Clara Louise Maass was a nurse who
contributed to the research on yellow fever
at the turn of the century. She was working
as a civilian nurse in Cuba, where army
Majors William Gorgas and Walter Reed were
conducting experiments to isolate the causeof the disease. Tests ruled out dirt and poor
sanitation as causes of yellow fever, and a
mosquito was the suspected carrier. Clara was
among the group who volunteered to be bitten
by the insect. She contracted the disease and
died on August 24, 1901. She was the only
woman to participate in the experiment and
among the few volunteers to die from it. With
her death, the study ended; the results of
the experiment provided conclusive evidence
that mosquitoes were the source of the
disease.