Brucellosis is an extremely contagious and infectious disease that mostly affects pigs, but may affect other species including humans. Many animals are carriers of the disease before demonstrating symptoms of an active infection. Unfortunately, while these carriers may not show signs of an active infections, they may spread the disease to other individuals even in the carrier state. Screening all individuals with a blood test is the only way to identify carrriers. If you have more than one pig, your risk of getting Brucellosis increases because it doesn't affect just one pig; it will affect the whole herd.