Comparative efficacy of different Carbopol concentrations as a stabilizer of live attenuated sheep pox virus vaccine against lumpy skin disease

In Egypt, the lyophilized live attenuated sheep pox virus vaccine has been used for the vaccination of cattle against lumpy skin disease virus to control its economic impact on livestock industry. In this endeavor, we validate the efficacy of Carbopol® as a stabilizer and adjuvant to enhance immunogenicity of such a heterologous sheep pox virus vaccine against lumpy skin disease. Lyophilization of sheep pox virus vaccine stabilized with Carbopol® produced better physical and antigenic properties than freeze-drying with lactalbumin/sucrose stabilizer; this was manifested by superior disc uniformity, thermo-stability at 37oC, and less reduction in virus titer. Immunization of calves' groups with variable sheep pox vaccine doses containing different Carbopol® concentrations revealed that 103.5 TCID50 of sheep pox virus vaccine enclosing 0.5 percent Carbopol® is the field dose of choice. Moreover, it induced protective serum neutralizing index of 2.5 and a ELISA S/P ratio of 36, by the 4th week post vaccination. Besides, the inclusion of 0.5 percent Carbopol® in formulation of the sheep pox virus vaccine was safe in bovines and enhanced cellular immune response to lumpy skin disease virus, as evidenced by increased T cell proliferation. Hence, it is recommended to use Carbopol® as 0.5 percent in preparation of live attenuated sheep pox virus vaccine to confer better protection against lumpy skin disease virus infection(AU)

En Egipto, la vacuna atenuada liofilizada contra el virus de la viruela ovina ha sido utilizado para la vacunación del ganado, contra el virus de la dermatosis nodular contagiosa, para controlar su impacto económico en la industria ganadera. En este trabajo, validamos la eficacia del Carbopol®, como estabilizador y adyuvante, para mejorar la inmunogenicidad de dicha vacuna heteróloga contra la dermatosis nodular contagiosa. La liofilización de la vacuna contra el virus de la viruela ovina estabilizada con Carbopol®, resultó en mejores propiedades físicas y antigénicas que la liofilización con el estabilizador de lactoalbúmina/sacarosa; lo anterior se manifestó en la uniformidad superior del disco, la termoestabilidad a 37°C y la menor reducción del título del virus. La inmunización de grupos de terneros con dosis variables de vacuna contra el virus de la viruela ovina, que contenían diferentes concentraciones de Carbopol®, reveló que la dosis de campo de elección fue 103,5 TCID50 de la vacuna contra el virus de la viruela ovina conteniendo 0,5 por ciento de Carbopol®, la que indujo un índice de neutralización sérica protectora de 2,5 y una relación S/P de ELISA de 36 a la cuarta semana después de la vacunación. Además, la inclusión de Carbopol® al 0,5 por ciento en la formulación de la vacuna contra el virus de la viruela ovina fue segura en los bovinos y potenció la respuesta inmunitaria celular contra el virus de la dermatosis nodular contagiosa, como lo demuestra el aumento de la proliferación de células T. Por lo tanto, se recomienda el uso de Carbopol® al 0,5 por ciento en la preparación de la vacuna viva atenuada contra el virus de la viruela ovina para conferir una mejor protección contra la infección por el virus de la dermatosis nodular contagiosa(AU)

Polymerase chain reaction for rapid diagnosis of a recent lumpy skin disease virus incursion to Egypt

In early 2006, a lumpy skin disease [LSD] outbreak has invaded cattle in different localities of Egypt, exerting severe economic losses to livestock industry. Representative specimens [skin biopsies] were collected form nodular skin lesions of infected foreign [imported from Ethiopia, at Ismailia private quarantine] and local cattle [at Fayoum, Menofia and Sharquia governorates]. A polymerase chain reaction [PCR] assay was used, as a basic step, for rapid diagnosis of the causative agent in clinical specimens to control spread of infection in the rest of Egypt. The PCR assay, utilizing a LSDV P32 based primer set, could identify LSDV in all outbreak clinical specimens. The specific PCR amplification products [amplicons] were purified and subjected to direct nucleotide sequencing. Blast search, multiple alignments and phylogenetic analyses of the nucleotide sequence data revealed that outbreak LSDV is closely related to other capripoxviruses of LSD, sheep pox and goat pox. Selection and processing of clinical specimens, methods of DNA isolation, and PCR assay applied in this endeavor, presented a reliable laboratory diagnostic tool for LSDV

Genetic identification of the foot-and-mouth disease virus caused 2006 outbreak in Egypt

In early February 2006, a foot-and-mouth disease [FMD] outbreak has struck cattle and buffaloes in different localities of Egypt exerting severe economic losses to livestock industry. Representative specimens [tongue epithelium and foot vesicular fluid] were collected from severely infected foreign [imported from Ethiopia] and local cattle in different governorates [Ismailia, Sharqia and Behairah]. Several assays of reverse transcription [RT] using random decamer primers, followed by FMDV VP1- based polymerase chain reaction [PCR], were used for rapid identification of the causative agent in clinical specimens, basically to circumscribe the countrywide spread of infection. The first PCR assay, utilizing a FMDV universal primer set, could identify the outbreak causative agent as a FMDV in all clinical specimens. FMDV specific primers were then utilized to determine the outbreak FMDV serotype. The specific PCR amplification products [amplicons] were purified and subjected to direct nucleotide sequencing. Blast searches, multiple alignments and phylogenetic analyses of the nucleotide sequence data revealed that outbreak FMDV is a serotype "A" which is a new serotype incursion to Egypt. Direct sequencing of the PCR amplicons was proved a relevant discriminative tool for genetic characterization of FMDV strains / isolates. Results of this endeavor initiated the potential to produce a bivalent FMDV vaccine, containing both of serotypes A and O[1], for the first time in Egypt

Evaluation of protective immunity induced by a recombinant baculovirus expressing two structural proteins of bovine viral diarrhea virus in calves

Two groups of calves were vaccinated with a double recombinant baculovirus expression product of a previously developed construct [rec-NE0], expressing the nucleoprotein [N] and the envelope glycoprotein [E0] of the NADL strain of bovine viral diarrhea virus [BVDV]. The baculovirus expression product, in rec-NE0 vaccine, were immunogenic in calves as viral neutralizing antibody [VN-Ab] titers of 2 to 8 were detectable following booster vaccination. Vaccinated and non-vaccinated calves were challenge exposed with either the homologous BVDVI-NADL or the local heterologous BVDV2-Iman strains. Vaccine-induced immunity conferred partial protection against homologous viral challenge exposure, focused in reducing severity and duration of clinical signs of disease, compared to non-vaccinated calves. However, neither systemic spread nor shedding of the challenge virus could be prevented by vaccination. The rec-NE0 vaccine could not cross-protect calves against heterologous virus challenge exposure. Findings of this study suggest that N and E0 regions of the BVDV genome comprise important antigenic epitopes. Furthermore, they share a role in protective immunity against BVDV infection. Immunogenicity of N and E0 along with the existing antigenic diversity among viruses should be considered in future development of recombinant vaccines for pestivirus control