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Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2020-09-15T12:54:59Z No. of bitstreams: 1 1985 - T?nia Ros?ria Pereira Freitas.pdf: 527520 bytes, checksum: e8b03f1e29f8fed547ea88ea11a40245 (MD5) Made available in DSpace on 2020-09-15T12:54:59Z (GMT). No. of bitstreams: 1 1985 - T?nia Ros?ria Pereira Freitas.pdf: 527520 bytes, checksum: e8b03f1e29f8fed547ea88ea11a40245 (MD5) Previous issue date: 1985-09-23 Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq The objective of the present study was to evaluate the potencial of stable fly, Stomoxys calcitrans, as carrier and mechanical vector of bovine leukemia virus (BLV). In the first experiment, sheep inoculated subcutaneously with 5,6 x 105 to 2,1 x 106 viable leukocytes recovered from the midgut of S. calcitrans, developed antibody to the major glycoprotein gp51 of VLB within three months. Only one of sheep that became infected also developed antibody to the structural polypeptide p25, first detected 18 months after experimental inoculation. Two uninoculated sheep that were maintained in close contact with the infected sheep did not develop antibody to either of the VLB antigens, during the experimental period of 36 months, indicating a lack of horizontal transmission of BLV among the sheep. Persistent lymphocytosis was not observed in any of sheep during 20 month observation period. Only a few type-C viral particles were observed in the leukocyte culture from the peripheral blood of one infected sheep as evaluated by eletron microscopy. ln a second experiment, three of the five sheep inoculated with 2,3 x 104 to 8,8 x 105 viable leukocytes recovered from the mouthparts of S. calcitrans, XV became infected with BLV within four months. After experimental inoculation and developed antibody to gp51 that persisted for the 24 months duration of the experiment. Two uninoculated sheep reared together with the infected sheep did not develop antibody to BLV antigens. Persistante lymphocutosis was not observed in any of the infected sheep nor were type-C viral particles observed in leukocyte culture from the same sheep. In a third experiment, from 90 to 174 stable flies from a colony reared in laboratory were used in an attempt to demonstrate mechanical transmission of BLV from an antibody-positive cow to five BLVserologically-negative sheep. During challenging periods varying three to ten months, the sheep were bitten a minimun of 135 and a maximum of 155 times. None of the sheep developed antibody to BLV antigens during BLV periods of 30 months (3 sheep) and 36 months (3 sheep). Its conclued that S. calcitrans carries BLV infectivity in leukocytes contained in the midgut and mouthparts for indetermined period of time, however, its role as a mechanical vector of BLV has not yet been elucidated. O objetivo do presente trabalho foi o de avaliar a potencialidade da m?sca do est?bulo, Stomoxys calcitrans como portadora e veiculadora do v?rus da leucemia bovina (VLB). No primeiro experimento, ovinos inoculados pela via sub-cut?nea com 5,6 x 105 a 2,1 x 106 leuc?citos vi?veis recuperados do intestino m?dio de S. calcitrans apresentaram anticorpos para a glicoprote?na maior Gp51 do VLB, no m?ximo tr?s meses de experimenta??o. Apenas um ovino infectado desenvolveu anticorpos par o polipept?deo interno p25, ao 18? m?s de experimenta??o. Os dois ovinos utilizados como testemunhas, n?o inoculados, e mantidos em contato com os ovinos infectados, n?o desenvolveram anticorpos durante o per?odo experimental de 36 meses indicando a aus?ncia de transmiss?o horizontal do VLB entre os ovinos. N?o foi observado o desenvolvimento de linfocitose persistente durante o per?odo de observa??o de 20 meses. Poucas part?culas virais do tipo C forma observadas em culturas de leuc?citos de um ovino infectado quando observadas pela microscopia eletr?nica. No segundo experimento, tr?s dos cinco ovinos inoculados com 2,3 x 104 a 8,8 x 105 leuc?citos vi?veis recuperados do x i i i aparelho bucal de S. calcitrans se infectaram com o VLB em um m?ximo de quatro meses ap?s a inocula??o e desenvolverem anticorpos para GP51 que persistiu durante o per?odo experimental de 24 meses. Os dois ovinos n?o inoculados e mantidos em contato com os ovinos infectados, n?o desenvolveram anticorpos para o VLB. Linfocitose persistente n?o foi observada em nenhum dos ovinos infectados desse experimento, nem foram observadas part?culas virais do tipo C nas culturas de leuc?citos dos mesmos ovinos. No terceiro experimento, entre 90 a 174 m?scas criadas em laborat?rio foram utilizadas para tentar veicular mecanicamente o VLB de um bovino positivo para cinco ovinos sorologicamente negativos. Em per?odos de tr?s a dez meses, os ovinos foram expostos ? picadas de S. calcitrans em um m?nimo de 135 a um m?ximo de 555 vezes. Entretanto, nenhum dos ovinos desenvolveu anticorpos para ant?genos do VLB durante o per?odo de observa??o de 30 meses (3 ovinos) e 36 meses (2 ovinos). Concluiu-se que S. calcitrans ? um portador da infectividade do VLB nos leuc?citos contidos no intestino m?dio e no aparelho bucal por per?odos de tempo n?o determinados. Por?m o seu papel como veiculador mec?nico do VLB, ainda n?o foi elucidado