The agent responsible for mad cow infection is

Explanation

Mad cow disease, also known as bovine spongiform encephalopathy (BSE), is a fatal neurodegenerative disorder that affects cattle. It is caused by prions, which are misfolded proteins capable of inducing abnormal folding of normal proteins in the brain. This leads to the formation of sponge-like lesions, resulting in progressive neurological symptoms such as abnormal behavior, lack of coordination, tremors, and difficulty walking. BSE can be transmitted to humans through the consumption of contaminated beef, causing a variant form of Creutzfeldt-Jakob disease (vCJD), which similarly affects the brain and is ultimately fatal. The disease has no cure, and prevention relies on strict control of animal feed and surveillance of livestock.