As of now, the disease has spread from Uganda and has now jumped the Red Sea, from east Africa to Yemen on the Arabian Peninsula, and is perfectly positioned to move on to Egypt, the Middle East, and Asia. The Middle East and Asia’s 160-plus million acres of fields, which account for a quarter of the word’s annual wheat harvest, are in the direct path of the disease’s advance. And the spores of this fungal disease of plants could reach our continent sooner or later.
The race is on for scientists to genetically modify wheat seeds that are more resistant to Ug99.
Check out the US Department of Agriculture's Ug99 Web site.
Here are a couple interesting articles about this threat.