Download Cross-border Mobility and its Link to Transmission of HIV, Syphilis

Borderline: Cross-border Mobility
and its Link to Transmission of HIV,
Syphilis and TB in the Mexico-US
Border Region
Steffanie A. Strathdee, Ph.D.
Associate Dean of Global Health Sciences,
Harold Simon Professor;
Chief, Division of Global Public Health,
Department of Medicine, University of California, San Diego
[email protected]
Overview
• Unique features about the context of HIV risks
along the Mexico/U.S. border
• Recent border studies
– HIV
– Syphilis
– TB
• Influencing policy
MEXICO
U.S.
U.S.
MEXICO
What makes the Mexico-US
border region different?
• Volume of cross-border traffic
~60 million crossings per year
• Major drug trafficking route
• Sex work is quasi-legal
• Main corridor for migration fueled by huge
economic disparities
>>Confluence of risk factors for infectious
diseases (e.g. HIV, STIs, TB)
Major US Drug Trafficking Routes
Major U.S. Drug Trafficking Routes
Tijuana
Cd. Juarez
Source: National Drug Intelligence Center, National Drug Threat Assessment 2006
Tijuana has one of the fastest
growing populations of
injection drug users (IDUs) in
Mexico, with ~21,000 drug
users, and ~10,000 IDUs
Most frequent drug injection sites in Tijuana (n=995)
Place of Birth among Tijuana’s
Injection Drug Users
2/3rds born Outside of Baja
California
Number
of
subjects
HIV and Migration:
What is the link?
• Family separation, changes in cultural environment,
homelessness, poverty, social isolation, greater sense of
anonymity (Deren, 2003; Lagarde, 2003; Organista et al, 2004; Parrado, 2004)
• Mobility can increase the chance of encountering HIVpositive persons (Kottiri et al, 2002)
• Mobile persons can act as bridge populations between
groups that normally wouldn’t interact (Paschane, 2000)
• Mobility can change sexual networks in the sending or
receiving community (Aral, 2007)
San Diego Tribune, Reuters, CNN, March 1, 2006
Tijuana
ADAPTED FROM: Report on the Global
AIDS Epidemic, UNAIDS, 2008
Reasons for moving to Tijuana, by gender
Gender
Male
Female
60
55
50
45
40
%
35
30
25
20
15
10
5
0
Deportation
Economic
Opportunities
Note: 15 males and 7 females listed other reasons.
Family Moved
Intended to
Born in the Area
Here
Cross the Border
to U.S.
Factors Independently Associated
with HIV infection by Gender
Variable
Age
# of arrests for track
marks (per 5 arrests)
Syphilis
# of different people
usually injects with*
(per 5 people)
Number of years lived
in Tijuana (per 10 year
increase)
Deportation
Adjusted
Odds Ratio
(Females)
Adjusted
Odds Ratio
(Males)
0.84
--
--
1.1
4.8
6.2
--
1.3
1.9
--
--
4.0
All p<0.05
Explanation #1: Is Deportation a marker for a high
risk subgroup of male IDUs who acquired HIV
in the US?
Courtesy of La Frontera, 2008
Explanation #2:
Is Deportation
a Risk Factor
for HIV
Acquisition?
All photos shared with permission
Impact of deportation on families
Prevalence
HIV Prevalence and Incidence among IDUs
in Tijuana: 2006-2008
HIV Prevalence
Sex Work in Mexico
• Quasi legal in Mexico
– Zone of tolerance (zona roja)
– Work permit
• Up to 9000 FSWs in Tijuana,
~4000 in Ciudad Juarez
• Many women/girls from
S. Mexico/Central America
• ‘Sex tourism’ is common
Sex work in the Mexico-US
Border Region
• 70% of FSWs in Tijuana
and Cd. Juarez are
migrants
• Migrant FSWs have:
– Lower HIV and STI
prevalence
– Less drug use
– More condom use
Over time, protective factors
associated with being a
migrant appear to erode
Ojeda et al, Sex Transm Infect 2009
Factors associated with HIV infection in FSWs
in Tijuana and Ciudad Juarez (n=924)
Baseline Characteristics
Adjusted Odds
Ratio, 95% CI
Injected cocaine past month
2.96 (1.29, 6.80)
Smoked, inhaled, or snorted
methamphetamine past month
3.32 (1.85, 5.95)
Syphilis titer >1:8 *
4.16 (2.28, 7.59)
HIV prevalence: 6%
* Consistent with active infection
Patterson et al, J Inf Dis (2008)
Male Clients of FSWs
in Tijuana and Ciudad Juarez
• 70% of FSWs have U.S.
clients
• FSWs with U.S. clients more
likely to have:
– Syphilis titers ≥ 1:8
– Injected drugs
– High client volumes
– Been paid more for
unprotected sex
Strathdee et al, Sex Trans Dis 2008
Prevalence
Prevalence of HIV testing and HIV/STIs among Mexican
(N=200) and U.S. clients (N=200) of Tijuana FSWs
Patterson et al, AIDS 2009
Factors Independently Associated with
