Dear Bhasindu I am sorry to hear yourbaby got Dengu fever.Dengu fever is also known as breakbone fever. It is an infectious tropical desease caused by virus and is transmitted by mosquito bite. 4 to5 days after infection it starts with high fever , headache,jointache, muscleache, swollen lymph glands, vomiting,and a rash. There is no specific treatment only symtometics eg oral fluid for dehydration, paracetamol for pain and fever.most of the cases recover fully. Only very fwe cases can be dangers by turning into Dengue haemorrhagic fever due to low level of platelets. There is no vaccine available.

I am sorry to hear about your kid suffering from Dengue fever. Here are a few answers for your questions which can be of use for others also.
Dengue fever means what ?
Dengue fever is a viral fever caused by four closely related viruses. It is transmitted by bite of mosquitos. It presents as fever and rash in infants and young children. Bone pain, body pain, pain in eyes may not be present in young children. Any fever without other symptoms like cough, diarrhea etc can be potentially dengue.
What makes dengue more dangerous than other viral infections ?
Dengue just like other viruses causes fever. Fever doesn't last for more than five days. Danger remains during the immediate 48 hrs after fever settles. Platelets drops down, fluid seeps out from blood vessels resulting in decreased circulating volume, decreased urine output, edema of face and body, shock(decreased BP) and bleeding tendencies. But only a small fraction of children enter into such complications.
How can i solve dengue problems in 3 year old child?
There is no antivirals available for Dengue fever. But good supportive care is enough as most children recover without any complications. Plenty of fluids to be given orally to prevent dehydration, paracetamol for fever is the most important home based treatment.
Keeping in touch with doctor and following their advice is most important. They will check your platelets and hematocrit regularly till it recovers well. They will follow your child's health status periodically and give appropriate advice.
Vomiting, abdominal pain, decreased urine output, bleeding tendencies, poor intake, altered sensorium are some of the red flag signs which needs immediate hospitalisation.

Summary will be : Dengue is easy to prevent
Dengue is easy to treat if appropriate supportive care is given
Dengue is easy to deteriorate if left unattended.

Hope your child recovers well and the information was useful for others also.