As the US fights the repercussions of its first case of mad cow disease (bovine spongiform encephalopathy or BSE) discovered last month - closed borders have already cost the beef industry $3 billion in lost revenue - physicists Daniel Cox, Rajiv Singh and colleagues are using mathematical models to study issues such as the incubation time, prion 'strains' and treatment or detection strategies.
Diseases such as BSE in cattle, Creutzfeld-Jakob disease in humans and chronic wasting disease in deer are all apparently caused by prions, misfolded versions of a normal brain protein.
Similar diseases have been found in other animals including cats, mink and rodents, and prion-type proteins have even been found in yeast.
Prions seem to cause disease by triggering normal versions of the same protein to spontaneously fold up the wrong way, creating growing mats and tangles.
The UC Davis researchers have developed mathematical models to simulate this process. The models reproduce how prions collect around an original 'seed' prion, and how these clumps subsequently break up and spread around the brain and nervous system.
Predictions from the models compare well with the course of actual disease in both small and large animals, Cox said.
Cox and colleagues are now using the model system to investigate the minimal requirements for prions to cause disease, how 'strains' of prions can exist and what effect they have, as well as any potential treatment strategies.
US delegates were in Japan- the leading importer of US beef - last week to convince the country to re-open the closed doors.
Japan devised thorough safety measures after mad cow disease was confirmed in domestic cattle in September 2001. Sales of beef in Japan have only just recovered following events in 2001, when consumption plummeted, inflicting $2 billion in losses on US, Australian and other beef exporters.
Japanese authorities introduced mandatory BSE testing for all domestic cattle bound for consumption, making Japan the only country to inspect all of its cows, regardless of age.