CJD IN BIRDS>>maybe???

[Guest guest]

I questioned this last year when I saw the artical about the bald

eagles. Maybe this is some type of CJD in birds. Im only on the read

CJD News list (to backed up a work) now so forgive me if someone

already posted this.

H.

Avian brain disease puzzles

scientists

March 30, 1999

Web posted at: 9:45 AM EST

A mysterious brain disease is killing

birds in the southeastern United

States and scientists can't find the

cause.

Birds with avian vacuolar

myelinopathy typically fly erratically or are

unable to fly completely.

According to USGS wildlife disease specialist Dr.

Kimberli , birds

may crash land, swim tipped to one side with one or

both legs or wings

extended, or be in the water on their backs with

their feet in the air.

" On land, " said , " birds appear intoxicated

-- they stagger and have

difficulty walking and may fall over and be unable

to right themselves. "

Affected birds, however, are usually alert and

still may bite when handled.

said that the only consistent finding in

affected birds is the

microscopic change in the nervous system.

Despite extensive testing by USGS, SCWDS, and

others, the cause of the

disease and the route of exposure is still unknown.

" All of the diagnostic, field and laboratory

efforts indicate the cause is most

likely a toxin, either one that is naturally

occurring or manmade, "

said.

In addition to toxicology tests, USGS pathologists

have tested the tissues

of dead birds for bacteria, viruses, parasites and

none have been found. In

humans and other mammals, similar lesions have been

associated with

genetic disorders, certain types of chemicals or

toxic plants. Tests for these

chemicals in the affected birds have been negative

or inconclusive.

" This is very frustrating for our scientists, " said

Dr. McLean,

director of the USGS National Wildlife Health

Center. " We have examined

more than 4,000 bald eagle carcasses from around

the country to

determine the cause of death, and have conducted

thousands of wildlife

mortality investigations on many other species, and

we are accustomed to

identifying and resolving these problems. With this

disease, however,

despite all our efforts and despite the extensive

involvement of leading

scientists from diverse disciplines and numerous

organizations, we have yet

to solve the puzzle about the exact cause of the

disease. "

McLean noted that " vexing " questions about the

disease still need to be

answered. " Is it emerging and spreading to new

locations and new species,

or has it been around for a long time and just now

being recognized

because more people are aware of the problem? If it

is an emerging

disease, finding out what is causing it may be just

the tip of the iceberg. "

USGS wildlife specialists have discovered the

disease in two species of

ducks found dead at Woodlake, N.C. It was

previously found only in bald

eagles and American coots.

The disease affects the brain and spinal cord by

damaging the myelin

sheath that insulates the nerve fibers. It is

diagnosed by microscopic

examination of very fresh brain and spinal cord

tissue.

Dr. , the USGS pathologist who first

described the lesion,

explained that " in affected birds the disease

appears as open spaces in the

white matter of the brain. " When the coating

surrounding the myelin is

damaged, said, " communication in the nervous

system is impaired,

causing a bird to become uncoordinated or

paralyzed " .

Dr. used an electron microscope to determine

that the spaces are

caused by separation of the myelin layers that

surround nerve fibers. Using

the same techniques, Dr. Fisher, a SCWDS

pathologist, confirmed

the lesion in a North Carolina mallard and

ringnecked duck, and a Strom

Thurmond Lake bald eagle.

For more information, contact Kim , USGS,

(608)270-2448, email:

kim_miller@....

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