A total of 430 avian-derived fecal specimens were randomly collected from selected Western Australian commercial aviaries, poultry farms, hatcheries, wildlife parks, and the Perth Zoo and screened for the presence of Cryptosporidium by PCR. Of these, 27 Cryptosporidium-positive isolates were detected, characterized, and compared with 11 avian-derived isolates from the Czech Republic at the 18S rRNA and actin gene loci. Sequence and phylogenetic analysis identified four genetically distinct genotypes, avian genotypes I to IV, from various avian hosts. In addition, the host range for Cryptosporidium galli was extended. Cryptosporidium muris and Cryptosporidium andersoni were also identified in a tawny frogmouth and a quail-crested wood partridge, respectively.Cryptosporidiosis is one of the most prevalent parasitic infections in domesticated, caged, and wild birds (33), and the parasite has been reported in more than 30 avian species worldwide, belonging to orders Anseriformes, Charadriiformes, Columbiformes, Galliformes, Passeriformes, Psittaciformes, and Struthiniformes (5,6,9,10,13,14,15,16,17,20,22,23,28,31,32,35,38,39). However, few studies have examined the genetic diversity of Cryptosporidium sp. among avian hosts.There are currently three accepted avian species of Cryptosporidium, C. baileyi, C. meleagridis, and C. galli, based on biological and genetic differences (3,24,25,26,29). Of these, only C. meleagridis is known to infect humans (37). Recent studies have identified six novel avian genotypes: goose genotypes I and II, the duck genotype, two unnamed genotypes in Canada geese (Branta canadensis) (9, 39), and the Eurasian woodcock (Scolopax rusticola) genotype (30). In addition to the host-specific avian genotypes identified, C. hominis and C. parvum were also identified in Canada geese (39). However, this was thought to be due to mechanical transmission (8,39).These studies indicate that the extent of genetic diversity among avian-derived Cryptosporidium isolates is greater than previously thought and that this warrants further investigation. The high prevalence of Cryptosporidium in domesticated, caged, and wild birds potentially represents a risk to humans (e.g., pet owners and poultry farmers) and other mammals that become infected with the parasite. The purpose of this study was to examine the prevalence and host range of Cryptosporidium species and genotypes among caged, domesticated, and wild birds and to determine if they are potential reservoirs of human-infectious species of Cryptosporidium.
MATERIALS AND METHODSFecal sample collection and DNA extraction. A total of 430 fresh fecal samples of various avian host species were randomly collected from March 2004 to December 2004 at selected commercial aviaries, poultry farms, hatcheries, wildlife parks, and the Perth Zoo. All samples were collected into individual 250-ml fecal collection pots and stored at 4°C until required. An additional 11 avianderived fecal specimens from the Czech Republic that were positive by microscopy for Cryptosporidium...
