Health workers have been urged to look out for symptoms of the Zika virus in patients from Somerset returning to the UK from countries affected by the outbreak.

Officials said that health professionals should consider the virus as a potential diagnosis of patients suffering from fever after returning from the Americas.

There is an unprecedented outbreak of the virus in Brazil and health experts have warned that it is likely it could spread to nearly all of the Americas.

The virus - which causes symptoms including rash, fever, conjunctivitis and headache - has been linked to birth defects in children born to mothers infected while they are pregnant.

Public Health England's (PHE) latest Health Protection Report states: " Health professionals should consider Zika virus among the differential diagnoses of patients with fever returning from the Americas.

"If a case of Zika virus is suspected, appropriate samples for testing (together with a full travel and clinical history with relevant dates) should be sent as early as possible to the PHE Rare and Imported Pathogens Laboratory.

"Health professionals should also be vigilant for any increase of neurological and autoimmune syndromes (in adults and children), or congenital malformations in new born infants (where the cause is not otherwise evident) in patients with a history of travel to areas where Zika virus transmission is known to occur."

Around 4,000 babies born to mothers infected with the Zika virus in Brazil have been born with microcephaly - a condition where the child has an underdeveloped brain.

Travel advice from the National Travel Health Network and Centre urges pregnant women to reconsider travel to areas where the outbreak has been reported.

Yesterday, the World Health Organisation said that the virus is likely to spread across nearly all of the Americas apart from Canada and Chile.

The virus has already been found in 21 countries: Barbados, Bolivia, Brazil, Colombia, Dominican Republic, Ecuador, El Salvador, French Guiana, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Puerto Rico, Saint Martin, Suriname and Venezuela.

There is no treatment or vaccine and many South American countries have called on women to consider the implications of the infection before getting pregnant.

A spokeswoman from UK travel organisation Abta said women reconsidering their plans would be able to get a medical certificate from their family doctor in order to claim on insurance.

" This new advice highlights just how important it is to check Foreign Office advice and the need to purchase travel insurance before booking your travel arrangements," she added.