France, Feb. 22 -- A study published this month shows climate conditions suitable for transmission of the virus now extend from southern Europe into parts of central and northern countries on the continent, raising the risk of outbreaks during warmer months.

Scientists found infections could occur for more than six months each year in Spain, Portugal, Italy and Greece. In countries including France, Belgium, Germany and Switzerland, transmission may be possible for two to five months annually.

In south-east England, the virus could be spread for around two months each year.

The research, led by Sandeep Tegar at the UK Centre for Ecology and Hydrology, analysed data from 49 earlier studies to understand how temperature affects how the c...