Zoonoses from Milk and Water Flashcards Preview

RUSVM Epi Summer 17 > Zoonoses from Milk and Water > Flashcards

Flashcards in Zoonoses from Milk and Water Deck (48)
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1

What are the (3) classic milkborne pathogens?

Mycobacterium bovis
Brucella
Coxiella burnetti

2

How do pathogens get into milk?

Bacteria infect the animal systemically and colonize the mammary glands

Bacteria can be secreted into milk in a chronic fashion, often with minimal symptoms in the animal

3

In addition to milk, there can be _____ transmission to people

Direct

Percutaneous or mucous membrane contact with infectious fluids
Aerosol exposure

4

Who are most at risk for zoonotic infections from organisms in milk?

People who work with infected animals or premises are at highest risk : farmers, veterinarians, and abattoir workers

5

T/F: Some imported soft cheeses are not pasteurized and therefore, have potential for zoonotic transfer

TRUE

6

Where do most cases of M. bovis occur?

Countries without pasteurization of milk or control programs in cattle

7

Pulmonary TB (M. bovis) cannot be discriminated from M. ________ via skin testing or x-rays, only by ________.

M. tuberculosis

culture

8

What percentage of "M. tuberculosis" cases in countries that do not pasteurize milk or test cattle are actually M. bovis?

10-30%

9

What are the 3 major zoonotic transmission routes of mycobacterium bovis?

Aerosol (from infected cattle to other cattle and to people who work with cattle)
Oral exposure: to milk, feces, LN contents
Percutaneous exposure: abattoir workers, necropsy, etc

10

How can M. bovis be controlled?

Eliminate the animal reservoir
Milk pasteurization

11

What clinical signs might you see in a person with Brucellosis?

aka "undulant fever" or "malta fever"

-recurring fever, can last for months
-abortions can occur if pregnant
-Pleiomorphic symptoms: neurological, endocarditis, possibly chronic fatigue

12

What is the causative agent of Q Fever? What signs might you see in a human infected?

Coxiella burnetii - causes a non specific febrile illness

Abortions if pregnant
Chronic pleiomorphic symptoms
May also present as atypical pneumonia or hepatitis

13

What is the most pathogenic species of brucella in people?

Brucella melitensis

It infects a variety of animals and is mostly found in the Mediterranean and other intensive goat-farming regions

14

What brucella species is highly pathogenic in people, and has a worldwide distribution (with the exception of places with successful eradication processes)?

Brucella abortus

Seen in cattle, bison, buffalo, horses, dogs etc

15

What two brucella spps are the least pathogenic in humans, but still a zoonotic concern?

B. suis and B. canis

16

How do people get infected with brucella?

Ingestion, mm exposure , or percutaneous inoculation with: aborted placenta, fetus or fetal fluids, unpasteurized milk, blood, urine, semen, feces, and vaginal secretions
*feed/water contaminated with these materials

17

What methods are taken to control brucella?

Elimination of the animal reservoir
Reduce public exposure by pasteurization of milk and milk used to make soft cheeses

18

Is there an eradication program for Coxiella burnetti in the USA?

NO

Greater than 90% of dairy herds in the US have C. burnetii (20-30% of cattle are shedding at any given time)

19

The basis of pasteurization standards is based upon what pathogen?

Coxiella burnetti

**this protects the public but not animal workers/farmers

20

How is C. burnetti transmitted?

***Aerosol exposure
Percutaneous and mm exposure

21

Is C. burnetti an environmental issue? Why or why not?

YES

It causes abortion - there are large amounts of pathogen in the aborted placenta and fetus: survives in water, soil, milk, and meat for WEEKS TO MONTHS
Chronically excreted in milk and feces (possibly urine)

22

What are some barriers to control?

Wildlife reservoirs
Social cost/veterinary infrastructure
Compliance of animal owners

23

What two protozoa pathogens pose a threat via water transmission?

Crypotosporidium
Giardia

24

How long can cryptosporidium and giardia survive in water if conditions are good?

MONTHS

25

T/F: Chlorinating water will prevent cypto and giardia

FALSE

**Must FILTER water

26

What spps of cryptosporidium is zoonotic and has cattle as the reservoir?

C. parvum

Outbreaks are typically rural
Often follow overflow/flooding of animal waste holding ponds or feedlot/dairy pens

27

What spps of crypto is transferred human to human - during outbreaks in urban municipal water systems?

C. hominis

Sewage tx does not always kill 100% of oocysts

28

What is the human infecting genogroup of Giardia?

A or B

29

T/F: Giardia in humans will typical cause acute intestinal infections

FALSE

giardia will cause chronic intestinal infections. Greasy, foul smelling dhr, weight loss

30

Who are the human amplifiers of giardia?

young children are better amplifiers than adults