Monique Brouillette, Scientific American, 1 March 2016 http://www.scientificamerican.com/article/scientists-breed-pigs-resistant-to-a-devastating-infection-using-crispr/
Porcine reproductive and respiratory syndrome virus (PRRSV)is a detrimental infection that affects pigs across the United States, estimated to cost swine producers $600 million annually. Researchers at the University of Missouri developing pigs resistant to PRRSV via the use of CRISPR/Cas9 technology . Upon exposure to PRRSV, normal pigs develop symptoms in 5 days. However, pigs engineered for resistance to the virus did not develop symptoms, and most importantly they did not produce PRRSV antibodies, indicating that the virus was unable to infect the modified pigs.