Discussion
We report the second case of human cryptococcosis
in which a genetically indistinguishable C. neoformans
isolate was recovered from excreta of a bird in
the patient’s environment. The isolate recovered
from the excreta of the magpie and the isolate from
the patient’s CSF were shown to be identical by ID
32C identification and karyotyping. Similarity with
AFLP analysis was 99.2%. Clinical isolates of
C. neoformans exhibit great variation in chromosome
number and size [12]. The high frequency of
chromosome differences between strains makes
electrophoretic karyotyping a highly discriminatory
technique for distinguishing amongst isolates
[8]. AFLP is a genotyping method with a high
discriminative power and reproducibility [9]. The
available data strongly suggest that the magpie
excreta were a reservoir for the strain of C. neoformans
that infected the patient. However, we cannot
exclude the possibility that both patient and the bird
excreta were infected by an undetermined third
source, although we consider this option less likely
than transfer from the bird to the patient.
Except for some rare cases of primary cutaneous
cryptococcosis, the infection is thought to result
initially from inhalation of airborne fungi from an
environmental source. Our case illustrates that
prolonged contact with birds may not be required
for exposure to C. neoformans. The magpie was not
let out of its cage and the patient was not involved
in cleaning the cage. Our patient’s contact with the
bird was limited to passing by the cage when
entering home. Staib [13] showed that C. neoformans
can be isolated from the ambient air near
caged birds. This has to be kept in mind when
asking patients for environmental exposure to
birds. A thorough anamnesis aimed at the identification
of bird contact (and not only handling of
birds or cleaning bird cages) is indicated when a
clinician is confronted with a patient with cryptococcosis.