Using math and physics to investigate mad cow disease (bovine spongiform encephalopathy or BSE) and similar diseases caused by infectious proteins called prions is the aim of research by physicists Daniel Cox, Rajiv Singh and colleagues at UC Davis. The researchers 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; and potential treatment strategies.