Sources said fire spread from the burning forests to the east Mizoram district.
The latest victim was a 15-year-old boy killed near Mizoram-Myanmar border of Melnuk village in Champhai district, about 80 km from here, on Saturday.
The police said Seilianthanga was burnt alive while trying to douse the fire.
A vast area of forest being protected by Young Mizo Association (YMA) near Bungchawm village in Serchhip district was also devastated by the fire raging for the past two days.