WHO spokesman Gregory Hartl told Asharq Al-Awsat that the surge in the number of microcephaly cases and the Zika virus may just be coincidental in terms of time and place. He cautioned, however, that experts are not ruling anything out.

“One of the curiosities is why we have so many neurological cases in, say, the northeast of Brazil, but we have not had it in other places,” he said. “So, we really need to understand what causes these microcephaly cases, for example, in children.”

Hartl dismissed fears that the Zika virus could pose a threat similar to that of Ebola, which caused more than 11,000 deaths in West Africa.

“Zika has never killed a person and it is transmitted by the mosquito,” he said. “So, we know that there are those two fundamental differences at least. Let us say that Zika on its own would not be the consideration of an emergency committee. What is the concern to the international community is the possible link with neurological disorders.”

He said pregnant women, in particular, should protect themselves by sleeping under mosquito nets, using mosquito repellents, and wearing long-sleeved shirts and pants.

The World Health Organization has declared an international public health emergency, in Geneva on Monday, over concerns – as yet unproven – that the virus causes brain damage and birth defects in children since more than 20 countries in Latin America have reported an outbreak and a rare case of the Zika.

Zika has been linked to the development of unusually small heads, known as microcephaly, and brain damage in babies.

The Red Cross has put out an emergency appeal for funding to help with the outbreak of the Zika virus, which could infect as many as 4 million people in the Americas this year.

The International Federation of Red Cross and Red Crescents Societies launched the appeal Tuesday for $2.3 million to support the regional response to the crisis.

French pharmaceutical company Sanofi said that it has begun research and development of a vaccine for the virus, which is named for a forest in Uganda where the mosquito-borne virus was first identified in 1947.