Our friends at Quasar Nautica sent us this note recently.  Here it is, edited a  bit for CNH Tours readers:

There is currently a large epidemic of Yellow Fever in Angola, Africa. In order to try and limit the spread of this disease as much as possible, the Pan American Health Organization (the Americas branch of the World Health Organization) has requested many governments, including the Ecuadorean Government, to assist in the monitoring of the disease. This monitoring ONLY involves travelers that may be coming from Africa to Ecuador or travelers going to Africa from Ecuador.

Please note there is no Yellow Fever epidemic in Ecuador, but due to the situation in Angola, the immigration authorities in Ecuador will be requesting a certificate / proof of Yellow Fever Vaccination for ALL passengers entering Ecuador from any African country, even if passengers are just in transit through Africa on a connecting flight to South America. All travelers are recommended to consult individual country requirements by contacting the embassy of each country they intend to visit. It should be noted that some countries require proof of vaccination from all travelers.