How Deadly is the Ebola Virus: It May Depend on Genetics in New Mouse Study

When it comes to how deadly the Ebola virus is, it may all come down to genetics. A newly developed mouse model suggests that genetic factors are behind the mid-to-deadly range of reactions to the Ebola virus.

People exposed to Ebola vary in how the virus affects them. While some completely resist the disease, others suffer moderate to severe illness and recover. Those who are most susceptible can eventually die from the disease.

So far, study of the Ebola virus has been partly hindered due to the lack of a mouse model that replicates the main characteristics of the human Ebola hemorrhagic fever. In previous studies, the scientists examined mice that they infected with a mouse form of the same species of Ebola virus that's causing the 2014 West Africa outbreak. They found that conventional laboratory mice previously infected with this virus died, but did not develop symptoms of Ebola hemorrhagic fever.

In this latest study, though, all of the mice infected lost weight after the first few days after infection. In addition about 19 percent of the mice were unfazed and not only survived, but regained their lost weight within two weeks. Another 11 percent were partially resistant, and less than half of these died. That said 70 percent of the mice had a greater than 50 percent mortality; 19 percent of this last group had liver inflammation with classic symptoms of Ebola, and 34 percent had blood that took too long to clot, which is a hallmark of the Ebola virus in humans.

"The frequency and different manifestations of the disease across the lines of these mice screened so far are similar in variety and proportion to the spectrum of clinical disease observed in the 2014 West African outbreak," said Angela Rasmussen, one of the researchers, in a news release.

The scientists hope that researchers can apply these findings to candidate therapeutics and vaccines. It's possible that this mouse model could be used to find genetic markers and conduct studies on how symptoms originate and take hold.

The findings are published in the journal Science.