A total of four cases of the virus which are thought to have been transmitted by mosquitoes as opposed to sexually or as a result of travel to other infected areas have been confirmed in the US state .

The news has meant UK government advice that pregnant women should not travel to the affected areas has been expanded to include Florida.

Now Thomas Cook, Thomson, First Choice and Virgin Holidays are all offering pregnant customers who were travelling to the family destination the chance to go elsewhere to avoid the danger of contracting the virus which is believed to cause defects in unborn babies.

A Thomas Cook spokesperson said: “We are closely monitoring the situation and would like to reassure any pregnant customers due to travel up to and including October 31, 2016, with Thomas Cook to one of the affected areas that we are happy to offer free amendments to alternative destinations.”

A Tui spokesperson added Florida has been added to an increasingly lengthy list of affected destinations, which includes Caribbean islands and parts of central America, following the latest news.

He said: “Once we have been notified that a customer has a doctor’s note, they have a month to book an alternative holiday to any Thomson or First Choice destination currently on sale.

“If the alternative holiday is cheaper than the original holiday, we will refund the difference – if it is more expensive the difference must be covered by the customer.”