37), CagA (p116) and VacA (p89). RESULT: Fiftyfive andfifty two (34.6%) were tested positive by the rapid test while 32.7% were positivefor the band of current infection marker (CIM). The 28 selected positive sera with complete history of housing and water supply were analysed. Thai children living in urban areas have a higher prevalence and the CagA+, VacA+ are found in 96.43% of infected patients. The transmission may be through the water supply. CONCLUSION: A high prevalence of Helicobacter pylori infection was found in childhood period in urban areas and may be associated with the local water supply.

Clinical and virological differences between hepatitis B virus genotypes B and C: a case-control study.

OBJECTIVE: The pathogenic significance of hepatitis B virus (HBV) genotypes is undefined. The aim of this study was to elucidate the differences in clinical and virologicalfeatures between HBV genotypes B and C by conducting a case-control study in Thai patients who were chronically infected with the virus. PATIENTS AND METHOD: HBV genotyping was assessed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) method in stored sera of 470 patients with chronic hepatitis B. Among these, 65 patients with HBV genotype B were enrolled and matched individually to those with HBV genotype C according to sex, age, and distribution of liver disease which included asymptomatic carrier, chronic hepatitis, cirrhosis and hepatocellular carcinoma. RESULTS: Serum alanine aminotransferase (ALT) was significantly higher in patients with genotype C than those with genotype B. Hepatitis B e antigen (HBeAg) was significantly more frequent in genotype C than genotype B patients (50.8 and 30.8%, respectively, p=0.03), but the levels of HBV DNA were comparable between them. Among patients who were positive for HBeAg, the mean age of genotype C patients tended to be older than genotype B patients. CONCLUSION: The present study demonstrated that patients with HBV genotype C had a significantly higher rate of HBeAg, experienced delayed HBeAg seroconversion and exhibited more severe liver disease compared to those with genotype B.

Epidemiology and clinical manifestation of rotavirus and norwalk-like viruses in Thai children.

Acute gastroenteritis is one of the most common diseases affecting children and rotavirus is the major etiological agent worldwide. Although the role of rotavirus as a causal agent of gastroenteritis has been previously established in Thailand, little is known about the epidemiology of Norwalk-like viruses. The present study was designed to determine the epidemiology and clinical manifestation of Norwalk-like viruses in comparison with rotavirus in Thailand. One hundred and one children with watery diarrhea between November 2002 and October 2003 were recruited into the study. The clinical data and stool specimens were collected for clinical analysis and rotavirus and Norwalk-like virus detection. Rotavirus and Norwalk-like viruses were detected viral agent by RT-PCR method. Of 101 stool samples obtained, rotavirus was detected in 25/101 (24.7%). Norwalk-like viruses were detected in 23/101 (22.7%). Dual infections were detected in 6/101 (5.9%). Rotavirus and Norwalk-like viruses peaked in the winter time. Clinical manifestations of rotavirus and Norwalk-like viruses were watery stool, nausea, vomiting, abdominal pain and fever Norwalk-like viruses and rotavirus were the most common etiologic agents in children with acute gastroenteritis in Thailand Epidemiology and clinical manifestations of rotavirus and Norwalk-like viruses were not different.

Detection and differentiation of human herpesviruses 1-5 by consensus primer PCR and RFLP.

Eight human viruses of the Herpesviridae family represent a significant public health problem world-wide. Detection and typing of five of the human herpesviruses (HSV-1, HSV-2, VZV, EBV, and CMV) was performed by applying a consensus primer polymerase chain reaction (PCR). The amplified PCR products from the five human herpesviruses were typed based on their restriction enzyme digestion polymorphism with Hinf I and Alu I. Fifteen clinically suspected specimens from herpesvirus-infected patients were also evaluated. A fragment of the DNA polymerase gene from each of the five human herpesviruses was successfully amplified by the set of consensus primers. Their amplicons obtained by PCR from the template DNAs were subjected to restriction endonuclease digestion and human herpesviruses 1-5 could be clearly differentiated and typed. This method can be used to detect and differentiate between the five human herpesviruses in clinical specimens. This study demonstrates the value of testing for five human herpesviruses by consensus PCR and restricted fragment length polymorphism (RFLP). These procedures are simple and straightforward techniques for the investigation of clinical specimens.

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.

Declining hepatitis A seroprevalence among medical students in Bangkok, Thailand, 1981-2001.

The severity of clinical symptoms following hepatitis A virus (HAV) infection is age dependent. Hepatitis A in children is mostly an asymptomatic disease while adolescents and adults usually show symptoms of clinical hepatitis. Improved personal hygiene and environmental sanitation has led to a decline in natural immunity acquired in childhood, creating a population of susceptible adults. In the past decade, the incidence and prevalence of hepatitis A disease in Thailand have decreased significantly. In this study, we used enzyme-linked immunosorbent assay to determine the prevalence of anti-HAV antibodies among medical students at two different time points in 1996 and 2001. We then compared these results with data from previous studies in 1981 and 1992. The seroprevalence was 73.01%, 30.23%, 16.67% and 6.67% in 1981, 1992, 1996 and 2001, respectively. A significant decline has happened over the past two decades (p < 0.001). Considering the decreasing immunity to HAV in the younger generations, more cases of symptomatic HAV infection could be anticipated. Further seroprevalence studies in other adolescence groups from different socioeconomic status are needed to elucidate the current situation of HAV infection in the young generation more comprehensively and to develop an appropriate prevention program.