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'€™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'€™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.

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'€™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'€™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.

As aves podem carregar um grande número de patógenos. As aves migratórias, por viajarem longas distâncias, são as principais responsáveis pela disseminação de agentes infecciosos. Entre os agentes, destacam-se os vírus, como por exemplo o retrovírus da Reticuloendoteliose aviária (REV), amplamente distribuído; e o vírus da febre do Oeste do Nilo (WNV), uma virose reemergente, com caráter zoonótico. Os principais sintomas da Reticuloendoteliose aviária incluem anemia, doença de Runting e síndrome não neoplásica aguda. Já o agente etiológico da Febre do Nilo Ocidental, é o Flavivirus West Nile (WNV).. As aves são seus hospedeiros definitivos e os humanos são hospedeiros acidentais, podendo manifestar quadro febril, e em menor porcentagem, meningite e encefalite. Mosquitos dos gêneros Culex e Aedes spp são os principais transmissores do vírus. Ao contrário do REV que não dispõe de evidências de sua circulação no Brasil, há evidências do WNV em aves e equinos e mais recentemente, em humanos. O objetivo desse trabalho foi investigar a presença do REV e do WNV em aves silvestres e de cativeiro da cidade de São Paulo e do Norte do estado do Pará. Sangue, soro e swab de cloaca foram coletados, totalizando mais de 1000 amostras. Através de técnicas moleculares foi possível detectar a presença do REV em 74 amostras (16%), todas do estado do Pará. O sequenciamento parcial dessas amostras e sua filogenia sugeriu que a migração de aves EUA-Brasil possa ter sido a rota utilizada. Através de ELISA anti-IgG de WNV, 4 amostras de São Paulo foram positivas. Apresentamos a primeira evidência do REV no país e sugerimos a presença do WNV no estado de São Paulo. / Birds can carry a large number of pathogens. The migratory birds are most responsible for the spread of infectious agents due to long distance travels. Among these pathogens, the most notable are viruses, such as the avian Reticuloendotheliosis retrovirus (REV), widely distributed; and the West Nile virus (WNV), a reemerging zoonotic disease. The main symptoms of avian reticuloendotheliosis include anemia, Runting\'s disease and acute nonneoplastic syndrome. The etiological agent of West Nile fever is Flavivirus West Nile (WNV). Birds are their definitive hosts and humans are accidental hosts, which generaly present febrile symptoms, but at less proportion,, meningitis and encephalitis. Mosquitoes of the genus Culex and Aedes spp are the main vectors of the virus. Differently from the REV that has no evidence of its circulation in Brazil, there is evidence of WNV in birds and horses and more recently in humans. The objective of this work was to investigate the presence of REV and WNV in wild birds and captive birds from the city of São Paulo and Northern from Pará State. Blood, serum and cloacal swab were collected, resulting in more than 1000 samples. Through molecular techniques it was possible to detect the presence of REV in 74 samples (16%), all from the State of Pará. The partial sequencing of these samples and their phylogeny suggested that the migration of US-Brazil may have been the route for the virus entry. Through anti-WNV IgG ELISA, 4 samples from São Paulo were positive. We present the first evidence of REV in the country and suggest the presence of WNV in the state of São Paulo.

As aves podem carregar um grande número de patógenos. As aves migratórias, por viajarem longas distâncias, são as principais responsáveis pela disseminação de agentes infecciosos. Entre os agentes, destacam-se os vírus, como por exemplo o retrovírus da Reticuloendoteliose aviária (REV), amplamente distribuído; e o vírus da febre do Oeste do Nilo (WNV), uma virose reemergente, com caráter zoonótico. Os principais sintomas da Reticuloendoteliose aviária incluem anemia, doença de Runting e síndrome não neoplásica aguda. Já o agente etiológico da Febre do Nilo Ocidental, é o Flavivirus West Nile (WNV).. As aves são seus hospedeiros definitivos e os humanos são hospedeiros acidentais, podendo manifestar quadro febril, e em menor porcentagem, meningite e encefalite. Mosquitos dos gêneros Culex e Aedes spp são os principais transmissores do vírus. Ao contrário do REV que não dispõe de evidências de sua circulação no Brasil, há evidências do WNV em aves e equinos e mais recentemente, em humanos. O objetivo desse trabalho foi investigar a presença do REV e do WNV em aves silvestres e de cativeiro da cidade de São Paulo e do Norte do estado do Pará. Sangue, soro e swab de cloaca foram coletados, totalizando mais de 1000 amostras. Através de técnicas moleculares foi possível detectar a presença do REV em 74 amostras (16%), todas do estado do Pará. O sequenciamento parcial dessas amostras e sua filogenia sugeriu que a migração de aves EUA-Brasil possa ter sido a rota utilizada. Através de ELISA anti-IgG de WNV, 4 amostras de São Paulo foram positivas. Apresentamos a primeira evidência do REV no país e sugerimos a presença do WNV no estado de São Paulo. / Birds can carry a large number of pathogens. The migratory birds are most responsible for the spread of infectious agents due to long distance travels. Among these pathogens, the most notable are viruses, such as the avian Reticuloendotheliosis retrovirus (REV), widely distributed; and the West Nile virus (WNV), a reemerging zoonotic disease. The main symptoms of avian reticuloendotheliosis include anemia, Runting\'s disease and acute nonneoplastic syndrome. The etiological agent of West Nile fever is Flavivirus West Nile (WNV). Birds are their definitive hosts and humans are accidental hosts, which generaly present febrile symptoms, but at less proportion,, meningitis and encephalitis. Mosquitoes of the genus Culex and Aedes spp are the main vectors of the virus. Differently from the REV that has no evidence of its circulation in Brazil, there is evidence of WNV in birds and horses and more recently in humans. The objective of this work was to investigate the presence of REV and WNV in wild birds and captive birds from the city of São Paulo and Northern from Pará State. Blood, serum and cloacal swab were collected, resulting in more than 1000 samples. Through molecular techniques it was possible to detect the presence of REV in 74 samples (16%), all from the State of Pará. The partial sequencing of these samples and their phylogeny suggested that the migration of US-Brazil may have been the route for the virus entry. Through anti-WNV IgG ELISA, 4 samples from São Paulo were positive. We present the first evidence of REV in the country and suggest the presence of WNV in the state of São Paulo.