It was a bacterium that caused it, but rats and fleas between them were the vector which spread the disease.
Metazoa.
The animal that started the plague first was the rat. They had parasites in their skin and spread it to humans
Plague is caused by a bacteria. Bacteria are not animals.
stuff...
The Black Plague!
locusts
The general definition of a plague is an epidemic outbreak that causes high rates of mortality.
The name of the bacillus that causes Bubonic plague is Yersinnia pestis.
Yersinia pestis.
The Plague
The two main causes were the rats and the fleas brought from Asia.
infested fleas in rats make it to humans after the host rat dies and infect them with the plague.