Seroprevalence of varicella zoster virus infections in Colombo district, Sri Lanka.

BACKGROUND: Although Varicella Zoster virus (VZV) infections occur worldwide, the epidemiology is remarkably different in tropical and temperate climates. VZV infections result in significant morbidity and mortality among adults in Sri Lanka. AIMS: For future VZV vaccination strategies, we set to determine the age-specific seroprevalence rate of VZV infections in Colombo, Sri Lanka. MATERIALS AND METHODS: The study was carried out from 1999 to 2000. Multi-stage cluster sampling technique was used to collect 913 blood samples, which were tested for the presence of VZV-specific IgG antibodies. RESULTS: VZV seroprevalence rates were markedly lower in all age groups when compared to temperate climates. The seroprevalence rates increased with age in both the rural and urban populations. Of those aged 60 years, only 50% in the rural population and 78.9% in the urban population were immune to VZV. Seroprevalence rates of VZV infections were significantly different between the urban and rural populations (P< 0.001), with VZV-specific IgG antibodies detected in 47.5% in the urban population and 27.9% in the rural population. It was found that 56.2% (131) of females of childbearing age were nonimmune to VZV. CONCLUSIONS: These findings highlight the need for a VZV vaccination program, which is likely to have a huge impact on the incidence of chickenpox and its associated morbidity and mortality.

Seroprevalence of hepatitis A antibodies in relation to social factors--a preliminary study.

INTRODUCTION: Hepatitis A is a benign illness in children with the rare possibility of fatal complications. Although an endemic disease, very few studies have been done in children regarding the seroprevalence of hepatitis A antibodies in Sri Lanka. OBJECTIVES: (i) To document the seropositivity for hepatitis A in a group of children admitted to a paediatric ward. (ii) To determine the relationship of hepatitis A viral infection to social factors in these children. METHOD: A prospective, descriptive, cross-sectional study was carried out in a ward at the Lady Ridgeway Hospital for 7 months from September 2001. Children admitted on predetermined days, needing venepuncture for their presenting illness, were studied while those who were seriously ill were excluded. Written consent was obtained and a questionnaire with details of socio-economic conditions, personal hygiene practices of the mother, access to water and sanitation and health related behaviour was administered. Total antibodies to hepatitis A were detected by ELISA on a sample of blood taken from each patient. RESULTS: Two hundred and eighty eight samples of blood were analysed. None of the children were immunised against hepatitis A. There were 158 boys (54.9%). Thirty one (10.8%) of the 288 patients had antibodies against hepatitis A. The seroprevalence was 11.6% in children under 10 years of age. Majority (78%) were from families with a monthly income of less than Rs 10,000/-. Fifteen (48.4%) of the 31 seropositive children were from families earning less than Rs 5000/- per month. Belonging to social classes IV and V and having mothers with only primary education were factors significantly associated with seropositivity. No significant difference in the presence of antibodies was observed regarding the personal hygiene practices analysed and access to basic amenities. Health related behaviour practices analysed were significantly associated with the presence of hepatitis A antibodies. CONCLUSIONS: Seroprevalence of 10.8% was observed in a selected group of children. Factors such as poor socio-economic background and having mothers with only primary education were associated with hepatitis A virus (HAV) antibodies as were certain health related behaviour practices of children.