Dengue diagnosis

Diagnosis of Dengue  can made from the following signs and symptoms

Fever
Presence of headache, pain behind the eyes
Body ache, mayalgia
Abdominal pain
Vomiting especially in kids
Bleeding of gums
Presence of petichiae ( these are reddish spots seen in the skin due to low platelet count)

Mode of transmission:
Transmitted by the bite of mosquito Ades aegypti
Lab test
Do a platelet count
Value less than 100000 is suggestive
Do a card test (immunochromatographic test) for NS1 antigen and  IgM and IgG antibodies
To confirm: Some lab have the facility of ELISA for the detection of IgM which is more specific.

Treatment
its mainly symptomatic with IV fluids
platelet transfusion in case of low platelet count (usually when < 20000)