Rift Valley fever (RVF) is largely located in sub-Saharan Africa and the Arabian Peninsula and constitutes great danger for livestock and human beings. The infection can lead to death of humans. In response to this challenge, our company provides an extensive range of specialized services designed to expedite the advancement of RVF vaccines and therapeutics.
Overview of Rift Valley Fever
The Rift Valley fever phlebovirus (RVFV) exists in Kenya and has been known since the early 1900s. It is an illness caused by infected mosquitoes. This disease has recurrently caused epidemics throughout the span of time which have had severe consequences for animal farming and humans. Although RVF is often contracted from mosquitoes, it is also possible for a person to become infected from an animal. It causes high rates of loss in newborn livestock and pregnancy, leaving behind devastating consequences. In humans, RVF has been linked to some overwhelming and dangerous medical conditions such as, fever, Meningoencephalitis, Retinitis, and Hemorrhagic fever.
Fig.1 Schematic illustration of Rift Valley fever phlebovirus (RVFV) genome organization. (Faburay B., et al., 2017)
Vaccine Development for Rift Valley Fever
- Subunit and Recombinant Protein Vaccines: These vaccines take into consideration key viral antigens such as glycoproteins Gn and Gc. An example is the production of a baculovirus-expressed RVF glycoprotein subunit vaccine that has shown strong neutralizing responses in sheep models.
- DNA and Viral Vectored Vaccines: With the aid of recombinant nucleic acid technology, preclinical studies have shown promise in which DNA vaccines containing RVFV target antigens have been developed. Also, the development of viral vector vaccines is being researched to deliver RVFV antigens via non-replicating viral vectors.
- Virus-Like Particles (VLPs): VLPs are devoid of any viral genetic material, hence VLPs can elicit an immune response without the risk of causing any infection as they mimic the virus structure. VLP-based vaccines are safe and effective such as RVFV VLPs which are Streptavidin-Functionalized and show promise in animal preclinical studies.
- DIVA-Compliant Vaccines: Differentiation of Infected from Vaccinated Animals (DIVA) Vaccines is important for disease control. The creation of such vaccines makes it possible to determine the specificity of RVFV antibodies against infection from neutralizing antibodies.
Table 1 Status of Rift Valley fever vaccines and vaccine candidates evaluated in different animal models. (Faburay B., et al., 2017)
| Type of Vaccine |
Host Species Evaluated/Used in |
DIVA (differentiating infected from vaccinated animals) |
| Mice |
Sheep |
Cattle |
NHP |
Other |
| Inactivated |
| NDBR103 |
√ |
|
|
|
√ (Human volunteers) |
No |
| TSI GSD 200 |
|
|
|
|
√ (Human volunteers) |
No |
| Formalin inactivated (Egypt) |
|
√ |
√ |
|
|
No |
| Formalin Inactivated (South Africa) |
|
√ |
√ |
|
|
No |
| Genetically non-modified-live |
| Smithburn |
√ |
√ |
√ |
|
|
No |
| MP12 |
√ |
√ |
√ |
√ |
√ (Human volunteers) |
No |
| Genetically modified-live |
| Clone 13, Cl13T |
√ |
√ |
√ |
|
√ (Human volunteers) |
Yes |
| R566 |
|
√ |
|
|
|
Yes |
| Recombinant ZH501 Δ/mutants |
√ |
√ |
|
|
|
Yes |
| Recombinant MP12 Δ/mutants |
√ |
√ |
|
|
|
Yes |
| Four-segmented RVFV |
√ |
√ |
|
|
|
Yes |
| Recombinant protein vaccines |
√ |
√ |
√ |
|
|
Yes |
| DNA vaccines |
√ |
|
|
|
|
Yes |
| Virus-like particles (VLPs) |
√ |
|
|
|
|
Yes |
| Virus replicons |
√ |
√ |
|
|
|
Yes |
| Virus-vectored |
|
|
|
|
|
|
| Poxviruses |
√ |
√ |
|
√ |
|
Yes |
| Newcastle Disease Virus |
√ |
√ |
√ |
|
|
Yes |
| Modified vaccinia Ankara |
√ |
√ |
|
√ |
|
Yes |
| Chimpanzee adenovirus |
√ |
√ |
√ |
|
√ (goats and camels) |
Yes |
| Equine herpesvirus virus type 1 |
|
√ |
|
|
|
Yes |
Therapeutics Development for Rift Valley Fever
Ribavirin: Ribavirin has in vitro action on RVFV and has activity as a broad-spectrum antiviral. However, side effects have limited in vivo efficacy.
Favipiravir: This nucleotide analogue is effective against RVFV in preclinical studies as both monotherapy or with ribavirin as a combination treatment.
Host-Targeted Therapies: Given the various cellular processes that RVFV employs, there is active investigation of strategies which target the host. One such approach involves the use of proteasome inhibitors such as bortezomib which alter the cellular environment to reduce viral replication.
Our Services
Vaccine Design and Development: A particular area of expertise of ours is the making of new vaccine candidates which can be made by using modern technologies including recombination protein expression and VLP production.
Antiviral Drug Discovery: Using high-throughput screening techniques, our team carries out an initial screening of potential antiviral products that are later optimized for best possible efficacy and safety.
Disease Models
- RVFV-induced Hepatitis Models
- RVFV-induced Cerebritis Models
- RVFV-induced Eye Lesions Models
- RVFV-induced Fever/Abortion Models
- RVFV-induced Viremia Models
We conduct comprehensive in vitro evaluations to assess the efficacy of vaccine and drug candidates against RVFV. In addition, detailed analysis of immune responses post-vaccination and the impact of therapeutics on viral loads are core components of our preclinical research. If you are interested in our services, please feel free to contact us.
References
- Faburay, Bonto, et al. "Current status of Rift Valley fever vaccine development." Vaccines 5.3 (2017): 29.
- Atkins, Colm, and Alexander N. Freiberg. "Recent advances in the development of antiviral therapeutics for Rift Valley fever virus infection." Future virology 12.11 (2017): 651-665.
All of our services and products are intended for preclinical research use
only and cannot be used to diagnose, treat or manage patients.
