How do prions cause
mad cow disease
Group #5
Wendy Carrillo
Intro
Luci Ramos-What is a prion?
What is a prion? They are not viruses, bacteria,
fungi, or parasites.
A protein particle that lacks nucleic acid and is
sometimes held to be the cause of various
infectious diseases of the nervous system e.g.
scrappie.
Maria Dominguez-
Hello
Luis Rodriguez-Diff. prion diseases
Scrapie: (transmissible spongiform encephalopathy): sheep -
farmers have reported cases of scrapie since the early 1700s in
England, Scotland, and the US.
BSE (bovine spongiform encephalopathy): cows - first noticed
in 1986 in England. Due to the similarities in the behavior of the
infected cows, BSE was suspected to be linked to the common
practice of feeding cattle with remnants of tissue from
slaughtered sheep.
TME (transmissible mink encephalopathy): mink - found in the
US
CWD (chronic wasting disease): deer, elk - found in the US
FSE (feline spongiform encephalopathy): housecats!
Joe-What diseases do
They affect the brain disrupting or destroying
neurons (brain cells) in large numbers, which
inevitably leads to death.
Caused by prions PrP (normal/protein) infective
agent protein called pRpSc.
Unknown how, but, PrPSC called protein folded
improperly into more PrPSC-which then attacks
brain cells.
Mariano Ferraris-How prions affect
proteins
Andrew Griffith-Symptoms of TSE
Animal and Human Consequences
Cows infected with BSE lose weight, show
abnormal behavior (skittishness), may become
paralyzed and die. Humans afflicted with nvCJD
begin with psychiatric problems (paranoia) or
perhaps problems with their senses. They later
develop problems in muscle coordination
(balance, speech), muscle spasms, problems with
their senses (hearing, vision) and memory loss.
They may finally lapse into coma and die.
Corey Wasson-Prevention
Preventive Measures
Public health control measures, such as enhanced BSE surveillance, the culling of sick
animals, and bans of specified risk materials (SRM), have been instituted in countries
of Europe to prevent potentially BSE-infected tissues from entering the human food
chain.
In June 2000, the European Union Commission on Food Safety and Animal Welfare
strengthened the European Union’s set of control measures in relation to BSE by
adopting a decision requiring all member states to remove SRMs from the animal feed
and human food chains as of October 1, 2000; such bans had already been instituted
in most member states.
(1) avoiding beef and beef products altogether or
(2) selecting beef or beef products, such as solid pieces of muscle meat (versus calf
brains or beef products such as burgers and sausages), which might have a reduced
opportunity for contamination with tissues that may harbor the BSE agent.
Milk and milk products from cows are not believed to pose any risk for transmitting
the BSE agent.
THE END!
For group five