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: The prevalence of ALD among adults with Addisons disease remains unknown .
### Output Text:
The prevalence of <span class="disease">ALD</span> among adults with <span class="disease">Addisons disease</span> remains unknown . 