Pataraporn Wisetsing

Maternally transferred neutralising dengue antibodies in Thai infants: a pilot study

Abstract In a dengue-endemic area, sera from 42 mother-infant pairs and sera collected from the infants at follow-up at the ages of 3 months (n =27), 6 months (n =34), 9 months (n =23) and 12 months (n =8) were tested for antibodies to four dengue serotypes using a plaque reduction neutralisation test (PRNT50), IgG ELISA and haemagglutination inhibition assay (HAI). The IgG ELISA and HAI tests were less sensitive than PRNT50 in detecting low levels of antibodies. Levels of maternally transferred dengue neutralising antibodies in the cord sera were very high and identical to those in the mothers. Neutralising antibody prevalences in the newborns were 95% to dengue serotype 1 (DEN-1), 93% to DEN-2 and DEN-3 and 91% to DEN-4. The antibodies decreased with increasing age. At least one dengue serotype neutralising antibody persisted in the infants at ages 3, 6 and 9 months in 92%, 69% and 13%, respectively. No maternally transferred antibody was observed in 12-month-old infants. In endemic areas therefore, where most infants have maternally transferred dengue antibodies, interference with dengue vaccine is likely to be less after 12 months of age than before then.

Comparative study of the effectiveness and pharmacokinetics of two rectal artesunate/oral mefloquine combination regimens for the treatment of uncomplicated childhood falciparum malaria

Abstract Background: Rectal artesunate has been shown to be an effective treatment for falciparum malaria and is useful in patients who cannot take medicine orally or when parenteral medication is inconvenient. A combination with mefloquine can decrease the duration of treatment, increase compliance and delay development of resistance. There are no clear data on whether a higher dosage of rectal artesunate results in a better clinical response. Aim: To assess two rectal artesunate/oral mefloquine regimens for treating uncomplicated multi-drug-resistant childhood falciparum malaria. Methods: Seventy children aged 1–14 years with uncomplicated falciparum malaria were randomly assigned to receive either 10 (range 8–12) or 20 (range 16–24) mg/kg/day rectal artesunate for 3 days followed by 25 mg/kg oral mefloquine. The study endpoints were fever clearance time, parasite clearance time and proportion of patients with recrudescence. Serum levels of artesunate and dihydro-artemisinin were measured after the first dose of rectal artesunate in 16 subjects. Results: Both regimens were safe and effective. The cure rate was 100% in the 53 patients who completed 28-day follow-up. All of the study endpoints were comparable between both treatment groups. Conclusion: A regimen of rectal artesunate 10 mg/kg/day for 3 days followed by mefloquine 25 mg/kg is optimal for the treatment of uncomplicated falciparum malaria. There was no definite benefit from increasing the dosage of rectal artesunate from 10 to 20 mg/kg/day.