Cryptococcus neoformans in the crops of pigeons following its experimental administration.

Cryptococcus neoformans (5 X 10(6) yeast cells) was given per os to 10 pigeons (Columba livia) proved to be free (crops and excreta) of C. neoformans prior to experimentation. The yeast was recovered from the droppings of 9 pigeons the day after ingestion but was still present in the droppings of 1 pigeon on the 22nd day after ingestion. The crop was much more constantly positive than the droppings and for a much longer time since positive in 9 pigeons on the first day it was still positive in 2 pigeons on the 86th day at the end of the observation period. The results of the experiment presented here and the results of previous work, indicate that C. neoformans can survive and could so be carried in the crop of pigeons.