Stan contracts mad cow disease from eating one of the cattle. This is the way mad cow disease spreads in reality, however near the end of the episode, the disease spreads between the cows by sneezing. Stan suffers from a fever, becomes delirious and hallucinates vividly, then eventually recovers. In fact vCJD, the human version of mad cow disease, causes a gradual and irreversible destruction of the brain, affecting all its functions until death occurs. There is no cure.
Mad Cow disease is a prion disease; and rarely becomes symptomatic in less than 10 years. And is only transmitted by eating brains or nerve tissue. The disease has also been spread by coming in contact with medical instruments contaminated by their use on a patient with Mad Cow, or vCJD.
Liquor stores in Virginia are operated by the Virginia Department of Alcohol and Beverage Control and are all named Virginia ABC. There would not be a store called "Booze Town".
Stan would have very little knowledge, if any at all, of Francine and Hayley vying for Roger's attention.