Where might Zika virus strike next?


The World Health Organization recently declared the Zika virus a global public health emergency. This virus is spread by certain mosquitoes, and therefore if we know where those mosquitoes are located, then we've got a pretty good idea of where the virus might spread.

Before we get to the numbers, here are a few pictures of mosquitoes that tormented me in my house, until they met their ultimate demise!


First, I did a little light reading about the Zika virus on Wikipedia, and the BBC website, and learned that the virus is spread by Aedes mosquitoes. I then found an article where the researchers had compiled a database of known locations of two types of Aedes mosquitoes and plotted them on a map. I decided to write some SAS code to plot their data on a map - first to see if I could create a better map, and second to provide a good starting point for researchers doing additional analyses of the Zika virus.

I downloaded their csv file, and found that it acted a bit odd in the tools I was trying to use on it (such as the vi editor in Linux, and Windows SAS Proc Import). I like to say there are always 10 ways of doing a given task in SAS, and I find that Excel is often a good 'gateway' for getting small data into a form that is easily imported. Therefore I opened the csv in Excel and saved it as an xls spreadsheet, which then imported cleanly into SAS.

The original article did a decent job of plotting the data, but I like to think I made a few improvements. Rather than using red dots on a medium gray map, I used red dots on a very light yellow map - I think the higher contrast makes it easier to see the red dots. Also, instead of using solid red dots, I used alpha-transparent red ... this way the red is darker where several dots overlap, and lighter where the dots are less dense. And finally, I added html hover-text so you can hover your mouse over the countries, and see their names (you'll have to click the image below and look at the full-size interactive version to see the hover-text).


So, do you live in any of the areas with Zika mosquitoes, or do you have any mosquito stories you'd like to share? Have you ever caught a disease from a mosquito (or another insect)? Feel free to leave a comment.Where might Zika virus strike next? #analytics Click To Tweet


About Author

Robert Allison

The Graph Guy!

Robert has worked at SAS for over 25 years, and is perhaps the foremost expert in creating custom graphs using SAS/GRAPH. His educational background is in Computer Science, and he holds a BS, MS, and PhD from NC State University. He is the author of several conference papers, has won a few graphic competitions, and has written a book (SAS/GRAPH: Beyond the Basics).

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