Answer:
Dengue fever is a mosquito-borne tropical disease caused by the dengue virus. 
where did it occur ? in Asia, Africa, and North America 
how did they start ?It was restricted to Africa and Southeast Asia until the mid-20th century
how did it spread?spread through the bite of the female mosquito 
how deadly are they? is fatal in 2.5% of cases. If dengue hemorrhagic fever is not treated, mortality (death) rates can be as high as 20%-50%.
Step-by-step explanation: