Sunday Rest: polydemic.

 Even though polydemic isn't an outbreak of several diseases simultaneously, The Word Den cannot recommend the use of this word.

It's likely to cause alarm and despondency.

Sunday Rest: polydemic. This word describes a plant or animal which exists in two or more separate regions of the world. It comes from the Greek polus, which means much, and endemic, which comes from the other Greek word endēmos, which means native.