Lecture 10 10/18/24

Question 1

Which virus causes pseudorabies in swine?

Answer 1

porcine herpesvirus 1

Question 2

What is the respiratory manifestation of pseudorabies?

Answer 2

-URI
-nasal discharge
-sneezing
-coughing
-dyspnea

Question 3

What is the neurologic manifestation of pseudorabies?

Answer 3

-ataxia
-paddling
convulsions

Question 4

What is the neurologic manifestation of pseudorabies in incidental hosts?

Answer 4

“mad itch”

Question 5

What is the reproductive manifestation of pseudorabies?

Answer 5

-infertility
-abortion
-mummified feti

Question 6

Why is it important to do serosurveillance in swine herd free of pseudorabies?

Answer 6

even though commercial hog populations are free of pseudorabies, they can come into wild animals that are not

Question 7

What are the characteristics of porcine reproductive respiratory syndrome (PRRS)?

Answer 7

-arterivirus
-RNA virus
-infects pulmonary macrophages
-transmitted through direct contact, aerosol, semen
-disseminates to multiple tissues after replicating in pulmonary macrophages

Question 8

What are the clinical signs of PRRS in sows?

Answer 8

-abortions
-fetal mummification
-stillborn pigs
-weak pigs with high mortality
-anorexia
-lethargy
-fever

Question 9

What are the clinical signs of PRRS in piglets?

Answer 9

-anorexia
-fever
-dyspnea
-cyanosis of ears and extremeties

Question 10

When are sows most susceptible to PRRS?

Answer 10

during late gestation

Question 11

Why does PRRS have a rolling epidemiologic curve?

Answer 11

-initial outbreak moves rapidly and persists for several months
-subclinical carrier animals maintain virus in the herd
-introduction of naive animals results in reemergence of the virus

Question 12

What are the characteristics of an eradication method to control PRRS?

Answer 12

-remove all hogs from premise
-repopulate with virus-free stock
-expensive

Question 13

What are the characteristics of an infection control method for PRRS?

Answer 13

-depopulation nursery where pigs are exposed
-decrease subpopulations of naive gilts
-select replacement gilts from the herd instead of bringing in new guilts
-vaccinate upon entry
-do controlled infection

Question 14

What are the characteristics of the PRRS vaccine?

Answer 14

-does not prevent infection
-produces consistent immunity
-vaccinate gilts prior to entry to herd
-reduces shedding in semen of boars
-MLV associated with reversion to virulence

Question 15

What is the most commonly isolated pathogen in porcine resp. disease complex?

Answer 15

P. multocida

Question 16

What are the clinical signs of bronchopneumonia in pigs?

Answer 16

-fever
-anorexia
-depression
-cough
-vomiting

Question 17

How is bronchopneumonia diagnosed in pigs?

Answer 17

-culture at necropsy
-nasal/pharyngeal swabs
-tonsillar scraping

Question 18

What are the characteristics of Actinobacillus pleuropneumoniae?

Answer 18

-gram neg.
-primary pathogen
-very aggressive and contagious
-causes a necrotizing fibrino-hemorrhagic pneumonia

Question 19

What are the virulence mechanisms of Actinobacillus pleuropneumoniae?

Answer 19

-anti-phagocytic capsule
-cytotoxins
-endotoxin

Question 20

Which animals are carriers of Actinobacillus pleuropneumoniae?

Answer 20

individuals that were originally mildly infected and are now chronic life long carriers

Question 21

When do outbreaks of Actinobacillus pleuropneumoniae occur?

Answer 21

-following cold snaps
-during periods of ventilatory stress

Question 22

What are the clinical signs of Actinobacillus pleuropneumoniae?

Answer 22

-death
-dyspnea
-depression
-pyrexia
-anorexia
-blood stained froth

Question 23

What are the case attack and case fatality rates for Actinobacillus pleuropneumoniae?

Answer 23

attack rate: 30-50% in nursery and finishing pigs
fatality rate: up to 50%

Question 24

What is the treatment and control for Actinobacillus pleuropneumoniae?

Answer 24

-mass medication
-commercial vx to attenuate clinical signs
-autogenous vx
-eradication/depopulation

Question 25

What are the characteristics of Mycoplasma hyopneumonia?

Answer 25

-causes bronchopneumonia -primary infection leading to PRD -commensal organism in sows/gilts

Question 26

What is the pathophysiology of Mycoplasma hyopneumonia?

Answer 26

-piglets are colonized in farrowing house -disease manifests in nursery -slow, smoldering infection -causes bronchitis, bronchiolitis, and mild pneumonia -predisposes to more severe PRD pathogens

Question 27

What are the characteristics of Mycoplasma hyopneumonia prevention?

Answer 27

-vx can attenuate clinical signs but does not prevent infection -want all in/all out control -begin with pathogen free females -improve management practices

Question 28

Which pathogen causes Glasser's disease?

Answer 28

Glasserella parasuis

Question 29

What is Glasser's disease characterized by?

Answer 29

polyserositis

Question 30

What are the CNS clinical signs of Glasser's?

Answer 30

-tremors -ataxia -recumbency -depression -opisthotonos

Question 31

What are the septic arthritis clinical signs of Glasser's?

Answer 31

-swollen lame joints -pigs standing on their toes

Question 32

What are the resp. clinical signs of Glasser's?

Answer 32

-dyspnea -cyanosis

Question 33

What is the pathophysiology of Glasser's?

Answer 33

-commensal organism in some animals -spreads to naive pigs -septicemia -colonization of multiple membrane bound structures/organs

Question 34

How is Glasser's controlled?

Answer 34

-vaccine attenuates clinical signs -all in/all out -good management

Question 35

How does Mycoplasma hyorhinis compare to Glasser's?

Answer 35

clinical signs are all the same except for the CNS signs, which do not occur with Mycoplasma hyorhinis

Question 36

How is Glasser's differentiated from Mycoplasma hyorhinis?

Answer 36

culture

Question 37

What are the characteristics of Mycoplasma hyorhinis control?

Answer 37

-no effective vaccine -maintain a pathogen free breeding stock -all in/all out management

Question 38

What are the clinical signs of Salmonella cholerasuis?

Answer 38

-fever -depression -anorexia -diarrhea -septicemia -cyanosis -muscle soreness/reluctance to stand -dyspnea -death

Question 39

Where does S. cholerasuis spread after colonizing the GI tract?

Answer 39

-CNS/meninges -joints -liver -kidneys

Question 40

How is S. cholerasuis controlled?

Answer 40

attenuated vaccine