Yeasts and yeast-like fungi
Public Health Significance of Urban Pests
Birds
255 254
thropic wild avian samples from excretions, the intestinal tract and other organs: Candida guilliermondii
, Candida krusei, Candida tropicalis, Candida pseudotropicalis and Candida parapsilosis
Frágner, 1962; Kawakita van Uden, 1965; Schönborn, Schütze Pöhler, 1969; Cragg Clayton, 1971; Kocan Hasenclever, 1972; Monga, 1972; Gugnani,
Sandhu Shome, 1976; Guiguen, Boisseau-Lebreuill Couprie, 1986; Pinowski, Kavanagh Górski, 1991; Hubálek, 1994; Haag-Wackernagel Moch, 2004. An outb-
reak of peritonitis due to C. parapsilosis in 12 patients undergoing peritoneal dialysis was attributed to contaminated pigeon excreta on window sills Greaves et al., 1992.
8.2.3.1.2. Crypotococcus Avian especially feral pigeon excretions represent a significant natural source of crypto-
coccosis in people. The first isolation of C. neoformans its teleomorph stage is Filobasidiella neoformans
, a basidomycetous yeast from the nests and droppings of feral pigeons Emmons, 1955, 1960 was followed by a number of similar reports worldwide Yamamoto,
Ishida Sato, 1957; Littman Schneierson, 1959; Frágner, 1962; Tsubura, 1962; Bergman, 1963; Muchmore et al., 1963; Silva Paula, 1963; Frey Durie, 1964; Partridge Winner,
1965; Procknow et al., 1965; Randhawa, Clayton Riddell, 1965; Taylor Duangmani, 1968; Hubálek, 1975; Gugnani, Sandhu Shome, 1976; Refai et al., 1983; Ruiz, Vélez
Fromtling, 1989; Yildiran et al., 1998; Haag-Wackernagel Moch, 2004; Chee Lee, 2005. The association between C. neoformans var. grubii formerly C. neoformansserotype A and
the feral pigeon is remarkable Denton Di Salvo, 1968, whereas the occurrence of the fungus in faeces of other wild bird species is surprisingly scarce. As many as a hundred
thousand to a million viable C. neoformans cells have been detected per gram of pigeon exc- reta in different parts of the world Emmons, 1960; Hubálek, 1975; Ruiz, Fromtling
Bulmer, 1981; Ruiz, Neilson Bulmer, 1982; Ruiz, Vélez Fromtling, 1989.
This association was shown to be conditioned nutritionally, due to the ability of the yeast- like organism to utilize all basic low-molecular-weight nitrogenous substances from avian
urine – that is, uric acid, creatinine, xanthine, guanine and urea – and due to the tena- city of the causative agent, C. neoformansStaib, 1962, 1963; Walter Yee, 1968; Hubálek,
1975; Ruiz, Neilson Bulmer, 1982. The birds pigeons serve therefore largely as a les- sor Hubálek, Juˇricová Halouzka, 1995 for the fungus. However, carriage of the fun-
gus has also been proved by isolating it from the feet and bills of feral pigeons Littman Borok, 1968 or from their lower and upper digestive tracts Sethi Randhawa, 1968;
Swinne-Desgain, 1976; Khan et al., 1978; Guiguen, Boisseau-Lebreuill Couprie, 1986; Rosario et al., 2005. In an experiment, pigeons with C. neoformans administered into the
crop excreted the fungus sporadically in faeces up to 22 days, but harboured it for at least 86 days in the crop Swinne-Desgain, 1976; this study demonstrated that pigeons could
carry the fungus in their upper digestive tract. Spontaneous natural cryptococcosis has only rarely been observed in feral columbiforms Hermoso de Mendoza et al., 1984. The
course of experimental avian infections is usually abortive; only intracerebral inoculation was sufficient to cause death in some pigeons; the agent persisted in the brain for up to
11 weeks Littman, Borok Dalton, 1965; Böhm et al., 1974. The low susceptibility of birds to cryptococcosis may be due to the poor or nil growth of the fungus at 41°C – that
is, at the avian body temperature. Mycobacterium avium
was also isolated from a collared dove Volner, 1978; in experi- ments, this dove species was found to be much less susceptible than the chickens, but
could be a potential carrier of the infectious agent Rossi, 1969; Hejlíˇcek Treml, 1993b. Mycobacteria, including M. avium-intracellulare complex, were detected in 19 of 153
faecal samples of feral pigeons collected in Japan Tanaka et al., 2005. However, biolo- gical and molecular typing sometimes even nucleotide sequencing of M. avium strains
from free-living birds seems to be necessary for a proper epidemiological evaluation of the birds as sources of human infections – that is, to compare the avian and clinical human
isolates closely and to detect whether they are identical or not Schaeffer et al., 1973; McFadden et al., 1992. Also, there are a few unconfirmed, anecdotal cases of M. avium
clinical infections of people ornithologists who collected and examined urban owl and raptor pellets.
Mycobacterium xenopi was occasionally found to cause human disease – for example, a
nosocomial outbreak in Le Havre, France, where 558 cases were diagnosed for the per- iod 1965–1967; free-living birds were the probable source of the outbreak, and the cau-
sative agent was isolated from droppings of local tree sparrows and common blackbirds Joubert, Desbordes-Lize Viallier, 1971. Other mycobacteria potentially pathogenic to
people M. avium-intracellulare, M. aquae, M. flavescens and M. fortuitum were isolated from rooks Kubín Matˇejka, 1967, anatids Schaefer et al., 1973, gulls and jackdaws
with necrosis in the liver and spleen Smit et al., 1987.