1.   But when rats are scarce, the rat fleas will bite people.

2.   The bacterium prefers to live in rats and spreads by hitching rides on rat fleas.

3.   The oriental and northern rat fleas transmit murine typhus fever among rodents and from rodents to people.

4.   Pneumonic plague is a highly-infectious and advanced variety of the disease caused by rat fleas and is transmitted through cough droplets in the air.

5.   Short-term preventive measures would include setting rat traps with poisoned bait and using pesticide sprays to kill rat fleas.