Zoonoses from Milk and Water Flashcards Preview

RUSVM Epidemiology > Zoonoses from Milk and Water > Flashcards

Flashcards in Zoonoses from Milk and Water Deck (45)
1

classically milk-borne bacteria

Brucella spp.
Coxiella burnettii
Mycobacterium bovis

2

"classic" milkborne pathogens

- Bacteria infect the animal systemically colonize the mammary glands
- Bacteria can be secreted into milk in a chronic fashion, often with minimal symptoms in the animal

3

Modern pasteurization is based on...

Coxiella burnetii

4

Do we pasteurize all milk?

Not quite...

– Farmers on the farm
– Foreign travel
– “Raw milk” movement
– Imported soft cheeses

5

True/False: there can be direct transmission to humans in addition to transmission via milk

True:
- Percutaneous or mucous membrane contact with infectious fluids
- Aerosol exposure

6

Most M. bovis cases occur in...

...countries without pasteurization of milk or control programs in cattle

7

Transmission routes: M. bovis

- Aerosol
- oral exposure (intestinal or cervical lymphadenitis)
- percutaneous exposure (lymphadenopathy of draining LN)

8

M. Bovis: Aerosol transmission to people =

pulmonary TB (culture to differentiate from M. tuberculosis)

9

Control of M. bovis

- Eliminate animal reservoir (test-and-slaughter)
- milk pasteurization

10

True/False: Human infections of Brucella and Coxiella are easy to diagnose

False: difficult to diagnose without good index of suspicion

11

“undulant fever” or “Malta fever”

Brucellosis in humans
- recurring fever, abortions, Pleiomorphic symptoms: neurologic, endocarditis, possibly chronic fatigue

12

"Q fever"

Coxiella burnetii in humans
- abortions, pleiomorphic symptoms
-may present as atypical pneumonia or hepatitis

13

most pathogenic Brucella spp in humans

Brucella melitensis

14

Brucella abortus

pathogenic in humans
worldwide distribution

15

Brucella suis and canis

less pathogenic in humans

16

Brucella transmission

Ingestion
mucous membrane exposure
percutaneous inoculation
(Aborted placenta, fetus, fetal fluids, Unpasteurized milk, blood, urine, semen, feces, and uterine/vaginal secretions, Feed/water contamination)

17

controlling Brucella spp

Eliminate reservoir
monitor swine
reduce public exposure: pasteurization of milk and milk used to make soft cheeses

18

Coxiella burnetii: Q Fever

Used for the basis of pasteurization standards
Infects all dairy species
No eradication program in USA
Pasteurization of milk

19

Transmission of Coxiella burnetii

Extremely infectious via aerosol exposure (percutaneous and mucous membrane)
An issue of environmental contamination (aborted placenta/fetus, milk, feces, water, soil, meat)
Veterinary exposure is most likely from environmental sources on farms

20

Barrier to control (milkborne)

wildlife reservoirs
social costs/veterinary infrastructure
compliance of animal owners

21

Cryptosporidium and Giardia

Protozoan parasites (Cryptosporidium is coccidia‐like; Giardia is flagellated)
transmission via water > food!
Infected animals can contaminate water supplies

22

True/False: both Cryptosporidium and Giardia are diverse

True

23

C. parvum

zoonotic
cattle are reservoir

24

C. hominis

human to human
urban municipal water systems

25

estimated number of people with Giardia

200 million people in Africa, Asia, and Latin America have Giardia but only 50,000 cases reported
exact zoonotic capacity of Giardia has been long debated

26

zoonotic types of Giardia

humans infection groups: type A and B
-10-20% cattle is type A
-50% dogs and cats have type A or B

27

True/ False: Cryptospiridiosis in humans is usually severe

False: mild=diarrhea; severe in immunocompromised patients

28

Giardia causes

chronic intestinal infections

29

prevention of Cryptosporidium & Giardia

proper treatment (filtration) of drinking water; wash produce; reduce exposure to recreational water; no diapers in swimming pools!

30

True/False: Leptospirosis is a waterborne disease

True

31

Leptospirosis infects...

kidneys/ excreted in urine

32

how long can animals excrete Leptospirosis in their urine

>1 year

33

Leptospirosis survives best in...

warm freshwater or mud

34

Leptospirosis infection via...

Ingestion of water containing Leptospira
Mucous membrane or broken skin contact with water containing Leptospira
Contact with animal urine containing Leptospira

35

Clinical Leptospirosis (acute)

Fever, depression, lethargy, +/‐ icterus
Headache/malaise/ocular pain in people
Acute renal damage or failure

36

Clinical Leptospirosis (chronic)

Large animal abortions, stillbirths, weak offspring
Chronic renal insufficiency

37

control of Leptospirosis

reduce reservoir (rodent control)
reduce human exposure (clean water, wear gloves when handling urine)

38

Trematode life cycle

Definitive host = a vertebrate
Intermediate host(s) = aquatic
Accidental hosts can be infected percutaneously

39

Trematodes as zoonosis

Anthroponotic as well as zoonotic species
Disease occurs anywhere with appropriate water conditions and presence of intermediate hosts

40

2nd most important human parasite after malaria

Schistosoma spp.

41

Schistosoma japonicum

zoonotic: have domestic animal reservoirs

42

Control of Schistosomiasis

Avoid swimming in fresh water
Treat reservoir hosts; kill intermediate molluscs

43

Swimmer’s Itch

Caused by skin invasion by the aquatic stage of bird trematodes (Humans cannot be the definitive host)
Humans are accidental hosts – can result in skin lesions

44

Fasciola spp. (Cattle Liver Flukes)

Important animal disease
Humans can be infected (vegetables contaminated with metacercariae)
- Humans are NOT infected via eating liver
In some parts of the world it is quite common in humans

45

cause bovine abortion and are zoonotic

Brucella abortus
Leptospira spp.
Coxiella burnetii
Listeria monocytogenes