Lr. Castanonolivares et R. Lopezmartinez, ISOLATION OF CRYPTOCOCCUS-NEOFORMANS FROM PIGEON (COLUMBA-LIVIA) DROPPINGS IN MEXICO-CITY, Mycoses, 37(9-10), 1994, pp. 325-327
To determine the ecological and epidemiological significance of pigeon
excrement in cryptococcosis in Mexico City, 251 samples of pigeon dro
ppings were studied. These were collected from houses, public building
s, churches, parks and pigeon nests. Each sample was suspended 1:10 in
isotonic saline solution and then cultured in Staib medium. Identific
ation of Cryptococcus neoformans was performed based on the developmen
t of brown-coloured colonies and the presence of encapsulated yeasts.
Of 251 samples, 52 (20.7%) were positive for Cr. neoformans. The highe
st frequency was observed in droppings from public buildings (31.2%),
followed by churches (22.0%) and houses (13.3%). No significant differ
ences in isolation frequency were observed between fresh or dried excr
ement. All isolates obtained were Cr. neoformans var. neoformans. As i
n other studies on Cr. neoformans from pigeons, performed in other cou
ntries, these frequency data are considered 'normal'. The results, how
ever, accentuate the potential risk of cryptococcosis acquisition, esp
ecially now that cryptococcosis frequency is increasing in Mexico, mai
nly in AIDS patients.