Genetic analysis of HIV type 2 from Ghana and Guinea-Bissau, West Africa.

Abstract

The phylogenetic variability of part of the long terminal repeat (LTR) region of HIV-2 strains isolated in 1995 from five individuals residing in Bissau, the capital city of Guinea-Bissau, and collected from seven persons from Kumasi, Ghana in 1996-1997, was analyzed. All Guinean samples and all but one Ghanaian sample clustered with HIV-2 subtype A. One Ghanaian sample (14%) was classified as HIV-2 subtype B. This study adds to previous reports on HIV-2 subtype distribution in West Africa indicating local prevalence of HIV-2 subtype B in Ivory Coast and neighboring Ghana.

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AIDS RESEARCH AND HUMAN RETROVIRUSES
Volume 17, Number 17, 2001, pp. 1661–1663
Mary Ann Liebert, Inc.
Sequence Note
Genetic Analysis of HIV Type 2 from Ghana and
Guinea-Bissau, West Africa
KOICHI ISHIKAWA,1,2WOUTER JANSSENS,3JACOB S. BANOR,2TEIICHIRO SHINNO,1
JOÃO PIEDADE,4TETSUTARO SATA,1WILLIAM K. AMPOFO,2JAMES A.M. BRANDFUL,2
YOSHIO KOYANAGI,5NAOKI YAMAMOTO,5WANDA F. CANAS-FERREIRA,4
YAW ADU-SARKODIE,6and TAKESHI KURATA1
ABSTRACT
The phylogenetic variability of part of the long terminal repeat (LTR) region of HIV-2 strains isolated in 1995
from five individuals residing in Bissau, the capital city of Guinea-Bissau, and collected from seven persons
from Kumasi, Ghana in 1996–1997, was analyzed. All Guinean samples and all but one Ghanaian sample clus-
tered with HIV-2 subtype A. One Ghanaian sample (14%) was classified as HIV-2 subtype B. This study adds
to previous reports on HIV-2 subtype distribution in West Africa indicating local prevalence of HIV-2 sub-
type B in Ivory Coast and neighboring Ghana.
1661
H
Senegal, The Gambia, Cape Verde Islands, Mali)1,2and in In-
dia.3In addition, HIV-2 infection has been documented mainly
in African immigrants.4In geographic regions where both HIV-
1 and HIV-2 are prevalent, their spread has been unequal. Stud-
ies have shown that HIV-2 is perinatally and sexually less trans-
missible than HIV-1.5,6Although HIV-2 AIDS appears to be
similar to HIV-1-induced AIDS, the rate of disease progression
in HIV-2-infected individuals is much slower than in those with
HIV-1.6,7The ratio of HIV-1 versus HIV-2 infections is rapidly
increasing over time. In Ghana, Hishida et al. reported that HIV
seroprevalence of HIV/AIDS patient or suspected cases in
1990–1992 for HIV-1, HIV-2, and dual infection were 65, 21,
and 14%, respectively.8According to the data of 1999 HIV sen-
tinel surveillance in Ghana, HIV-1, HIV-2, and dual infection
rates were 92.8, 2.8, and 4.4%, respectively.9Seven HIV-2 ge-
netic subtypes, A to G, have been reported to date.10–12HIV-2
subtype A viruses have been documented in diverse locations
UMAN IMMUNODEFICIENCY VIRUS TYPE 2 (HIV-2) is com-
mon in West Africa (Ivory Coast, Ghana, Guinea-Bissau,
across western Africa1,2as well as in Europe,4India,3and South
Korea.13Subtype B exhibits a more restricted geographical dis-
tribution and has been reported mainly in Ivory Coast14and
Ghana,15with a few cases documented in Europe16and the Mid-
dle East.17Subtypes C, D, E, F, and G are each represented by
single sequences that were obtained from HIV-2-seropositive
individuals living in rural areas of Liberia (subtypes C and D),
Sierra Leone (subtypes E and F), or Ivory Coast (subtype
G).10–12
The present study focuses on HIV-2 subtype distribution
among HIV-2-seropositive individuals in Guinea-Bissau (n 5
5) and Ghana (n 5 7). Ninety-four Guinean individuals attend-
ing an outpatient clinic at the Tropical Medicine Center of Bis-
sau, the capital city of Guinea-Bissau, in 1995 were screened
for HIV-1 and HIV-2 antibodies by enzyme-linked im-
munosorbent assay (ELISA) (Innotest HIV-1/HIV-2 Ab sp;
Innogenetics, Zwijnaarde, Belgium). Reactive specimens were
subsequently confirmed by Western blot analysis (New Lav
Blot 1–2; Sanofi Diagnostics Pasteur, Marnes-la-Coquette,
1National Institute of Infectious Diseases, AIDS Research Center, Tokyo 162-8640, Japan.
2Noguchi Memorial Institute for Medical Research, Ghana University, Accra, Ghana.
3Institute of Tropical Medicine, 2000 Antwerp, Belgium.
4Unidade de Virologia, Instituto de Higiene e Medicina Tropical (UNL), Lisbon P-1349-008, Portugal.
5Tokyo Medical and Dental University, Tokyo 113-8519, Japan.
6School of Medical Sciences, Kumasi, Ghana.

