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Description:
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Reticuloendotheliosis virus (REV ) is a retrovirus that causes a neoplastic disease in a wide range of avian hosts including chickens , turkeys , and ducks . In 1993 , REV was detected in the endangered Attwater's prairie chicken (Tympanachus cupido attwateri ) , a subspecies of Tympanachus cupido . Subsequent infections of this prairie chicken have been identified at captive breeding facilities throughout Texas . The implications of these infections have severely hindered repopulation efforts by these facilities . This study focused on investigating REV infection of captive Attwater'Ã Â Ã Â s prairie chicken in order to better understand the disease affecting these endangered birds . The overall objective was to develop a means of eliminating this threat to the repopulation of the Attwater's prairie chicken . Several aspects of virus infection were investigated . Reagents capable of recognizing prairie chicken IgY and viral gag polypeptides were developed for use in assays for detection of antibody responses and titration of viral concentrations . Sequencing data of genomes collected from isolates of Texas prairie chickens and domestic chickens , as well as three REV prototype viruses , were compared to determine relationships among strains and identify the potential origin of the REV infecting Attwater'Ã Â Ã Â s prairie chicken . Additionally , a flow cytometry technique of segregating the lymphocyte population from peripheral blood mononuclear cells (PBMC ) using a pan leukocyte monoclonal antibody was developed to more accurately measure changes within lymphocyte populations . This technique combined with intracellular labeling was used to deduce the target cells of REV infection . A nested polymerase chain reaction (PCR ) test was developed for greater sensitivity in detecting infection in birds than the previous method of single amplification PCR . This greater sensitivity results in earlier identification of the virus in infected birds , which allows for earlier removal of infected birds to minimize transmission of the virus throughout the flock . The sensitivity of the nested PCR diagnostic test was determined in a dose response pathogenesis study , which was conducted on hybrid greater /Attwater's prairie chicken to observe the experimental development of disease in these birds . Finally , a vaccine was developed using plasmid DNA with REV encoded genes and tested on naturally infected prairie chickens to determine its efficacy in reducing viral load . Although no reduction in viral load was detected , the vaccine may be effective in providing prophylactic protection in future studies . |