Recently, there have been 974 outbreaks of communicable disease ___ to the consumption of raw milk.

attributed 意為「歸因於」。原主動用法為 attribute A to B，此處為被動語態的關係子句簡化（disease which is attributed to...），指疾病爆發歸因於喝生乳，語意與文法皆完美契合。