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The hypothesis that copper acquisition plays an essential role in virulence is further corroborated by the findings that a hypovirulent CUF1 - deletant strain of C . neoformans retrieved from infected mice contains almost a 6 - fold lower concentration of intracellular copper than the pathogenic wild - type strain .
 Chemical: copper; Chemical: copper
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: copper; Chemical: copper