Diseases transmitted by mosquitos have increased tremendously in the last decade, Especially in developing nations. I am from India and we never used to hear about cases of Dengue or Chikungunya 10-15 years ago. Now its all too common. Looks like this is a similar disease, now with links to microcephaly. 
Dramatic increase in city populations, poor infrastructure result in increased mosquito breeding grounds 
These nations need to heavily invest in taking out disease carrying mosquitoes or situations like these are only going to increase.