Nearly a week after a six-year-old died of dengue in Hyderabad, the death of a 13-year-old boy has sparked concern among parents in the city who are demanding better hygiene at schools and neighbourhoods. T John Elisha Winston, a student of Class 8, died on Saturday. His last rites were held today in the Sahebnagar area of the city. Last week, a 6-year-old, whose father and grandfather are both doctors, had died of dengue.