A new study
on the Zika virus in mice has revealed that a genetic mutation in the virus may be the reason that contemporary infections are causing worse outcomes than infections years prior.
Once seen as a mild infection when it was discovered in 1947, the Zika virus of today can cause devastating microcephaly
in newborns and can lead to Guillain-Barré Syndrome
(GBS) in adults. To this end, researchers set out to determine what happened to the virus since it was first discovered that enabled it to become such a serious infection.
The research team, led by Ling Yuan of the Chinese Academy of Sciences in Beijing, China, used mice to compare 3 current strains of the virus with an older isolate from 2010 that was captured in Cambodia. According to the research results, the 3 contemporary strains, “killed all lab mice exposed to them, producing a series of neurological symptoms. On the other hand, the 2010 strain only killed about 17% of mice.” Upon further examination, the investigators found that “a critical mutation that altered a key protein in the protective coating of newer Zika viruses. This single change greatly enhanced Zika's ability to infect, damage and destroy human precursor brain cells.”
The investigators speculate that this mutation occurred sometime in 2013, prior to an outbreak of Zika virus in French Polynesia. The first reports of Zika-related microcephaly and GBS also occurred around that time.
Although he was not involved in the research, Michael Osterholm, PhD, MPH, director of the University of Minnesota's Center for Infectious Disease Research and Policy remarked on how this discovery suggests that more disturbing surprises may be in store. “The mutation that potentially caused this health outcome in humans is occurring in a virus where additional mutations could still occur,” stated
Dr. Osterholm. “[This] could bring us other new health challenges.” He is quick to add that more research is needed, however, as research on animals does not always produce the same results in humans.
As more information comes to light on the Zika virus, the Centers for Disease Control and Prevention (CDC) recently announced that it is deactivating its emergency response for the virus in order to “transition efforts to normal program operations.” The Zika Emergency Operations Center (EOC) was first activated in January 2016 in response to the devastating effects of the virus seen in newborns. According to the CDC, “a team of experts from across the agency, called the Zika Coordination and Operations Transition Team, will lead the transition from EOC activation to routine, long-term activities and will ensure timely coordination and collaboration on scientific, communication, and policy activities.”
The deactivation of this EOC for Zika does not mean that the threat posed by the virus is lessened. The virus remains a public health threat around the world, particularly for pregnant women. The CDC state that “the possibility of local transmission in the continental United States and Hawaii still exists. CDC remains committed to protecting the health of Americans and will continue working to protect the nation from the threat of Zika. CDC recommends travelers to areas with a risk of Zika
take steps to prevent Zika by preventing mosquito bites
and sexual transmission
of Zika during and after travel. CDC continues to recommend that pregnant women avoid travel to areas with risk of Zika.”
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