Monday, February 27, 2012

Colonialism in Africa helped launch the HIV epidemic a century ago

Colonialism in Africa helped launch the HIV epidemic a century ago


By Craig Timberg and Daniel Halperin


The Washington Post


Monday, February 27, 5:55 PM


We are unlikely to ever know all the details of the

birth of the AIDS epidemic. But a series of recent

genetic discoveries have shed new light on it, starting

with the moment when a connection from chimp to human

changed the course of history.


We now know where the epidemic began: a small patch of

dense forest in southeastern Cameroon. We know when:

within a couple of decades on either side of 1900. We

have a good idea of how: A hunter caught an infected

chimpanzee for food, allowing the virus to pass from

the chimp's blood into the hunter's body, probably

through a cut during butchering.


As to the why, here is where the story gets even more

fascinating, and terrible. We typically think of

diseases in terms of how they threaten us personally.

But they have their own stories. Diseases are born.

They grow. They falter, and sometimes they die. In

every case these changes happen for reasons.


For decades nobody knew the reasons behind the birth of

the AIDS epidemic. But it is now clear that the

epidemic's birth and crucial early growth happened

during Africa's colonial era, amid massive intrusion of

new people and technology into a land where ancient

ways still prevailed. European powers engaged in a

feverish race for wealth and glory blazed routes up

muddy rivers and into dense forests that had been

traveled only sporadically by humans before.


The most disruptive of these intruders were thousands

of African porters. Forced into service by European

colonial powers, they cut paths through the exact area

that researchers have now identified as the birthplace

of the AIDS epidemic. It was here, in a single moment

of transmission from chimp to human, that a strain of

virus called HIV-1 group M first appeared.


In the century since, it has been responsible for 99

percent of all of the world's deaths from AIDS -- not

just in Africa but in Moscow, Bangkok, Rio de Janeiro,

San Francisco, New York, Washington. All that began

when the West forced its will on an unfamiliar land,

causing the essential ingredients of the AIDS epidemic to combine.


It was here, by accident but with motives by no means

pure, that the world built a tinderbox and tossed in a spark.


The chimps of Cameroon


Many simians, such as gorillas and monkeys, can carry a

virus that resembles HIV. But scientists now know that

HIV-1 group M was born from a virus circulating among a

community of chimpanzees concentrated in Cameroon, a

sprawling country with bustling Atlantic Ocean ports,

populous highlands, and a lightly developed southern

region where relatively few people live even today.

This was home to the chimps.


Finding a more exact location took a remarkable degree

of scientific ingenuity. An international research team

led by Beatrice Hahn of the University of Alabama at

Birmingham and Paul Sharp of the University of

Edinburgh developed an elaborate project that involved

searching for the simian virus in chimp feces collected

across a vast swath of southern Cameroon.


To find a strain of the simian virus that was, on a

genetic level, essentially indistinguishable from the

most lethal form of HIV, the research team set up 10

stations across the region. Two of the stations were in

the particularly remote southeastern corner of the

nation, as far as possible from major population centers.


It was in these two stations where Hahn and Sharp's

team discovered samples of the simian virus that was

almost a perfect match for the HIV-1 group M that

eventually killed tens of millions of humans.


This discovery, published in the journal Science in

2006, intensified the quest for a birth date for the

virus. Again, genetic research offered the key clues.


Scientists had long known that a blood sample,

preserved from 1959, showed that HIV had been

circulating in Kinshasa, the capital of Congo, for

several decades before the virus first drew

international attention in the 1980s. In 2008,

evolutionary biologist Michael Worobey sharpened that

picture when he reported in the journal Nature the

discovery of a second sample of the virus, trapped in a

wax-encased lymph node biopsy from 1960.


By comparing these two historic pieces of virus and

mapping out the differences in their genetic structures

in his lab at the University of Arizona, Worobey

determined that HIV-1 group M was much older than

anyone had thought. Both samples of the virus appeared

to have descended from a single ancestor at some time

between 1884 and 1924. The most likely date was 1908.


Taken together, these two discoveries offered the

clearest clues to the birth and early life of the epidemic.


Not far from where HIV-1 group M was born was a major

river, the Sangha, flowing toward the heart of Central

Africa. This section of the Sangha was not ideal for

navigation because of its ribbons of sandbars and the

dense vegetation along its banks.


