A new study of Great Lakes basin rivers shows human viruses are more apt to be found in urban streams while bovine-related viruses show up more in streams influenced more by agriculture. And then there is the Milwaukee River. The study shows that the Milwaukee River — in both urban and rural areas — ranked among the highest for viruses linked to both humans and cows. The study underscores the river's heavy effects from farming in the northern reaches and sharply different influences as it flows toward Lake Michigan.