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: Complement C7 deficiency ( C7D ) is associated frequently with recurrent bacterial infections , especially meningitis caused by Neisseria meningitidis .
### Output Text:
<span class="disease">Complement C7 deficiency</span> ( <span class="disease">C7D</span> ) is associated frequently with recurrent <span class="disease">bacterial infections</span> , especially <span class="disease">meningitis</span> caused by <span class="disease">Neisseria meningitidis</span> . 