The health belief model and factors relating to potential use of a vaccine for shigellosis in Kaeng Koi district, Saraburi province, Thailand

Shigellosis is an important cause of morbidity and mortality throughout the world. Approximately, 1.1 million deaths occur a year due to this disease, making it the fourth leading cause of mortality worldwide. This paper explores local interest in and potential use of a vaccine for shigellosis in Thailand where Shigella poses an important public-health concern. Data for this study were collected during June-November 2002 from 522 subjects surveyed using a sociobehavioural questionnaire in Kaeng Koi district in central Thailand. The community demand and likely use of a vaccine were examined in relation to the Health Belief Model, which provides analytical constructs for investigating the multiple issues of local readiness to accept and access a new vaccine. As the key outcome variable, most respondents showed interest in receiving a vaccine against dysentery which they thought would provide useful protection against the disease. However, there was only a moderate number who perceived dysentery as serious and themselves as susceptible to it, although it was perceived to cause some burden to and additional expense for families. Most people identified a number of groups who were thought to be especially vulnerable to dysentery, such as the elderly, pre-school, and school-age children, and poor labourers. Other outcomes of the study included the identification of acceptable and convenient sites for its delivery, such as government health clinics and private clinics, and respected sources for information about the vaccine, such as health clinic personnel and community health volunteers. This information suggests that components of the Health Belief Model may be useful in identifying community acceptance of a vaccine and the means of introducing it. This health information is important for planning and implementing vaccine programmes.     

Effects of cocaine on heart rate variability in healthy subjects

In this study, we found that cocaine decreased the high-frequency power of heart rate variability in normal volunteers, implicating a decrease in vagal tone. However, the results of our autonomic blocking studies indicated the opposite, suggesting a major influence of cardiac sympathetic drive on the high-frequency power of heart rate variability.     

Neonatal screening program in Thailand

The Neonatal Screening Program for congenital hypothyroidism (CHT) and phenylketonuria (PKU) commenced in 1996 with the objective of bringing better quality of life to people throughout the country, especially in the remote areas. This involved the implementation of routine services to the public health infrastructure all over the country. The plan of action has been designed so that by the year 2000 all public health service units throughout the country may provide screening services which can cover 1.2 million babies/ annum. Implementation of the screening program has been performed through public health sectors all over the country. These involved: education of the health personnel and communities, implementation of routine specimens collection and delivery systems to the central laboratories, establishment of central laboratory screening services, routine follow up and case management. Local in-house reagents using ELISA and IRMA techniques have been developed and utilized as screening and confirmation tests for CHT. In addition, Guthrie's test has been used for PKU screening and the automated Fluorometry has been selected for PKU confirmation. All 724 community hospitals have provided newborn screening services as one of the basic requirements for newborns according to public health policy. Of 1,425,025 babies screened, 3,450 (0.24%) were above the first screening cut off for CHT (TSH > 25 mU/l) and 321 (0.02%) for PKU (PKU > 4mg/dl). With a 63.10% follow up rate, the incidences were 1:3,314 for CHT and 1:237,504 for PKU. Newborn screening has been implemented as routine practice for all public health sectors of the country for CHT and PKU. It is expected that by the year 2003, all Thai newborns will be provided with screening services resulting in a better quality of life for the next generation.     

Risk factors for shigellosis in Thailand.

