French pharmaceutical giant Sanofi announced Tuesday that it had begun research and development into a vaccine against the mosquito-borne Zika virus, blamed for causing a surge in brain-damaged babies.

The company said the success of its Sanofi Pasteur vaccines division in developing a vaccine against dengue fever could be "rapidly leveraged" in the fight against Zika.

"Sanofi Pasteur leads the vaccine field for viruses in the same family as Zika virus (ZIKV), with licensed vaccines against yellow fever, Japanese encephalitis and, most recently, dengue," it said in a statement.

It continued that "Sanofi Pasteur's expertise and established R&D and industrial infrastructure for the newly licensed vaccine for dengue, Dengvaxia, can be rapidly leveraged to help understand the spread of ZIKV and potentially speed identification of a vaccine candidate for further clinical development."

The announcement comes a day after the World Health Organization declared an international emergency over the Zika virus which it last week warned was "spreading explosively" in the Americas.

The UN health body also said a surge in serious birth defects in South America was "strongly suspected" of being caused by the Zika virus.

Brazil has now warned pregnant women to stay away from the Olympics due to open in August in Rio de Janeiro.

"Sanofi Pasteur is responding to the global call to action to develop a Zika vaccine given the disease's rapid spread and possible medical complications," vaccine project head Nicholas Jackson said in the statement.

"In addition to the serious possibility of congenital complications associated with Zika, investigations are also underway to assess another reported connection between Zika and a dangerous neurological disorder," he added.

There is currently no treatment for Zika. The virus is transmitted by the Aedes aegypti mosquito, which also spreads dengue fever, and which is found everywhere in the Americas except Canada and Chile.

WHO has warned that the Americas region could see up to four million Zika cases this year alone.