Genetic factors could have a significant role in determining whether a person survives from an Ebola infection or not, new research suggests.
There have been almost 5,000 fatalities caused by the Ebola virus since its current outbreak, which has done most of its damage in West African countries including Sierra Leone, Liberia and Guinea.
However, thousands of people have also survived from being infected with Ebola, with the difference in outcomes among patients still not fully understood.
A study on mice that were infected by Ebola saw the animals reveal different symptoms of being infected by the virus.
Most lab mice are almost identical in terms of their genes, making them desirable subjects for experiments because the characteristic adds more control to the results. However, to gain understanding on why Ebola causes death in some patients but spares others, study authors Michael Katze and Angela Rasmussen used special mice.
The mice, called "Collaborative Cross" mice, were infected with a mouse-adapted version of Ebola Zaire, which is a similar disease but not entirely identical with the strain that is currently on outbreak in West Africa.
Regular lab mice died from being infected with Ebola without showing any symptoms, but the CC mice reacted differently.
The CC mice demonstrated a trend similar to what is being observed in West Africa, with some patients entirely resisting the virus, some patients falling ill but eventually recovering, and some patients dying from Ebola due to organ failure, bleeding and shock.
Rasmussen likens the genetic makeup of mice to a deck of playing cards. In an interview with Newsweek, Rasmussen says that classic lab mice represent only the jacks, queens and kings of the deck, covering only about 10 percent of the total genetic diversity of mice. The CC mice, however, represent a more complete and well-shuffled deck.
"We're hoping to use this platform as a beginning to look at genes in mice [related to] resistance and susceptibility," said Katze.
The study, which was published in the journal Science, said that all of the infected mice lost weight. About 20 percent of the subjects were completely immune to Ebola and gained back the weight that they lost within two weeks of becoming infected by the virus.
About 40 percent of the mice died without showing symptoms, similar to what regular lab mice exhibited. The remaining 40 percent, however, died from symptoms of Ebola hemorrhagic fever.
According to Rasmussen, the proportions of reactions within the CC mice are roughly about the same compared to the proportion of reactions among humans affected by the current Ebola outbreak.
University of Warwick virology professor Andrew Easton said that the study provides valuable data to the current efforts to combat Ebola. However, the information could not be directly applied to humans due to the higher variety in the genetic combinations of humans compared to those of mice.
