ELISA-based evaluation of antibody response to Leishmania in a region endemic for cutaneous leishmaniasis.

Leishmaniasis includes several clinical forms. While routine diagnosis of cutaneous leishmaniasis (CL) is by microscopy, an antibody response to CL has been reported in several recent studies. This study evaluated anti-leishmanial immunoglobulin G (IgG) antibody responses as a biomarker of active leishmaniasis and a measure of exposure to Leishmania. Sera from 50 untreated CL patients, 140 patients under treatment and 280 healthy individuals residing in endemic regions collected as part of an epidemiological survey, was analysed with an enzyme-linked immunosorbent assay established in-house using receiver operator characteristic curve at optimized cut-off value. The assay showed high performance as a diagnostic tool in identifying exposure in endemic individuals (sensitivity: 98%, specificity: 90.3%). All patients showed lower antibody levels over time since onset of lesion/s. Antibody levels were higher (p Ë‚ .01) and persisted for a longer period in untreated patients. In patients under treatment, the level of anti-IgG antibodies was negatively correlated with the total duration the patient had been on treatment. The anti-leishmanial IgG response in Leishmania donovani-induced CL is transient and is unlikely to confer protective immunity. Optimized serological assays may be useful in endemic settings for diagnosis and monitoring the treatment response in CL.

Impact of vitamin A supplementation on health status and absenteeism of school children in Sri Lanka.

The objective of this study was to determine the impact of Vitamin A supplementation on health status and absenteeism of school children. A randomized double blind placebo controlled trial over a period of 13 months was conducted in a rural area of Sri Lanka involving 613 school children attending Grades 1-5 (aged 5 to 13 years). Children were assigned to either 200,000 IU of Vitamin A (n=297) or placebo (n=316) once every 4 months. Socio-demographic data were obtained at baseline, and anthropometry and haemoglobin concentrations were assessed at baseline and post intervention. Serum vitamin A concentrations were assayed by HPLC in a subgroup of children (n=193) before administration of each dose. School absenteeism was recorded. The two groups of children were similar at baseline in all variables. The subgroup of children was comparable to the main study population. The prevalence of vitamin A deficiency (< 20 microg/dL) in the subgroup of children was 8.2%. Changes in anthropometric indices and haemoglobin concentrations were similar in the two groups. The major causes for absenteeism were non-health causes and supplemented children lost a fewer number of school days due to illness than placebo children (p=0.053). Vitamin A concentrations improved with each dose and the improvement was greater with better compliance. Vitamin A supplementation with 200,000 IU every 4 months over 13 months improved vitamin A status and school attendance but not anthropometric status of these children.