Current epidemiological situation
Since the late 1990s, the geographic spread of the disease, with the emergence of PPR outbreaks in countries which had been disease-free, and re-emergence in countries and zones known to be enzootic, has radically changed the situation.
Epidemiological surveillance has revealed that lineage IV is continuing to spread in Asia in an easterly direction, but is also extending west and invading Africa, where it is becoming the dominant lineage.
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A similar phenomenon occurred in West Africa with lineage II, today alone present in Senegal, having taken the place of lineage I.
Note :
These upheavals in the distribution of lineages must be interpreted cautiously as epidemiological data collected in the field remains very incomplete due to inadequate surveillance. While the link between animal mobility and the spread of the virus is now certain, it cannot alone explain the dominance of lineage IV in West and Central African countries which have no tradition of small ruminant exchanges with countries east of the Red Sea. One answer may be found in the capacity of PPRV to adapt its pathogenicity to selective changes in its environment, notably to the different susceptibility of its different hosts.