|
|
Letter
HIV-1 CRF07_BC Infections,
Injecting Drug Users, Taiwan
Yi-Ming Arthur Chen,*
Yu-Ching Lan,* Shu-Fen Lai,* Jyh-Yuan Yang,† Su-Fen Tsai,† and Steve Hsu-Sung
Kuo†
*National Yang-Ming University, Taipei, Taiwan, Republic of China; and
†Center for Disease Control, Taipei, Taiwan, Republic of China
Suggested
citation for this article
To the Editor: To date, Taiwan's human immunodeficiency virus
type 1 (HIV-1) epidemic has primarily spread via sexual contact. The subtype
B and circulating recombinant form (CRF) 01_AE account for >95% of
all infections (1). However, since 2003 Taiwan
has experienced a major outbreak of CRF07_BC among injecting drug users
(IDUs).
The first wave of HIV-1 infections in Taiwan can be traced to the early
1980s, when a group of hemophilia patients received imported HIV-1-contaminated
antihemophilia medications. By the time these medications had been replaced
by heat-treated factor VIII concentrates, at least 53 patients had contracted
HIV-1 infections (2). According to Taiwan's Center
for Disease Control (CDC), HIV infections have been diagnosed in 9,229
persons (including 523 foreigners) as of July 31, 2005 (3).
The number of persons living with HIV-1/AIDS has increased rapidly in
the past few years, with a 77% increase in 2004, compared to 11% in 2003
(Table). According to the results of a risk factor
analysis of people living with HIV-1/AIDS reported to the Taiwan CDC,
the proportion of IDUs increased from 1.7% (13/773) in 2002 to 8.1% (70/861)
in 2003 to 30.3% (462/1,521) in 2004 (Table). The
Taiwan CDC received reports of 1,241 IDUs diagnosed with HIV-1 infections
from January 1 to July 31, 2005; these account for >75% of all reported
HIV-1 infections in 2005 (3). The evidence points
to an explosive epidemic of HIV-1 infections among IDUs in Taiwan since
2003, with no indication of a slowdown.
Taiwan has ≈60,000 IDUs (1). According
to the Republic of China Ministry of Justice, the number of incarcerated
drug offenders increased from 5,988 in 2003 to 9,303 in 2004; the rate
of HIV-1 seropositive inmates increased from 13.3/100,000 in 2002 to 56.8/100,000
in 2004 (Y-M. Wu, Ministry of Justice, pers. comm.). Since all inmates
are routinely tested for HIV-1 in detention centers, and all infected
inmates are separated from HIV-1-seronegative inmates, the potential of
HIV-1 transmission in prisons is remote. We therefore suggest that the
Taiwanese IDU population and its HIV-1 seropositive rate have both increased
rapidly in the past few years.
To identify the primary HIV-1 strains in the current epidemic, we collected
blood specimens from HIV-1-infected inmates in 3 detention centers (1
each located in the northern, central and southern regions of Taiwan).
HIV-1 subtypes were determined by polymerase chain reaction, DNA sequencing,
and phylogenetic analyses of pol or env genes. Our results
indicate that 145 (96%) of 151 IDUs were infected with CRF07_BC and 6
(4%) were infected with subtype B; 97% of the CRF07_BC cases were diagnosed
in 2003 or 2004. According to our phylogenetic analysis of the env
gene, the Taiwanese CRF07_BC strains clustered with CRF07_BC strains drawn
from IDUs in China (Figure).
CRF07_BC is a recombinant of the B´ and C subtypes. Several studies
have suggested that CRF07_BC originated in China's Yunnan Province, with
subtype B´ from Thailand mixing with subtype C from India before
moving northwestward to Xinjiang Province along a major Chinese heroin
trafficking route (4–6). To our knowledge, this
is the first report of a large group of IDUs in northeastern Asia having
CRF07_BC infections. It may have followed another drug trafficking route
from Yunnan Province to southeast China, moving through Guangxi Province
and Hong Kong to Taiwan (7–9). In a bid to combat
skyrocketing HIV/AIDS infection rates among IDUs, the Taiwan CDC has proposed
a 5-year harm reduction program to the Republic of China Executive Yuan.
Acknowledgments
We thank Yi-Ru Chang
for her technical assistance, the Sequencing Core Facility of National
Yang-Ming University's Genome Research Center for its technical assistance,
and professor Kathleen Ahrens of National Taiwan University for her
help in preparing this letter.
This research is
partially supported by funds from the AIDS Molecular Virology Laboratory
Program of the Taiwan CDC (CDC-94-RM-102, DOH93-DC-1043) and the ROC
National Science Council's National Research Program for Genomic Medicine
(95-0324-19-F-01-00-00-00-35).
