The Centers for Disease Control and Prevention has provided a major update on the first human case of bird flu in the US with no known animal exposure. HN51 has spread like wildfire in dairy cows and poultry since it was first detected in April. Nearly 200 dairy herds in 14 states have tested positive for the strain. As of August, 13 humans exposed to infected dairy cows and poultry have tested positive.Cases have been mild – patients presented with typical flu symptoms such as fever and chills – and isolated. However, the 14th human case confirmed earlier this month marks a major turning poin…