Efficacy Of Freeze-Dried Inactivated Rift Valley Fever Vaccine

Atwa M.H,Marwa F Mahmoud,Maha Abd El-Fadeel,Alaa El-Kholy,Heba A Khafagy,Ebtsam E.Z Kotb

doi:10.21608/javs.2020.85571

Abstract

Rift Valley Fever (RVF) is an acute infectious zoonotic arthropod-born viral disease, affecting many species of animals and it causes great economic losses in animal wealth and has a zoonotic implication. Eradication of mosquito and vaccination is an important and best method for preventing and controlling the disease. This study was applied for the preparation and evaluation of Rift Valley Fever inactivated vaccine in a lyophilized form that is reconstituted at the time of inoculation using saponin that acts as an adjuvant. The prepared vaccine was proved to be sterile and safe. ED50 Potency test of the prepared vaccine in mice gave 0.0010 ED50/ML (permissible limit less than 0.02/ml). Sheep were vaccinated with 1ml SC of the prepared lyophilized inactivated RVF vaccine and another group was vaccinated S|C with 1ml of Aluminum hydroxide inactivated RVF vaccine. The immune response of different vaccinated sheep groups was evaluated using SNT and ELISA. The Prepared lyophilized inactivated RVF vaccine gave protective NI at the second-week post-vaccination (2.1 and 0.286 OD) , then reach to peak at the 4th week (3.28 and 0.343OD) then began to decline till ten months (1.8 and 0.241 OD), while the Aluminum hydroxide inactivated RVF vaccine gave protective NI at the second-week post-vaccination (1.7 and 0.277 OD) then reach to its NI peak at the 4th week (3.13 and 0.312 OD) then began to decline till ten months (1.73 and 0.228 OD). From the obtained results, it was found that the prepared lyophilized inactivated RVF vaccine was safe, potent and gave approximately similar immune response as aluminum hydroxide inactivated RVF vaccine but it is better as it reduces time and effort consuming during vaccine production.

Highlights

Rift Valley fever (RVF) is an acute viral anthropoid zoonotic disease (Ndeye et al, 2015)
Three to four days old baby mice were supplied by Breeding Unit, Veterinary Serum and Vaccine Research Institute (VSVRI), Abbasia, Cairo, were used for detection of virus inactivation completion, each mice was inoculated I/C with 0.1 ml inactivated RVF virus which was supplied RVF Department, (VSVRI)
Sixty Swiss albino weaned mice and specific pathogen-free, 21-30 days old were supplied by the Breeding Unit, (VSVRI) and it was used in ED50 potency test

Summary

Introduction

Rift Valley fever (RVF) is an acute viral anthropoid zoonotic disease (Ndeye et al, 2015) It is caused by the Rift Valley Fever virus which a member of Phlebovirus of the Bunyaviridae, single-stranded RNA virus (Samia, 2011). The disease mainly affects sheep, goats, cattle, camels, buffaloes, and humans cause fever, salivation, weakness, fetid diarrhea, decreased milk production with explosive abortions in pregnant animals (FAO, 2003). It causes a headache, conjunctivitis with ocular complications in the human CDC (2015). RVF outbreaks were associated with mosquito spreading (Nguku et al, 2006)

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