George F. Lemp

The epidemiology of HIV among Mexican migrants and recent immigrants in California and Mexico.

For Mexican migrants and recent immigrants, the impact of migration from Mexico to California has the potential to lead to an increased risk for HIV infection. Until recently, the prevalence of HIV in Mexico and among Mexican migrants in California appeared to be stable and relatively low. Recent studies have raised new concerns, however, that the HIV epidemic may expand more aggressively among this population in the coming years. Unfortunately, the insufficient amount of data available within recent years makes it difficult to fully assess the potential for rapid spread of the HIV epidemic among this population. Consequently, there is a critical need for an ongoing binational surveillance system to assess prevalence and trends in HIV/STD/TB disease and related risk behaviors among this population both in Calfornia and within this population’s states of origin in Mexico. This enhanced epidemiologic surveillance system should provide improved data on the subpopulations at the highest risk for HIV/STD/TB, such as men who have sex with men, and should provide the opportunity to evaluate the impact of migration on the transmission dynamics, risk behaviors, and determinants of behavior on each side of the border. It is essential that this potential threat be assessed and that intervention programs are developed and implemented to combat this possible escalation in the HIV epidemic.

Going North: Mexican migrants and their vulnerability to HIV.

Background: Mexican migrants are at higher risk for HIV than Mexicans who do not migrate to the United States. Migration to the United States was the driving factor of the early Mexican HIV epidemic, and it is likely that it continues to strongly influence incidence. An overview of migration of Mexicans to the United States identifies many pervasive environmental and structural factors as well as risk behaviors that render migrants vulnerable to HIV infection. However, published studies sampling Mexicans while in the United States suggest a relatively low prevalence of HIV among the general migrant population. To better understand this apparent paradox, we sought to identify any demographic variables among Mexicans while in Mexico that may indicate that migrants have or acquire resources that have a protective effect from their vulnerability due to migration. Methods: A California-Mexico binational collaboration project, with a respondent-driven sample with population-based quotas, was conducted in five Mexican states from December 2004 to January 2005, in areas with a high index of migration to the United States. We compared demographic and behavior variables of Mexicans with a history of migration to the United States in the past 12 months to nonmigrant Mexicans living in the same community. Results: A total of 1539 migrants and 1236 nonmigrants were recruited from five Mexican states. Migrants (men and women) reported more HIV risk behavior than nonmigrants in the past 12 months. Migrants reported more sexual partners and noninjected drug use. Migrants reported higher condom use during vaginal sex and were more likely to have taken an HIV test. Conclusion: Though migrants reported higher HIV-related risk behaviors, they also reported higher condom use. Migrants were more likely to have accessed an HIV test indicating an opportunity for a prevention intervention. More binational collaborations are needed to research the different levels of vulnerability among Mexican migrants and actual acquisition of HIV infection. In addition, more research is needed to identify protective factors for HIV prevention interventions among Mexican migrant communities in Mexico and in the United States.

Continuing high prevalence of HIV and risk behaviors among young men who have sex with men : The young men's survey in the San Francisco Bay area in 1992 to 1993 and in 1994 to 1995

Several recent studies have shown high rates of HIV infection and risk behavior among young men who have sex with men (MSM). To assess the direction of the epidemic in this population, we replicated a venue-based study performed in the San Francisco Bay Area during 1992 and 1993. From May 1994 to September 1995, we surveyed 675 MSM aged between 17 and 22. After statistical adjustment for age, ethnicity, residence, and site of recruitment, seroprevalence did not change significantly between the 1992 to 1993 (8.4%) and the 1994 to 1995 (6.7%) surveys. Similarly, no significant changes were found in the rates during the previous 6 months of unprotected receptive anal intercourse (23.4% versus 24.9%), injection drug use (8.0% versus 7.8%), or needle sharing among injection drug users (56.3% versus 64.5%) between the two surveys. Despite the increased attention that the problem of high risk behavior among young MSM has received, effective prevention interventions for MSM are needed as profoundly now as they had been several years ago.