OBJECTIVES: To assess the potential risk factors for shigellosis including housefly density. METHODS: A matched case-control study to investigate potential risk factors for shigellosis was conducted in a semi-urban area, Kaengkhoi District, Saraburi Province, central Thailand. Shigella cases were ascertained from a two-year population-based surveillance study detecting diarrhea and shigellosis in the area. The study evaluated a wide range of exposures, which were assessed by odds ratios (OR) adjusted for proxy markers of socioeconomic status: family income, and type of residence, using conditional logistic regression analysis. RESULTS: Hygiene behaviors such as regular hand washing (p<0.05), a clean environment surrounding the household (p<0.001), and the availability of water to flush the toilet (p=0.08) were associated with a reduced risk for shigellosis in the multivariate model. In contrast factors indicating a lower than average socioeconomic status, such as having to rent instead of owning one's housing (p<0.001) and a low family income (p<0.01) were associated with an increased risk for shigellosis. For children, breastfeeding showed a strong protective effect in reducing the risk of shigellosis (p<0.01). Prior to adjustment for environmental factors, fly density in the kitchen area was associated with an increased risk of shigellosis (p<0.01). CONCLUSIONS: We found a correlation between socioeconomic status and the risk for shigellosis. To reduce shigellosis in this setting, we recommend interventions focused on three aspects: improved water supply and sanitation (especially latrines and garbage disposal) including fly control, health education on hand washing, and the promotion of breastfeeding.     

Shigellosis remains an important problem in children less than 5 years of age in Thailand

This is a review of existing data on the burden of shigellosis in Thailand to determine trends, vulnerable groups, predominant species and serotypes, and antimicrobial resistance patterns. Diarrhoea and dysentery morbidity and mortality data from 1991 to 1999 was collected from the routine surveillance system and demographic data from the government census. International and local literature published between 1988 and 2000 was systematically reviewed. Based on the routine surveillance system, the annual incidence of bacillary dysentery decreased from 1.3 to 0.2/10,000 persons per year. The remaining burden is highest in children <5 years of age at 2.7/10,000 persons per year. In comparison, a prospective study utilizing active surveillance found an incidence in children <5 years of age that was more than 100-fold higher at 640/10,000 persons per year. Despite the decrease in morbidity and mortality based on routinely collected data, shigellosis remains an important problem in children <5 years of age in Thailand.     

Cockroach allergen detection and cockroach allergens of allergic Thai patients

Hybridomas secreting monoclonal antibodies (MAb) specific to American cockroach (Periplaneta americana) were produced through a fusion of immune splenocytes of a BALB/c mouse immunized with crude cockroach (CR) extract and mouse myeloma cells. Two hybridomas namely 38G6 and 3C2 were established. These specific hybridomas secreted IgG1 monoclonal immunoglobulins with antigenic specificities to CR protein components of over 207 to 72 kDa and 45 to 40 kDa, respectively. The monoclonal antibodies were applied to select their specific epitopes out of the crude CR extract using affinity chromatography. A Prausnitz-Kustner test revealed that these epitopes were allergens which caused wheals and flares of the skin of a guinea-pig previously sensitized with a pool of serum samples from CR allergic patients. The monoclonal antibodies were also used in a capture ELISA to detect specific IgE in serum samples of allergic Thai patients. It was found that 72% and 76% of the patients had IgE antibodies to the epitopes of MAb 38G6 and MAb 3C2, respectively, indicating that the two epitopes are major CR allergens among the CR allergic Thai patients. An antibody-sandwich ELISA was developed for quantitative detection of CR allergens using the two monoclonal antibodies as a capture reagent and rabbit polyclonal antibodies to crude CR extract as a detection reagent. The assay could detect allergenic epitopes contained in as little as 122 pg of crude cockroach extract, and has high potential for direct measurement of the marker allergens in extracts of environmental samples.     

Recombinant American cockroach component,Per a 1, reactive to IgE of allergic Thai patients

