18. a.
Humans
b.
19. d
20. c
23. a.
The bite of a rat flea
b.
Inhaling plague organisms
c.
24. a.
Wild rodents
b.
27. a.
Presence of small rodents
b.
Presence of ungulates (hoofed mammals)
c.
28. a.
May burn the host
b.
Could cause the tick to regurgitate rickettsiae into the host.
29. a
30. b
End of Lesson 5
MD0152
5-67