Nearly 50,000 British holidaymakers who are currently staying in Florida are advised to avoid unprotected sex for the rest of the summer holidays because of the risk from Zika virus.

An outbreak of four mosquito-transmitted cases on yesterday forced the Public Health England (PHE) to suggest pregnant women to postpone non-essential trips to the southern US state.

But for the large numbers of British tourists who have been already there, should refrain from sex without a condom for eight weeks, even if neither partner has symptoms of the disease and there is no prospect of a pregnancy.

PHE advised that males returning from a Zika-affected area who show symptoms of the virus, including a rash, itching and headaches, should be strictly restricted from unprotected sex for a full six months to avoid onward transmission.

More than 1,650 cases of Zika have been identified in the US. However, this is thought to be the first time the disease has been spread by local insects, rather than as a result of foreign travel or sexual intercourse.

Florida has now announced aggressive mosquito-control measures, although the evidence from South America, where the outbreak started, is that these have limited benefit.

Zika causes a mild illness in most of the people, but the infection in pregnant women may cause foetal microcephaly, or abnormal smallness of the head in babies, and other severe birth defects. It can also lead towards miscarriage.

British tour operators Thomas Cook, Thompson & First Choice and Virgin Holidays have announced yesterday that they would provide free holiday cancellations for pregnant tourists with trips booked up until December 31.

More than 50 people have already tested positive for the virus in Britain after visiting infected countries since it started in May 2015.

Also Read: CDC probes possible first homegrown case of Zika in US!

By Prakriti Neogi