New research suggests that online hookup sites are responsible for the rise in sexually transmitted disease and HIV infections.

Researchers at the University of Maryland found that the introduction of Craigslist resulted in a 13.5 percent increase in HIV-infection cases over a four-year period, The Economic Times reported. Having casual sex and transmitting sexually transmitted diseases have been made exponentially easier with online hookup sites.

For the study, researchers measured the " magnitude of the effect of one platform on HIV infection rates in one state, and offered a detailed look at the varying effects on subpopulations by race, gender and socio-economic status," The Times reported. They looked at the years between 2002 to 2006 and found that Craigslist led to an additional 1,149 Floridians contracting HIV.

The findings, which are detailed in the forthcoming journal Management Science, "underscores the need for broader communication and dissemination of the risks posed by the type of online matching platforms studied here," said Ritu Agarwal, a professor at the University of Maryland's Robert H. Smith School of Business and founding director of the Center for Health Information and Decision Systems (CHIDS).

Researchers also found that African-Americans accounted for 63 percent od the new HIV cases,

"That is a bit of paradox, because research suggests that the African American community is one which uses the Internet the least, even though the gap is narrowing," Agwar said. However, "not only have studies shown there is lower utilization of the Internet for welfare-enhancing activities, but now there's evidence of utilization for negative activities as well."

Craigslist also led to an increase in new HIV cases among Latinos and Caucasians -- although only intermittently statistically significant and not statistically different from each other.