How frequently do outbreaks of severe dengue (dengue hemorrhagic fever) occur?
In Manila, 1953 the first outbreak of severe dengue, also known as, dengue hemoorhagic fever, was reported. The outbreaks of dengue became frequent over time. Some of the dengue outbreaks evolved into dengue hemorrhagic fever. Dengue hemorrhagic fever outbreaks were occasional but eventually, occured yearly. Currently, the pattern of outbreaks repeats after 3 years.