Twelve similar recombinant Per a 1 clones were produced from an American cockroach (CR) cDNA library. The nucleotide sequence of a representative cline, i.e. clone A6, contained 579 base pairs (bp) and a 372 bp open reading frame (2-373) encoding 124 amino acids. A stop codon was found at position 374-376 followed by a 3' end untranslated region with an AATAAA polyadenylation signal and a poly (A) tail. The estimated molecular mass of the 24 amino acid residue protein was 13.8 kDa, with a predicted isoelectric point value of 4.74. Cysteine or N-linked glycosylation was not found. The deduced amino acid sequence of the A6 revealed 84.68-95.97% identity to other previously reported Per a 1 clones and 65.87-69.60% homology to the previously reported Bla g 1 clones. However, while previously reported Per a 1 clones showed homology to ANG12, a precursor protein in the midgut of the female Anopheles gambiae secreted after the blood meal, the A6 DNA sequence was found to have homology (37.1%) to DNA of G2, a putative protein in the midgut of Aedes aegypti (AY 050565). The deduced amino acid sequence of A6 contained a mitochondrial energy transfer protein signature, phosphorylation sites for the cAMP-and cGMP-dependent protein kinase C and casein kinase II. Hydrophobic and hydrophilic characteristics of the A6 deduced peptide indicated that it was a transmembrane protein. This is the first report that Per a 1 is a transmembrane protein. The deduced amino acid sequence of the A6, which contained the sequence LIRSLFGLP, differed in one amino acid from two previously reported epitopes, i.e. LIRALFGL and IRSWFGLP, of Per a 1.0104 which bound 80% and 100%, respectively, to IgE of the allergic patients tested. The A6 DNA sequence was deposited in the GenBank (Accession number AY 259514) and has been designated Per a 1.0105. The A6 expressed protein bound to monoclonal antibodies (MAb 3C2) specific to American cockroach and also bound to IgE of all (100%) of the 20 allergic Thai patients.     

Novel Neutralizing Epitope of PEDV S1 Protein Identified by IgM Monoclonal Antibody

Porcine epidemic diarrhea virus (PEDV) causes devastating enteric disease that inflicts huge economic damage on the swine industry worldwide. A safe and highly effective PEDV vaccine that contains only the virus-neutralizing epitopes (not enhancing epitope), as well as a ready-to-use PEDV neutralizing antibody for the passive immunization of PEDV vulnerable piglets (during the first week of life) are needed, particularly for PEDV-endemic farms. In this study, we generated monoclonal antibodies (mAbs) to the recombinant S1 domain of PEDV spike (S) protein and tested their PEDV neutralizing activity by CPE-reduction assay. The mAb secreted by one hybrodoma clone (A3), that also bound to the native S1 counterpart from PEDV-infected cells (tested by combined co-immunoprecipitation and Western blotting), neutralized PEDV infectivity. Epitope of the neutralizing mAb (mAbA3) locates in the S1A subdomain of the spike protein, as identified by phage mimotope search and multiple sequence alignment, and peptide binding-ELISA. The newly identified epitope is shared by PEDV G1 and G2 strains and other alphacoronaviruses. In summary, mAbA3 may be useful as a ready-to-use antibody for passive immunization of PEDV-susceptible piglets, while the novel neutralizing epitope, together with other, previously known protective epitopes, have potential as an immunogenic cocktail for a safe, next-generation PEDV vaccine.     

<Emphasis Type="Italic">OPCML</Emphasis> Gene as a Schizophrenia Susceptibility Locus in Thai Population

Opioid-binding protein/cell adhesion molecule (OPCML) gene has been recently identified as a susceptibility gene for schizophrenia in Europeans. This study aims to investigate the association between single nucleotide polymorphisms (SNPs) in the OPCML gene and risk of schizophrenia in a Thai population. DNA samples of 115 schizophrenia patients and 173 normal controls were genotyped using high-resolution melting analysis and analyzed by chi-square test of SPSS software. We observed a strong association between an intronic SNP of the OPCML gene (rs1784519) and the risk of schizophrenia in the Thai population [P = 0.00036; odds ratio for the minor A allele, 2.11(1.57–2.84)]. The previously discovered SNP associated with schizophrenia in Europeans, rs3016384, also showed significant association with schizophrenia in the Thai population [P = 0.01; odds ratio of the minor T allele, 0.59 (0.44–0.79)]. Therefore, the OPCML gene is considered to be a schizophrenia-susceptible gene in the Thai population.