Source - R&D Magazine
In December 2013, Ebola broke out in Guinea, Liberia and Sierra Leone. Since then, approximately 28,000 people were suspected or confirmed to have contracted the Ebola virus disease (EVD). And more than 11,300 people have already died from the infection, according to an August 2015 World Health Organization (WHO) report.
The disease also spread to other countries since its outbreak. Other African countries, including Mali, Nigeria and Senegal, reported deaths in half of their cases (14 deaths in 29 cases). Europe had cases in Italy, Spain and the U.K., and the U.S. reported four cases, including one death.
A major challenge posed by the Ebola virus is the difficulty in distinguishing Ebola symptoms from those of other infectious diseases. “Many symptoms of EVD are relatively generic”, says Dr. Paul Pickering, CEO, Ubiquitome. “They are common to the flu and to other tropical diseases, such as malaria, that are endemic in many parts of Africa.” The U.S. Centers for Disease Control and Prevention (CDC) notes the following list of symptoms for EVD: fever, severe headache, muscle pain, weakness, fatigue, diarrhea, vomiting, abdominal (stomach) pain and unexplained hemorrhage (bleeding or bruising).
Pharmaceutical companies are working to develop vaccines and drugs to combat the future spread of the virus. However, making a vaccine or drug to combat Ebola can be complicated. It requires well-controlled clinical trials, which can be lengthy and expensive, and the truth remains that financing vaccines and drugs for developing countries has been unattractive to the private sector. Studies needed to create an effective vaccine or drug are therefore subject to the budget constraints of developed world economies.
However, there is hope. As published recently in The Lancet, promising results were seen in a Phase 3, cluster, randomized trial of a novel Ebola virus vaccine sponsored by WHO. Using the “ring vaccination” strategy, the study employed 7,651 people in Guinea and tested the efficacy of a recombinant, replication-competent vesicular stomatitis virus-based vaccine that expresses a surface glycoprotein of Ebola (Zaire). The conclusion: the interim analysis indicates the vaccine “might be highly efficacious and safe.”
The importance of point-of-care diagnostics
Important tools in diagnosing EVD are point-of-care diagnostics, as people who show symptoms of EVD are infectious to others and should be isolated as soon as possible to reduce disease transmission. “Having access to simple, rapid and accurate viral testing in remote villages would be extremely useful for quelling EVD epidemics as the numbers of new cases decreases, and will be important for detecting future outbreaks,” says Dr. Scott Rose, Director of Enzyme Development and Molecular Biology Reagents, Integrated DNA Technologies.
The goal of point-of-care diagnostics is to stop disease transmission and facilitate improved patient outcomes in locations without nearby medical care. And while current diagnostic lab tests are accurate, they are time-consuming and complex. They also create challenges related to sample storage and transportation, laboratory biosafety and staff expertise in performing the assays.
“By eliminating the need to transport samples to a testing laboratory, point-of-care diagnostics can greatly reduce the time needed to obtain test results,” says Dr. Brian Taylor, Research Scientist, Battelle. Point-of-care diagnostics also minimize complications during sample storage or transportation.
Yet, point-of-care diagnostics have limitations compared to traditional lab tests, the main one typically being throughput. “Although point-of-care diagnostics are usually designed for distributed use, which tends to be low-throughput by nature, it is a concern,” says Dr. Pickering. “Often, these field tests are used as a screening method to determine which patients need follow-up and medical resource support, including additional laboratory-based tests.”
An efficient assay to detect Ebola
To aid the accuracy of point-of-care diagnostics, Battelle worked with IDT on validating an RT-qPCR assay to detect Ebola in the field. The Ebola assays were designed by an IDT scientist using a combination of free, online software from IDT (PrimerQuest design tool) and the National Center for Biotechnology Information (NCBI sequence accession and BLAST).
The initial assay validation was done at IDT to verify its robustness, sensitivity and reproducibility using a traditional qPCR platform. Secondary testing was done at Battelle with the Freedom4 device. Battelle scientists followed the FDA’s Emergency Use Authorization process, which includedin vitro testing of the assay, cross reactivity studies against targets from common pathogens relevant to the Ebola outbreak and benchmarking against an FDA-cleared device.
The assay offers the benefits of portability, reliability, simplicity and ease-of-use, which are critical requirements for onsite testing in areas of potential outbreak. “The highly sensitive, specific PrimeTime qPCR assays used on the portable, rugged Ubiquitome Freedom4 platform meet all those criteria. One of the main advantages of our technology is to get testing closer to possible patients and disease outbreaks,” says Dr. Rose. “We know that in outbreak scenarios, implementing effective containment early can greatly mitigate disease transmission.”
In addition, the Freedom4 device allows real-time monitoring of qPCR amplification plots either from a laptop or mobile phone. Results can be uploaded to a Cloud interface.
The next step for the technology is to complete the FDA’s Emergency Use Authorization process. Once done, the technology will be ready to provide a much needed solution for detecting and mitigating deadly Ebola outbreaks.
To download a copy of the scientific poster, click here.