Phylogenetic analysis suggests independent introduction of feline immunodeficiency virus clades A and B to Central Europe and identifies diverse variants of clade B.

Phylogenetic analysis of European feline immunodeficiency virus sequences confirms a highly distinct pattern in the occurrence of FIV-subtypes within Germany and Austria, indicating little mixing and at least two independent introductions of FIV. There is also evidence for a North to South gradient of FIV subtype distribution in Europe, with subtype A being more common in the North, while subtype B is prevalent in the South of Europe. In addition, among Austrian subtype B sequences, considerable differences from classical subtype B sequences were detected by bootscanning, which either suggests recombination with so far unrecognized subtypes, or a long period of independent evolution.