This is not the deadly bird flu that has been making its way across the world in migrating bird populations. West Nile is a much less virulent disease, and cannot be spread to people by either birds or other humans. It is spread by mosquitoes, through their bites. There is no need to panic, as most people with West Nile experience either no symptoms, or very mild, flu-like symptoms. Fewer than 1% of people who get the disease will ever go on to develop the much more serious complications that have made headlines in the past.
Multnomah County's public health folks are asking people to take precautions to protect themselves from mosquitoes. You can do that by draining all standing water that might serve as breeding grounds, such as gutters, unused hot tubs, old tires, watering cans, etc. in your yard. You can also change water in bird baths frequently to prevent mosquitoes from breeding there.
Also, if you wear long sleeves and pants, and if you keep screens over windows, mosquitoes will have more trouble trying to bite you. They're more active at dawn and dusk, so staying inside at those times also reduces the chance of a bite.
The key is to be informed and not to panic. Remember that mosquitoes are an important part of our ecosystem too, and don't be too hard on them about this. (In the past, the "cure" for mosquito borne illnesses was often worse than the cause. Remember DDT?) It may be better to just live in the world and be aware than to make war on the world or those in it every time a scare like this comes along.