An Insect Nidovirus Emerging from a Primary Tropical Rainforest

Zirkel, Florian; Kurth, Andreas; Quan, Phenix-Lan; Briese, Thomas; Ellerbrok, Heinz; Pauli, Georg; Leendertz, Fabian H.; Lipkin, W. Ian; Ziebuhr, John; Drosten, Christian; Junglen, Sandra

To estimate the habitat association of the putative common ancestor of the 39 virus isolates, sequence fragments were subjected to phylogenetic analysis using a minimum evolution model, considering either the numbers of pairwise synonymous nucleotide exchanges or the percentages of overall (synonymous and nonsynonymous) pairwise nucleotide exchanges. CAVV/A4/CI/ 2004 was used as an outgroup. Phylogenies were subjected to ancestral state reconstruction under a parsimony assumption. These simple models of phylogeny and trait evolution were chosen because the ordered and sparse pattern of nucleotide exchange across the alignment suggested the absence of multiple or saturating exchanges. As shown in Fig. 1 , ancestral state reconstruction suggested the most recent common ancestor linked to the outgroup, as well as the common ancestor of the ingroup, to have existed in a primary forest habitat. This matches the general concept wherein novel viruses are being transferred to areas of human settlement in the course of agricultural exploitation of primary habitats.