A new weapon in the arsenal in the fight against Ebola has a Mount St. Mary’s University researcher hopeful that progress is being made toward finding a cure for the devastating viral disease.
A recently-tested vaccine called rVSV-ZEBOV, developed in Canada and licensed by Merck, was the focus of a new study performed in Guinea with positive results. There were zero cases of Ebola virus disease in the 2,014 individuals who received the vaccine immediately after being identified as at-risk for Ebola exposure, while there were 16 cases in the comparison group, which included about the same number of people.
“I know I should be cautiously optimistic, but I’m truly so excited by this study,” said Kathryn E. Gunn-Dye, Ph.D., Mount St. Mary’s University assistant professor of biology. “The burden shouldered by these researchers in moving forward this testing, the first of its kind, is awe-inspiring. They are giving hope to people who live in fear.”
Although not involved in the current study, Gunn-Dye recently worked with a team that identified Ebola’s Achilles heel. Her research program focuses on two aspects of the Ebola virus life cycle: virus replication within infected cells and entry of Ebola virus into cells. Because she studies the nuts and bolts of Ebola virus infection, it’s possible that she will learn lessons and develop strategies that are broadly applicable to the fight against other viruses.
Her laboratory at Mount St. Mary’s University has studied Ebola virus infection since 2010, and she has been investigating the virus in collaboration with researchers at the U.S. Army Military Research Institute of Infectious Diseases (USAMRIID) since 2008. Her main focus with regard to virus replication is understanding what it takes for the virus to make all of its parts correctly — to fold all of its proteins into the proper shapes so that new viruses can be produced and released to spread to other cells in the host.
“We’re developing tools that will allow us to test the importance of protein folding in Ebola replication,” Gunn-Dye said. “However, the fact that all viruses are made of proteins makes the protein folding problem universal for viruses. We aim to move the Ebola field forward and then to use the tools we’ve developed and the lessons we’ve learned to make advances in the fight against other deadly viruses.”
The Guinea study, published July 31 in the medical journal, The Lancet, uses a ring vaccination method, which Dr. Gunn-Dye calls, “elegantly simple.” Essentially, all of the family, friends, and neighbors of a confirmed Ebola case are vaccinated, generating a protective ring around the case to keep the disease from spreading to people beyond the ring.
According to Gunn-Dye, an exciting aspect of this method is its ability to generate herd immunity, which is the idea that the more people in a population who are vaccinated, the less likely it becomes that unvaccinated individuals will become infected. The herd protects them. “The ring vaccination method was used to eradicate smallpox. We know it can be highly effective.”
Ebola virus burst onto the scene in 1976, bringing with it widespread public fear of death by hemorrhagic fever. That fear heightened in 2014 as the global community witnessed the largest Ebola epidemic in history, affecting multiple countries in West Africa. Through July of this year, there have been nearly 28,000 total cases of the disease and more than 11,000 deaths, according to the Centers for Disease Control and Prevention.
“People fear Ebola because there are no approved treatments or vaccines for infection, and 50-90 percent of the people who get it die,” said Dr. Gunn-Dye. “Therefore, it’s realistic to be fearful, even if you understand that Ebola is only transmitted by close contact with a sick individual and that most of what Hollywood shows us is highly exaggerated.”
Asked if the success of the rVSV-ZEBOV vaccine means that she and other Ebola researchers can take a break, Gunn-Dye said, “Absolutely not. We need to keep our options open with other vaccines because it will be many years before we know the long-term effects and protective qualities of rVSV-ZEBOV. Treatments and medicines that can stop the disease once it’s begun will always be needed. It’s inevitable that some people will be in a race against the clock after they become exposed; if they’ve not been vaccinated and then fall sick before they can be vaccinated, therapies may be their only hope.”
Gunn-Dye’s specific research focuses on fighting the spread of Ebola virus by developing and investigating strategies to halt virus entry and replication.
Her study published in the May 26 edition of the online journal mBio describes work conducted by Gunn-Dye, and collaborators from around the world, in which they identified the molecular “lock” the deadly Ebola virus must “pick” to gain entry to cells. The findings, made in mice, suggest that drugs blocking access to this lock could protect against Ebola infection.
Researchers found that the Ebola virus can’t infect cells unless it first attaches to a host protein called Niemann-Pick C1 (NPC1) in membrane compartments called lysosomes deep within cells. Mice lacking both copies of the NPC1 gene, and therefore having no NPC1 protein, were completely resistant to infection.
“We have a lot to do before we reach a solution, but the work is promising. The world needs ammunition for the fight against Ebola and a number of other emerging and deadly viruses,” said Gunn-Dye.
Dr. Gunn-Dye’s research, then, will continue in earnest.