Lecture 10 10/18/24 Flashcards
Which virus causes pseudorabies in swine?
porcine herpesvirus 1
What is the respiratory manifestation of pseudorabies?
-URI
-nasal discharge
-sneezing
-coughing
-dyspnea
What is the neurologic manifestation of pseudorabies?
-ataxia
-paddling
convulsions
What is the neurologic manifestation of pseudorabies in incidental hosts?
“mad itch”
What is the reproductive manifestation of pseudorabies?
-infertility
-abortion
-mummified feti
Why is it important to do serosurveillance in swine herd free of pseudorabies?
even though commercial hog populations are free of pseudorabies, they can come into wild animals that are not
What are the characteristics of porcine reproductive respiratory syndrome (PRRS)?
-arterivirus
-RNA virus
-infects pulmonary macrophages
-transmitted through direct contact, aerosol, semen
-disseminates to multiple tissues after replicating in pulmonary macrophages
What are the clinical signs of PRRS in sows?
-abortions
-fetal mummification
-stillborn pigs
-weak pigs with high mortality
-anorexia
-lethargy
-fever
What are the clinical signs of PRRS in piglets?
-anorexia
-fever
-dyspnea
-cyanosis of ears and extremeties
When are sows most susceptible to PRRS?
during late gestation
Why does PRRS have a rolling epidemiologic curve?
-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
What are the characteristics of an eradication method to control PRRS?
-remove all hogs from premise
-repopulate with virus-free stock
-expensive
What are the characteristics of an infection control method for PRRS?
-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
What are the characteristics of the PRRS vaccine?
-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
What is the most commonly isolated pathogen in porcine resp. disease complex?
P. multocida
What are the clinical signs of bronchopneumonia in pigs?
-fever
-anorexia
-depression
-cough
-vomiting
How is bronchopneumonia diagnosed in pigs?
-culture at necropsy
-nasal/pharyngeal swabs
-tonsillar scraping
What are the characteristics of Actinobacillus pleuropneumoniae?
-gram neg.
-primary pathogen
-very aggressive and contagious
-causes a necrotizing fibrino-hemorrhagic pneumonia
What are the virulence mechanisms of Actinobacillus pleuropneumoniae?
-anti-phagocytic capsule
-cytotoxins
-endotoxin
Which animals are carriers of Actinobacillus pleuropneumoniae?
individuals that were originally mildly infected and are now chronic life long carriers
When do outbreaks of Actinobacillus pleuropneumoniae occur?
-following cold snaps
-during periods of ventilatory stress
What are the clinical signs of Actinobacillus pleuropneumoniae?
-death
-dyspnea
-depression
-pyrexia
-anorexia
-blood stained froth
What are the case attack and case fatality rates for Actinobacillus pleuropneumoniae?
attack rate: 30-50% in nursery and finishing pigs
fatality rate: up to 50%
What is the treatment and control for Actinobacillus pleuropneumoniae?
-mass medication
-commercial vx to attenuate clinical signs
-autogenous vx
-eradication/depopulation
What are the characteristics of Mycoplasma hyopneumonia?
-causes bronchopneumonia
-primary infection leading to PRD
-commensal organism in sows/gilts
What is the pathophysiology of Mycoplasma hyopneumonia?
-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
What are the characteristics of Mycoplasma hyopneumonia prevention?
-vx can attenuate clinical signs but does not prevent infection
-want all in/all out control
-begin with pathogen free females
-improve management practices
Which pathogen causes Glasser’s disease?
Glasserella parasuis
What is Glasser’s disease characterized by?
polyserositis
What are the CNS clinical signs of Glasser’s?
-tremors
-ataxia
-recumbency
-depression
-opisthotonos
What are the septic arthritis clinical signs of Glasser’s?
-swollen lame joints
-pigs standing on their toes
What are the resp. clinical signs of Glasser’s?
-dyspnea
-cyanosis
What is the pathophysiology of Glasser’s?
-commensal organism in some animals
-spreads to naive pigs
-septicemia
-colonization of multiple membrane bound structures/organs
How is Glasser’s controlled?
-vaccine attenuates clinical signs
-all in/all out
-good management
How does Mycoplasma hyorhinis compare to Glasser’s?
clinical signs are all the same except for the CNS signs, which do not occur with Mycoplasma hyorhinis
How is Glasser’s differentiated from Mycoplasma hyorhinis?
culture
What are the characteristics of Mycoplasma hyorhinis control?
-no effective vaccine
-maintain a pathogen free breeding stock
-all in/all out management
What are the clinical signs of Salmonella cholerasuis?
-fever
-depression
-anorexia
-diarrhea
-septicemia
-cyanosis
-muscle soreness/reluctance to stand
-dyspnea
-death
Where does S. cholerasuis spread after colonizing the GI tract?
-CNS/meninges
-joints
-liver
-kidneys
How is S. cholerasuis controlled?
attenuated vaccine
