Medical specialists and network security experts have worked out that the HIV virus spreads through the body in a similar way to that of a computer worm.
Using a model call “hybrid spreading” they found that the virus progresses through the bloodstream and directly between cells. This, they say, is similar to computer worms that progress through both internet and local networks to infect as many computers as possible.
Prof Benny Chain, the co-senior author of the research, from University College London’s infection and immunity division, said: “I was involved in a study looking in general at spreading of worms across the internet and then I realised the parallel. They have to consistently find another computer to infect outside.
“They can either look locally in their own networks, their own computers, or you could remotely transmit out a worm to every computer on the internet. HIV also uses two ways of spreading within the body.”
The model has helped to predict patients’ progression from HIV to AIDS. According to the experts, early treatment is key to staving off AIDS.
HIV infects CD4 T cells, which play an important role in our immune system and help to protect us against opportunistic infections.
As the concentration of HIV increases it reduces the number of active CD4 T cells.
At a certain level the body’s immune system cannot work properly. This point is typically when the CD4 count falls below 200 and is described as acquired immune deficiency syndrome or AIDS.
At present, the World Health Organisation recommends anti-retroviral treatment in all adolescents, adults and pregnant women with a CD4 count less than 500 with this being especially important in those with counts less than 350.
But the latest research using this new model says treatment should start as soon as possible after infection to prevent AIDS from developing in the long term.
“The number of HIV cells in the bloodstream is always relatively low, and our model shows that HIV spread through the bloodstream alone would not be enough to cause AIDS,” Professor Chain added.
“It is likely that when HIV gains a foothold somewhere with a high T-cell population, such as the gut, it uses a cell-to-cell transfer mechanism to efficiently spread directly between them.
“Our model suggests that completely blocking cell-to-cell transfer would prevent progression to AIDS, highlighting the need to develop new treatments.”