Sentence:  Bats host many high-profile viruses that can infect humans, including severe acute respiratory syndrome and Ebola. A recent study explored the ecological variables that may contribute to bats' propensity to harbor such zoonotic diseases by comparing them with another order of <WSD>common</WSD> reservoir hosts: rodents. 
Meaning of the word marked with <WSD> tags:  Occurring or happening regularly or frequently; usual.