L20: Herpesviruses (Waltzek) Flashcards
herpesvirus structure
- conserved morphology
- dsDNA
- icosahedral capsid
- tegument (b/w capsid and envelope)
- ENVELOPED
herpesvirus disease characteristics
- NUCLEAR INCLUSIONS
- host specific**; rare zoonosis
- persist in host for life in latent state!
- Recrudesce under stress = lifelong shedding
DNA viruses form inclusions of nucleus***
RNA viruses form inclusions of cytoplasm***
:)
Where do alphaherpesviruses hide?***
in neurons
Name 3 diseases caused by Bovine herpesvirus-1 (BHV1)
Infectious Bovine Rhinotracheitis (IBR)
Infectious Pustular Vulvovaginitis (IPV)
Infectious Pustular Balanoposthitis (IPB)
Infectious Bovine Rhinotracheitis (IBR) chars.
- caused by BHV1
- ranges from mild to fatal dz
- CS: dyspnic, febrile, necrotic mucosal lesions, abortion
- component of Shipping Fever Complex**
Shipping Fever Complex
- effects young calves
- caused by many viral and bacterial etiologies including IBR
- CS variable: depression, loss of appetite, coughing, d, sudden death
- Tx: supportive care, abx, +/- anti-inflammatories
BHV1 associated ocular lesions
- conjunctivitis
- corneal keratitis and ulceration
- assoc. with “cancer eye”
BHV1 infection chars.
- death in young calves
- abortion follows from RESPIRATORY, not genital infection
- mastitis can be assoc.
- not zoonotic
- detect virus by virus isolation
Is BHV1 zoonotic?
No
Control/Preventrion of BHV1
various vaccine
Name 2 diseases caused by bovine herpesvirus 2?
Bovine mammillitis
Pseudo-lumpy skin disease
Bovine Herpesvirus 2 chars.
- CS: mild inflammation to ulcers on teats/udder, mastitis
- not as severe as true Lumpy Skin disease
- transmitted direct contact, insect vector
- tx: supportive care
disease caused by pseudorabies virus
Pseudorabies (Mad Itch, Aujeszky’s Disease)
Pseudorabies pathogenesis (in pigs)
- replicates in upper respiratory tract
- can spread to brain via nerves**
- virus shed from nose
- goes into latency!**
alphaherpesvirus that causes disease in domestic animals. Key characteristic?
Bovine herpesvirus 1,2 Pseudorabies Equine herpesvirus 1,3,4 Canine herpesvirus 1 Feline herpesvirus 1 Avian herpesvirus 1,2 *can ascend from neurons into the brain*
epidemiology of pseudorabies
- pigs reservoirs
- mainly airborne spread
- can be transmitted sexually, via milk
- activated by stress
CS of pseudorabies in pigs
2 wks old: anorexia, CNS signs, dyspnea, 5-25% mortality
Adults: varying signs: anorexia, abortion, incoordination, resp. symptoms, etc.
Control of Pseudorabies**
- modified live and recombinant vaccines prevent disease but not infection with field strains
- serology can determine if animal was vaccinated or naturally infected
- US eradicating it with gene deleted vaccines
drawback of live attenuated vaccines
serology can’t determine if you have disease or have been vaccinated; gene-deleted vaccines are helping with this
Pseudorabies in cattle, sheep, cats, dogs all can present with these common signs:
- sudden death
- intense pruritis (“Mad Itch”)
- self mutilation
- dead end hosts; contract from contact with pigs
- convulsions
Equine herpesvirus 4 causes what disease?
Rhinopneumonitis
Equine Rhinopneumonitis incidence, CS
(caused by EHV-4)
- worldwide
- CS: nasal d/c, anorexia, lymphadenopathy, 2ary bact. infection, cough
EHV-1 causes what disease?
equine abortion/myeloencephalitis
EHV-1 incidence, etiology, path.
