What does swine flu do to you?

Many things: Influenza virus invades susceptible cells and damages those cells. In the process the body releases chemicals called cytokines in response, and these are responsible for many of the symptoms, including cough, headache, runny nose, fever, chills, GI symptoms and muscle aches. Because of the damage to normal cells it lowers immunity to other organisms and you develop secondary infections.

Swine Flu: Symptoms of swine flu may include: sore throat, cough, headache, fever, chills, musculoskeletal aches & pains, nausea, vomiting & diarrhea.

Flu and animals: Influenza is one of the few viruses that can infect both people and animals. In the winter, people, in the summer, animals, typically farm animals. As it passes through animals the virus varies a bit, creating new strains. If it does so via pigs, it is called a swine flu when it comes back to infect humans.