The World Health Organization has warned that the Zika virus is likely to spread across almost all of the Americas. The infection, which causes symptoms such as headaches, conjunctivitis and mild fewer, has been found in 21 countries in the region.

Related: What expectant moms need to know about the Zika virus

Zika is transmitted by the bite of Aedes mosquitoes, which is found in all of the Americas, apart from Chile and Canada. Australia has already warned pregnant women not to travel to affected areas, including Micronesia, French Polynesia and Latin America, as they could give birth to babies with defects that impact brain development. Daniel Lucey, adjunct professor of microbiology and immunology at Georgetown University Medical Center, U.S., explains how the virus will impact the region.

The World Health Organization says Zika will hit the Americas. Are countries prepared for the virus?

Each country has started to get ready and several, especially Brazil where the virus was first recognized in May 2015, are more preapred.

What kind of preparations should they be making?

The strategies and specific tactics in preparation for the Zika pandemic are specified in the Zika webpage of the Pan American Health Organization, which is the regional office for the Americas of the World Health Organization. Broadly speaking, these strategies include eliminating places where the Aedes mosquitos live and breed, increasing testing and surveillance for persons infected with Zika and advising women who are pregnant or planning to become pregnant about potential issues related to this viral infection.

Related: Obama calls for rapid Zika research as virus is spreading

What impact could Zika have on the region?

Beyond the current reported impact, the approaching February Carnival of Brazil celebrations and August 2016 Olympics will mean many more visitors from around the world could be exposed to the virus.

What are the other major threats to human life?

Already several countries have advised that pregnant women should consider postponing travel to nations with ongoing Zika infection.

Is it a global problem?

Yes, but so far, the World Health Organization has not issued a global travel notice, alert or warning in regard to the Zika virus.

Could the virus be heading for Europe?

The European Center for Disease Control and Prevention just issued on January 21, 2016 a comprehensive risk assessment for the possibility of the Zika virus coming to Europe. To date, very few cases have occurred in Europe.

How should the global society confront the virus?

The virus needs to be tackled through coordinated, effective, transparent international leadership, including by the World Health Organization headquarters in Geneva.

What can we expect in the coming months?

The situation will likely become much worse in the coming weeks and months. Coordinated, effective, operational global health leadership must increase. Research translated quickly into ways to control the Aedes mosquitos that spread the virus (as well as dengue virus, chikungunya virus, and yellow fever virus) must take place. Urgent research to develop antiviral drugs and vaccines for Zika virus has started but must be rapidly accelerated.