Exactly what does your lease say about cleaning?

Does it provide, for example, that you are to leave the unit in a condition as clean as when you moved in -- in which case the landlord is likely reasonable in taking the position that you are responsible to remove animal hair and dander even if from an ESA?

Or does the lease provide that "tenants with pets must shampoo the carpets" (or something similar) without imposing any similar requirement on other tenants, which would support your position that the requirement does not apply to an ESA?

Or is it silent on the issue of carpet cleaning/shampooing?