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Monday, 15 August 2011

Malaria is killing off our sparrows and owls as mosquitoes invade

Sparrows, chaffinches, owls and nightingales are being killed off by an upsurge in malaria.
Experts say at least 30 species of British birds are affected and growing numbers are dying.
They believe the tropical disease is on the rise because the mosquitoes that spread it have benefited from this country’s warmer and wetter climate.
Thirty per cent of UK house sparrows are affected with malaria now, compared with under ten in 1990
Malaria rates among great tits has increased by five fold in the last ten years
Soaring: Malaria rates for house sparrows has risen to 30 per cent since 1990, while great tits have seen a five-fold increase to 15 per cent
Thirty per cent of UK house sparrows are infected with malaria – compared with barely 10 per cent in 1990. 
Two thirds of the country’s 38,000 tawny owls are hit. In 1996, just one in 40 had the disease. The great tit has seen its infection rate soar fivefold to 15 per cent. 
All three species are non-migratory and must have been infected with avian malaria in the UK, through mosquito bites.
The disease, which is brought into the country by infected migratory birds, cannot spread to humans. Grahame Madge, of the Royal Society for the Protection of Birds, said: ‘Malaria is circulating at low levels in the UK. 
‘It is not always fatal as many birds have resistance to it, but if we get new strains and new types of mosquitoes it poses an increasing hazard to an already declining population.
To blame: Mosquito bites to migratory birds allow the disease to be moved into the UK where it affects species which do not migrate
To blame: Mosquito bites to migratory birds allow the disease to be moved into the UK where it affects species which do not migrate
‘Climate change is bringing warmer weather conditions that are likely to favour the colonization of some insects to our shores that cannot survive at the moment, and that could bring an upsurge in disease.’
Since 1970, sparrow populations have declined by 67 per cent, and nightingales by 90 per cent, for a variety of reasons, including other diseases, predators and threats to their habitats. 
Ben Sheldon, professor of ornithology at Oxford University, said: ‘Malaria is a significant cause of mortality, but how it is transmitted is not straightforward. It is quite hard to predict.’
The avian malaria epidemic was identified in a study published in May by Laszlo Garamszegi, an expert with the Spanish government.
In the largest analysis carried out so far he examined malaria infection rates from more than 3,000 species around the world, dating back over 70 years.
He found that an increase in global temperatures of 1c was accompanied by a two- to three-fold increase in the average prevalence of malaria in birds. 
 He said there had been big increases in the past 20 years.
The paper, published in the journal Global Change Biology, suggests higher temperatures could herald a return of human malaria to northern Europe.
Around 3,000 Britons a year are infected with the disease, mainly from tropical holidays. But if human malaria started to be transmitted here through mosquitoes, rates would rise.
Avian malaria is also ravaging the native birds of Hawaii and wreaking havoc in New Zealand.

Originally posted by dailymail.co.uk

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