That's the good news.
In 2005 (latest available year of data) approximately 68 percent of gonorrhea cases reported to the Centers for Disease Control occurred among non-Hispanic blacks. The infection rate for Blacks—626.4 cases per 100,000 population—was 18 times that of non-Hispanic whites and 4 times that of Hispanics. (Table 1.)
Syphilis, a rarer though more virulent STD, infects Blacks at the rate of 9.8 per 100,000 population. That's over five times the non-Hispanic white rate (1.8 per 100,000) and about three times the Hispanics rate (3.3 per 100,000).
Similarly, blacks and Hispanics—each with about 13 percent of the U.S. population—accounted for 49 percent and 18 respectively percent of new HIV/AIDS diagnoses, respectively, in 2005.
In other words, one quarter of the population, minorities, has two-thirds of the HIV/AID infection.
The racial gap is narrowing, with Blacks coming off their highs and Hispanics continuing up. Here are the percentage moves in the number of cases reported to CDC between 2001 and 2005:
(The number of STD cases reported for white, non-Hispanics rose even faster than those of Hispanics—but, of course, from a much lower base. [Table 1.])
Needless to say, the growing bifurcation between Black and Hispanic infection trends has received little notice. CDC's official boilerplate merely notes that:
"Race and ethnicity in the United States are risk markers that correlate with other more fundamental determinants of health status such as poverty, access to quality health care, health care seeking behavior, illicit drug use, and living in communities with high prevalence of STDs. Acknowledging the disparity in STD rates by race or ethnicity is one of the first steps in empowering affected communities to organize and focus on this problem." [Racial and Ethnic Minorities—STD Surveillance 2006]
The role of immigration, while obvious, is never explicitly mentioned—in part because recent CDC health statistics no longer record nativity. (Why not?).
Foreign-born Latinos are more likely than their U.S.-born counterparts to have sex with prostitutes and less likely to use condoms in those encounters. Mexican immigrants in particular are found to engage in risky behavior at higher rates than other immigrant group. [Condom use self-efficacy among U.S.- and foreign-born Latinos in Texas, Journal of Sex Research, Nov, 2004]
An optimist might say this is a temporary aberration. Most Hispanic immigrants enter the U.S. poor and single. Over time, they'll find jobs and marry. Acculturation will surely lead to more responsible sexual behavior.
Alas, even the CDC doesn't buy this rosy scenario:
"Research has shown that Hispanic/Latino cultural concepts of masculinity and femininity, and thus the social norms of sexuality, have created double standards and power inequalities that have been linked to HIV risk and protective behaviors . For some Hispanic/Latino men, the traditional gender role of machismo has positive implications for HIV prevention, such as strength and protection of the family . However, proving masculinity through power and dominance can lead both straight and gay Hispanic/Latino men to engage in risky sex behavior, such as sex with multiple partners , unprotected sex with women or men [14, 16], or sexual coercion . Familismo, or a strong commitment to family, can be a strong incentive for some Hispanic/Latino men to reduce unprotected sex with casual partners. Familismo can also be a source of conflict for Hispanic/Latino men who have sex with men (MSM), whose families may have a negative view of homosexuality . Further, many Hispanic/Latino MSM identify themselves as heterosexual and, as a result, may not relate to prevention messages crafted for gay men [19, 20].…
"Greater acculturation into the US culture has been associated with the adoption of several health-protective behaviors among Hispanics/Latinos, including communicating with partners about sexual safety  and disclosing positive HIV serostatus . However, high levels of acculturation have also been associated with increased HIV risk behaviors among Hispanic/Latino(a) men and women . In one study, highly acculturated HIV-positive Hispanic/Latino men were more likely to use drugs before sex, which increased unsafe sexual behavior . For Hispanic/Latina women, those who were more highly acculturated were more likely to inject drugs and to have had a greater number of sex partners ."[Hispanic/Latino Cultural Beliefs: Risk and Protective Factors, Fact Sheet: HIV/AIDS among Hispanics/Latinos in the United States]
But, of course, there is no screen for macho culture.