Origin of HIV

HIV pandemic was created by 'perfect
storm' of factors, study reveals
Scientists believe the findings have
finally nailed the origin of Aids pandemic
to a single source
Some experts believe service outsourcing
to private firms has reduced access to HIV
testing
By STEVE CONNOR
Thursday 02 October 2014
A “perfect storm” of factors that came
together in colonial Africa early last
century led to the spread of Aids in the
human population and eventually a full-
blown pandemic infecting more than 75
million people worldwide, a study has
found.
A genetic analysis of thousands of
individual viruses has confirmed beyond
reasonable doubt that HIV first emerged
in Kinshasa, the capital of the Belgian
Congo, in about 1920 from where it
spread via the colonial railway network to
other parts of central Africa.
Scientists believe the findings have finally
nailed the origin of the Aids pandemic to
a single source, a colonial-era city then
called Leopoldville which had become the
biggest urban centre in Central Africa and
a bustling focus for trade, including a
market in wild “bush meat” captured
from the nearby forests.
The study, based on analysing the subtle
genetic differences between various
subtypes of HIV, found the human virus
had evolved from a simian virus infecting
chimps which were hunted for food by
people who had probably carried HIV
with them into Kinshasa.
Rapid social changes, such as an increase
in commercial sex workers and the re-use
of dirty syringes, aided the transmission
of the virus which was also carried to
distant parts of the Congo by the millions
of passengers who used the newly-built
railway network, the scientists said.
“For the first time we have analysed all
the available evidence using the latest
phylogeographic techniques, which
enable us to statistically estimate where a
virus comes from,” said Professor Oliver
Pybus of Oxford University, a senior
author of the study published in the
journal Science.
“This means we can say with a high
degree of certainty where and when the
HIV pandemic originated. It seems a
combination of factors in Kinshasa in the
early 20 Century created a ‘perfect storm’
for the emergence of HIV, leading to a
generalised epidemic with unstoppable
momentum that unrolled across sub-
Saharan Africa,” Professor Pybus said.
Previous research had suggested that HIV
was first transmitted from chimps to
humans and that the pandemic probably
originated in central Africa in the first
half of the last century. However, the
latest research provides the strongest case
for it emerging at a definite time and
place – namely Kinshasa in 1920.
“We have managed to integrate spatial
information to see where the virus
emerged and how it spread to become a
full-blown pandemic. Kinshasa at that
time was growing fast, it was the biggest
city in central Africa at that time and was
very well connected to the rest of the
Congo,” said Nuno Faria of Oxford,
another member of the team.
“Data from colonial archives tells us that
by the end of the 1940s over one million
people were travelling through Kinshasa
on the railways each year. Our genetic
data tells us that HIV very quickly spread
across the Democratic Republic of Congo,
a country the size of Western Europe,” Dr
Faria said.
Further social changes brought about as a
result of independence in 1960 helped the
virus to “break out” from small groups of
infected people into the wider population,
including immigrant workers from Haiti
who then carried their infection back
home from where it would eventually be
transmitted to visitors from the US.
“Our research suggests that following the
original animal-to-human transmission of
the virus, probably through the hunting
or handling of bush meat, there was only
a small window during the Belgian
colonial era for this particular strain of
HIV to emerge and spread into a
pandemic,” Professor Pybus said.
“By the 1960s, transport systems such as
the railways that enabled the virus to
spread vast distances were less active, but
by that time the seeds of the pandemic
were already sown across Africa and
beyond,” he said.
Previous studies have suggested that the
initial transmission of HIV from chimps to
humans probably occurred in the south-
east part of Cameroon not far from the
border with the Belgian Congo, Dr Faria
said.