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Isolation of Lumpy skin disease virus form naturally infected cattle previously vaccinated with live attenuated sheep poxvirus vaccine
2007
S. M. Tamam
Lumpy skin disease virus (LSDV) was isolated, from naturally infected cattle that have a history of previous vaccination with live attenuated sheep pox virus (SPV) vaccine. The virus was isolated on chorio-allantoic membrane (CAM) of specific pathogen free (SPF) embryonated chicken eggs (ECE) and identified by agar gel precipitation test (AGPT) and neutralization test using specific hyperimmune serum against LSDV and SPV. Characteristic intracytoplasmic inclusion bodies was detected in trypsenized cell of infected CAM stained with H&E. Laboratory studies for characterization of isolated LSDV revealed that it was stable at a wide range of pH, but it was inactivated by exposure to 56 0C for 15 minutes. Treatment of isolated LSDV with lipid solvents (20% ethyle ether and chloroform) reduced the virus titer 3.2 and 4.4 log respectively after 24 hrs at 4 0C .On cross neutralization testcomplete neutralization of isolated LSDV was obtained with both reference LSDV and SPV antisera. Cattle vaccinated with live attenuated SPV vaccine under experimental condition found to be protected against natural field infection with LSDV.
Show more [+] Less [-]Characterization of Variant Strain of Newcastle Disease Virus in Egypt
2007
A. S. Abdel-Moneim | Azza A. El-Sawah | M. A. Kandil
During 2005, velogenic Newcastle disease virus (NDV) caused a major outbreak among commercial broiler chicken in Egypt. The outbreak raised concerns regarding the protective immunity of commercially available vaccines for prevention and control of this virus in poultry. The virus was isolated from broiler farm suffered from more than 95% mortalities. The isolate was confirmed not to be avian influenza virus (AIV) by rapid chromatographic strip test, and characterized as NDV using reverse transcription-polymerase chain reaction (RT-PCR) which amplified a portion of the fusion gene of NDV and haemagglutination inhibition (HI) test. This isolate confirmed to be velogenic viscerotropic NDV by mean death time (MDT) test and pathogenicity to 7-week old chickens. We tried to determine whether the existing commercial live NDV La Sota vaccine could provide protection against the isolated virus or not. Birds received a single dose of live La Sota type vaccine at 3 weeks of age and were challenged 2 weeks postvaccination with a lethal dose of NDV. Results indicated that the live vaccine did not protect against morbidity but reduced mortality in comparison to controls. All unvaccinated control chickens challenged with NDV died within 5 days post-challenge (pc). Protection from disease did not correlate with the presence of antibody titers (determined by HI) at day of challenge. These results underscore the need to develop new NDV vaccines and vaccine strategies for use during outbreak situations to protect birds from both disease and infection and to reduce virus shedding.
Show more [+] Less [-]Determination of electrophoretic pattern of infectious bovine rhinotrachities virus of cattle
2007
Hanan, A. Fahmy | Omayma, M. El Desawy
A total number of 80 nasal swabs collected from apparently normal cattle slaughtered in Basateen abattoir were screened for the presence of infectious bovine rhinotracheitis virus. Among 80 examined samples, 4 samples found positive after the 3rd passage on MDBK cell line with appearance of the specific cytopathic effect (grape like clusters). The isolated virus titers were 103.9, 104.2, 105, 105.6 TCID50 / 0.1 ml. The four positive isolates were identified by agar gel precipitation test (AGPT), virus neutralization test (VNT) and gave the intracytoplasmic granules by indirect fluorescent antibody technique (IFAT). Electrophoretic profile of IBR in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was described and visualized by Coomassie blue stain. The mobilities of electrophoretic bands were determined with molecular weight marker at approximate range from 206.39 to 22.14 kDa.
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