In the especially treacherous middle section, near

where Hahn and Sharp's team found the viral ancestor of

HIV, few major human settlements ever developed. But

there were numerous communities on the Sangha's more

accessible stretches. And due south, past riverside

trading towns, was the mighty Congo River itself, the

superhighway of Central Africa.


Once the virus made the jump from chimp to human, a

single infected person could have carried HIV down the

Sangha, onto the Congo River and into Kinshasa. The

Belgians had founded the city in 1881, during what

historians call "The Scramble for Africa," when

colonial powers carved up the continent into areas of

influence. By the early 20th century Kinshasa, then

called Leopoldville, was the biggest city in Central

Africa, fueled by the dizzying growth of trade with the

outside world.


A final, powerful bit of evidence supported the theory

that Kinshasa lay at the heart of the epidemic's early movements.


Scientists studying HIV-1 group M already had found

many related varieties, what scientists call subtypes,

each with slightly different genetic structures and

paths through the world. One, scientists discovered,

had traveled east from Kinshasa toward Lake Victoria.

One went south to Zambia, Botswana and South Africa.

One hopped all the way across the ocean to Haiti, then

to the United States and Europe.


Many others traveled not very far at all, staying in

the Congo Basin. But as scientists plotted out the

genetic histories of these varieties and built an

extensive family tree for HIV, they all appeared to

have spread from a single explosion, a big bang of the

AIDS epidemic: Ground Zero was Kinshasa.


Ivory and rubber


Powering the big bang was the burgeoning trade of

colonial Africa.


Ivory may seem a touch quaint today, but in its heyday

it was seen as beautiful, versatile and essential to

many everyday products. It was used to make billiard

balls, jewelry and cutlery. Furniture makers

incorporated it into their cabinets, artists into their

statues. Bagpipe makers used ivory for mounts,

ferrules, buttons and mouthpieces.


When supplies of ivory gradually grew short, as

colonial agents killed the once plentiful elephants by

the thousands, rubber took its place as the economic

lifeblood of colonialism in the Congo Basin. The first

inflatable rubber tires for bicycles became popular in

the 1890s. Mass production of cars soon spiked demand

for rubber tires again.


The only obstacle to European companies' reaping huge

profits was that collecting ivory and rubber required

massive amounts of labor. Getting ivory from an

elephant meant stalking the animal, killing it and

cutting off its tusks. Getting rubber from vines

required slashing them, collecting the oozing white sap

and drying it -- sometimes on the collector's own skin.


The solution to the manpower demands soon became

obvious. Colonial powers created what was essentially

slavery: cheap muscle at the point of a gun.


This approach was not confined to collecting ivory and

rubber. These industries created tremendous new needs

for infrastructure to get goods to oceangoing ships

along the Atlantic coast. That meant African porters

had to carry goods and supplies anyplace the steamboats

couldn't reach.


Workers were needed to build railroads, trading

stations, dormitories. And somebody needed to operate

the steamboats, load the railroad cars, carry the tusks

or gobs of rubber in from the jungle. When workers

became unruly, the colonial companies deployed heavily

armed soldiers to keep the cogs of these vast

enterprises moving.


All these roles were filled by Africans, many imported

from villages hundreds or even thousands of miles away.

African life here was beyond cheap. It was disposable.

Contemporary accounts by journalists and missionaries

tell of colonial officials across the Congo Basin

ordering mass slaughters and the torching of restive

villages while creating forced settlements that

resembled nothing so much as concentration camps.


The role of African porters


In December 1895 German colonial authorities heard

reports that Cameroon's southeastern corner contained

fabulously rich ivory and rubber stocks awaiting exploitation.


The Germans soon after gave authority to a colonial

company to take control of the region by force. Over

the next four years they extended their power all the

way through southeastern Cameroon and established a

trading station on the Ngoko River about 75 miles

upstream from where its waters merged with the Sangha.

In the wedge of land defined by these two rivers, HIV

either had just been born or soon would be.


The trading station was called Moloundou, and a busy

town remains there today. But at the time it was almost

unimaginably remote. Few human settlements had

developed among these forbidding forests. And there

were only two practical ways out: by steamship down the

Ngoko to the Sangha and on to the Congo River; or

overland by foot to the Atlantic.


