The UN’s health agency has warned of the possible spread of the Zika virus to new parts of the world including Europe – even as the outbreak declines in Brazil.
The World Health Organisation warned Zika’s range is likely to expand beyond Latin America and the Caribbean as summer – and the mosquitoes that transmit the virus – arrive in the northern hemisphere.
The organisation’s assistant director general Dr Marie-Paule Kieny told a conference in Paris: “As seasonal temperatures begin to rise in Europe, two species of Aedes mosquito which we know transmit the virus will begin to circulate.
“The mosquito knows no borders.”
Zika Virus: Will It Spread And Can We Stop It?
Dr Kieny warned that the added risk of sexually transmitted infection “could see a marked increase in the number of people with Zika and related complications”.
She also said cooler temperatures in the tropics and subtropics meant the outbreak in Brazil, which has been hardest hit, was “clearly on the decline” – although she did not provide numbers.
Scientists are in broad agreement that Zika causes microcephaly, a form of severe brain damage in newborns, and adult-onset neurological problems such as Guillain-Barre Syndrome, which can cause paralysis and death.
But at the Zika conference – attended by 600 experts from 43 countries – scientists expressed concern about gaps in knowledge about the virus.
David Heymann, from the London School of Hygiene and Tropical Medicine, told AFP: “We can’t make recommendations (for prevention) if we don’t understand the full potential of a virus or bacteria.”
Describing Zika as a “global emergency”, Dr Kieny said the most urgent priority was for new tools to quickly diagnose Zika – particularly among pregnant women.
She said particular vigilance was required in Africa, where the virus was first discovered in Uganda in 1947.
For Europe, the risk is lower because the mosquito Aedes albopictus, present in 20 countries in summer, is less “prone” to causing outbreaks than its cousin A. aegypti in the tropics, according to new research unveiled by the Pasteur Institute.
While cases of local transmission are possible, the risk of a full-blown European outbreak “appears low”, French immunologist Jean-Francois Delfraissy said.