Parasitic organism?

Question

how can inflammation be beneficial to a host but detrimental to a parasitic organism?

Answer 1

It prevents the spread of infection.

Answer 2

One of the purposes of inflammation is to close off pathways by which the parasite could be transmitted to other parts of an organism.  So that benefits the "host" or organism being attacked while preventing the spread of the parasite or could even prevent movement of food (if a fluid) to the parasite.

In animals (this question was posted in Botany) inflammation is often accompanied by an increase in temperature (fever) if the organism can regulate its temperature.  The increase in temperature could affect the function of proteins/enzymes of the parasite and cause it to die.