Sierra Leone samples: Ebola evidence in West Africa in 2006

July 14, 2014
Electron micrograph of an Ebola virus virion. Credit: CDC/Cynthia Goldsmith

Analysis of clinical samples from suspected Lassa fever cases in Sierra Leone showed that about two-thirds of the patients had been exposed to other emerging diseases, and nearly nine percent tested positive for Ebola virus. The study, published in this month's edition of Emerging Infectious Diseases, demonstrates that Ebola virus has been circulating in the region since at least 2006—well before the current outbreak.

First author Randal J. Schoepp, Ph.D., recently returned from Liberia and Sierra Leone, where he spent six weeks helping to set up an Ebola testing laboratory and training local personnel to run diagnostic tests on suspected Ebola hemorrhagic fever clinical samples. He is part of a team from the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) that has been providing assistance to the Ebola outbreak in West Africa since March.

Three other USAMRIID personnel also have been involved in this ongoing effort: Wes Carter, who traveled with Schoepp to Liberia; Aileen O'Hearn, Ph.D., who recently returned from providing laboratory support to Kenema Government Hospital (KGH) in Sierra Leone; and Matthew Voorhees, who is currently onsite at KGH.

USAMRIID has been working in the region since 2006, when it began a collaborative project to develop and refine diagnostic tests for the Lassa fever virus endemic to Sierra Leone, Liberia and Guinea. As those assays have matured, the scientists have begun to optimize additional tests for a number of emerging diseases.

Because the team was working on disease identification and diagnostics, and had pre-positioned assays in the region, said Schoepp, "We had people on hand who were already evaluating samples and volunteered to start testing right away when the current Ebola outbreak started."

According to the publication's authors, between 500 and 700 samples are submitted each year to the KGH Lassa Diagnostic Laboratory in Sierra Leone. Generally, only 30 to 40 percent of the samples test positive for Lassa fever, so the aim of this study was to determine which other viruses had been causing serious illnesses in the region.

Using assays developed at USAMRIID that detects the presence of IgM, an early protein produced by the body to ward off infection, the research team found evidence of dengue fever, West Nile, yellow fever, Rift Valley fever, chikungunya, Ebola, and Marburg viruses in the samples collected between 2006 and 2008.

In addition, of the samples that tested positive for Ebola, the vast majority reacted to the Zaire strain, which was unexpected, according to the authors.

"Prior to the current outbreak, only one case of Ebola had ever been officially reported in this region, and it was from the Ivory Coast strain," said Schoepp. "We were surprised to see that Zaire—or a variant of Zaire—was causing infection in West Africa several years ago."

The laboratory testing site in Kenema is supported by the Armed Forces Health Surveillance Center-Global Emerging Infections Surveillance and Response System. In collaboration with the host country, the site enables collection of samples that can be used in research toward new medical countermeasures, and allows USAMRIID to evaluate the performance of previously developed laboratory tests using samples collected on-site. The Institute hopes to eventually obtain viral isolates for medical countermeasure development and receive data on the performance of the diagnostic assays.

In addition to providing laboratory testing and training support for the current outbreak, USAMRIID has provided more than 10,000 Ebola assays to support laboratory capabilities in Sierra Leone and Liberia. The Institute also supplied personal protective equipment to Metabiota Inc., a non-government organization (NGO) involved in the testing.

Other contributors to the work include the Department of Defense Joint Program Executive Office-Critical Reagents Program, the Defense Threat Reduction Agency (DTRA) Cooperative Biological Engagement Program, and the DTRA Joint Science and Technology Office.

COL Erin P. Edgar, commander of USAMRIID, called the project "a great example of medical diplomacy at work."

"This collaboration allows USAMRIID to bring our expertise to bear in responding to an international health crisis," he said. "In addition, it enables us to test the medical diagnostics that we develop in a real-world setting where these diseases naturally occur."

USAMRIID's mission is to protect the warfighter from biological threats and to be prepared to investigate disease outbreaks or threats to public health. Research conducted at USAMRIID leads to medical solutions—vaccines, drugs, diagnostics, and information—that benefit both military personnel and civilians. The Institute plays a key role as the lead military medical research laboratory for the Defense Threat Reduction Agency's Joint Science and Technology Office for Chemical and Biological Defense. USAMRIID is a subordinate laboratory of the U.S. Army Medical Research and Materiel Command.

Explore further: Sierra Leone reports two Ebola deaths, 12 cases

More information: Schoepp RJ, Rossi CA, Khan SH, Goba A, Fair JN. Undiagnosed acute viral febrile illnesses, Sierra Leone. Emerg Infect Dis. 2014 Jul. DOI: 10.3201/eid2007.131265

Related Stories

Sierra Leone reports two Ebola deaths, 12 cases

May 30, 2014
Health officials in Sierra Leone say there have been two deaths from Ebola and a dozen other cases of the deadly disease.

Death toll in W.African Ebola outbreak rises to 467: WHO

July 1, 2014
The number of people believed to have died from Ebola in west Africa has risen sharply to 467, the World Health Organisation said Tuesday.

Sierra Leone Ebola outbreak death toll now five

June 3, 2014
A British mining company says some of its personnel have left Sierra Leone amid an outbreak of the Ebola disease that has killed at least five people.

Sierra Leone defends its record on Ebola outbreak

June 21, 2014
Sierra Leone says it is dismayed by allegations that it is not doing enough to combat the Ebola outbreak ravaging West Africa.

Death toll in W.African Ebola outbreak rises to 518, WHO reports

July 8, 2014
The number of people believed to have died from Ebola in west Africa has jumped to 518, the World Health Organization said Tuesday.

Sierra Leone steps up measures to tackle Ebola outbreak

June 20, 2014
Sierra Leone, one of three neighbouring west African countries facing an Ebola epidemic, has stepped up measures to fight the highly contagious and deadly disease, the health minister has said.

Recommended for you

Novel approach to track HIV infection

August 18, 2017
Northwestern Medicine scientists have developed a novel method of tracking HIV infection, allowing the behavior of individual virions—infectious particles—to be connected to infectivity.

Faulty gene linked to obesity in adults

August 18, 2017
Groundbreaking new research linking obesity and metabolic dysfunction to a problem in the energy generators in cells has been published by researchers from the Harry Perkins Institute of Medical Research and The University ...

Two lung diseases killed 3.6 million in 2015: study

August 17, 2017
The two most common chronic lung diseases claimed 3.6 million lives worldwide in 2015, according to a tally published Thursday in The Lancet Respiratory Medicine.

New test differentiates between Lyme disease, similar illness

August 16, 2017
Lyme disease is the most commonly reported vector-borne illness in the United States. But it can be confused with similar conditions, including Southern Tick-Associated Rash Illness. A team of researchers led by Colorado ...

Addressing superbug resistance with phage therapy

August 16, 2017
International research involving a Monash biologist shows that bacteriophage therapy – a process whereby bacterial viruses attack and destroy specific strains of bacteria - can be used successfully to treat systemic, multidrug ...

Can previous exposure to west Nile alter the course of Zika?

August 15, 2017
West Nile virus is no stranger to the U.S.-Mexico border; thousands of people in the region have contracted the mosquito-borne virus in the past. But could this previous exposure affect how intensely Zika sickens someone ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.