Surveyors were taken hostage in Yemen, accused of being representatives of Dracula in Papua New Guinea, worked in sandstorms and temperatures of 50 degrees Celsius in Ethiopia.
It was all part of the day's work for some of the thousands of people who have completed what the organizers say is the largest ever survey of an infectious disease, examining 2.6 million people in 29 countries for the eye infection trachoma.
"They faced tribal warfare and rogue villagers in Papua New Guinea who spread a rumor that the teams were vampires," said Anthony Solomon, chief scientist of the Global Trachoma Mapping Project (GTMP).