How HIV turned pandemic

A piece of research into the early spread of HIV that I find interesting seems to have slipped the attention of the science press. In two papers published online recently Jacques Pépin and colleagues test a hypothesis of how outbreaks of the disease turned into a pandemic – and I’m thinking this could tell us something about how to control other blood-borne zoonoses.

The work is the first to provide evidence supporting the idea that HIV began to spread widely in sub-Saharan Africa with the use of unsterilised medical equipment beginning in colonial times, in the early 20th century – when large-scale infection control programmes were put in place to tackle endemic diseases like malaria.

The idea is that spread of the virus through unsafe equipment built up a “pool” of infections first, and then sex took over as the primary mode of transmission. Thomas Strickland of the University of Maryland writes in a a commentary that the data are convincing.

As I mention in the story [PDF], the hypothesis is not new, but no one has been able to test it until now. To me, it’s fascinating not only as an explanation for the early spread of HIV beyond isolated outbreaks, but as an insight into how widespread transmission of blood-borne zoonoses might be prevented.

The origin of HIV is still being debated but I’m assuming here, like most experts believe and as suggested in these papers, that it crossed the species barrier to cause outbreaks as people got exposed to infected ‘bush meat’.

I’m not saying that doctors would risk not taking precautions against any disease, especially big killers like Ebola haemorrhagic fever, an example of a zoonosis that we know about and which has clearly identifiable symptoms. But what if a blood-borne virus slips under the radar – are improvements in medical practice and resources now adequate to prevent something similar from happening again, in Africa or elsewhere?

There is momentum in global health policy towards strengthening healthcare systems. This research may be pointing to a reason to focus even more on making sure that health care is safe in zoonotic disease hotspots.