scholarly journals Genetic Reassortment of Rift Valley Fever Virus in Nature

1999 ◽  
Vol 73 (10) ◽  
pp. 8196-8200 ◽  
Author(s):  
A. A. Sall ◽  
P. M. de A. Zanotto ◽  
O. K. Sene ◽  
H. G. Zeller ◽  
J. P. Digoutte ◽  
...  

ABSTRACT Rift Valley fever virus (RVFV), a phlebovirus of theBunyaviridae family, is an arthropod-borne virus which emerges periodically throughout Africa, emphasizing that it poses a major threat for animal and human populations. To assess the genetic variability of RVFV, several isolates from diverse localities of Africa were investigated by means of reverse transcription-PCR followed by direct sequencing of a region of the small (S), medium (M), and large (L) genomic segments. Phylogenetic analysis showed the existence of three major lineages corresponding to geographic variants from West Africa, Egypt, and Central-East Africa. However, incongruences detected between the L, M, and S phylogenies suggested that genetic exchange via reassortment occurred between strains from different lineages. This hypothesis, depicted by parallel phylogenies, was further confirmed by statistical tests. Our findings, which strongly suggest exchanges between strains from areas of endemicity in West and East Africa, strengthen the potential existence of a sylvatic cycle in the tropical rain forest. This also emphasizes the risk of generating uncontrolled chimeric viruses by using live attenuated vaccines in areas of endemicity.

2016 ◽  
Vol 5 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Marycelin Baba ◽  
Daniel K Masiga ◽  
Rosemary Sang ◽  
Jandouwe Villinger

1992 ◽  
Vol 130 (12) ◽  
pp. 247-249 ◽  
Author(s):  
F. Davies ◽  
T. Logan ◽  
Y. Binepal ◽  
P. Jessen

1950 ◽  
Vol 5 (5) ◽  
pp. 243-247
Author(s):  
Minoru MATSUMOTO ◽  
Saburo IWASA ◽  
Motosige ENDO

PLoS ONE ◽  
2015 ◽  
Vol 10 (5) ◽  
pp. e0128215 ◽  
Author(s):  
Nazly Shafagati ◽  
Lindsay Lundberg ◽  
Alan Baer ◽  
Alexis Patanarut ◽  
Katherine Fite ◽  
...  

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Halima Rhazi ◽  
Najete Safini ◽  
Karima Mikou ◽  
Meryeme Alhyane ◽  
Khalid Omari Tadlaoui ◽  
...  

Abstract Background Animal vaccination is an important way to stop the spread of diseases causing immense damage to livestock and economic losses and the potential transmission to humans. Therefore effective method for vaccine production using simple and inexpensive bioprocessing solutions is very essential. Conventional culture systems currently in use, tend to be uneconomic in terms of labor and time involved. Besides, they offer a limited surface area for growth of cells. In this study, the CelCradle™-500A was evaluated as an alternative to replace conventional culture systems in use such as Cell factories for the production of viral vaccines against small ruminant morbillivirus (PPR), rift valley fever virus (RVF) and lumpy skin disease virus (LSD). Results Two types of cells Vero and primary Lamb Testis cells were used to produce these viruses. The study was done in 2 phases as a) optimization of cell growth and b) virus cultivation. Vero cells could be grown to significantly higher cell densities of 3.04 × 109 using the CelCradle™-500A with a shorter doubling time as compared to 9.45 × 108 cells in Cell factories. This represents a 19 fold increase in cell numbers as compared to seeding vs only 3.7 fold in Cell factories. LT cells achieved modestly higher cell densities of 6.7 × 108 as compared to 6.3 × 108 in Cell factories. The fold change in densities for these cells was 3 fold in the CelCradle™-500A vs 2.5 fold in Cell factories. The titers in the conventional system and the bioreactor were not significantly different. However, the Cell-specific virus yield for rift valley fever virus and lumpy skin disease virus are higher (25 virions/cell for rift valley fever virus, and 21.9 virions/cell for lumpy skin disease virus versus 19.9 virions/cell for rift valley fever virus and 10 virions/cell for lumpy skin disease virus). Conclusions This work represents a novel study for primary lamb testis cell culture in CellCradle™-500A bioreactors. In addition, on account of the high cell densities obtained and the linear scalability the titers could be further optimized using other culture process such us perfusion.


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