Volunteers of National Service Scheme (NSS) pose with HIV/AIDS awareness messages on their faces.Reuters

An HIV infection normally takes at least 10 years to progress into AIDS. Scientists in Belgium say an aggressive type of HIV strain discovered recently in Cuba needs only three years to cause AIDS.

Progression of the HIV infection into AIDS involves a few steps. The strain uses certain proteins on the cell membrane called anchor points to enter the human cells. Using the anchor point CCR5 initially, the strain later switches to anchor point CXCR4.

This switching process takes many years and the patient can live healthy till the transition. However, the co-receptor switch from CCR5 to CXCR4 speeds up the progression of HIV into AIDS.

The case, detailed in EBioMedicine, cautioned against engaging in unprotected sex with multiple partners as it increases risk of being exposed to several strains of HIV and creation of a new strain.

The new strain, according to Professor Anne-Mieke Vandamme and colleagues from KU Leuven in Belgium, directly targets the anchor point CXCR4 and facilitates rapid transmission of HIV into AIDS.

The study looked at 95 patients. Of the 73 recently infected patients, 52 had AIDS and 21 were free from the syndrome. The rest 22 patients developed AIDS after a gap of some healthy years.

On testing their blood samples, researchers found that, the recently infected people had high doses of the new HIV strain and defensive molecules part of the immune system called RANTES. These molecules work by binding to CCR5, which the HIV virus also requires to enter human cells. This scarcity of CCR5 anchor points might have led the new strain to target the CXCR4 directly, the authors said.

Providing more solid evidence to prove this theory, the patients infected with the new recombinant HIV strain developed AIDS within three years.

Researchers said that the ability of the new strain to target CXCR4 directly may be an enzyme called protease. Presence of this enzyme facilitates the virus to duplicate more and successfully bind to anchor point CXCR4.

A similar case was reported by IBTimes India in November 2013. Researchers reported that the new strain known as A3/02, a recombination of two common forms of HIV in West Africa, known as 02AG and A3, needed less than five years to progress into AIDS.