Mary Mallon, known as "Typhoid Mary," was immune to the typhoid she carried. Working as a cook, she spread the disease in New York and ended up quarantined on Brother Island (above) for more than two decades.
Kenyan health officials take the temperatures of passengers arriving at the Nairobi airport on Thursday. Kenya has no reported cases of Ebola, but it's a transportation hub and so is on alert.
Simon Maina/AFP/Getty Images