University of Khartoum

Development of Live Attenuated Camelpox Vaccine from a Local Isolate of the Virus

Development of Live Attenuated Camelpox Vaccine from a Local Isolate of the Virus

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Title: Development of Live Attenuated Camelpox Vaccine from a Local Isolate of the Virus
Author: Mohamed, Muaz Magzob Abdellatif
Abstract: The Camelpox virus used in this study is a pathogenic field strain isolated from sick camels in Butana area, eastern Sudan. The virus was serially passaged in Vero cells until passage hundred and fifteen. A phenotypic and genotypic character of the wild type, low and high passage virus preparations was studied. The replication of the highly passage viruses induced relatively rapid CPE in comparison with the wild type virus. Inoculation of the wild type virus induces embryo mortality of 20%, while no losses were seen after infection with the high passaged viruses. Thermostability testing revealed that viral stability was affected during serial passages. Nucleotide sequence alignments of Virulence and host range genes revealed multiple point mutations of single nucleotide substitutions, deletion and insertion mutations on both genes. The candidate live attenuated vaccine was subjected to potency and safety tests in experimental rabbitts as pilot study, low levels of Anti-CPV antibodies were detected when inoculated with low and high passage virus preparations. On the other hand slight shift in virulence between viral passages was observed. Camels vaccinated with CPDB100 remained apparently healthy without any adverse reactions and clinical signs of illness 30 days post vaccination. Camels vaccinated subcutaneously and by scarification showed local skin lesions confined to the site of inoculation which disappeared completely within 10 days without any other complications. Vaccinated camels developed protective immune response as measured by SNT which reached a plateau at around 21 days post immunization. Similar antibody response was obtained in camels inoculated subcutaneously with 104.5 and 105.5, while the scarified camel displayed relatively higher titer. In-contact control dromedary didn't show presence of serum antibodies, despite inducing a poor primary antibody response all vaccinated animals were protected against challenge with wild type virus. Cell mediated immunity as measured by DHT showed that all vaccinated camels reacted positively with a remarkable increase in skin thickness as compared with controls. To exclude unwanted reactions live vaccine (CPDB115) was tested in eight young camels for both safety and potency. Vaccinated camels remained apparently healthy without any adverse reactions and clinical signs of illness 30 days post vaccination. While camels inoculated with low dose (103.8 TCID50) induced relatively low antibody titer, no significant variation was observed in the antibody response of camels inoculated with 1ml and 3ml of 105.8 of the CPDB115. Field trial of the live vaccine was performed in small farm with different ages. All vaccinated animals showed seroconversion at the first week that reached a plataeu 3 weeks post vaccination, notably adult animals with prevaccination antibodies induced relatively low titre. Our findings indicated the safety and potency of the candidate live vaccines in experimental camels
Description: 163 Pages
URI: http://khartoumspace.uofk.edu/123456789/16754
Date: 2015-10-26


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