FREDERICK, Md. — Scientists from Fort Detrick say the number of Ebola cases in West Africa is much larger than official estimates indicate.
Researchers from the U.S. Army Medical Research Institute of Infectious Diseases, who have worked in Sierra Leone and Liberia, say the current outbreak reaches beyond the 1,200 confirmed, suspected or probable cases and 670 deaths that the World Health Organization has identified in West Africa as of July 23.
"You can't get a very real idea of how extensive the number of cases out there actually are," said Randal Schoepp, a USAMRIID researcher working in the Liberia Institute for Biomedical Research. "Here in Liberia, at least, we're only seeing and identifying a small number of cases."
The outbreak of the Ebola virus disease, the largest in history, has caused overcrowding in hospitals and widespread fear in Guinea, Liberia and Sierra Leone, whose governments have reported hundreds of confirmed cases and deaths.
The disease has flu-like symptoms, followed by bleeding and often death. It is spread through contact with bodily fluids but is notoriously "fragile" and will not spread through air, according to USAMRIID researcher Aileen O'Hearn, who recently returned to Frederick from Kenema Government Hospital in Sierra Leone.
USAMRIID's researchers, with help from staff from the National Institute of Allergy and Infectious Diseases Integrated Research Facility at Fort Detrick, are working at hospitals in Sierra Leone and Liberia to identify the presence of the Ebola virus in patients who believe they may have been exposed.
That can be a difficult task in an overcrowded hospital, O'Hearn said. Since families of an infected patient often come to the hospital together, they run the risk of becoming unnecessarily infected. After patients are admitted, some contract secondary infections.
"Some of them had malaria, some had bacterial infections in their limbs from their IV lines," she said. "It's not kept to the standards we'd have here."
O'Hearn said they can confirm within four hours whether a patient has the Ebola virus.
"It's so critical to make that correct decision, so there's a lot of stress on the lab people to get it right. You make a wrong decision, and you might be sending a perfectly well patient into the Ebola ward," Schoepp said.
The fact that the virus has spread beyond villages and into densely populated city centers like Monrovia in Liberia makes it difficult to track and contain, according to Schoepp. Fear and ignorance about the disease worsen the conditions.
"There's still people that say Ebola isn't real, this is all a government conspiracy to get more money," he said.
Matthew Voorhees, a USAMRIID researcher who also recently returned from Kenema Government Hospital, said there's another layer of pressure and stress when nurses and doctors become infected.
Respect for the virus and knowledge of safety procedures are essential, Schoepp said.
"You would be stupid to not be concerned about getting infected," he said.
The layered protection they must wear in the labs includes a Tyvek suit with gloves and booties taped on to create a sealed environment. In labs without air conditioning, that can mean dealing with 100-degree heat for hours.
"Most of us are here because we want to be here, we want to help, but you also have to be cognizant of your own health," Schoepp said.
Researchers working with the virus at Kenema Government Hospital and the Liberia Institute for Biomedical Research take precautions when leaving containment labs. Unless there is a reason to suspect a staff member is infected, O'Hearn said, there are no special requirements for decontamination.
But government officials in Liberia have closed the country's borders, and Voorhees said checkpoints have been set up in Sierra Leone preventing people with fevers and Ebola virus disease symptoms from leaving the area.
"That's an indication that it's not going to end anytime soon," Schoepp said.
Outside of West Africa, Voorhees said there is little reason for people to be concerned about the virus.
"The odds are so vanishingly small," he said.
In the U.S., since resources are more readily available, Schoepp said any cases that are confirmed would be controlled quickly.
"It's something to be respected but not feared," he said. "We can handle that."
USAMRIID researchers, led by Schoepp, demonstrated in a recent paper that the Zaire strain of Ebola, currently dominating the outbreak, was present in the area before the outbreak started.
Each year, Kenema Government Hospital receives 500 to 700 unconfirmed samples of the Lassa fever virus, which has symptoms similar to Ebola virus disease and may also become fatal. Though only 30 to 40 percent of the samples received from 2006 to 2008 ended up testing positive for the Lassa virus, they also found Rift Valley fever, Ebola virus, Marburg virus, yellow fever and West Nile virus, among others, in the samples.
The USAMRIID researchers found that the majority of the samples that were Ebola-positive were the Zaire strain. The Zaire strain has been associated with large outbreaks of Ebola virus disease in Africa, according to the World Health Organization.
Before the current outbreak, only one case of Ebola had been reported in the region, but the researchers' work found that the disease was much more common as early as 2006.
According to Schoepp, researchers at Fort Detrick are putting together a schedule to continue their presence in Liberia and Sierra Leone during the current outbreak.