The Zika virus is a single-stranded RNA virus which is mainly transmitted via bites from infected Aedes species mosquitoes. Approximately 20% of infected people become symptomatic with fever, a maculopapular rash, arthralgia/myalgia, conjunctivitis or headache.

Generally the disease is mild and self-limiting. However, there have been concerns in Brazil over an association between maternal infection during pregnancy and the development of microcephaly and other adverse outcomes in the infant.

Until more is known, the CDC has put travel advisories in place, recommending that women who are pregnant postpone travel to areas where there is known to be ongoing transmission of the Zika virus.

If they do have to travel to such an area then strict non-drug measures to avoid mosquito bites should be instituted. Women who are planning a pregnancy should follow similar advice.