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France). Twenty-one of 94 (22.3%) Guinean individuals tested
positive for HIV-2. Eighteen of 21 Guinean samples were con-
firmed HIV-2 positive by nested polymerase chain reaction
(PCR) using long terminal repeat (LTR) and/or env primers
(primers L100/L200 and L101/L201 for LTR, and primers
SE24/SE25bis and SE28/SE27bis for env) as described previ-
ously.18
Five Guinean HIV-2-positive samples and seven samples
isolated from HIV-2-positive individuals from Ghana (Kumasi)
in 1996–1997 were used for subtyping purposes. Genomic DNA
was extracted from primary peripheral blood mononuclear cells
(PBMCs) of HIV-2-seropositive individuals. A 324-base pair
fragment encoding part of the LTR region (nucleotides 60 to
383 according to HIV-2 ROD; accession number X05291) was
PCR amplified as described previously.18PCR products were
purified with a QIAquick gel extraction kit (Qiagen, Valencia,
CA). The recovered PCR products were subjected to direct se-
quencing in both directions, using an ABI PRISM dye termi-
nator cycle sequencing Ready Reaction kit (Applied Biosys-
tems, Foster City, CA) and an automatic sequencer (ABI model
373A: Applied Biosystems). The newly determined HIV-2 LTR
sequences were aligned with 15 previously documented se-
quences of HIV-2 isolates representing HIV-2 subtypes A, B,
and G, for which LTR sequence information is currently avail-
able. Distance calculation, tree construction, and bootstrap anal-
ysis were realized with the software package TREECON, as
previously described.19
Phylogenetically, all Guinean samples and six (86%) Ghana-
ian samples are classified as HIV-2 subtype A; one Ghanaian
sample (14%; NJ205) belongs to HIV-2 subtype B. Within sub-
type A, four Ghanaian samples (NJ42, NJ79, NJ206, and
NJ207) strongly clustered with HIV-2 ROD, previously isolated
from a person of the Cape Verde Islands (Fig. 1). Our results
indicate that at least two different subtypes of HIV-2, subtype
A and subtype B, cocirculated in Kumasi, Ghana between 1990
and 1997. So far only HIV-2 subtype A has been found in
Guinea-Bissau.20In Ghana, cocirculation of HIV-2 subtypes A
and B has already given rise to HIV-2 A/B recombinants.15
This study adds to the previous reports on HIV-2 subtype
distribution in Guinea-Bissau and Ghana. Regarding HIV-2
subtype distribution, so far subtype B has mainly been identi-
fied in Ivory Coast, where the majority of HIV-2 infections are
due to subtype B (71%, 20 of 28),14and to less extent in Ghana.
The reason for this local prevalence of HIV-2 subtype B is un-
clear. There are currently no studies indicating differences in
pathogenesis and transmissibility for HIV-2 subtypes. How-
ever, data on molecular epidemiology of HIV-2 subtypes re-
main scarce, and on the basis of our current knowledge it is
ISHIKAWA ET AL.
1662
FIG. 1.
Sequences determined in this study are represented in italic. A total of 1000 bootstrap samples were analyzed. Bootstrap values
are given in percentages at the internodes if they exceed the 70% level. The distance between two sequences is obtained by sum-
ming the lengths of the connecting branches by using the scale at the top. The tree is rooted arbitrarily. Strain names of samples
from Guinea-Bissau and Ghana identified in this study are preceded by country codes GW and GH, respectively.
Phylogenetic tree based on 346 unambiguously aligned positions of 28 HIV-2 sequences encoding part of the LTR.

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speculative to address evolutionary advantage to either subtype.
As the earliest samples documented for HIV-2 subtype distri-
bution in Ivory Coast were of both subtype A and B, sharing a
similar range of diversity, it seems plausible to believe that the
relative success of subtype A in most West African countries
is due to a founder effect. Further studies of HIV-2 isolates may
reveal the differences in biological properties between HIV-2
subtypes A and B.
ACKNOWLEDGMENTS
We acknowledge the staff of the Virology Unit, Noguchi
Memorial Institute for Medical Research. This work was par-
tially supported by the Japanese Human Science Foundation
(Tokyo, Japan) and the Japan International Cooperation Agency
(JICA).
SEQUENCE DATA
The HIV-2 LTR nucleotide sequence data were deposited in
the EMBL, GenBank, and DDBJ nucleotide sequence databases
under the following accession numbers: AY039114–
AY039125.
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Address reprint requests to:
Koichi Ishikawa
AIDS Research Center
National Institute of Infectious Diseases
1-23-1 Toyama Shinjyuku, Tokyo, Japan
E-mail: kishikaw@nih.go.jp
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