Another possible bird flu case in a child in Marin county.

If confirmed this would be the third case with an unknown source of infection. Most of the human cases so far have been among dairy and poultry workers in close contact with infected animals.

This would be the second case in a child. Last month there was another case in Alameda County.

H5 wastewater activity in California is quite high (mostly from infected cows/milk. Wastewater surveillance doesn't distinguish between animal and human sources).