Evaluation of a blocking ELISA using a urease conjugate for the detection of antibodies to pseudorabies virus

A blocking enzyme-linked immunosorbent assay (ELISA) using a urease conjugate (U-B-ELISA) was evaluated for screening sera for antibodies to pseudorabies virus under field conditions, A total of 764 serum samples were analyzed by U-B-ELISA. Of these, 264 were evaluated by both virus neutralization and U-B-ELISA, and the results were compared. U-B-ELISA showed 98.5% and 98.9% sensitivity and specificity, respectively. This test combines the sensitivity and specificity of the blocking ELISA format while allowing visual assessment of results.Facultad de Ciencias Veterinaria

Enfermedad de Marek : II - Reproducción experimental de la enfermedad

Se realizaron con éxito investigaciones tendientes a reproducir experimentalmente la Enfermedad de Marek de las aves. Se obtuvieron 10 aislamientos caracterizados como virus Herpes, a partir de material extraído de planteles comerciales con diagnóstico patológico de Enfermedad de Marek y provenientes de diferentes puntos geográficos del país. En todos los casos el agente aislado demostró una estrecha asociación celular y la reproducción de la enfermedad se logró fácilmente con preparaciones celulares infectadas. De dos de los aislamientos, FCV-5 y FCV~6 se obtuvo virus libre de elementos celulares, reproduciendo la enfermedad en aves y reaislando al agente en cultivos celulares. En ambos casos el agente pasó previo a la inoculación por filtros de 450 nm de diámetro de poro, pero fue retenido por filtros de 100 nm de diámetro.Through several experiments, MD was successfully transmitted and experimental reproduction achieved. Virus was isolated from 10 different field outbreaks and maintained in cell cultures. in all cases MD infectivity for chickens was highly cell associated and the propagation of the isolated agent to chicks accomplished when cells were present in the inoculum. From two isolates, FCV-5 and FCV~6 cell~free virus was obtained from feather follicle and MD successfully reproduced. The agent was not retained by 450 nm. membrane filters but no infectivity was recovered after filtration through 100 nm filters.Facultad de Ciencias Veterinaria

Enfermedad de Marek : II - Reproducción experimental de la enfermedad

Se realizaron con éxito investigaciones tendientes a reproducir experimentalmente la Enfermedad de Marek de las aves. Se obtuvieron 10 aislamientos caracterizados como virus Herpes, a partir de material extraído de planteles comerciales con diagnóstico patológico de Enfermedad de Marek y provenientes de diferentes puntos geográficos del país. En todos los casos el agente aislado demostró una estrecha asociación celular y la reproducción de la enfermedad se logró fácilmente con preparaciones celulares infectadas. De dos de los aislamientos, FCV-5 y FCV~6 se obtuvo virus libre de elementos celulares, reproduciendo la enfermedad en aves y reaislando al agente en cultivos celulares. En ambos casos el agente pasó previo a la inoculación por filtros de 450 nm de diámetro de poro, pero fue retenido por filtros de 100 nm de diámetro.Through several experiments, MD was successfully transmitted and experimental reproduction achieved. Virus was isolated from 10 different field outbreaks and maintained in cell cultures. in all cases MD infectivity for chickens was highly cell associated and the propagation of the isolated agent to chicks accomplished when cells were present in the inoculum. From two isolates, FCV-5 and FCV~6 cell~free virus was obtained from feather follicle and MD successfully reproduced. The agent was not retained by 450 nm. membrane filters but no infectivity was recovered after filtration through 100 nm filters.Facultad de Ciencias Veterinaria

Evaluation of a blocking ELISA using a urease conjugate for the detection of antibodies to pseudorabies virus

A blocking enzyme-linked immunosorbent assay (ELISA) using a urease conjugate (U-B-ELISA) was evaluated for screening sera for antibodies to pseudorabies virus under field conditions, A total of 764 serum samples were analyzed by U-B-ELISA. Of these, 264 were evaluated by both virus neutralization and U-B-ELISA, and the results were compared. U-B-ELISA showed 98.5% and 98.9% sensitivity and specificity, respectively. This test combines the sensitivity and specificity of the blocking ELISA format while allowing visual assessment of results.Facultad de Ciencias Veterinaria

Herpesvirus bovinos 1 y 5

Los virus herpes bovino 1 y 5 (BHV-1 y 5) afectan naturalmente al bovino, especie en la que provocan diversas manifestaciones clínicas: rinotraqueítis, vulvovaginitis pustular infecciosa (IPV), balanopostitis (IPB), conjuntivitis, aborto y encefalitis. La distribución de la infección es mundial, con incidencias que varían de un país a otro. En los últimos años se han conformado importantes grupos de investigación y los conocimientos acerca de estos virus se han visto incrementados. El presente trabajo es una revisión que actualiza dichos conocimientos y señala aquellas líneas de investigación de relevancia en la actualidad.Bovine herpesvirus 1 and 5 (BHV-1 and 5) affect naturally to cattle, in which they cause a variety of clinical entities: rinotracheitis, infectious pustular vulvovaginitis (IPV), balanoposthitis (IPB), conjunctivitis, abortion and encephalitis. The distribution of the infection is worldwide, and the incidence vary from a country to another. Recently, it has been conformed important investigation groups around the world and the knowledge about these virus has been increased. The present work is a review that modernizes this knowledge and it points out those lines of investigation of relevance at the present time.Facultad de Ciencias Veterinaria

