Common ragweed is already the biggest cause of hayfever in the US
Highly allergenic pollen from the plants has been found in England
Leicester University researchers fear hayfever season will be extended
Deborah Waddell from Asthma UK said this will cause misery for many
For those who suffer from hayfever, the onset of autumn may usually be a great relief.
But British scientists fear the season of sneezing and snuffling may be extended, after they found the first signs of pollen from invasive foreign plants.
Common ragweed – a highly allergenic plant which emits a billion pollen grains in a single season – is already the biggest cause of hayfever in the US.
It invaded the Eurppean mainland in the 1960s – brought over in contaminated seed – and has been spreading north ever since.
Common ragweed is already the biggest cause of hayfever in the America and now the pollen in being found in England
Usually the plant, which grows in late summer and early autumn, would not cope with our chilly September weather.
But scientists think it has managed to establish itself in the UK thanks to our long and warm summer.
Researchers at the University of Leicester, who have been monitoring pollen levels for 40 years, found signs of ragweed pollen on four consecutive days earlier this month.
On one of the days the ragweed pollen count at their East Midlands recording site reached 38 – a level high enough to cause significant hayfever attacks and problems for asthmatics.
One in five British people suffer from hayfever – and another one in 12 have asthma.
Because ragweed is so allergenic – far more than grass – it could become a real health problem if it becomes established.
It would also extend the hayfever season, which currently ends for most people by early August.
Experts last night warned asthmatics to make sure they have their inhalers with them at all times, given the increased risk.
Deborah Waddell, lead clinical advisor at Asthma UK, said: ‘The milder weather and presence of ragweed pollen may now result in a longer pollen season this year which will cause misery for people with asthma and hay fever in the UK.
‘The 79 per cent of people with asthma who find that pollen makes their symptoms worse may also be at an increased risk of a potentially life threatening asthma attack.’
Microbiologist Dr Catherine Pashley, who led the research in Leicester, said the plant – which grows up to three feet in height – had probably come into Britain in birdseed imported from Europe or the US.
She said isolated cases of ragweed had been reported before in Britain, particularly on the south coast – but they had never become established and had never created a pollen problem before.
But because of the mild autumn, she fears ragweed may have enough time to grow sufficiently to survive the winter – and may be a real problem next year.
She said: ‘Ragweed can’t survive [here] because of our cooler climate compared to North America and Central Europe, so we were very surprised to see it when we analysed the pollen and fungi in the air earlier this month.
‘Whether or not we continue to see more ragweed will very much depend on how mild this autumn is and when we have the first frost. If it is a late frost, it is likely that ragweed levels may increase this time next year.
One in five British people suffer from hayfever – and another one in 12 have asthma
‘Pollen counts change on a daily basis and seasonally. It is really important to monitor pollen levels in the air to inform treatment for the millions of hayfever and asthma sufferers in the country. It can also be used as an indicator of climate change.’
Dr Jonathan Storkey, a plant biologist at the Rothamsted Research centre in Hertfordshire, said controls on bird seed are far from rigorous.
When contaminated seed is put out in bird feeders in the garden, some may drop out and germinate in the soil below.
‘This is mainly a problem of sunflower seed imports,’ he said. ‘This grows as a weed among sunflowers in the US – and controls on bird seed are far less stringent than for plant seed.
‘This has certainly been the year for ragweed to establish itself, if that is what it has done – this late summer spell of good weather is perfect for it.
‘However, this could be a case of airborne pollen coming over from France. It has been spreading through central and northern France for some time – the right wind and some settled weather could explain why it is being picked up in the Midlands.’
Dr Richard Gornall, director of the Leicester Botanic Garden, said there is a chance the seeds could have been carried to the UK by birds.
‘The ragweed fruit – which encases the seed – has wings and spines that can become attached to animals and birds.
‘That is the most probable cause. But whatever had caused this, it is very unusual to see this level of ragweed pollen.
‘The source is clearly local to the East Midlands – these levels suggest a number of plants have become established in the recent past.’
Source: Daily Mail
