| | Study I | Study II |
| | Sampling year | 1997/1998 | 2003 | | Analysis year (enhanced ELISA assay) | 2005 | 2009 | | Median horse contact among students | 9% | 12% | | No. of samples | 293 | 97 | | Samples < dl | 74% | 29% | | GM U/m2/day (Total) | 8.4 | 20.8 | | GM U/m2/day (in classes above median rate of horse contact) | 10.5 | 32.6 | | GM U/m2/day (in classes below median rate of horse contact) | 6.3 | 13.2 |
|
|