Says who? All wild animals can carry disease; no need to pick on the birdies!
Besides, there's very little that can be absorbed through her head! Just don't kiss it on the beak.
Read-up on it, A. West Nile isn't on the list, but it's only a shortened list...
http://www.birds.cornell.edu/cfw/challenges/bird_diseases.html
Bacteria and germs on the head/hair can be easily transmitted to the hands, then to the eyes, nose, mouth etc. Bird nests are notorious for being improperly-handled and giving humans all kinds of medical problems.
Tweety-Pie Bird is taking a shower at this very moment...