She had not traveled outside the region, meaning the possible infection occurred locally, said Maria Iacobo, a spokeswoman for the county Department of Health Services.The diagnosis surprised health officials because ongoing monitoring of birds and mosquitoes had shown no trace of the virus in California.
"The virus' arrival in California is anticipated, but unexpected at this time since it is not present in any contiguous states," said Dr. Thomas Garthwaite
This makes me wonder if she contracted the problem through some means other than a mosquito bite. (I'm thinking of the reports of it being contracted through organ transplants and blood transfusions.)
I'm also wondering if She had not traveled outside the region means this past summer only, or if it means never. If it's showing up in organs and blood, then it seems to me that people can carry the virus without ever showing any symptoms of disease. Then if something weakens the immune system sufficiently, they could develop symptoms at that time.
If that's true, it's likely to freak people out when the news breaks.