Punnee Vasiknanonte

Japanese encephalitis virus remains an important cause of encephalitis in Thailand

BACKGROUND Japanese encephalitis virus (JEV) is endemic in Thailand and prevention strategies include vaccination, vector control, and health education. METHODS Between July 2003 and August 2005, we conducted hospital-based surveillance for encephalitis at seven hospitals in Bangkok and Hat Yai. Serum and cerebrospinal (CSF) specimens were tested for evidence of recent JEV infection by immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) and a plaque reduction neutralization test (PRNT). RESULTS Of the 147 patients enrolled and tested, 24 (16%) had evidence of acute flavivirus infection: 22 (15%) with JEV and two (1%) with dengue virus. Of the 22 Japanese encephalitis (JE) cases, 10 (46%) were aged ≤ 15 years. The median length of hospital stay was 13 days; one 13-year-old child died. Ten percent of encephalitis patients enrolled in Bangkok hospitals were found to have JEV infection compared to 28% of patients enrolled in hospitals in southern Thailand (p < 0.01). Four (40%) of the 10 children with JE were reported as being vaccinated. CONCLUSIONS JEV remains an important cause of encephalitis among hospitalized patients in Thailand. The high proportion of JE among encephalitis cases is concerning and additional public health prevention efforts or expanded vaccination may be needed.

Factors associated with bed sharing and sleep position in Thai neonates

BACKGROUND Sleep in a supine position and in a bed separate from but proximate to adults is recommended, in several Western countries, to prevent Sudden Infant Death Syndrome (SIDS). Cultural differences and a lower rate of SIDS in Asian populations may affect concern with this problem and thus infant sleeping arrangements. Objective To study bed sharing and sleep position in Thai neonates and the relationship to infant and maternal characteristics. METHODS A cross-sectional survey based on interviews with parents of infants aged 21 days old, was conducted under the Prospective Cohort Study of Thai Children. RESULTS Of the total sample, 2236/3692 (60.6%) infants shared a bed with their parents. Sixty per cent of the parents placed their infants to sleep in a supine position, 32.2% on their side and 4.9% in a prone position. Bed sharing was associated with older maternal age, higher education, Muslim mother, and with work status of professional career or unemployed. Placing the infants to sleep in a prone position was associated with infant birth weight of greater than 2500 g, older maternal age, higher education, Buddhist mother, mother with professional career and middle-class household economic status. CONCLUSIONS Infant bed sharing is a common practice in the Thai culture, as in other Asian countries. The prone sleep position is less common than in Western populations. The main factor associated with both bed sharing and putting infants to sleep in the prone position was a higher maternal socioeconomic status (SES), in contrast to previous studies in some Western countries in which both practices were associated with low maternal SES. Cultural differences may play an important role in these different findings.

Two Thai families with Norrie disease (ND): Association of two novel missense mutations with severe ND phenotype, seizures, and a manifesting carrier

We describe two Thai families with Norrie disease (ND) in three generations, including 10 affected males and one manifesting female. All affected males in each family had severely defective eye development with complete loss of vision. In addition, three male patients (one from family 1 and two from family 2) suffered from epilepsy, and one female carrier from one family manifested blindness with phthisis bulbi in her right eye. Mutation analysis of the ND gene (NDP) revealed two different novel missense mutations (L16P and S75P) that co-segregated with ND in each family, suggesting that the newly appearing proline at codon 16 or codon 75 alters the conformation of the ND protein and contributes to the severe phenotype of ND in each family. Other studies suggest that epileptic seizures or growth retardation that is associated with ND is the consequence of loss of contiguous genes, because most such patients had deletions extending beyond the Norrie locus. Our finding that the three affected males in the two families with the missense mutations had epilepsy does not support a contiguous gene effect, but favors the pleiotropism of NDP, at least as far as the epileptic manifestation is concerned. The unilateral blindness in the female carrier may have been due to non-random X-inactivation.

Mutation screening of the CDKL5 gene in cryptogenic infantile intractable epilepsy and review of clinical sensitivity

PURPOSES To perform CDKL5 mutation screening in Thai children with cryptogenic infantile intractable epilepsy and to determine the clinical sensitivity of CDKL5 screening when different inclusion criteria were applied. METHODS Children with cryptogenic infantile intractable epilepsy were screened for CDKL5 mutation using multiplex ligation-dependent probe amplification and DNA sequencing. The clinical sensitivity was reviewed by combining the results of studies using similar inclusion screening criteria. RESULTS Thirty children (19 girls and 11 boys) with a median seizure onset of 7 months were screened. Almost a half had infantile spasms and one fifth had stereotypic hand movements. A novel c.2854C>T (p.R952X) was identified in an ambulatory girl who had severe mental retardation, multiple types of seizures without Rett-like features. Her mother had a mild intellectual disability, yet her grandmother and half sister were normal despite having the same genetic alteration (random X-inactivation patterns). The pathogenicity of p.R952X identified here was uncertain since healthy relatives and 6 female controls also harbor this alteration. The clinical sensitivity of CDKL5 mutation screening among females with Rett-like features and negative MECP2 screening was 7.8% while the clinical sensitivity among females having cryptogenic intractable seizures with an onset before the ages of 12, 6 and 3 months were 4.7, 11.6 and 14.3%, respectively.

Infectious Causes of Encephalitis and Meningoencephalitis in Thailand, 2003-2005

Although many causes were identified, most remain unknown.