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Where Does Ebola Hide Between Epidemics?
National Geographic ^ | February 19, 2003 | Stefan Lovgren

Posted on 02/22/2003 10:14:52 AM PST by Dog Gone

When villagers in the remote jungles of the Republic of Congo began falling ill last month, scientists quickly suspected Ebola. The virus had been confirmed in tests on the bodies of animals found dead in surrounding forests, and bush meat is a staple among the local population.

Knowing how people may initially have contracted the virus has given medical experts a jumpstart on the epidemic, which has so far killed at least 64 people. But the larger question remains. Where does the deadly Ebola virus hide between outbreaks?

"Primates die from Ebola," just like humans, said Dick Thompson, a spokesperson for the World Health Organization, which has sent a team of experts to the region. "The virus must live somewhere else in the environment."

The search for a natural host has eluded scientists ever since the first Ebola epidemics in 1976. The quest is a catch-22. While an outbreak offers the best opportunity to find the natural reservoir, the priority for virus hunters is to contain the epidemic. In the process, the trail often goes cold because the virus kills so swiftly it covers its tracks.

Ebola is one of the most contagious viruses known to man. A simple handshake can transmit the disease. Depending on the strain, Ebola kills anywhere from 50 to 90 percent of its victims through massive internal bleeding. Worst of all, there is no cure.

Finding out where the virus is hiding between outbreaks would help predict how often it will strike and could aid in the adoption of safety measures. The genetic variability of the virus in its natural host may help design a vaccine.

Immune to Ebola

There has long been speculation among scientists that bats are the natural reservoir for Ebola. In scientific experiments, researchers have injected bats with the Ebola virus, and the bats have survived. "You find bats in almost every outbreak," said Bob Swanepoel, head of the Special Pathogens Division at South Africa's National Institute for Communicable Diseases.

Bats were found in the roof of a Sudanese cotton factory where six people died in a 1976 epidemic. A Danish student died of Ebola after visiting a bat-infested cave in Kenya. At least 60 miners in northeastern Congo died from Marburg, an Ebola-related virus that may share Ebola's natural reservoir, during a 1999 outbreak. Six of the seven mining quarries were open, the seventh was located underground with an estimated 30,000 bats living in it. All of the miners who contracted the disease worked in the underground mine.

Swanepoel has collected bats during several Ebola and Marburg outbreaks. "We have seen evidence of Ebola in bats," he said. "But we have never been able to isolate the virus." He believes only a fraction of the bats may host the virus. Catching the right specimens is almost impossible.

Transmitting the Virus

The latest outbreak began after researchers from the Wildlife Conservation Society reported a massive decline in ape populations in the Lossi Gorilla Sanctuary in northern Republic of Congo. In mid-December, scientists from the Centre International de Recherches Medicales de Franceville (CIRMF) in neighboring Gabon collected samples from four gorilla and two chimpanzee carcasses and confirmed the presence of Ebola in all six cases.

Even without lab confirmation on the human deaths, scientists are treating this epidemic as an Ebola outbreak. "The clinical presentation of the cases, the high death rates and confirmed reports of primate deaths which tested positive for Ebola all point in that direction," said the WHO's Thompson.

The first victim, or "index case," is believed to have eaten or come in contact with an infected animal. An Ebola epidemic in the same region in 2001, which killed 73 people, was also linked to people eating infected primates. After the initial infection, the virus is usually transmitted from human to human.

Containing the epidemic is particularly difficult because the affected villages are tucked into impenetrable forests about 440 miles (710 kilometers) from Brazzaville, the capital of the Republic of Congo. Cordoning off the area is impossible. Cultural practices also complicate efforts. Religious rites, for example, dictate that family members wash the body of a dead person before burial.

While past outbreaks have been concentrated in, say, a village, the current epidemic is "multi-centric," or spread over a vast area. This suggests that the natural host for Ebola could also be active over a large area. Scientists have speculated that insects, or maybe birds, could carry the virus.

New Research

In December, a Purdue University science team presented new research that links Ebola with birds. According to the study, the outer protein shell of filoviruses, such as Ebola, have a biochemical structure similar to retroviruses carried by birds, making a common evolutionary origin more likely.

"There can be no doubt now that an ancestral virus had a shell that evolved to become the shells of the Ebola virus and bird retroviruses," said David Sanders, the professor who headed the research team.

Sanders stresses that his discovery does not prove that birds are the natural reservoir for Ebola. But it makes them more plausible hosts. The prospect of migratory birds carrying Ebola has obvious health implications.

Some scientists already worry that Ebola could mutate and become airborne. Recent outbreaks have suggested it can evolve on its own. All the Ebola subtypes have shown the ability to be spread through airborne particles under research conditions. One strand, Ebola-Reston, may have been transmitted from monkey to monkey through the air in a Virginia science lab. So far there have been no similar transmissions involving humans.



