In the sentence extracted from biomedical literature, identify all the disease entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="disease"> to denote a disease.

### Input Text: Musculus / M . spretus backcross placed the Wasp locus near the centromere of the mouse X chromosome , inseparable from Gata1 , Tcfe3 , and scurfy ( sf ) .
### Output Text:
Musculus / M . spretus backcross placed the Wasp locus near the centromere of the mouse X chromosome , inseparable from Gata1 , Tcfe3 , and scurfy ( sf ) . 