HIV Infection among Male Clients of
FSWs in Tijuana, Mexico (N=400)
Adjusted Odds
Ratio
95% Confidence
Interval
Resides in Mexico
(vs. United States)
2.26
0.91–5.58
Lives alone
2.88
1.23–6.71
Ever used methamphetamine
4.34
1.31–14.36
Tested positive for syphilis
9.36
2.41–36.42
Variable
Patterson et al, AIDS 2009
HIV
Syphilis Incidence on the U.S.-Mexico Border (Per 100,000)
United States
National syphilis incidence: 4.5 (2008)
5.7
CA
AZ
NM
TX
7.4
San Diego
(increased
from 3.8 to
11.8 from
2003 to
2007)
B.C.
3.8
SON
CHI
COH
NL
Mexico
National Syphilis Incidence: 1.2 (2007)
Sources: CONASIDA, US Centers for Disease Control, SD County Health Dept
TAM
California – Primary and Secondary Syphilis
Rates by County, 2008
Source: California
Department of Public
Health, STD Control
Branch
Mexico
Prevalence of HIV and lifetime syphilis infection among
high risk groups in Tijuana and Cd. Juarez (2004-2009)
Proportion of Lifetime Syphilis Infections with current
titers > 1:8* by Risk Group in Tijuana and Cd. Juarez
*Consistent with active infection
Tijuana
ADAPTED FROM: Report on the Global
AIDS Epidemic, UNAIDS, 2008
HIV
TB - The forgotten epidemic
TB Incidence on the U.S.-Mexico Border
United States
National TB Incidence: 4.4
CA
7.5
AZ
NM
4.8
2.6
TX
57.3
San Diego
(9.0)
B.C.
25.4
6.3
18.7
SON
CHI
11.7
COH
21.9
NL
31.1
Mexico
National TB Incidence: 15.7
TAM
Source: CDC, USA ,2007 & DGE Mexico, 2004. Incidence per 100,000 population
HIV and TB Co-infection:
What’s the link?
• Of ~42 million people
with HIV worldwide,
one third also have TB.
• Among HIV+ people,
risk of progressing from
latent to active TB is
10% per year.
Trends in HIV-TB Co-infection in San Diego by Ethnicity
(1993-2007)
100%
90%
80%
70%
60%
42%
82%
Hispanic
White
50%
Black
40%
Asian/Pac. Islander
30%
American Indian
20%
10%
0%
1994
2007
Rodwell et al, AJPH 2010
Factors independently associated with HIV-TB
co-infection in San Diego (1999-2007)*
Adjusted* Odds Ratio
95% Confidence Interval
3.23
2.11 - 4.95
Male sex
2.86
1.97 - 4.14
Hispanic ethnicity
3.90
2.79 - 5.45
Ever injected drugs
2.30
1.19 – 4.43
Characteristic
Age in years**
30-39 years
*Odds ratios are adjusted for all other variables in the table.
**reference group: 20-29 years
Rodwell et al, AJPH 2010
Prevalence
Prevalence of Latent TB Infection (LTBI)* among
High Risk Populations in Tijuana, Mexico
*Tested through IGRA (Quantiferon Gold), Cellestis Inc;
IDUs=injection drug users; FSWs= female sex workers.
Garfein et al, Emerg Inf Dis (in press)
Factors associated with tuberculosis infection
among high risk groups for HIV in Tijuana: 2007
Characteristic
Adjusted* Odds Ratio (95% Confidence Interval)
Age in years
1.03 per yr
(1.01 – 1.05)
Years lived in Tijuana
1.02 per yr
(1.01 – 1.04)
Location of incarceration
Never jailed
1.00
Jailed in US only
1.61
(0.98 – 2.63)
Jailed in Mexico, or BOTH
2.28
(1.48 – 3.51)
US and Mexico
* Odds ratios are adjusted for all other variables in the table.
Garfein et al, in press
Prevalence
Characteristics of Active TB Cases among IDUs in
Tijuana (n=103/1060)
Deiss et al, AJPH 2009
Influencing Policy
The Prevemovihl
• Donated a
mobile vehicle
for HIV
prevention to
our partner
NGO which
became the
prototype for
HIV service
delivery
across Mexico
2010: Mexico to receive $76 M USD
for HIV Prevention
Lessons Learned

The Mexico-U.S. border region is vulnerable
to epidemics of HIV, syphilis and TB
Cross-border infectious disease transmission
is bi-directional, and depends on factors
such as:




Host
Agent
Environment (physical, social, economic, policy)
Implications




Mobility can confer either protection or risk
shaping an individual’s risk of infection.
Immigration policies and health policies
should not work at odds.
Discrimination and blame represent
significant barriers to prevention and
treatment of mobile populations in border
regions.
Prevention and treatment for overlapping
epidemics requires binational cooperation
Acknowledgements
• UCSD Center for AIDS Research , USAID
• National Institutes of Drug Abuse and Mental
Health: K01 DA020364, R01 DA019829,
RO1 MH065849 ; T32 DA023356
• Staff from the PrevenCasa, A. C., Patronato ProCOMUSIDA, UCSD, and Programa Companeros
• San Diego County Public Health Dept
• Most importantly, the participants who gave their
time