Knock-Knock: A Population-Based Survey of Risk Behavior, Health Care Access, and Chlamydia trachomatis Infection among Low-Income Women in the San Francisco Bay Area

To estimate the prevalence of urogenital chlamydial infection among young, low-income women in northern California and to describe correlates of infection, a population-based door-to-door household cluster survey was conducted from 1996 through 1998. The participants included 1439 women 18-29 years of age, with a mean age of 24 years, most of whom were African American (43%) or Latina (23%) and had a median income of

The effect of migration on HIV high-risk behaviors among Mexican migrants.

500-

PARTNER NOTIFICATION AND THE CONTROL OF HUMAN IMMUNODEFICIENCY VIRUS INFECTION : TWO YEARS OF EXPERIENCE IN SAN FRANCISCO

999 per month. Most (94%) had received health care in the past year, and approximately 50% was covered by state insurance programs. Although more than half (62%) had had a recent pelvic examination, only 42% had recently used a condom with a new partner. The prevalence of urogenital chlamydial infection was 3.2% (95% confidence interval, 2.2%-4.2%). Women with chlamydia were more likely to be younger (18-21 years of age) and nonwhite and to have lower socioeconomic status. These data demonstrated an approximately 2-3-fold greater burden of infection than routine surveillance data have suggested.

METHAMPHETAMINE AND COCAINE USE AMONG MExICAN MIGRANTS IN CALIFORNIA: THE CALIFORNIA-MExICO EPIDEMIOLOGICAL SURVEILLANCE PILOT

Background:Previous studies have shown an association between Mexican migration to the United States and an increased frequency of HIV high-risk behaviors among male Mexican migrants. However, the individual level change in these behaviors after migration has not been quantified. Objective:To estimate the change in HIV high-risk behaviors among Mexican migrants after migration to the United States. Methods:A case-crossover study was embedded in the California-Mexico Epidemiological Surveillance Pilot, a targeted, venue-based, sampling survey. We implemented the study from July to November 2005, studying 458 Mexican migrants at sites in rural and urban areas in Fresno County and San Diego County and directly comparing individual HIV high-risk behaviors before and after migration. Results:After migration, there were increases in the odds of male migrants engaging in sex with a sex worker [odds ratio (OR) = 2.64, P < 0.0001], sex while under the influence of drugs or alcohol (OR = 5.00, P < 0.0001), performing sex work (OR = 6.00, P = 0.070), and sex with a male partner (OR = 13.00, P = 0.001). Those male Mexican migrant subgroups at particularly elevated risk were those in the United States for more than 5 years, those from the youngest age cohort (18–29 years old), or those frequenting high-risk behavior venues and male work venues. Conclusions:Our results show that Mexican migrant men were significantly more likely to engage in several HIV high-risk behaviors after migration to the United States. However, a smaller proportion of men reported low condom use after migration, indicating increased adoption of some prevention methods. Our results also identified subgroups of Mexican migrants at elevated risk who should be targeted for HIV prevention interventions.

Migración y ruralización del SIDA: relatos de vulnerabilidad en comunidades indígenas de México

To evaluate partner notification of opposite-sex sexual partners of AIDS patients as a means of limiting sexual and vertical transmission of human immunodeficiency virus (HIV), the authors examined the first 27 months of their experience with partner notification. Overall, of 145 AIDS patients eligible to participate, 51 (35%) were interviewed and identified 135 opposite-sex sexual partners. Of the 135 partners, 59 (44%) were interviewed and 34 (25%) were tested, resulting in the diagnosis of 7 (5%) HIV-infected partners. Refusal rates for index patients and partners were low (9% and 12%, respectively). Costs for the program were

Effect of the revised AIDS case definition on AIDS reporting in San Francisco: evidence of increased reporting in intravenous drug users

454 per partner interviewed and

Projected incidence of AIDS in San Francisco: the peak and decline of the epidemic.

2,203 per seropositive partners identified. The authors conclude that although partner notification is more expensive than more widely targeted AIDS prevention and education efforts, its ability to target case finding, education, and counseling to women at highest risk of infection makes it potentially cost-effective for prevention of vertically transmitted HIV infection.