London School of Hygiene & Tropical Medicine

With the summer holiday season approaching Jimmy Whitworth, Professor of International Public Health, assesses the risk Zika poses for those planning a trip to America.

"At this time of year the US climate is generally too cold for Aedes aegypti, the main vector for Zika, to survive and thrive. However, as the temperature rises in the summer months, this mosquito can be found in southern states including Texas, Louisiana and Florida.

"Although we don't think there's any Zika in mosquitoes in the US right now the virus is spreading in Central American countries, including Mexico which of course borders the US. It's entirely possible that southern US states could have active Zika transmission in a few months. The risk to the middle and northern states is much lower. US Public Health authorities are well aware of the potential for transmission during the summer months and will be doing all they can to minimise the risk. However, this cannot be removed entirely.

"There is now a proven link between Zika and microcephaly as well as other birth defects. Pregnant women and couples looking to conceive should think twice about travelling to parts of the US where active Zika transmission could occur. Holidaymakers should follow public health advice wherever they travel, including taking all the necessary precautions to avoid getting bitten.

"It's important to remember that Zika is generally only a minor health risk to most people. Four in five of those infected experience no illness and, in those that do, symptoms are usually limited to fever and mild joint pain. If you are not pregnant or not thinking of getting pregnant, then Zika is not something to overly worry about."

Related links:

• Short course on Preventing the Zika Virus 
• School Zika virus research
• Previous expert comment on the Zika virus outbreak in the Americas 
• Previous expert comment on Zika threat to Europe
• Media highlights: Latest comment from our experts in the news
• Seminar recording: Prof Laura Rodrigues on the epidemic of microcephaly in Brazil