Harendra De Silva

Background: Low birth weight (LBW), a substantial global public health problem, is associated with a range of both short-term and long-term consequences affecting human capital. The present study aims to investigate sociodemographic and pregnancy-related determinants of birth weight through analysis of Sri Lanka Child Growth Cohort (SLCGC) data. Methods: SLCGC is a retrospective cohort study that recruited 1875 children aged 12–24 months, born at term, using a stratified cluster sample across the country. The present analysis included 1563 mother-baby pairs, with data collected through the Child Health Development Record (birth weight, gestational age at birth, sex), Pregnancy Record (birth order, pre-pregnancy body mass index (BMI), gestational weight gain, diabetes, hypertension, haemoglobin), through interview (household assets to calculate wealth index, maternal age, education and employment, birth order, birth interval, supplements used) and through anthropometric measurements (maternal and paternal height). Univariate regression analyses were carried out to estimate the effects of a series of independent variables on birth weight, followed by a multiple regression analysis using the generalised linear model adjusting for confounders at a significance considered at p<0.05. Results: Mean birth weight was 2926 g (SD 406.9) and the LBW prevalence in term-born children was 12.5%. Adjusted analyses show that birth weight (g) of term-born children increases significantly with their parental height (maternal β=9.7, 95% CI 6.7 to 12.7, p<0.01; paternal β=2.4, 95% CI 1.4 to 4.5, p<0.01), pre-pregnancy BMI (β=19.2, 95% CI 15.2 to 23.1, p<0.01), gestational age at birth (β=131.3, 95% CI 114.5 to 148.0, p<0.01) and weight gain during pregnancy (β=20.9, 95% CI 16.9 to 24.9, p<0.01). Birth weight is significantly higher in males in contrast to females, the second or higher birth orders compared with first-born and those living in urban and rural sectors in contrast to the estate sector (plantations). Having diabetes during pregnancy has increased birth weight significantly, whereas hypertension reduced it. These associations were considered significant at p<0.05 Conclusion: Birth weight is determined by multiple factors. The consistent associations of parental height, pre-pregnancy BMI, weight gain during pregnancy, gestational age at birth and presence of diabetes and hypertension in pregnancy may have programmatic implications to achieve optimal birth weight in low- and middle-income countries.

Universal salt iodisation (USI) plays an essential role in the provision of iodine (I) to populations worldwide. Countries adopting USI programmes, adhering to strict criteria laid down by expert organisations such as the Iodine Global Network, are estimated to have reduced the prevalence of I deficiency by 75% (protecting 720 million individuals worldwide). Despite this success, doubts have been raised as to the desirability of continuing such programmes because of (a) the need to reduce salt intake for cardiovascular prevention and (b) the induction of thyroid autoimmunity. We present current evidence from cross-sectional studies in several disparate populations of the possible short-term modulation of thyroid autoimmune markers, thyroid peroxidase (TPOAb) and thyroglobulin antibodies (TgAb), with minimal disruption of biochemical thyroid function. We also present evidence from longer term, mainly cross-sectional studies, that indicate a reduction in the prevalence of TPOAb and TgAb, and the persistence of normal biochemical thyroid function over as long as two decades of USI. We believe these studies indicate that USI is safe, and that long-term salt iodisation does not cause an increase in autoimmune thyroid disease in the populations studied and should not be a safety concern based on current evidence. More long-term and better-designed studies are required.

Genetic variations in dengue virus (DENV) play a distinct role in epidemic emergence. The DENV 3′ UTR has become a recent interest in research. The objective of the study was to examine the genetic variation in the domain II, 3′ UTR region of human and mosquito-derived DENV. DENV-infected human sera were orally infected to laboratory reared Aedes aegypti mosquitoes. The domain II, 3′ UTR of each human- and mosquito-derived sample was amplified. The nucleotide sequence variation, phylogenetic and secondary structure analysis was carried out incorporating respective regions of so far recorded Sri Lankan and the reference genotype strains of the DENV3 and DENV1 serotypes. The human- and mosquito-derived domain II, 3′ UTR were identical in nucleotide sequences within the serotypes isolated, indicating the conserved nature of the region during host switch. The sequence analysis revealed distinct variations in study isolates compared to so far recorded Sri Lankan isolates. However, despite single nucleotide variations, the maintenance of structural integrity was evident in related strains within the serotypes in the secondary structure analysis. The phylogenetic analysis revealed distinct clade segregation of the study sequences from so far reported Sri Lankan isolates and illustrated the phylogenetic relations of the study sequences to the available global isolates of respective serotypes.

