Slight dengue?

She received a text message that her brother has slight dengue. Is there such things as slight dengue? There has been numerous dengue cases in the Philippines and lives have been taken. She got worried and called her brother. They were able to talk and found out that her brother can still go to school as he did not want to miss any classes. What a studious boy. Her heart was sort of broken. If only she could give much and really take care of him but their mother will not allow it. Long story that you might not understand... Anyways, get well soon, brother.