Are there any countries more susceptible to plague infections?

If diagnosed early. It can be treated effectively with antibiotics . However , because it is not common it is not easily diagnosed . By the time it is diagnosed it will be late for treatment.
African countries. Almost all of the approximately 3000 annually reported cases of plague in the world occur in African countries: Botswana, Kenya, Madagascar, Mozambique, Tanzania, and Zaire. A few cases are seen in other parts of the world. The U.S. has 10-15 cases per year. Europe has not had plague since WWII. Australia also does not have plague.