In August, 2010, my husband had a hemorrhagic stroke which affected the right side of his body. In August, 2011, he contracted West Nile Virus which left him with a polio-like effect, affecting the left side of his body worse than the already damaged right side. A few months later, he was diagnosed with Myasthenia Gravis which not only affected the weakened muscles more, but also breathing. So, yes, in our case, and from what the Infectious Disease doc said, the WNV can trigger MG. Living proof here. August, 2013 is coming up. We're holding our breath!