TOPICS: Culture/Society
KEYWORDS: ebola
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1 posted on 02/22/2003 10:14:53 AM PST by Dog Gone
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To: Dog Gone
Where Does Ebola Hide Between Epidemics?

Iraq?

2 posted on 02/22/2003 10:19:18 AM PST by null and void
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To: null and void
The prospect of migratory birds carrying Ebola has obvious health implications.

Beware of African Swallows.

3 posted on 02/22/2003 10:22:29 AM PST by Dog Gone
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To: Dog Gone
Damm straight! If they can carry a coconut, God knows what else they could carry...
4 posted on 02/22/2003 10:23:51 AM PST by null and void
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To: Dog Gone
In monkeys that are inmmune to it.(?) (Don't eat the monkeys!)
5 posted on 02/22/2003 10:28:14 AM PST by blam
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To: Dog Gone
"All the Ebola subtypes have shown the ability to be spread through airborne particles"

"Ebola is one of the most contagious viruses known to man. A simple handshake can transmit the disease. Depending on the strain, Ebola kills anywhere from 50 to 90 percent of its victims through massive internal bleeding. Worst of all, there is no cure."

Sounds like something to worry about, even more than smallpox.

6 posted on 02/22/2003 10:35:07 AM PST by sd-joe
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To: blam
One strand, Ebola-Reston, may have been transmitted from monkey to monkey through the air in a Virginia science lab.

I'm losing interest in becoming a lab worker in Virginia.

7 posted on 02/22/2003 10:36:02 AM PST by Dog Gone
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To: Dog Gone
Ebola is one of the most contagious viruses known to man. A simple handshake can transmit the disease.

This is actually B$ ... ebola does not have a decent protein coat to survive as an airborne or contact disease well. Body fluids exchange or close contact is what it take to spread ebola.

If it ever does go airborn like the flu or like smallpox, God help us all because it will get out of Africa and kill billions.

8 posted on 02/22/2003 10:40:34 AM PST by Centurion2000 (Take charge of your destiny, or someone else will)
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To: Dog Gone
No guts, no glory...
9 posted on 02/22/2003 10:40:55 AM PST by null and void
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To: Centurion2000
It's no accident my counter protest sign says:

Save Billions of lives
Stop Saddam now!

10 posted on 02/22/2003 10:43:10 AM PST by null and void
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To: null and void

11 posted on 02/22/2003 10:47:25 AM PST by Dog Gone
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To: Dog Gone
Bump for later
12 posted on 02/22/2003 10:57:03 AM PST by lorrainer (EVERYBODY thinks I'm paranoid!)
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To: sd-joe
There is a Tom Clancy book about a group who develops a resistant strain of ebola for use in a world epidemic.

Can't remember the title.
13 posted on 02/22/2003 11:00:01 AM PST by Rebelbase
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To: Rebelbase
Executive Orders.
14 posted on 02/22/2003 11:10:35 AM PST by null and void
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To: Rebelbase
There is a Tom Clancy book about a group who develops a resistant strain of ebola for use in a world epidemic.

By Muslim group in "Executive orders", and there's an environmentalist group that tries to wipe out all of mankind (except for the elite like them) in "Rainbow Six"

15 posted on 02/22/2003 11:15:58 AM PST by SauronOfMordor (To see the ultimate evil, visit the Democrat Party)
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To: Centurion2000; Dog Gone
Now you can start worrying, if this is true. (It's always something!)

Purdue Research Hints That Birds Could Spread Ebola Virus

16 posted on 02/22/2003 11:22:01 AM PST by blam
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To: Rebelbase
There is a much better nonfiction book on Ebola that is both exciting and informative called "The Hot Zone" by Richard Preston (he also just released one, "The Demon in the Freezer", covering smallpox, anthrax, biowar, Iraq, the French, etc. It's phenomenal, and blesters the French). I recommend it highly.
17 posted on 02/22/2003 11:24:00 AM PST by Chancellor Palpatine (those who unilaterally beat their swords into plowshares wind up plowing for those who don't)
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To: Dog Gone
Let's go ahead and link all the scary 'stuff' together.

5 Who Died had Flu-Like symptoms

18 posted on 02/22/2003 11:27:30 AM PST by blam
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To: SauronOfMordor
"The Hot Zone" by Richard Preston is probably the best factual book on the Ebola virus. It was published in 1994 so it is a bit out of date but it provides great background on some of the initial African outbreaks and the episode at the Reston Virginia Primate facility.

If the human lethal type of this virus develops the ability to spread via air, we're screwed.

And it ain't a pretty way to die.
19 posted on 02/22/2003 11:28:37 AM PST by XRdsRev
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To: null and void
SauronOfMordor got it on #15. Exec. orders was about the Islamic Nuke. Rainbow Six was the one with the envirowackos and ebola.
20 posted on 02/22/2003 11:28:51 AM PST by Rebelbase
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