- worldwide
- causes abortion, neuro dz
- replicates in upper resp. tract
- can invade fetus
EHV-1 CS
same as EHV-4 (resp. signs) plus: abortion, ascending neurological disease*, death
Dx of EHV1 and 4
- CS
- Necropsy findings such as intranuclear inclusions, petechia
- Virus isolation
- Serology (ELISA)
- histopath
- PCR
- IFA
Prevention of EHV1 and 4
- vax (efficacy questionable): reduces CS only
- quarantine and hygiene
what disease does EHV-3 cause?
equine coital exanthema
coital exanthema chars. (all)
(caused by EHV-3)
- worldwide
- often subclinical; causes local superficial infection only**
- CS: vesicles on skin of vulva or penis, depigmented areas, +/- 2ary bacterial infection
- venereal trans.
- Tx: sexual rest, topical abx
- no vax available
Canine herpesvirus 1 causes what disease?
hemorrhagic disease of pups
epidemiology and transmission of canine herpesvirus
- worldwide
- common in feral dogs or dogs w/ high contact to other dogs
- deadly in very young puppies, mild in older puppies***
CS of canine herpesvirus
- puppies: depression, restlessness, hypothermia, hemorrhage**, hepatomegaly, CNS signs, etc.
- adults: asymptomatic, mild resp. signs, or infection of repro tract
what kind of inclusions in canine herpesvirus?
intranuclear
Tx/prevention of canine herpesvirus
- tx: supportive care
- prevent: vaccination not available in U.S.
- antiserum, isolation, disinfect, remove puppies via C-section
Feline herpesvirus 1 causes what disease?
Feline viral rhinotracheitis (similar to Shipping Fever in cattle)
possible causes of feline upper resp. tract infection*
herpesvirus calicivirus chlamydia Bordetella mycoplasma
trans. of feline URI
direct/indirect contact, aerosolization
which CS in feline URI indicates herpesvirus as more likely cause?*
corneal ulceration**
abortion
neonatal death
rhinitis, pharyngitis
which CS in feline URI indicates Calicivirus as more likely cause?
oral ulceration
pneumonia
polyarthritis
which CS in feline URI indicates chlamydi or mycoplasma as more likely cause?
conjunctivitis
Tx of ACUTE feline URI
- supportive
- steam/vapor
- topical antivirals for corneal ulcers/conjunctivitis
- abx if CS severe
- NO GLUCOCORTICOIDS
Tx of CHRONIC feline URI
-facilitte drainage of discharge
-chronic abx therapy
-lysine
+/- glucocorticoids, turbinectomy and frontal sinus ablation as last resort
prevention of feline URI
- vax to lessen severity
- avoid ML vax in sick or pregnant
Avian herpesvirus causes what dz?
Infectious laryngotracheitis
Infectious larngotracheitis chars.
(caused by AHV-1)
- worldwide in chickens/pheasants
- CS: “pump handle respiration”: neck raised and head extended during inspiration, loud gasping, coughing
- morbidity 100%, variable mortality depending on strain
- dec. egg production
most important poultry disease prior to vaccination in 1970**
Marek’s Disease (caused by AHV2)
3 forms of Marek’s Disease
1) Acute: causes paralysis, high mortality
2) Ocular: blindness, rare
3) Cutaneous: nodular lesions
vaccine for Marek’s Disease
- decreases incidence of lymphoproliferative and neoplastic effects but not neuro effects
- virus developing resistance
- decreases mortality
general CS of Marek’s Disease
- lymphoma, paralysis
- effects young birds most
Name a betaherpesvirus that causes dz in domestic animals. What dz does it cause?
porcine (suid) herpesvirus 2. Causes Inclusion Body Rhinitis; generalized Cytomegalovirus Infection.
Porcine Cytomegalovirus infection chars.
(caused by SHV-2)
- worldwide
- rhinitis up to 10wks, then goes subclinical
- most severe in very young
- horizontal or vertical trans.
- creates large basophilic intranuclear inclusions
Which 2 viruses cause Bovine Catarrhal Fever? What type of virus are they?***
Alcelaphine Herpesvirus 1
Ovine Herpesvirus 1
they are GAMMAherpesviruses
Bovine Catarrhal Fever chars.
- GAMMAherpesvirus
- African and N. American forms
- wildebeest, sheep asymptomatic shedders
- cattle, bison will get symptoms (dead end hosts)
- CS: inflamm. of mucosa, encephalitis, enlarged LN -> fever, dyspnea, gastroenteritis -> listless, CNS signs, bilateral corneal opacity**, death
- HIGH MORTALITY, LOW MORBIDITY
- No tx
