Do you have customers or passengers traveling to Ecuador, Nicaragua and Bolivia after a trip to Brazil, Angola, Congo, or Uganda? 

Beware that since February 10, 2017, it is mandatory for travelers coming from those countries to being vaccinated from Yellow Fever, and the only way to prove it is through the International Vaccination Certificate of Yellow Fever. Remember them to bring it if this policy affects them. In that way, they can avoid any issue during the customs process in Ecuador, Nicaragua and Bolivia.