New York: In a major development in the fight against the deadly Ebola virus, a new test has been shown to accurately detect within minutes if an individual is infected by the virus.
This new rapid diagnostic test (RDT) could cut back on the lengthy process usually required to confirm if a patient has Ebola Virus Disease (EVD) or not, help identify case contacts and ultimately curb the spread of Ebola, said the study published in the journal, The Lancet.
The study is the first to show that a point-of-care EVD test (ReEBOV Antigen Rapid Test; Corgenix) is faster and as sensitive as a conventional laboratory-based molecular method used for clinical testing during the recent outbreak in Sierra Leone.
“Laboratory results can sometimes take days. Delays like this, result not only in the failure to diagnose and treat Ebola-infected patients, but also in individuals without Ebola being admitted to holding units where they may be subsequently infected with the virus,” said senior study author Nira Pollock from Boston Children’s Hospital, US.
“This test, on the other hand, is capable of detecting the Ebola virus in just a small drop of blood tested at the bedside and could help us in the fight against Ebola.”
Currently, diagnosis of EVD requires a full vial of venous blood to be shipped to a laboratory with a high level of biosafety and staff expertise for testing by real-time Reverse Transcription Polymerase Chain Reaction (RT-PCR).
In this study, researchers compared the diagnostic accuracy of the new RDT against the benchmark RT-PCR test (altona Diagnostics) being used for clinical diagnosis in the field reference laboratory run by Public Health England at Port Loko in Sierra Leone.
The study involved 106 suspected Ebola patients admitted to two treatment centres in Sierra Leone during February 2015 who were tested by both RDT (performed on a finger stick blood sample at the point-of-care) and by standard RT-PCR (performed on plasma in the laboratory).
The rapid diagnostic test detected all confirmed cases of EVD that were found positive by the benchmark method, with sensitivity of 100 percent (identifying all patients with EVD as per the benchmark method) and a specificity of 92 percent (identifying patients who did not have EVD).
At a research facility in Gabon, one isolated building stands behind an electrified fence, under round-the-clock scrutiny by video cameras. The locked-down P4 lab is built to handle the world’s most dangerous viruses, including Ebola.
“Only four people, three researchers and a technician, are authorized to go inside the P4,” said virologist Illich Mombo, who is in charge of the lab, one of only two in all of Africa that is authorized to handle deadly Ebola, Marburg and Crimean-Congo haemorrhagic fever viruses. The other is in Johannesburg.
The P4 was put up 800 metres (half a mile) distant from older buildings of the Franceville International Centre for Medical Research (CIRMF), in large grounds on the outskirts of Franceville, the chief city in the southeastern Haut-Ogooue province.
Filming the ultra-high-security lab or even taking photos is banned and the handful of people allowed inside have security badges. Backup power plants ensure an uninterruptable electricity supply. “Even the air that we breathe is filtered,” Mombo explains.
When he goes into the P4 lab to work on a sample of suspect virus such as Ebola — which has claimed 28 lives in the Democratic Republic of Congo (DRC) during an outbreak in the past six weeks — Mombo wears a head-to-foot biohazard suit.
The special clothing is destroyed as soon as he has finished. Draconian measures are in force to prevent any risk of contamination, with potentially disastrous effects.
‘Teams on alert’
Once a suspect virus has been “inactivated” — a technique that stops the sample from being contagious — it is carefully taken from the P4 unit to other CIRMF laboratories in the compound, where it is analysed.
Specialized teams will scrutinize it, looking to confirm its strain of Ebola and hunting for clues such as the virus’s ancestry and evolution, which are vital for tracking the spread of the disease.
CIRMF director Jean-Sylvain Koumba, a colonel in the Gabonese army and a military doctor, said lab teams had been “placed on alert” to handle Ebola samples sent on by the National Institute of Biomedical Resarch in the DRC capital Kinshasa.
The nature of the sample can be determined with rare precision, for the facility has state-of-the-art equipment matched in few other places worldwide.
“On average, it takes 24 to 48 hours between the time when a sample arrives and when we get the results,” Mombo said.
Founded in 1979 by Gabon’s late president Omar Bongo Ondimba to study national fertility rates, the CIRMF moved on to AIDS, malaria, cancer, viral diseases and the neglected tropical maladies that affect a billion people around the world, according to the WHO.
The center is financed by the Gabonese state, whose main wealth is derived from oil exports, and gets help from France.
In all, 150 people work for the CIRMF and live on the huge premises. Its reputation draws scientists, students and apprentices from Asia, Europe and the United States, as well as Africa.
“[The] CIRMF is uniquely suited to study infectious diseases of the Congolese tropical rain forest, the second world’s largest rain forest,” two French scientists, Eric Leroy and Jean-Paul Gonzalez, wrote in the specialist journal Viruses in 2012.
“[It] is dedicated to conduct medical research of the highest standard … with unrivaled infrastructure, multiple sites and multidisciplinary teams.”
The facility also conducts investigations into how lethal tropical pathogens are able to leap the species barrier, said Gael Darren Maganga, who helps run the unit studying the emergence of viral diseases.
“A passive watch consists of taking a sample from a dead animal after a request, while the active watch is when we go out ourselves to do fieldwork and take samples,” he said.
A major center of interest is the bat, seen as a potential “reservoir” — a natural haven — for the Ebola virus, said Maganga. Staff regularly go out all over Gabon to take samples of saliva, fecal matter and blood.
The consumption of monkey flesh and other bush meat is common practice in central Africa.
“It’s still a hypothesis, but the transmission to human beings could be by direct contact, for instance by getting scratches [from a bat] in caves, or by handling apes which have been infected by bat saliva,” he said. (VOA)