A study published Wednesday in the journal Nature confirms the fact that the battle against the HIV virus is far from coming to a happy end. "It's very clear there's a battle going on between humans and this virus, and the virus is evolving to become unrecognized by the immune system," said Dr. Bruce Walker, one of the researchers and director of the Ragon Institute, at Massachusetts General Hospital in Boston. "It does make clear what a huge challenge making a vaccine is."

For instance, Last month the health ministry reported that the number of new HIV cases and AIDS diagnoses in Japan hit a high of 1,545 in 2008. According to the health ministry, 1,113 people were found to be infected with the HIV virus that can lead to AIDS, and 432 others were diagnosed with AIDS. This is the sixth consecutive year that a record number of new HIV cases has been reported, and the third straight year that a record number of AIDS diagnoses has been made.

In the meantime, health officials in northwest China are reporting a sharp increase in the number of AIDS cases being reported. The number of reported cases of HIV/AIDS rose by 50 percent last year to 216 in northwest China's Gansu Province. Fifty-five people already showed full-blown AIDS symptoms and 34 others had died of the disease in the past year, said Yu Ailing, head of STD/HIV/AIDS prevention at the GPCDC.

"The main reason behind the rising number of HIV/AIDS cases year on year lies in the fact the government has stepped up efforts to prevent and control the spread of HIV/AIDS, and tests and monitoring were tightened accordingly," said Yu.

Although treatments exist that can suppress HIV, there is no vaccine or cure. Prevention remains the only fully effective defense against the deadly virus. One doesn't have to "sleep around" to contract HIV; just a single exposure to the virus can result in infection. And because symptoms can take years to appear, many infected people are unaware they are carrying the virus. Ever since the AIDS virus was first identified more than 25 years ago, over 25 million lives have been lost because of the disease.

Throughout the study mentioned above, researchers from the Ragon Institute, Oxford University in England, Kumamoto University in Japan, and Royal Perth Hospital and Murdoch University in Australia analyzed the genetic sequences of HIV and human leukocyte antigen genes in 2,800 people total.

Infection with HIV occurs by the transfer of blood, semen, vaginal fluid, pre-ejaculate, or breast milk. Within these bodily fluids, HIV is present as both free virus particles and virus within infected immune cells. The four major routes of transmission are unprotected sexual intercourse, contaminated needles, breast milk, and transmission from an infected mother to her baby at birth. Screening of blood products for HIV has largely eliminated transmission through blood transfusions or infected blood products in the developed world.