After circulation of lineages Ka1 Ka3 had stopped, circulating VDPV was again detected in Katanga in late 2011 (Ka4 and Ka5).
The partial N-gene sequences available in GenBank for Africa through December 2014 were aligned and used for constructing a neighborhood-joining phylogenetic tree that confirmed co-circulation of lineage II PPRV along with lineage III and IV in Tanzania (11 – 14 ).
The analysis, of one dead horse in Emilia Romagna, confirmed the circulation of WNV lineage 2. Lineage 2 circulation has been confirmed in mosquitoes and in wild birds in Veneto, Lombardy, Emilia Romagna, and Sardinia regions [ 82].
In addition, the co-circulation of lineages 1 and 2 in the same area [ 22] may create the favourable conditions for possible changes in the virulence of the viral strains, potentially leading to unexpected and adverse consequences.
Circulation of this lineage apparently stopped abruptly in 2005; no additional related viruses were detected in later years.
Similarly, WNV lineage 2 has been sporadically detected in birds in Austria, whereas a considerable number of human cases were associated with the circulation of this lineage in Romania, Hungary, Greece, and Russia.
The circulation of distinct lineages of DENV2 in Brazil had already been observed before [15] and was ascribed either to independent introductions in different time points or as a result of local evolution.
In the Americas, bats maintain the circulation of different lineages of rabies virus (RABV, genotype 1) (1 ).
Previous RSV-G studies have demonstrated concurrent circulation of related lineages in distant areas (13 ).
All of these observations suggest that the similarities of PDV/USA2006 to the 1988 virus may be due to circulation of multiple lineages.
More complete phylogenetic studies, and full sequences of Madagascar 2008 isolates, are needed to detect the circulation of >1 lineages during the 2008 outbreak and to get a better understanding of the movements and evolution of Madagascar and Kenya isolates.
