Evidence of protection against clinical and chronic hepatitis B infection 20 years after infant vaccination in a high endemicity region

Vaccination against hepatitis B virus (HBV) immediately after birth prevents neonatal infection by vertical transmission from HBV carrier mothers. There is an ongoing debate whether infant vaccination is sufficient to protect against infection when exposed to HBV later in life. We studied 222 Thai infants born to HBsAg -/+ and HBeAg -/+ mothers who were vaccinated with recombinant hepatitis B vaccine at 0-1-2-12 months of age. A subset of 100 subjects received a booster dose at age 5 years. Blood samples collected yearly for 20 years were examined for anti-HBs antibodies and serological markers of hepatitis B infection (anti-HBc, HBsAg, and in selected cases HBeAg, anti-HBe, HBV DNA). During the 20-year follow-up, no subject acquired new chronic HBV infection or clinical hepatitis B disease. During the first decade, possible subclinical breakthrough HBV infection (anti-HBc seroconversion) was only observed in subjects born to HBsAg +/HBeAg + mothers (6/49 [12.2%]). During the second decade, breakthrough HBV infections were detected in all groups (18/140 [12.8%]). Increases in anti-HBs concentrations that were unrelated to additional HBV vaccination or infection were detected in approximately 10% of subjects in each decade. Primary infant vaccination with a recombinant hepatitis B vaccine confers long-term protection against clinical disease and new chronic hepatitis B infection despite confirmed hepatitis B exposure. (http://www.clinicaltrials.gov NCT00240500 and NCT00456625)

The effects of Kaempferia parviflora on anti-internalization activity of Helicobacter pylori to HEp-2 cells

Helicobacter pylori, an etiological agent of active chronic gastritis and peptic ulcer disease, is now considered to be an invasive enteropathogen. Anti-adhesion and anti-internalization are new strategies for prevention and treatment of bacterial infection including the alternative of medicinal plants. In this study, four parts of Kaempferia parviflora’s extracts composing of volatile oil, hexane, ethyl acetate and methanol were examined for their antibacterial and anti-internalization activities of H. pylori against HEp-2 cells. All extracts except volatile oil showed significant antibacterial activity and had a minimum inhibitory concentration (MIC) ranging from 32 - 64 ìg/ml. The most active extract of ethyl acetateexhibited significant anti-internalization activity which corresponded to dose and time of treatment. Moreover, K. parviflora’s ethyl acetate extract could significantly inhibit the invasion of both H. pylori virulent strains (cagA+) and non-virulent strains (cagA-) in HEp-2 cells. Thus, K. parviflora is one of the effective herbs for potential prevention and treatment of H. pylori infection

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 evidence of herpesvirus infection in gibbons

BACKGROUND: Herpesviruses are not only infectious agents of worldwide distribution in humans, but have also been demonstrated in various non-human primates as well. Seventy-eight gibbons were subjected to serological tests by ELISA for herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), Epstein-Barr virus (EBV) and cytomegalovirus (CMV). RESULTS: The prevalence of IgG antibodies against HSV-1, HSV-2, EBV and CMV was 28.2%, 28.2%, 14.1% and 17.9%, respectively. CONCLUSIONS: Antigenic cross-reactivity is expected to exist between the human herpesviruses and gibbon herpesviruses. Gibbons have antibodies to human herpesviruses that may reflect zoonotic infection with human herpesviruses or infection with indigenous gibbon herpesviruses. Therefore, it is difficult to draw concrete conclusions from serological studies alone. Identification should be based on further isolation and molecular characterization of viruses from seropositive animals

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

Complete coding sequence characterization and comparative analysis of the putative novel human rhinovirus (HRV) species C and B

<p>Abstract</p> <p>Background</p> <p>Human Rhinoviruses (HRVs) are well recognized viral pathogens associated with acute respiratory tract illnesses (RTIs) abundant worldwide. Although recent studies have phylogenetically identified the new HRV species (HRV-C), data on molecular epidemiology, genetic diversity, and clinical manifestation have been limited.</p> <p>Result</p> <p>To gain new insight into HRV genetic diversity, we determined the complete coding sequences of putative new members of HRV species C (HRV-CU072 with 1% prevalence) and HRV-B (HRV-CU211) identified from clinical specimens collected from pediatric patients diagnosed with a symptom of acute lower RTI. Complete coding sequence and phylogenetic analysis revealed that the HRV-CU072 strain shared a recent common ancestor with most closely related Chinese strain (N4). Comparative analysis at the protein level showed that HRV-CU072 might accumulate substitutional mutations in structural proteins, as well as nonstructural proteins 3C and 3 D. Comparative analysis of all available HRVs and HEVs indicated that HRV-C contains a relatively high G+C content and is more closely related to HEV-D. This might be correlated to their replication and capability to adapt to the high temperature environment of the human lower respiratory tract. We herein report an infrequently occurring intra-species recombination event in HRV-B species (HRV-CU211) with a crossing over having taken place at the boundary of VP2 and VP3 genes. Moreover, we observed phylogenetic compatibility in all HRV species and suggest that dynamic mechanisms for HRV evolution seem to be related to recombination events. These findings indicated that the elementary units shaping the genetic diversity of HRV-C could be found in the nonstructural 2A and 3D genes.</p> <p>Conclusion</p> <p>This study provides information for understanding HRV genetic diversity and insight into the role of selection pressure and recombination mechanisms influencing HRV evolution.</p