Fort Detrick scientists target Ebola

June 11, 1995|By Douglas Birch | Douglas Birch,Sun Staff Writer

FREDERICK -- Behind sea-green cinder block walls and stainless steel doors, protected by space suits and sterilizing chemical showers, scientists here are searching for weapons to fight one of Earth's most dangerous predators.

This is Fort Detrick's U.S. Army Medical Research Institute of Infectious Diseases, or USAMRIID, one of only five laboratories in the world equipped for the study of such super-lethal, untreatable diseases as Marburg, Lassa and Crimean-Congo hemorrhagic fever.

But recent books, a movie and a deadly epidemic in Africa have focused an international spotlight on USAMRIID's work on one murderous microbe in particular: the Ebola virus.

Last week, two USAMRIID scientists -- an entomologist who studies mosquitoes that carry disease and a veterinarian specializing in large animals -- left the institute for Zaire to find the roots of the latest Ebola outbreak.

The two Fort Detrick scientists will join nine others from the national Centers for Disease Control and Prevention, as part of an effort to discover the animal that shelters the virus between human epidemics and how the virus launches its sporadic, deadly assaults on humans.

Here at USAMRIID, meanwhile, work continues in Biosafety Level Four laboratories -- equipped to handle the most dangerous pathogens known -- on finding ways of attacking Ebola. Samples of the virus from its six known outbreaks since 1976 are locked in freezers.

Ten scientists in this beige concrete building, which resembles a modest suburban hospital, are conducting research on Ebola. Some are hunting for a vaccine to protect against infection. Others are testing drugs, being developed for unrelated

diseases, that might cure or control the virus. And some are trying to develop a faster test to identify the microscopic killer.

"The ultimate goal, as with anything, is to come up with countermeasures," said Lt. Col. Jerry B. Jennings, a veterinarian and microbiologist who is chief of USAMRIID's 50-person virology division.

If a vaccine for Ebola is invented, he said, it would probably come from USAMRIID. But it's not coming soon. "We're talking probably -- and this is tremendously optimistic -- three to five years" for the development of a prototype vaccine, he cautioned. "And three to five years would be if nothing went wrong."

When and if researchers create a prototype vaccine, it would take several years to test it for safety and effectiveness in the test tube, in animals and, eventually, in humans.

Seeking a quicker fix

In the meantime, Colonel Jennings said, Army researchers are searching for a quicker fix. Specifically, he said, they are looking at drugs that pharmaceutical firms are developing to fight Respiratory Syncytial Virus, or RSV, a respiratory disease that can be dangerous to small children, to see if they also could treat Ebola.

These experimental drugs, he said, appear to block RSV's production of certain enzymes produced by the virus after it invades a cell. Those enzymes change the virus itself, better adapting it to commandeering the cell's machinery.

USAMRIID researchers say they suspect these new drugs might have the same effect on Ebola. (Viruses are encapsulated packages of genetic material that are not alive in the sense cellular organisms are. A virus invades a cell, then turns the cell into a factory to make more virus.)

Once established, the virus kills rapidly by liquefying organs and other tissue, causing massive bleeding.

Though Ebola was discovered almost 20 years ago, much about it remains a mystery. For example, scientists don't know why it can be so lethal.

The CDC said Friday that its latest figures showed 202 of 248 Ebola victims in Zaire died -- an 81 percent fatality rate. However, health officials said the epidemic appeared to be ending.

Scientists risk death

Scientists studying Ebola in institute laboratories risk infection and death themselves. Though shielded in a cocoon of technology, including head-to-toe pressurized plastic space suits, they could be stuck with syringes or nicked by sharp

bones in bodies of lab animals.

Anyone known to be exposed to a dangerous disease must be quarantined in the four-bed isolation ward, called "the Slammer."

Cheryl Parrott, a spokeswoman for the institute, said that in the past 26 years, only 20 people have been confined to the Slammer. None died and only one developed an illness, a form of dengue fever that wasn't life-threatening.

CDC and institute researchers in Zaire also will risk infection as they search for Ebola's hiding place.

Rescuing them would be the job of Maj. Stephen W. Lomax, an Army nurse.

Major Lomax is chief of a 16-member aeromedical isolation team, on standby to evacuate any U.S. citizens who might contract Ebola in Zaire. Patients would be placed in a portable isolation stretcher, essentially a plastic tent equipped with an air lock and air pumps to create a negative airflow -- meaning unfiltered air could flow into the tent, but not out of it.

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