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| Author(s): |
Alex Akira Nakamura
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD) |
| Defense date: | 2008-08-28 |
| Examining board members: |
Marcelo Vasconcelos Meireles;
Sandra Mayumi Nishi;
Rodrigo Martins Soares
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| Advisor: | Marcelo Vasconcelos Meireles |
| Abstract | |
Cryptosporidiosis is considered a major protozoan infection in birds, and has been described in more than 30 species of birds of various orders, as Anseriformes, Charadriformes, Columbiformes, Galliformes, Passeriformes, Psitaciformes and Struthioniformes. Three species of Cryptosporidium are considered valid in birds: Cryptosporidium baileyi, Cryptosporidium galli and Cryptosporidium meleagridis. Besides these species, there are several genotypes genetically distinct from the species of Cryptosporidium described in birds, as avian genotypes I, II, III and IV. There are several reports of gastrointestinal, respiratory and bursa of Fabricius infections in birds, resulting in major economic losses and mortality. The aim of this study was the detection and molecular characterization of Cryptosporidium spp. in fecal samples of domestic birds and in exotic birds kept in captivity in Brazil. A total of 966 samples from 18 families of birds were collected and stored in 2.5% potassium dichromate solution at 4º C until processing. Oocysts were purified in Sheather sugar solution following microscopic analyses, in 463 samples, by malachite green negative stain and extraction of genomic DNA of oocysts in samples positive by microscopy or, alternatively, DNA extraction was accomplished without previous microscopic analyses in another 503 samples. Molecular analyses were performed using n-PCR for amplification of fragments of the 18S subunit of rRNA gene and of the actin gene. It was observed amplification for Cryptosporidium DNA fragments in 47 (4.86%) samples. Sequencing of amplified fragments and phylogenetic analyses allowed the identification of the three species that infect birds: C. galli in canaries (Serinus canaria), domestic chicken (Gallus gallus domesticus) and calopsita (Nymphicus hollandicus), C. meleagridis and C. baileyi in domestic chicken (G. g. domesticus), Cryptosporidium avian genotype I in peacock (Pavo cristatus) and canary (Serinus canaria), Cryptosporidium avian genotype III in agapornis (Agapornis roseicolis) and cockatiel (N. hollandicus), and Cryptosporidium avian genotype II in ostriches (Struthio camelus). (AU) | |