References
- Chen YM, Huang KL, Jen I, Chen SC, Liu YC, Chuang
YC, et al. Temporal
trends and molecular epidemiology of HIV-1 infection in Taiwan from
1988 to 1998. J Acquir Immune Defic Syndr. 2001;26:274–82.
- Shen MC, Liu FY, Kuo YP, Hsie RF. A
longitudinal study of immunological status in Chinese hemophiliacs:
importance of the heat viral inactivation of factor concentrates. I.
Immunological associations with the consumption of factor concentrates.
Haemophilia. 1995;1:243–8.
- Republic of China Center for Disease Control, Department of Health.
Reported cases of HIV/AIDS by year in Taiwan 1984-2004. 2005. [cited
2005 Jul 31]. Available from http://www.cdc.gov.tw/en/index/asp
- Su L, Graf M, Zhang Y, von Briesen H, Xing H, Köstler J, et al. Characterization
of a virtually full-length human immunodeficiency virus type 1 genome
of a prevalent intersubtype (C/B') recombinant strain in China.
J Virol. 2000;74:11367–76.
- Yang R, Xia X, Kusagawa S, Zhang C, Ben K, Takebe Y. On-going
generation of multiple forms of HIV-1 intersubypte recombinants in the
Yunnan province of China. AIDS. 2002;16:1401–7.
- Zhang L, Chen Z, Cao Y, Yu J, Li G, Yu W, et al. Molecular
characterization of human immunodeficiency virus type 1 and hepatitis
C virus in paid blood donors and infecting drug users in China.
J Virol. 2004;78:13591–9.
- Piyasirisilp S, McCutchan FE, Carr JK, Anders-Buell E, Liu W, Chen
J, et al. A
recent outbreak of human immunodeficiency virus type 1 infection in
southern China was initiated by two highly homogeneous geographically
separated strains, circulating recombinant form AE and a novel BC recombinant.
J Virol. 2000;74:11286–95.
- Cohen J. Asia
and Africa: on different trajectories? Science. 2004;304:1932–8.
- Lim WL, Xing H, Wong KH, Wong MC, Shao YM, Ng MH, et al. The
lack of an epidemiological link between HIV type 1 infections in Hong
Kong and Mainland China. AIDS Res Hum Retroviruses. 2004;20:259–62.
|
Table. Annual number
of HIV/AIDS cases reported to Taiwan Center for Disease Control,
classified by risk group
|
|
|
Risk factors
|
No. case by year
|
|
|
1994
|
1995
|
1996
|
1997
|
1998
|
1999
|
2000
|
2001
|
2002
|
2003
|
2004
|
|
|
HIV+
|
174
|
228
|
277
|
350
|
401
|
479
|
535
|
654
|
773
|
859
|
1513
|
|
AIDS
|
63
|
98
|
159
|
135
|
152
|
179
|
179
|
161
|
178
|
227
|
254
|
|
Heterosexuals
|
85
|
109
|
134
|
154
|
189
|
214
|
235
|
275
|
310
|
251
|
244
|
|
Homosexuals
|
46
|
70
|
96
|
137
|
141
|
178
|
223
|
287
|
335
|
341
|
339
|
|
Bisexuals
|
27
|
41
|
37
|
47
|
59
|
70
|
61
|
64
|
79
|
51
|
54
|
|
Hemophiliacs
|
1
|
1
|
2
|
1
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
|
Injection drug users
|
6
|
6
|
6
|
5
|
3
|
1
|
7
|
4
|
13
|
70
|
462
|
|
Blood recipients
|
1
|
1
|
0
|
1
|
1
|
0
|
3
|
0
|
0
|
0
|
2
|
|
Vertical transmission
|
0
|
0
|
0
|
0
|
0
|
6
|
1
|
0
|
0
|
1
|
2
|
|
Unknown
|
8
|
0
|
2
|
5
|
8
|
10
|
5
|
24
|
36
|
145
|
410
|
|
Total
|
174
|
228
|
277
|
350
|
401
|
479
|
534
|
654
|
773
|
859
|
1513
|
|
Suggested citation
for this article:
Chen Y-MA, Lan Y-C,
Lai S-F, Yang J-Y, Tsai S-F, Kuo SH-S. HIV-1 CRF07_BC infections, injecting
drug users, Taiwan [letter]. Emerg Infect Dis [serial on the Internet].
2006 Apr [date cited]. Available from http://www.cdc.gov/ncidod/EID/vol12no04/05-0762.htm
|
