The Zika virus is expected to spread to parts of Europe in late spring and summer, health leaders have said.
Many holiday spots have been classed as a “moderate” risk including France, Italy, Spain, Croatia, Greece, Turkey and Switzerland.
If the virus spreads to France, there could be implications for the Euro 2016 football championships. Thousands of supporters from the UK will travel to France for the tournament, which begins on 10 June.
Health officials have already been forced to consider the impact of the virus in Brazil ahead of the 2016 Olympic and Paralympic Games in Rio.
Last week, the World Health Organisation (WHO) urged pregnant women not to travel to the area and issued advice for athletes and visitors.
A third of countries in Europe and surrounding regions have a “moderate” risk of a Zika outbreak, according to the latest WHO risk assessment.
While the UK is deemed to be “low” risk, global health chiefs have urged preparedness. Officials should continue to be alert to detect imported cases early and provide public health advice to travellers, WHO said.
What is the Zika virus?
Zika is a virus that began ringing public health alarm bells in May 2015, spread quickly throughout South and Central America last year, and is now threatening to reach Europe, according to the World Health Organisation (WHO). It is a mosquito-borne virus first identified in rhesus monkeys in the Zika forest of Uganda in 1947, but was first found in humans in 1952.
How is the virus spread?
Zika is an arbovirus (arthropod-borne virus), spread by bites from Aedes mosquitoes – which are also responsible for spreading other viruses such as dengue, chikungunya and yellow fever. Without mosquitoes, individual sufferers are not directly contagious, but blood-borne infection may be a possible risk and guidelines on blood donation and transfusion will need to be updated.
A small number of cases of infection have occurred through sexual transmission, and there is increasing evidence of transmission from mother to fetus.
If a person acquires Zika abroad and becomes ill on their return to the UK, any public health risk to the wider population is negligible, as the mosquito that transmits the virus is not found in the UK.
What are its effects?
Until last year Zika was thought to cause only a minor illness, with up to 80 per cent of individuals experiencing no symptoms. People with symptoms usually suffer from a fever lasting four to seven days, possibly accompanied by a rash, conjunctivitis, muscle and joint pain, and headache, commencing two to seven days following exposure.
However, during large outbreaks in French Polynesia and Brazil in 2013 and 2015 respectively, national health authorities reported potential neurological and auto-immune complications, including an increase in birth defects.
There is now a scientific consensus that Zika is a cause of microcephaly, an abormal smallness of the head associated with incomplete brain development and potentially lethal at birth, and other congenital anomalies as well as Guillain Barré syndrome, “a rare and serious condition of the peripheral nervous system”, according to the NHS.
Which countries are currently affected by Zika?
The European Centre for Disease Control (ECDC) says there are 50 countries with “active local Zika virus transmission”. This is where there has been a confirmed case in the last three months, and includes much of the Caribbean, Central America and South America. Thailand is included in a Foreign Office list that stretches beyond three months to nine months.
Zika does not occur in the UK. However, a total of 25 cases have been diagnosed in British travellers since 2015.
Which countries may be affected this summer, according to the WHO?
The WHO’s European branch has said the overall risk of Zika reaching Europe is small to moderate. It is highest in areas where Aedes mosquitoes thrive, in particular on the island of Madeira, off the coast of Portugal and popular with British holidaymakers, and the north-eastern coast of the Black Sea.