The structure and rhetorical style that the author uses in the letter to the editor of the Daily News is to inform readers about the new ideas about the disease using scientific evidence as support. They used problem/solution with a logical appeal. 
        
             
        
        
        
I think the answer is either Furthermore or Therefore! I would go with Furthermore... Hope this helps.
 
        
                    
             
        
        
        
'Nobody' is basically contracted in itself, I don't believe you can decrease the word further.