A MYSTERIOUS illness affecting birds in America has left many scientists confused as they are unable to diagnose the sick animals who are suffering from swollen eyes and are left unable to fly.

Thousands of US birds have come down with the unknown disease which causes crusty and swollen heads and neurological conditions which leave them unable to fly or walk. The result means many die off as scientists have struggled to diagnose the illness – potentially meaning a new sickness has emerged. Initially spotted in April in Washington DC, birds with the disease have been found in Ohio and Indiana as the illness moves westwards across North America.

Birds with the illness are reported to have eyes that are swollen shut, crusty faces which are also swollen and are unable to fly or walk. 

The animals have been tested for a wide range of diseases like Avian Flu but have been unable to pin down what it could be.

However, experts suggest the arrival of Brood-X cicadas in some parts of America correlate with the recording of dead birds. 

They suggest perhaps the insects are spreading the unknown disease either by being eaten or simply by contact. 

Those with pets have been told to keep them away from dead birds over fears the illness could be transmissible between species. 

Experts in the US have also told those who have bird feeders in the gardens to remove them as they are vectors for spreading the disease.

They add they should be washed in a mild bleach solution to kill off any remnants of the disease on the feeder before putting it out again. 

It appears the illness only targets certain types of birds making it more worrisome.

Blue Jays, Common Grackles, European Starlings and American Robins appear to be the main birds who suffer from the fatal illness, according to the University of Pennsylvania

The event has been branded as the “East Songbird Epidemic” by some scientists.

Toxicology Professor Lisa Murphy looked at the origin of the disease and said: “To date, all of the findings have either been inconsistent or inconclusive.”