Infection rates for the human immunodeficiency virus (HIV) in the United States have declined by a whopping 30 percent over the past 10 years according to a recently released study.

The study, published in the Journal of the American Medical Association (JAMA), details how 493,372 people were diagnosed with HIV in the US between 2002 and 2011.

While this number might appear depressingly large, it is in-fact an encouraging statistic. According to the study 24 cases of HIV were diagnosed per every 100,000 people in 2002, but by 2011, this rate had dropped to an estimated 16 cases per 100,000 - a 33.2 percent drop.

This encouraging finding was released by researchers from the Division of HIV/AIDS Prevention at the US Centers of Disease Control and Prevention (CDC) in preparation for the International AIDS Conference, which kicks off tomorrow in Melbourne, Australia.

Interestingly, the researchers are quick to point out that they did not even adjust for an obvious factor - an increase in HIV testing services in the US.

"The HIV testing services were expanded during the analysis period and early outcomes of testing initiatives often indicate increases in diagnoses," the authors of the study wrote.

In other words, even if the rate of HIV was decreasing, more cases were going to be identified with the advancement of technology and outreach. Even so, "our study found overall decreases in annual diagnosis rates despite the implementation of testing initiatives during the period of analysis."

Still, while overall rates saw a significant drop, infection rates among men who have sex with men (MSM) continued to climb within the same 10 years.

"Among [MSM groups] unprotected risk behaviors in the presence of high prevalence and unsuppressed viral load may continue to drive HIV transmission," the authors write, worried at a 132.5 percent increase in infections among potentially 'closeted' young males.

Risky behavior and a secretive culture may in-part drive this trend,  according to the study, but Nature World News also recently explained how there is even a biological explanation for why HIV appears to target this vulnerable group.