The river route was the easier of the two, and

steamships transported the bulk of the ivory and rubber

collected in southeastern Cameroon. But overland routes

were necessary to connect Moloundou with other trading

stations and inland areas rich with rubber and ivory.


For these journeys the bounty was borne by Africans who

carried loads averaging 55 pounds each. At the peak of

the foot traffic that would develop between inland

areas and the coast, the busy way station recorded more

than a thousand porters passing by on a typical day.


Trade routes, disease routes


Ominously, something else followed the rubber trade

through Cameroon: disease. Sleeping sickness, smallpox

and skin infections were the most obvious.


Colonial authorities attempted mass inoculation

campaigns for smallpox and set up quarantine zones that

restricted where the porters were allowed to travel.

But even so, the diseases spread.


Among them was syphilis, which arrived with the

Europeans. In just a few years it reached epidemic

proportions along porter routes and riverside trading

posts in Cameroon and throughout the Congo Basin. It's

impossible now to determine how much of this spread

resulted from rapes as opposed to other kinds of

encounters, but it's clear that colonial commerce

created massive new networks of sexual interactions --

and massive new transmissions of infections. (In later

decades, transmission through the reuse of hypodermic

needles in medical care probably had some role in HIV's

spread as well.)


So HIV's first journey looked something like this: A

hunter killed an infected chimp in the southeastern

Cameroonian forest, and a simian virus entered his body

through a cut during the butchering, mutating into HIV.


This probably had happened many times before, during

the centuries when the region had little contact with

the outside world. But now thousands of porters -- both

men and women -- were crossing through the area

regularly, creating more opportunities for the virus to

travel onward to a riverside trading station such as Moloundou.


One of the first victims -- whether a hunter, a porter

or an ivory collector -- gave HIV to a sexual partner.

There may have been a small outbreak around the trading

station before the virus found its way aboard a

steamship headed down the Sangha River.


For this fateful journey south, HIV could have ridden

in the body of these first victims, or it could have

been somebody infected later: a soldier or a laborer.

Or it could have been carried by a woman: a concubine,

a trader.


It's also possible that the virus moved down the river

in a series of steps, maybe from Moloundou to Ouesso,

then onward to Bolobo on the Congo River itself.


There might even have been a series of infections at

trading towns along the entire route downriver. Yet

even within these riverside trading posts HIV would

have struggled to create anything more than a

short-lived, localized outbreak.


Most of this colonial world didn't have enough

potential victims for such a fragile virus to start a

major epidemic. HIV is harder to transmit than many

other infections. People can have sex hundreds of times

without passing the virus on. To spread widely, HIV

requires a population large enough to sustain an

outbreak and a sexual culture in which people often

have more than one partner, creating networks of

interaction that propel the virus onward.


To fulfill its grim destiny, HIV needed a kind of place

never before seen in Central Africa but one that now

was rising in the heart of the region: a big, thriving,

hectic place jammed with people and energy, where old

rules were cast aside amid the tumult of new commerce.


It needed Kinshasa. It was here, hundreds of miles

downriver from Cameroon, that HIV began to grow beyond

a mere outbreak. It was here that AIDS grew into an epidemic.


Laying the scientific story alongside the historical

one offers one final revelation. In the 1920s, as

railroads became widely available, the Sangha River's

value as a steamship route dwindled sharply. Global

rubber prices also collapsed. The pace of human

movement through the region eased.


So the improbable journey of the killer strain of HIV

was feasible for only a few hectic decades, from the

1880s to the 1920s. Without "The Scramble for Africa,"

it's hard to see how HIV could have made it out of

southeastern Cameroon to eventually kill tens of

millions of people. Even a delay might have caused the

killer strain of HIV to die a lonely death deep in the forest.


From "Tinderbox" by Craig Timberg and Daniel Halperin.

Reprinted by arrangement with The Penguin Press, a

member of Penguin Group (USA) inc. Copyright (c) Craig

Timberg and Daniel Halperin, 2012. Timberg, a former

foreign correspondent in Africa, is acting national

security editor of The Washington Post. Halperin was a

senior HIV prevention adviser in the U.S. government's

global AIDS program and is now an epidemiologist at the

University of North Carolina.


(c) The Washington Post Company


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