Tracking Ebola

The children of West Africa.
Trekking through the jungle.

Last March, Scripps Research scientist Erica Ollmann Saphire traded her climate-controlled La Jolla lab for the 95 degree humidity of the West African jungle. There, she and her 64-year-old administrative assistant, Ellen Klahn, spent two weeks tracking the Ebola virus, which had been the subject of her research for the past five years.

"It was an opportunity to see where Ebola lives," Ollmann Saphire says. "In the lab we're so reductionist, we look at molecules. But these molecules are made this way so they can live in a hot, sticky rainforest or cave. To understand why they are the way they are, you have to see them in nature."

The Ebola virus is among the more horrific known to humankind. It spreads when people come into contact with the bodily fluids of an infected individual. Symptoms first include a sudden fever, headache, and sore throat, then progress to vomiting, diarrhea, rash, and kidney and liver failure. In the final stages, massive hemorrhaging causes heavy bleeding from body openings and internal organs.

Although relatively rare in humans – there have been fewer than 30 known outbreaks and around 1,200 human deaths since it was first identified in Zaire, now the Democratic Republic of Congo, in 1976 – it seems to be devastating primate populations in Central Africa. One study, published in 2006 in the journal Science, suggests that Ebola was responsible for the death of one quarter of the world's gorilla population during the previous 12 years.

The Scripps Research team's two weeks were spent trekking through the jungle and waiting for the moment when an animal would appear – something that might give them a better picture of how Ebola spreads. Based on seroreactivity among the wild animal population, Ollmann Saphire was confident there were Ebola viruses circulating in places like this, even where there has never been a human outbreak.

Back at her lab, Ollmann Saphire applied this close-up look at the virus's home to her efforts to characterize it on the molecular level.

"Viruses are here to propagate themselves just like us," she says. "Basically, we're competing for the same resources."

Ollmann Saphire's breakthrough study appeared on the cover of the journal Nature, lifting the veil from the virus's spike-shaped protein, a critical step in understanding how Ebola works and an essential step for any potential development of a treatment or vaccine.

The Ebola virus glycoprotein itself, the one thing that is necessary for attaching to and infecting a host, has been a therapeutic target for more than 10 years. But because the structure was unknown, no one knew how to take advantage of it.

The glycoprotein comes covered in what has been described as a "cotton candy coating" of jumbled proteins and carbohydrates, which helps stabilize the virus and enables it to escape the immune system by keeping the all-important binding mechanism hidden.

The structure uncovered by the lab showed the few surface sites not hidden by that carbohydrate-protein coating, and explained how the pathogen evades the human immune system. The structure also gives researchers weaknesses to target in developing any potential therapeutic.

"Those sites are chinks in the virus's elaborate armor that we can target antibodies against," says Ollmann Saphire.

The recent spurt of fame that followed her Ebola breakthrough is a rare, although appreciated, moment of glory.

"We toil in obscurity, so when we succeed like this, we can show [those] who fund our work what their investment can do."

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