Lecture 5 10/15/24 Flashcards
What is caused by bovine herpesvirus 1.1?
-infectious bovine rhinotracheitis
-conjunctivitis
-abortion
-immune suppression
What is caused by bovine herpesvirus 1.2?
-infectious pustular vulvovaginitis
-infectious balanoposthitis
-abortion
What is caused by bovine herpesvirus 1.3/BHV-5?
-encephalomyelitis
-abortion
What is the pathophysiology of BHV-1?
causes:
-nasal and oral mucosal erosions
-severe tracheitis
-conjunctivitis
-abortions
-immunosuppression
When do abortions occur with BHV-1?
during resp. outbreaks and up to 100 days after
What are the characteristics of BHV-1 latency?
-maintained and spread by latently infected carriers
-latency occurs in trigeminal ganglion cells
-stress causes recrudescence and shedding of the virus
Which tests can be done to detect an active viral infection?
-virus isolation
-PCR
-antigen capture ELISA
-immunofluorescence
-histopathology
Which samples are used to detect an active viral infection?
-serum/plasma
-whole blood
-nasal swabs
-transtracheal wash/bronchoalveolar lavage
-tissue
-fetus/placenta
-semen
Which tests can be done to detect a previous viral infection?
-serology
-antibody ELISA
-complement fixation
-card agglutination
-intradermal allergen test
-caudal fold test
Which samples are used to detect a previous viral infection?
-serum/plasma
-whole blood
-intradermal antigen deposition
Which diagnostic methods are most commonly used for diagnosis of BHV-1?
-PCR
-serology
-virus isolation
-immunofluorescent antibody staining
-histopathology
What is the hallmark finding of herpes infections on histopath?
inclusion bodies
What result on paired antibody ELISA titers indicates infection?
4 fold or greater increase in titers
What is the typical treatment for viral infection?
-fluids
-antibiotics for secondary bacterial infections
-NSAIDs
-avoiding further stress
-maybe steroids; but they induce immunosuppression
How is infectious bovine rhinotracheitis/BHV prevented?
vaccination and biosecurity
What are the characteristics of the BHV MLV?
-best cell mediated immunity
-may cause abortions in cows not previously vaccinated
-cannot be used in neonates
-can cause latent “vaccine infections”
What is the main characteristic of the BHV killed vx?
safe for pregnant cows
What are the characteristics of the BHV intranasal MLV?
-fastest means of protection
-mucosal immunity through IgA prod.
-good cell mediated immunity
-no interference with maternal antibodies
-circulates between animals after vx
-short lived; 6 week duration
What are the potential BVDV genotype and biotype combinations?
-genotype 1, non-cytopathic
-genotype 1, cytopathic
-genotype 2, non-cytopathic
-genotype 2, cytopathic
How does cytopathic BVDV differ from non-cytopathic BVDV?
cytopathic kills cells in culture while non-cytopathic does not
What is the most important manifestation of BVDV?
immunosuppression
What are the manifestations of BVDV?
-immunosuppression
-diarrhea
-abortion
-upper resp. infection
-persistent infections
-persistent testicular infections
-mucosal disease
-congenital malformation
Which lymphoid cells are effected by BVDV?
-Th cells
-B cells
-neutrophils
-monocytes
-cytotoxic T cells
-NK cells
-dendritic cells
-pulmonary alveolar macrophages
How does BVDV impact lymphoid cells?
-reduces lymphoid cell number
-impairs interferon production, phagocytosis, chemotaxis, and microbial killing
-reduces MHC I and II expression and Th cell response
What is a persistent BVDV infection?
-NCP virus infects the calf at 40-125 days of gestation
-calf’s immune system is developing at this time and recognizes the virus as self, allowing for immunotolerance
Why are BVDV PIs important?
serve as a reservoir for BVDV transmission to the rest of the population
What are the diagnostic methods for BVDV?
-virus isolation: 2 samples 3 weeks apart
-immunohistochemistry
-antigen capture ELISA
Which samples are used for each BVDV diagnostic method?
-virus isolation: nasal swab, ear notch, whole blood buffy coat
-immunohistochemistry: ear notch
-antigen capture ELISA: ear notch, whole blood
How long does it take for BVDV to transmit from a PI to another individual?
1 hour of fence line contact (very contagious)
What are the characteristics of the BVDV vaccine?
-prevents clinical disease
-limits viral shedding
-protects fetus from abortion and PI
-used in the cows
