Whenever I see these games I wonder if there is some effort to solve the task with ml as well.
It seems like if you are getting a large number of players then you should have data on how those players are classifying the red blood cells.
Given that data we can at least attempt a couple different techniques at a classifier.
The benefit could be two fold. On one hand a decent classifier could 'help eliminate the high cost and sometimes poor accuracy of diagnosis.'
On the other hand if a diagnostician is looking at a blood sample having a classifier give some probability of classification (ie. saying 'this sample is 90% probable to be malaria infected') could help the doctor in their diagnosis.
I'd love to work on that problem. A very quick search of google scholar and citeseer doesn't pop up anything on the subject though, and I don't see any api on the linked site.