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Development of Dual Vaccines for the Control of Peste des Petits Ruminants and Capripox Infections of Small Ruminants

Gebreeziabher, Berhe. Development of Dual Vaccines for the Control of Peste des Petits Ruminants and Capripox Infections of Small Ruminants. PhD, Institut National Polytechnique de Toulouse, 2006

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Official URL: http://ethesis.inp-toulouse.fr/archive/00000442/


Two highly contagious diseases, Peste des Petits Ruminants and Sheep and Goat Pox, constitute main constraints to small ruminants production in many countries in Asia, the Near and Middle East and Africa. Peste des Petits Ruminants (PPR), also known in the past as goat plague, is a highly contagious viral disease affecting domestic and wild small ruminants. It is caused by a virus which belongs to the Morbillivirus genus of Paramyxoviridae family: the Peste des Petits Ruminants Virus (PPRV). It is a rinderpest-like infection of goats and sheep characterized by erosive stomatitis, enteritis, pneumonia and death. Economically, it is the most important small ruminant disease in areas where it is endemic. In the same regions, there is a second contagious viral disease, Sheep and goat pox. The responsible pathogens, the sheeppox virus (SPPV) and goatpox virus (GTPV), cause acute to sub acute disease of infected sheep and goats respectively. The clinical signs of infection may include generalized pox lesions throughout the skin and mucous membranes, persistent fever, lymphadenitis, and often a focal pneumonia and nodules lesions distributed uniformly throughout the lungs. There is no curative medical treatment against these two viral diseases. Therefore, the only way of tackling them is by means of sanitary and medical prophylaxis. Sanitary prophylaxis to be effective needs the existence of efficient veterinary services, the implementation of animal movement controls with sometimes the stamping out policy. The cost needed for the effective implementation of these means in a short period is too high for most of countries where these diseases are endemic. Therefore the only way for effective control of PPR and sheep and goat pox in those countries is the medical prophylaxis, i.e. the vaccination. Currently, efficient attenuated vaccines exist against each of these diseases. Unfortunately, in most cases they are used only in case of outbreaks to limit their extension. The cost of the logistic needed for systematic vaccination campaigns of small ruminants against either PPR or capripox may be too high for countries if only the individual economic value of goat or sheep, excluding their social value, is considered. The way to cut down this cost is the use of polyvalent vaccine which would enable, in one shot, the protection of animals against more than one economic important disease. The objective of our thesis work was to develop a recombinant thermostable (a characteristic linked to capripoxes) vaccine that could be used to protect sheep and goats against both PPR and capripox and thereby that would contribute to cut down the cost of vaccination campaigns. For that, the complementary DNA, cDNA, corresponding to the gene of PPRV immune protective proteins, the fusion (F) and the haemagglutinin (H) proteins were inserted into the genome of the attenuated strain capripox virus strain KS1. Such a recombinant vaccine may be thermotolerant, a characteristic of poxviruses and this may improve the quality of the vaccine for its use in hot climate conditions. Capripox viruses are highly host-specific microorganisms. They are not pathogenic to human and their host range is limited to cattle and small ruminants and possibly buffaloes. Therefore they constitute an ideal and safe vector for the development of recombinant vaccines for use against ruminant diseases. The present manuscript in which we report on the results we have obtained during our thesis work is composed of the following different parts: a general introduction, a literature review of PPR and capripox viruses, the construction of two recombinant vaccines FPPR/Capripox and HPPR/Capripox, the comparison of efficacy of three poxvirus promoters in HPPRV

Item Type:PhD Thesis
Institution:Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Laboratory name:
Research Director:
Picavet, Pierre Dominique
Deposited On:21 Nov 2012 13:49

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