Arch Virol (2002) 147: 1061–1070
Phylogenetic analysis of ﬁve Portuguese strains of FIV
, M. I. Marques
, L. Tavares
, and M. Fevereiro
Centro de Investigação Interdisciplinar em Sanidade Animal (CIISA) – Faculdade de
Medicina Veterinária da Universidade Técnica de Lisboa, Portugal
Laboratório Nacional de Investigação Veterinária, Departamento de Virologia,
Instituto Gulbenkian de Ciência, Oeiras, Portugal
Received May 3, 2001; accepted October 25, 2001
Published online April 18, 2002 © Springer-Verlag 2002
Summary. Feline immunodeﬁciency virus (FIV) was isolated from ﬁve
Portuguese cats. The ﬁve strains were named RP1, PP2, TLP3, FP4 and CP5.
The LTR, the CA region of the gag gene, and the V3-V5 region of the env gene
were ampliﬁed by PCR, cloned and sequenced. The phylogenetic relationships
among these three regions and other previously published sequences revealed an
independent clustering of the Portuguese isolates in the LTR and CA protein.
Based on the V3-V5 region the Portuguese isolates were classiﬁed as Subtype B,
although they appear to be a subcluster within Subtype B. The study of these new
FIV isolates showed the presence of Subtype B in Portugal and could provide a
contribution for the understanding of FIV’s genetic diversity.
FIV is a Lentivirus responsible for an immunodeﬁciency in cats , primarily
caused by deplection of T-lymphocytes , causing a gradual impairment of the
immune response .
Based on the genetic diversity of V3-V5 region of env gene, FIV was classi-
ﬁed in ﬁve phylogenetic subtypes, unevenly distributed geographically. Subtype
A is found in the USA, Australia and Europe [1, 10, 11, 26, 28, 32], subtype B
in Japan, Europe and USA [1, 17, 26] and subtype C in Canada, Europe and
Taiwan [14, 17, 32]. Subtypes D and E are found in Japan  and Argentina
. The knowledge of the genetic diversity of FIV will contribute to the under-
standing of the mechanisms of molecular evolution and provide an insight into
the epidemiological heterogeneity of infection.