Over the coming weeks I will be writing about and commenting on some of my research involving the West Nile Virus here in Dallas, its impact, WHERE it is hitting, and why it may be hitting certain places and not other places. When we read about a disease (or anything) impacting people living in certain areas, we often think of it as a "blanket result" -- everyone in all parts of the area are equally affected.
The truth is (as you can figure out from your own experiences) is that "it ain't necessarily so."
Last year, the Dallas City Council decided that the way to deal with West Nile Virus was to spray from the air -- in spite of the uproar from citizens. Organic farmers, beekeepers, naturalists, and a lot of other folks were very upset by this (and many saw some impact from it) and a small coalition has formed to see if we can stop it this year. Some beekeepers asked me if I would look at the data and see if I can help.
More below the squiggle.
We don't all look at data in the same way, either. Now, this is a particularly un-handsome image since the only place I could find a zip code map was a fairly low resolution version of it. I colored in the areas that had the highest number of cases (the black area had THE highest number of cases)... and then I did the one thing that I haven't seen done: colored in the areas where there were NO cases and said, "What's different about these?"
Now, all zip codes have residential areas (even downtown Dallas.) Population density varies, of course, but the interesting thing is that the virus hits hardest in the wealthiest parts of town. It could be that this is the area of town where people have enough economic power to go to the doctors and get a diagnosis, but I think that's an over-simplified answer. I can say from experience that the area with the most cases (the one in black) also had a huge mosquito problem -- big enough that one of the most popular outdoor places in Dallas (a botanical garden called the Arboretum) had enough of a mosquito problem that they had cans of bug spray stationed at the entrance information booth and encouraged people to use the mosquito spray.
Six miles south of that, at the Trinity River Audubon Center, we had very few mosquitoes.
Both sites have water (one is a big lake, the other has many ponds and lakes that were drying up in the drought) and both have habitats that mosquitoes like (they're not very picky critters. Give 'em enough water to keep eggs and larvae wet for 10 days and you have a flock of happy mosquitoes flitting around.)
So I'm looking at the areas (walking them... not just sitting on Google Earth and speculating about conditions) and thinking about them. If we can get enough people involved in being proactive about this then maybe we can keep mosquito numbers down and disease levels down and eliminate the "need" in the minds of the City Council to carpet-bomb the city with insecticide.
It's a crazy plan, but it might work.
