New York, March 27 (IANS): In the absence of antiretroviral therapy, the human immunodeficiency virus (HIV) that causes AIDS can begin replicating in the brain as early as four months after initial infection, a new research has found.

The findings published in the journal PLoS Pathogens stress the importance of routine HIV testing to catch the infection as early as possible to allow the prompt initiation antiretroviral therapy.

"One-third of people not taking antiretroviral therapy (ART) to control their HIV will eventually develop HIV-associated dementia," said researcher Ronald Swanstrom, director, Center for AIDS Research (CFAR), University of North Carolina in the US.

The study followed 72 participants during the first two years of HIV infection. The participants were not taking antiretroviral therapy (ART) to control their HIV at the time of the study.

Through analysis of cerebral spinal fluid (CSF) and blood samples, 20 percent of the participants showed replication in the central nervous system (CNS) at four months.

Additionally, 30 percent of participants showed evidence of a marked CSF inflammatory response in at least one time point and 16 percent of study volunteers showed a marked CSF inflammatory response at multiple time points, suggesting an ongoing infection in the CNS.

"This shows that viral replication and inflammation can occur early in infection with the concern being that the damage caused could be irreversible," Swanstrom noted.

"HIV and inflammation have the potential to accelerate the aging process and cause neurocognitive impairment, in the extreme case resulting in HIV-associated dementia," Swanstrom pointed out.