Zoonotic Diseases

Question 1

what type of virus is West Nile Virus? Is it an RNA virus or a DNA virus?

Answer 1

Enveloped positive-stranded RNA virus

Question 2

what animal is the primary vector?

Answer 2

Mosquito

Question 3

what species of animal is the maintenance host or reservoir?

Answer 3

birds

Question 4

what species (2) are the main incidental hosts?

Answer 4

humans & horses

Question 5

what body system is most severely affected?

Answer 5

central nervous system

Question 6

do chickens typically develop clinical signs for WNV? Why might we use them in a sentinel program?

Answer 6

• No chickens don’t develop clinical signs
• Use the chickens to search for antibodies

Question 7

what is qRT-PCR?

Answer 7

Real-time quantitative Reverse transcription PCR

Question 8

what is the treatment for WNV?

Answer 8

none

Question 9

what is the best method to control WNV spreading in an area?

Answer 9

• Control mosquito population within the area
• Sentinels

Question 10

are vaccines available for horses? For birds?

Answer 10

Horses = vaccine available
Birds = not available

Question 11

how do the rabies virus spreads from a bite wound to the salivary glands.

Answer 11

• The virus travels from the peripheral nerves to the spinal cord. Then from the spinal cord to the brain
• From the brain, the virus then travels via peripheral nerves to the salivary glands

Question 12

the two clinical forms of rabies infection.

Answer 12

• Inflammation of the brain
• Inflammation of the spinal cord

Question 13

is rabies typically treatable in humans? In animals?

Answer 13

Humans = treatable
Animals = not treatable

Question 14

name one state that is free of rabies

Answer 14

hawaii

Question 15

what is the typical reservoir for rabies?

Answer 15

Wildlife (skunks, raccoons, bats, and canines)

Question 16

what is the typical incubation period for rabies?

Answer 16

21-80 days

Question 17

RABIES

what is one factor affecting the length of the incubation period?

Answer 17

Partially determined by the location of the wound (distance to the brain)

Question 18

what test is used to test for rabies?

Answer 18

• PCR
• Necropsy
• Antibody staining of the brain

Question 19

what a. structure is used to provide a preliminary diagnosis histologically?

Answer 19

brain

Question 20

what animal is the definitive host for Toxoplasmosis?

Answer 20

cats

Question 21

Toxoplasmosis

what is the infectious stage of this parasite that is found in feces?

Answer 21

Sexual stage (oocysts)

Question 22

Toxoplasmosis

which stage can be found in muscle (tissues)?

Answer 22

Bradyzoite

Question 23

Toxoplasmosis

which infectious stage is responsible for dissemination in tissues and disease?

Answer 23

Tachyzoite stage

Question 24

Toxoplasmosis

how long does it take for the oocysts to become infectious?

Answer 24

After 1-5 days

Question 25

Toxoplasmosis what stages can be found in hosts other than cats?

Answer 25

Tachyzoites/bradyzoites

Question 26

Toxoplasmosis what is the most important clinical presentation in small ruminants?

Answer 26

- Abortion/stillbirth/birth defects

Question 27

what are the tests that can be used to diagnose acute toxoplasmosis.

Answer 27

- Serologic tests - Microscopic examination

Question 28

what other protozoa can look like Toxoplasma? What tests can be used to differentiate them?

Answer 28

- Sarcocystis, neospora - Tests to differentiate them: o PCR o immunohistochemistry

Question 29

what can be used to treat Toxoplasma?

Answer 29

- Drugs (clindamycin)

Question 30

Toxoplasma what are some ways to avoid exposure in humans?

Answer 30

- Pregnant women should avoid cleaning litter boxes - Avoid digging in the soil where cats have defecated

Question 31

what does BSE stand for?

Answer 31

Bovine spongiform encephalopathy

Question 32

what disease in small ruminants does it resemble?

Answer 32

Scrapie of sheep’s and goats

Question 33

what is the causative agent?

Answer 33

prion

Question 34

what is the difference between BSE and vCJD?

Answer 34

BSE is found in cattle, where vCJD is a human-form of disease branching off from BSE

Question 35

what is the most likely mode of transmission between animals?

Answer 35

- Maternal transmission - Feed contamination

Question 36

how do humans contract vCJD?

Answer 36

Humans consuming animal products with BSE

Question 37

what is the typical incubation period for BSE in cattle?

Answer 37

2-8 years

Question 38

what is the part of the brain that we target for BSE testing in ruminants?

Answer 38

Region of the obex (brain)

Question 39

BSE what is the histologic change caused by prions in the brain?

Answer 39

- Spongiform changes in gray matter - Abnormal prion protein

Question 40

what is the gold standard test for BSE? What are some other tests?

Answer 40

- Immunohistochemistry tests (IHC) gold standard - Other tests: o Rapid diagnostic tests

Question 41

what are the causes of the 3 types of spongiform encephalopathies in humans and how do they differ?

Answer 41

- Kuru, affected mostly women and children. Cannibalism was the main source - vCJD, consuming BSE-contaminated foods - CJD, is not caused by eating BSE-contaminated food products