Herpesvirus bovinos 1 y 5

Los virus herpes bovino 1 y 5 (BHV-1 y 5) afectan naturalmente al bovino, especie en la que provocan diversas manifestaciones clínicas: rinotraqueítis, vulvovaginitis pustular infecciosa (IPV), balanopostitis (IPB), conjuntivitis, aborto y encefalitis. La distribución de la infección es mundial, con incidencias que varían de un país a otro. En los últimos años se han conformado importantes grupos de investigación y los conocimientos acerca de estos virus se han visto incrementados. El presente trabajo es una revisión que actualiza dichos conocimientos y señala aquellas líneas de investigación de relevancia en la actualidad.Bovine herpesvirus 1 and 5 (BHV-1 and 5) affect naturally to cattle, in which they cause a variety of clinical entities: rinotracheitis, infectious pustular vulvovaginitis (IPV), balanoposthitis (IPB), conjunctivitis, abortion and encephalitis. The distribution of the infection is worldwide, and the incidence vary from a country to another. Recently, it has been conformed important investigation groups around the world and the knowledge about these virus has been increased. The present work is a review that modernizes this knowledge and it points out those lines of investigation of relevance at the present time.Facultad de Ciencias Veterinaria

Virus herpes equino tipo 1 (EHV-1): patrones de restricción de ADN, perfiles proteicos y estudio de patogenicidad en ratones

Se estudiaron siete cepas de herpesvirus equino 1 (EHV-1) aisladas en Argentina desde 1979 hasta 1996 y una cepa de referencia japonesa, analizándose los patrones de restricción del ADN, perfiles proteicos en geles de poliacrilamida (SDS-PAGE) y los biotipos, para determinar posibles diferencias entre las mismas y su correlación con la patogenicidad en el ratón. El análisis genómico con enzimas de restricción demostró que todas las cepas pertenecen al tipo 1P de EHV-1. Sólo el primer aislamiento realizado en el país (cepa SP) mostró diferencias en su patrón de restricción del ADN. Esta cepa y la cepa aislada en el año 1985 (cepa LP) presentaron además diferencias en sus perfiles proteicos. El estudio de patogenicidad en ratones indicó la presencia de tres biotipos, no encontrándose correlación con las variaciones halladas en los electroferotipos y con la sintomatología clínica en el equino.Seven strains of equine herpesvirus 1 (EHV-1) isolated in Argentina from 1979 to 1996 and reference Japanese strain, were compared by restriction fragments analysis (RFA), polyacrylamide gel electrophoresis (SDS-PAGE) and inoculation of baby mice. The RFA revealed that all EHV-1 strains belonged to genome type 1P. Only the first isolate (SP strain) showed differences. This strain and the LP strain isolated in 1985 presented a small differences for SDS-PAGE analysis. Baby mice inoculation revealed that three biotypes could be distinguished on the basis of pathogenicity. However, no strict correlation with pathogenicity in the natural host was seen

A rapid and sensitive diagnosis of bovine leukaemia virus infection using the nested shuttle polymerase chain reaction

Bovine leukaemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). In Argentina, where a program to eradicate EBL has been introduced, sensitive and reliable diagnosis has attained high priority. Although the importance of the agar gel immunodiffusion test remains unchanged for routine work, an additional diagnostic technique is necessary to confirm cases of sera with equivocal results or of calves carrying maternal antibodies. Utilizing a nested shuttle polymerase chain reaction, the proviral DNA was detected from cows experimentally infected with as little as 5 ml of whole blood from BLV seropositive cows that were nonetheless normal in haematological terms. It proved to be a very sensitive technique, since it rapidly revealed the presence of the provirus, frequently at 2 weeks postinoculation and using a two-round procedure of nested PCR taking only 3 hours. Additionally, the primers used flanked a portion of the viral genome often employed to differentiate BLV type applying BamHI digestion. It is concluded that this method might offer a highly promising diagnostic tool for BLV infection.Facultad de Ciencias Veterinaria

Isolation of a Newcastle virus strain of a remarkable pathogenicity in Argentina. 1 I.P.I. and thermostability index

Una cepa de virus de Enfermedad de Newcastle seleccionada entre varios aislamientos realizados durante la epizootia de 1970 en Argentina, fue probada a 37º~46º y 56ºC y a diferentes tiempos de exposición. La dosis letal 50% y las pruebas de hemoaglutinación fueron realizadas con el objeto de conocer el efecto de ambas variables (temperatura y tiempo) y comparados con controles sin tratar. Para determinar el índice de patogenicidad intracerebral, pollos de dos días de edad, fueron Inoculados con la cepa de Newcastle aislada, la que previamente fue tratada con una suspensión de células nerviosas de pollo.A Newcastle virus strain, selected after several isolating experiments which produced a Epizootia in Argentina, was tested at 37, 46 and 56ºC, at different exposition times. Letal embryo 50% and hemagglutination tests were conducted in order to know the effect of both variables (temperature and time), and compared with controls without treatment. To determine the intracerebral pathogenicity index, chickens of 2 days of age were inoculated with the isolated Newcastle strain which was previously treated with a suspension of chicken nervous cells.Facultad de Ciencias Veterinaria

Isolation of equine herpesvirus-2 from the lung of an aborted fetus

This study describes the isolation of equine herpesvirus-2 (EHV-2) from the lung of an aborted equine fetus in Argentina. The isolated virus was confirmed as EHV-2 by indirect immunofluorescence using a rabbit anti-EHV-2 polyclonal antiserum and by virus-neutralization test using an equine polyclonal antibody against EHV-2. Restriction endonuclease DNA fingerprinting with BamHI also confirmed the identity of the virus as EHV-2. Furthermore, viral nucleic acid was detected by polymerase chain reaction from the original lung sample and from the DNA obtained from cells infected with the virus isolate. This work constitutes the first reported isolation of EHV-2 from an aborted equine fetus. The presence of EHV-2 in the lung of the aborted fetus would indicate that this virus is capable of crossing the placental barrier. However, no cause-effect relationship was established between the EHV-2 isolate and the abortion.Facultad de Ciencias Veterinaria