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Travel
and the introduction of human immunodeficiency virus type 1 non-B
subtype genetic forms into western countries [Thompson MM and
N'jera R. CID 2001;32:1731]: The
authors review genetic diversity of HIV-1 and its implications with
regard to international travel in the "Travel Medicine"
section of this journal. In North America and Western Europe, B
subtype has largely dominated, and the non-B subtypes have been
identified primarily in immigrants or travelers returning from sub-Saharan
Africa and Southeast Asia. For travelers, the risk of non-B subtypes
comes from different categories including immigrants, military personnel,
sailors, tourists, expatriates, diplomats, and businessmen. The
frequency of these non-B subtypes in Western Europe and the U.S.
is summarized as follows: U.S. military seroconverters with acquisition
outside the United States-7%, recent infections in Germany-33%,
heterosexual transmission in the Netherlands-40%, newly detected
cases in Switzerland-28%, newly detected cases in France-16%, and
Belgium-32%. The distribution of subtypes is shown in the following
table:
|
Americas
|
B
|
|
Western & Central Europe
|
B
|
|
Africa
|
|
Western
|
A, G, F02
|
|
East
|
A, D
|
| South
|
C
|
|
West Central |
All
M, N, O
|
| India |
C
|
| Southeast
Asia |
A/E,
F01
|
The genetic diversity
of HIV-1 stands to have an impact on: 1) vaccine efficacy; 2) resistance
testing, which has been reported as decreased for some genetic forms
(J Virol 1997;71:8893; AIDS 1998;12:1109); 3) non-validity
of resistance tests (JCM 1999;37:2533; AIDS 2000;14:1064);
and 4) viral load testing, which may not be accurate (JCM 2000;38:1247;
CID 2000;31:798).
Comment: This article points out an important
issue in the evolving interest in HAART therapy in the developing
world as well as the implications of increasing genetic diversity
in western countries from travel or immigration. The practical application
of these data concern vaccine development, efficacy of antiretroviral
drugs, detection of drug resistance, and the ability to monitor baseline
HIV levels and response to therapy.
posted
7/6/2001
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