Background: More than 80,000 dengue cases including 215 deaths were reported nationally in less than 7 months between 2016 and 2017, a fourfold increase in the number of reported cases compared to the average number over 2010–2016. The region of Negombo, located in the Western province, experienced the greatest number of dengue cases in the country and is the focus area of our study, where we aim to capture the spatial-temporal dynamics of dengue transmission. Methods: We present a statistical modeling framework to evaluate the spatial-temporal dynamics of the 2016–2017 dengue outbreak in the Negombo region of Sri Lanka as a function of human mobility, land-use, and climate patterns. The analysis was conducted at a 1 km × 1 km spatial resolution and a weekly temporal resolution. Results: Our results indicate human mobility to be a stronger indicator for local outbreak clusters than land-use or climate variables. The minimum daily temperature was identified as the most influential climate variable on dengue cases in the region; while among the set of land-use patterns considered, urban areas were found to be most prone to dengue outbreak, followed by areas with stagnant water and then coastal areas. The results are shown to be robust across spatial resolutions. Conclusions: Our study highlights the potential value of using travel data to target vector control within a region. In addition to illustrating the relative relationship between various potential risk factors for dengue outbreaks, the results of our study can be used to inform where and when new cases of dengue are likely to occur within a region, and thus help more effectively and innovatively, plan for disease surveillance and vector control.

Sri Lanka Journal of Child Health, 2019; 48(3): 270-272

Background: More than 80,000 dengue cases including 215 deaths were reported nationally in less than seven months between 2016-2017, a fourfold increase in the number of reported cases compared to the average number over 2010-2016. The region of Negombo, located in the Western province, experienced the greatest number of dengue cases in the country and is the focus area of our study, where we aim to capture the spatial-temporal dynamics of dengue transmission. Methods: We present a statistical modeling framework to evaluate the spatial-temporal dynamics of the 2016-2017 dengue outbreak in the Negombo region of Sri Lanka as a function of human mobility, land-use, and climate patterns. The analysis was conducted at a 1 km × 1 km spatial resolution and a weekly temporal resolution. Results: Our results indicate human mobility to be a stronger indicator for local outbreak clusters than land-use or climate variables. The minimum daily temperature was identified as the most influential climate variable on dengue cases in the region; while among the set of land-use patterns considered, urban areas were found to be most prone to dengue outbreak, followed by areas with stagnant water and then coastal areas. The results are shown to be robust across spatial resolutions. Conclusions: Our study highlights the potential value of using travel data to target vector control within a region. In addition to illustrating the relative relationship between various potential risk factors for dengue outbreaks, the results of our study can be used to inform where and when new cases of dengue are likely to occur within a region, and thus help more effectively and innovatively, plan for disease surveillance and vector control.

Gillespie syndrome is a rare, congenital, neurological disorder characterized by the association of partial bilateral aniridia, non-progressive cerebellar ataxia and intellectual disability. Homozygous and heterozygous pathogenic variants of the ITPR1 gene encoding an inositol 1, 4, 5- triphosphate- responsive calcium channel have been identified in 13 patients recently. There have been 22 cases reported in the literature by 2016, mostly from the western hemisphere with none reported from Sri Lanka. A 10-year-old girl born to healthy non-consanguineous parents with delayed development is described. She started walking unaided by 9 years with a significantly unsteady gait and her speech was similarly delayed. Physical examination revealed multiple cerebellar signs. Slit lamp examination of eyes revealed bilateral partial aniridia. Magnetic resonance imaging of brain at the age of 10 years revealed cerebellar (mainly vermian) hypoplasia. Genetic testing confirmed the clinical suspicion and demonstrated a heterozygous pathogenic variant c.7786_7788delAAG p.(Lys2596del) in the ITPR1 gene. The report of this child with molecular confirmation of Gillespie syndrome highlights the need for careful evaluation of ophthalmological and neurological features in patients that enables correct clinical diagnosis. The availability of genetic testing enables more accurate counseling of the parents and patients regarding recurrence risks to other family members.

Sri Lanka Journal of Child Health, 2018; 47(2): 166-168

Sri Lanka Journal of Child Health, 2018; 47(2): 169-171