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Epidemiology and diagnosis of microsporidia in psittacine birds
Abstract
Microsporidia are single-celled, obligate intercellular parasites with a wide host range covering most invertebrate phyla and all five classes of vertebrates. Numerous reports have implicated Encephalitozoon hellem, a microsporidia organism first described in humans, as the causative agent of severe disease in immunocompromised patients. Enc. hellem has been recently identified in psittacine bird hosts using histolytic and molecular methods. This study was designed to initiate the investigation of microsporidial infection in a variety of asymptomatic psittacine birds, especially lovebirds. Cloacal smears and droppings were examined for the presence of spores using calcofluor white M2R stain as the primary screening technique. Indirect immunofluorescent assay (IFA) using polyclonal antiserum to Encephalitozoon hellem was used to confirm positive and seceded age and species matched negative slides based on the calcofluor staining results. A total of 198 clinically normal lovebirds were surveyed including peach-faced (Agapornis roseicollis) lovebirds (113), masked (A. personata) lovebirds (32), and Fischer's (A. fischeri) lovebirds (53). Since Psittacine Beak and Feather Disease Virus (PBFDV) is possibly an immunosuppressive virus, 111 lovebirds were tested by the polymerase chain reaction (PCR) for virus at an independent commercial laboratory. Previously unreported exciting new data about subclinical microsporidial infections in avian hosts have been generated from this study including: (1) adaptation of methods from the medical literature for veterinary diagnostic use; (2) comparison of diagnostic methods for deletion of parasite spores; (3) calculation of the point prevalence of microsporidial spore shedding in three species of asymptomatic lovebirds and in lovebird flocks; (4) correlation of microsporidial shedding by lovebird species; (5) correlation of microsporidial shedding by lovebird age; and, (6) correlation of microsporidial spore shedding with PBFDV inferiors. These data indicate that microsporidial infections are currently under-diagnosed in healthy psittacine birds. Further investigation will determine if birds serve as a reservoir for zoonotic transmission of Enc. hellem.
Description
Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references (leaves 67-73).
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Citation
Barton, Casey Elizabeth (1999). Epidemiology and diagnosis of microsporidia in psittacine birds. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1999 -THESIS -B373.
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