1. Chapter 13 Zoonotic bacteria

2. What’s zoonosis? Zoonosis Zoonotic bacteria
a disease that can be transmitted from animals to humans
Zoonotic bacteria
bacteria causing zoonosis

4. What’re primary zoonotic bacteria?
Content
Source of human infection
Disease
Brucella
Pigs, cattle, goats, sheep
Brucellosis
Yersinia pestis
Rodents
Plague
Bacillus antracis
Cattle, goats, sheep, horses
Anthrax

5. Brucella

6. Brucella B.abortus: cattle B.melitensis: goat,sheep B.suis: swine
B.canis: dog

7. Biological properties
Shape and structure
Coccobacillus: ～ μm
Gram-negative
Nonmotile, non-spore-forming
microcapsule (some)

8. Biological properties
Culture
Obligate aerobes
5-10% CO2 (B. abortus)
fastidious
slow growth: 2～5d
Facultative intracellular pathogens

9. Biological properties
Antigenic types
LPS, endotoxin
two major serological determinants: A and M
A---abortus antigen
M---melitensis antigen

10. Pathogenicity Virulence factor endotoxin (main)
invasiveness: capsule, hyaluronidase

11. Pathogenicity Transmission intestinal tract: infected milk
respiratory tract: aerosols containing the bacteria
contact

12. Pathogenicity animals: infections of genital systems
Disease: brucellosis
animals: infections of genital systems
abortion (erythritol)
inapparent infections (source)
humans: undulant fever
organism (as a facultative intracellular parasite) → lymphatic system → blood （bacteremia）
liver, spleen, bone marrow, lymph nodes
undulant fever

14. Immunity
Cell-mediated immunity (CMI)
Humoral immunity

15. Control Prevention Treatment tetracycline, ampicillin
pasteurization of milk for drinking
animals: slaughter
immunization
humans: vaccination for persons at high risk
Treatment
tetracycline, ampicillin
prolonged treatment

16. Yersinia

17. Yersinia Species Transmission Disease Y. Pestis Flea bite
Respiratory tract
Plague
Y. Enterocolitica
Digestive tract Contact
Enterocolitis
Y. Pseudotuberculosis
Digestive tract

18. Y. Pestis During 14th century over a 5-year period
25 million deaths
The most recent pandemic in Asia in 1904
a million deaths

19. Biological properties
Shape and structure
～1-2μm, coccobacillus
Gram-negative, bipolar staining
capsule
nonmotile
non-spore-forming

20. Biological properties
Cultivation
facultative aerobes
slow growth
colony--irregular and rough
optimum temperature: 27～30℃

21. Biological properties
Antigenic structure
F1 antigen (fractionⅠ): capsular antigen
V-W antigen: protein-lipoprotein
Yop (Yersinia outer membrane proteins)
murine toxin (MT): exotoxin
released only when cells are lysed
potent
endotoxin: LPS

22. Pathogenicity
Virulence factor
F1 antigen
V-W antigen
Yop
endotoxin MT

23. Pathogenicity Transmission
rat ←→ rat (by direct contact or biting of rat fleas)
↓by rat fleas
person ←→ person (by human fleas or respiratory route)

24. Pathogenicity Disease--- plague Bubonic plague Pneumonic plague
Septicemic plague

25. Pathogenicity Bubonic plague the most common
enlarged and inflamed lymph nodes (around armpits, neck and groin)
mortality rate: 30-75%

26. Pathogenicity Pneumonic plague mortality rate: 90-95%
the second most common
mortality rate: 90-95%

27. plague / black death
Infected fleas bite bubonic plague spreads pneumonic plague disseminated intravascular coagulation intravascular thrombi and purpuric lesion gangrene and blackening all over the body (the black death)

28. Pathogenicity Septicemic plague the most rare
mortality rate: close to 100%

29. Control Prevention elimination of rats and fleas Treatment
effective formalin-killed vaccine
Treatment
streptomycin, tetracycline
rapid treatment

30. Bacillus

31. Bacillus
B.anthracis: anthrax
B.cereus: food poisoning

32. B. cereus Virulence factor: enterotoxin Disease food poisoning
transmission: digestive tract
clinical types: emetic type, diarrheal type
eye infection
transmission: trauma
clinical manifestations: keratitis, endophthalmitis,
panophthalmitis
others

33. B.anthracis

34. Bacillus
B.anthracis: anthrax
B.cereus: food poisoning

35. B.anthracis

36. Biological properties
Shape and structure
1-3～5-10μm
Gram positive
rod with square ends in long chains (bamboo)
central spore
capsule (D-glutamate)
nonmotile

37. Biological properties
Culture
aerobic or facultative anaerobic
colony: irregular margins
non-hemolytic

38. Biological properties
Resistance
strong resistance: dry heat
desiccation
disinfectant
sensitivity: oxidant
autoclaving

39. Pathogenicity Virulence factors capsule: Poly-D-glutamate polypeptide
anthrax toxin: protective antigen (PA): proteolytic activation
lethal factor(LF)
edema factor(EF)
PA+EF=edema toxin
PA+LF=lethal toxin
responsible for shock and death

40. Pathogenicity Disease - anthrax source: herbivorous animals
transmission:
direct contact
digestive tract
respiratory tract
clinical types:
cutaneous anthrax (90%)
intestinal anthrax (5%)
pulmonary anthrax (5%)
Papule丘疹- Vesicle水泡- Ulcer - Eschar焦痂
eschar

41. Control Prevention Treatment animals: burn or deep bury vaccination
humans: vaccination
Treatment
Penicillin, tetracycline, erythromycin
Sporulation of B anthracis requires oxygen
therefore does not occur inside a closed carcass
regulations in most countries forbid postmortem examination of animals when anthrax is suspected
The vegetative cells in the carcass are killed in a few days by the process of putrefaction

42. B. cereus Virulence factor: enterotoxin Disease food poisoning
transmission: digestive tract
clinical types: emetic type, diarrheal type
eye infection
transmission: trauma
clinical manifestations: keratitis, endophthalmitis,
panophthalmitis

43. Question 1. What is zoonosis ?
2. B.anthracis is responsible for three clinical forms of anthrax. Name them and the route of acquisition.
3. What are the two major virulence factors of B.anthracis ?
4. Please choose the one best response to each question.
1)Transmission of Y.pestis (bubonic form) is by
a. fleas b. ticks c. lice
2) Plague is caused by
a. Y. pestis b. Y. enterocolitica c.Y. pseudotuberculosis
3) which bacteria can be cause food poisoning?
a. B.cereus b. Y. pestis c. B.anthracis

44. 4)Yersinia pestis, the causative agent of plague, is enzoonic in the United States west of the one-hundredth meridian. Human plague can be bubonic or pneumonic. The primary epidemiologic difference between the two clinical forms of plague is
a. season of the year b. route of infection
c. age of the patient d. health of the animal vector
5. Please match the organisms with the animal reservoir
B.abortus
goat
B.melitensis
cattle
B.suis
dog
B.canis
swine

45. Disease Anthrax--- herbivorous animals ---Sudden onset
---Bleeding from body openings (epistaxis)
--- Edema (bloating)
--- High fever
--- "Peracute" death (within hours after onset)

46. Evolution of an anthrax eschar in a 4-year-old boy.
(A&B) the lesion when first seen (day 0).Note the arm swollen from the characteristic edema.
(C) Day 6. (D) Day 10. (E) Day 15.