Keeping close track of the lineages
 Phylogenetic trees help identify the animal movement networks responsible for the spread of PPRV. (click on the image to enlarge it). | To monitor the geographic circulation of the 4 PPRV lineages, scientists are using molecular phylogenetics. The 2 viral proteins, F and N, are considered to be representative markers that can be used to establish a phylogenetic link between the different PPRV lineages. Thanks to these proteins, the complete sequencing[1] of the genome is unnecessary. This was demonstrated by Shaila et al. in 1996 through the partial sequencing of the F fusion protein gene (a segment containing 322 nucleotides) and by Kwiatek et al. in 2007 with a fragment containing 255 nucleotides of the N nucleoprotein gene. It has now been proven that the N nucleoprotein, less exposed to pressure from the immune system, best reflects the geographic movements of the virus over time. These movements are related to animal movements (historic trade and transhumance routes). Molecular epidemiological studies therefore prefer to focus on the N protein to establish phylogenetic and phylogeographic trees. |
Fundamental :
The comparative analysis of genetic sequences of PPRV strains isolated in different countries of Africa, the Middle East and Asia at different periods and in different hosts (goats, sheep and dromedaries) provides information on the circulation dynamics of the 4 viral lineages, which are closely linked to animal movements. This analysis allows a better understanding of the geographic spread of PPR.
