TEXAS, United States, Thursday May 19, 2016 – Scientists have for the first time cloned the Zika virus, an important development towards fast-tracking a vaccine against the disease.
The genetically engineered copy is a replica of the strain that is spreading across Latin America and the Caribbean, bringing an increase in microcephaly, a condition in which babies are born with abnormally small heads and underdeveloped brains.
Until now, researchers had known the structure of Zika, but they had not replicated it – at least not this strain, which is carried by mosquitoes but can also be sexually transmitted.
A team from the The University of Texas Medical Branch at Galveston was able to genetically engineer Zika, so researchers can now make the virus in test tubes and on Petri dishes, according to a study published this week in the journal Cell Host & Microbe.
According to lead author Pei-Yong Shi, his team’s manmade Zika means scientists can study and adapt the virus to develop a vaccine. It could also be used to test the efficacy of their own vaccines.
The researchers were able to infect mosquitoes with the cloned virus, as well as mice, the latter of which went on to develop neurological diseases.
“What we’ve created is something that is reproducible, meaning that batches of this virus can be made in large quantities,” Shi said.
He indicated that provided scientists are able to adapt the virus to make a safe vaccine, trials on animals could start soon and human clinical trials would follow.
“But of course this will depend on whether we see serious side effects. We don’t even know yet what the full impact of Zika is, besides microcephaly and some other neurological diseases,” Shi said.
Some scientists have been researching the virus in mouse models to learn more about how it behaves and how it leads to devastating neurological deficits. The hope there too is that this is a starting point toward the development of a treatment and vaccine.
While Zika can cause serious harm to unborn babies, it often has no visible symptoms in the mother. Experts say a vaccine to protect expectant women, and others at high risk of infection, is one of the most effective ways of beating it.
Many different research groups around the world are working to make such a vaccine, and the US National Institute of Allergy and Infectious Diseases hopes to start human clinical trials on its vaccine candidate by September, according to a BBC News report.
Any vaccine must be a “safe” version of Zika that will be enough to make the body ward off the infection without actually causing disease.
The University of Texas scientists say their cloned virus should help achieve this.
The development has been welcomed in the international scientific community.
Arturo Reyes-Sandoval, an associate professor at Oxford University’s Jenner Institute who is working on a Zika vaccine, said the new cloned virus would enable his team to better test its efficacy.
“The Zika virus took all of us by surprise, and one of the difficulties in developing preventative measures has been the lack of tools available to test the vaccine. So a development like this will help for sure,” Reyes-Sandoval said.
The London School of Hygiene and Tropical Medicine’s Professor Polly Roy said: “This is good. Scientists have everything to play around with now.”
Roy said that as well as designing a vaccine, researchers would also be able to test antiviral drugs that might lessen the effects of Zika if someone was already infected.
The virus has caused panic in some areas of the Americas, with some countries advising women to postpone pregnancy until an effective vaccine has been developed.
The World Health Organization (WHO) says Zika is also linked to Guillain-Barré Syndrome, a rare disease in which a person’s own immune system damages the nerve cells, causing muscular weakness and, in some cases, paralysis.