A new survey of the first US community in which heterosexual sex was shown to be the main way HIV was transmitted has found that although prevention programs may have helped, infection rates remain high.

HIV rates did not increase in the rural Florida community over the period from 1986 to 1998-2000, the results show, but living in a neighborhood where prostitution and crack cocaine use were common was a risk factor for HIV infection.

“This indicates that HIV infection evolves over time into a disease that persists in focal geographic areas without spreading to the community at large,” Dr. Tedd V. Ellerbrock of the Centers for Disease Control and Prevention in Atlanta and colleagues write in the American Journal of Epidemiology.

Belle Glade and the surrounding community of western Palm Beach County in Florida was first studied in 1986 to determine if insects could be spreading HIV infection. The survey disproved that notion, but found that over 3 percent of the population was HIV positive.

Between 1998 and 2000, Ellerbrock and his team conducted a survey of households in western Palm Beach County, eventually enrolling 516 residents and testing 447 of them for HIV.

The researchers found the rate of HIV infection was 1.6 percent in western Palm Beach County and 1.7 percent in Belle Glade.

The team also compared 217 HIV-infected individuals with 395 people who were not infected.

Both the 1986 and 1998-2000 surveys found that the number of sex partners, history of sexually transmitted disease, and having sex for drugs and money were all risk factors for HIV infection.

While men who had sex with men were at higher risk for HIV in the earlier study, this was not the case in the later survey. And while residence in a high-risk neighborhood was not a risk factor in 1986, it had become one by 1998-2000.

After the 1986 survey, a community-wide HIV prevention program was introduced that involved education about HIV infection and distribution of condoms.

“While the importance of community-wide prevention programs in limiting the spread of the epidemic cannot be conclusively established, it is likely that they contributed to slowing its growth,” the researchers write.

“We conclude that HIV infection has remained a heterosexually transmitted infection in this community, facilitated by other sexually transmitted infections and crack cocaine use,” they continue.

Making further inroads into the high rate of infection “may require a better understanding of the social networks that exist in these endemic neighborhoods, and ethnographic studies focusing on the identification of factors affecting heterosexual HIV transmission.”

SOURCE: American Journal of Epidemiology, September 15, 2004.