dr. cheryl burgess joins us to explain how to protect yourself. good morning. it is really bad this morning, isn't it? >> it is getting bad. >> we were reporting in dallas that they actually sprayed the whole city because they had -- >> 43 states now that have detected west nile virus. and the first case was detected in 1999. so, it is each year there are more and more cases. >> tell us quickly, what is west nile virus, so people know. >> it is a virus commonly seen more in asian africa and it has made its way, since 1999, to the united states. a virus that infects birds. the mosquito bites the bird and then the mosquito is the transmitter of the virus to humans and an amales. >> and what are the symptoms? >> well, most people, 80% of people, if they're bit by a mosquito that contains the west nile virus have headache and nausea, vomiting, eye pain, kind of almost flu-like symptoms and it usually occurs 3 to 14 days after you've been bitten. so, that is the time when you really want to go to the doctor within a week of your symptoms because we can do an antibod