While the Unit is working to find alternatives to the use of laboratory animals in our research, at this time some crucial work can only be done in mice. Dr Emmanuel Asante and his team have developed a key series of animal models of human prion disease. This involves introducing various forms of the human prion protein gene into mice so that they produce human PrP. This includes both, M and the V form, as well as various genetic mutations that are seen in patients with inherited forms of prion disease (also known as familial CJD and GSS). Such mice are very sensitive to infection with CJD prions and have allowed us to study the various strains of human prions, including notably the strain (known as type 4) which causes variant CJD. These studies have formed an important part of the evidence showing that variant CJD is the human counterpart of BSE and we have been able to reproduce the characteristic features of variant CJD seen down the microscope (known as “florid plaques”) in these mice. This model then allows us to test possible treatments for the human disease.