Exam 2 Zoonoses from Milk & Water

Question 1

Classic Milk born pathogens

Answer 1

• Mycobacterium bovis
• Brucella spp.
• Coxiella burnetii

Question 2

Mycobacterium bovis: What disease in people

Answer 2

Tuberculosis, intestinal TB

Question 3

Mycobacterium bovis: What USA Control Program

Answer 3

Eradication in cattle

Pasteurization

Question 4

Brucella spp: What disease in people

Answer 4

Undulant fever

Malta fever

Question 5

Brucella spp: Waht USA Control Program

Answer 5

Eradication in cattle
Eradication in swine
Pasteurization

Question 6

Coxiella burnetii: What disease in people

Answer 6

Q fever

Question 7

Coxiella burnetii: What USA Control Measure

Answer 7

Pasturization

Question 8

What organism is modern pasteurization based on?

Answer 8

Coxiella burnetii

Question 9

In addition to milk, how can these organisms be transmitted?

Answer 9

• percutaneous or mucous membrane contact with infectious fluids
• aerosol exposure

Question 10

What people or premises are at risk?

Answer 10

Veterinarians
Farms
Abattoir workers

Question 11

When isn’t the milk pasteurized?

Answer 11

• Farmers on the farm
• Foreign travel
• “Raw Milk”
• Imported soft cheeses

Question 12

M. bovis and M. tuberculosis cannot be distinguished vis skin test (T/F)

Answer 12

True

Question 13

10-30% of “M. tuberculosis” cases in countries that don’t pasteurize milk or test cattle are actually M. bovis. (T/F)

Answer 13

True

Question 14

M. bovis transmission routes

Answer 14

• aerosol
• oral: intestinal form seen in cats and people
• percutaneous: causes lymphadenopathy, can become systemic

Question 15

Controlling M. bovis

Answer 15

• eliminate animal reservoir (test-and-slaughter); difficult controlling wild reservoir & mexican cattle
• milk pasteurization: doesn’t protect workers

Question 16

Brucella & Coxiella diagnosis difficulties

Answer 16

Need good suspicion to help with diagnosis.
Bruc: “undulant or Malta fever,” recurrent , can last for months. Abortion possible. pleiomorphic symptoms
Cox: “Q fever” nonspecific fever. Abortions possible.pleiomorphic symptoms

Question 17

Brucella melitensis

Answer 17

• most pathogenic for people
• goats (& sheep, caribou, pigs, dogs…)
• Mediterranean & goat-farming areas

Question 18

Brucella abortus

Answer 18

• pathogenic in people
• Cattle (bison, buffalo, elk…)
• worldwide, except where eradicated

Question 19

Brucella suis & canis

Answer 19

less pathogenic for people

Question 20

Brucella transmission

Answer 20

-ingestion
-mucous membane exposure
-percutaneous inoculation
(B. canis rare in humans, but several vet cases from blood contact)

Question 21

Brucella control

Answer 21

• eliminate reservoir (vaccination, milk monitored, testing on sale, slaughter of infected animals)
• swine monitored
• pasteurization of milk

Question 22

Coxiella burnetti: Q fever

Answer 22

• basis of pasteurization standards
• infects all dairy species (subclinical mastitis??)
• NO Eradication program in US. >90% of herds are positive
• Pasteurization

Question 23

Coxiella burnetti transmission

Answer 23

• Aerosol Exposure very infectious!

- Environmental contamination from: aborted placenta & fetus, milk & feces. Survives in water, soil, milk, meat

Question 24

Problems with control of milk born organizms

Answer 24

• wildlife reservoirs reinfect herds
• social cost
• compliance of owners

Question 25

Which is worse: water or food born?

Answer 25

Water - difficult to kill with chlorine, must filter water - environmentally stable life stage, can survive for months in water - can also contaminate surface of food

Question 26

Cryptosporidum parvum

Answer 26

- zoonotic - cattle are reservoir - typically rural settings - flooding of waste ponds into surface water

Question 27

Cryptosporidium hominis

Answer 27

- human-to-human - urban municipal water systems - seware treatment doesn't always kill oocysts

Question 28

Giardia

Answer 28

- affects many species (which then become infectious) - 200 million people have it, but only 50,000 cases are reported - 10-20% of cattle have type A - up to 50% of cats & dogs have Type A or B - humans have type A or B

Question 29

Cryptosporidiosis in people

Answer 29

- usually mild - diarrhea - severe disease in immunocompromised pt.

Question 30

Giardia in people

Answer 30

- chronic intestinal infection - intermittent shedding of cysts - young children "amplify"

Question 31

Prevention of crypto & giardia

Answer 31

- proper filtration of drinking water - wash produce - reduce exposure to recreational water - no diapers in swimming pools

Question 32

Estimate of US surface water contaminated with giardia

Answer 32

97%

Question 33

Leptospira reservoirs

Answer 33

- waterborne - domestic & wild animals - clinical disease in people, dogs, livestock, horses, ect

Question 34

Leptospira infects which system?

Answer 34

Urinary - bacteria in urine for >1 year - causes renal insufficiency and sometimes hepatic damage

Question 35

Leptospira infection via

Answer 35

- warm freshwater or mud - ingestion of contaminated water - mucous membrane or broken skin contact - contact with contaminated urine

Question 36

Leptospira acute diesase

Answer 36

``` -fever, depression, lethargy +/- icterus -Headache/malaise/ocular pain -Acute renal damage or failure -May have biliary stasis, hepatic necrosis ```

Question 37

Leptospira chronic disease

Answer 37

- LA abortions, stillbirths, weak offspring | - Chronic renal insufficiency

Question 38

Control of Leptospirosis

Answer 38

- reduce reservoir (rodent control, treatment w/ Ab, vaccines) - reduce human exposure (clean/treated water supply, PPE when suspected case)

Question 39

Trematode life cycle

Answer 39

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

Question 40

Schistosomiasis

Answer 40

- 2nd most important human parasite after Malaria | - Africa, South America, South/southeast Asia

Question 41

Schistosomiasis control

Answer 41

- avaid swimming in freshwater | - treat reservoir hosts; kill intermediate molluscs

Question 42

Schistosomiasis in humans

Answer 42

- Swimmer's itch - skin invasion by aquatic stage of bird trematodes - humans are accidental hosts- can result in skin lesions

Question 43

Fasciola (cattle liver flukes)

Answer 43

- cattle/sheep infected via vegetation near streams with snails - humans infected by contaminated vegetable (ie watercress), NOT via eating liver

Question 44

4 organisms that cause bovine abortion and are zoonotic

Answer 44

- Brucella abortus - Leptospira spp. - Coxiella burnetii - Listeria monocytogenes