DNA viruses Flashcards
List of DNA viruses
herpesviridae
asfarviridae
Hepadnaviridae
Poxviridae
Adenoviridae
Papillomaviridae
Parvoviridae
Circoviridae
herpes viruses shape and size
- 200-250nm in diameter
- double stranded DNA in icosahedral capsid
herpes viruses cell entry and replication
- enter cells by fusing with membrane
- replicate in nucleus (DNA virus)
herpes virus once in body is:
- latent in sensory ganglia, disease manifests when stressed
herpes virus in the environment is
- labile in environment (need close contact for transmission)
- quarantine is effective for control
herpes virus infects what types of cells?
Infect epithelial or endothelial cells
* Skin
* Mucous membranes
* Tracheal mucosa
* Liver
* Brain
active infections of herpes virus results in?
Active infection results in cell death
* Ulcers
* Erosions
* Hepatocellular necrosis
* Vasculitis
bovine herpesvirus 1 subtypes
Three Subtypes: BHV1.1, 1.2 (1.2a, 1.2b)
* BHV1.1: Respiratory (infectious bovine rhinotracheitis- IBR) and reproductive (abortion)
* BHV 1.2: Genital (infectious pustular valvovaginitis)
* 1.2a: abortions/1.2b: no abortions
infectious bovine rhinotracheitis (IBR)
- BHV-1 (bovine herpes virus) subtype 1.1
- Aerosol transmission (nose-to-nose contact)
- Virus replicates in the mucous membranes of the upper respiratory tract
- Becomes latent in the trigeminal ganglia
- Reactivated in times of stress
- Large amounts of virus are shed in nasal secretions
- Strong immunity develops but secondary bacterial infections can result in severe disease
Respiratory disease
* Rhinitis
* Tracheitis
* Predisposes to secondary bacterial pneumonia – bovine respiratory disease complex
Reproductive disease
* Viremia in pregnant cows and infection of the fetus results in abortion
* Multifocal hepatic necrosis in the fetus with intranuclear inclusions
Equine herpesvirus 1 strains
Two strains: EHV1 D752, N752
* A single nucleotide change results in more severe disease
* D752 – respiratory (rhinopneumonitis)/reproductive (abortion)/ neurologic
* N752 – respiratory/reproductive/non-neurologic
equine rhinopneumonitis
- EHV-1 and EHV-4
- Aerosol transmission (nose-to-nose contact)
- Virus replicates in the mucous membranes of the upper respiratory tract and regional lymph nodes
- Becomes latent in the trigeminal ganglia
- Reactivated in times of stress
- Large amounts of virus are shed in nasal secretions
equine rhinopneumonitis respiratory disease
- rhinitis
- tracheitis
- may extend into lungs especially in young animals
Equine Rhinopneumonitis reproductive disease
- Viremia in pregnant mares results in abortion
- EHV-1 has a predilection for vascular endothelium resulting in placental vasculitis and thrombosis
- Multifocal hepatic necrosis in the fetus with intranuclear inclusions
Equine Herpes Myeloencephalopathy
- Typically associated with the D752 strain EHV-1
- Follows an outbreak of respiratory disease or abortion on the farm
- The neurologic form is reportable in Virginia to the State Veterinarian
- Vasculitis, necrosis, and hemorrhage in the spinal cord and brain
Canine herpesvirus 1
- Aerosol or in utero transmission (through the placenta)
- Virus replicates in the mucous membranes of the upper respiratory tract, pharynx, and tonsils
- Becomes latent in the trigeminal ganglia
- Reactivated in times of stress
- Large amounts of virus are shed in nasal and vaginal secretions
- DIFFERENCE: Replication is most efficient in temperatures BELOW body temperature
Canine herpesvirus 1 and whelping/puppies
- Neonatal pups are most susceptible, especially in the first 3 weeks of life (hard time regulating body temp)
- If the dam is infected within 3 weeks of whelping, the puppies will be infected through the placenta
- The entire litter may be affected
- Morbidity and mortality are high
- The dam will develop immunity and subsequent litters will be unaffected
- Dead puppies will have multifocal necrosis in multiple organs, and hemorrhage in the kidneys with intranuclear inclusions
feline herpesvirus 1
- Aerosol transmission (nose-to-nose contact)
- Virus replicates in the mucous membranes of the upper respiratory tract and conjunctivia
- Becomes latent in the trigeminal ganglia
- Reactivated in times of stress
- Large amounts of virus are shed in nasal secretions
feline viral rhinotracheitis
Accounts for 40% of respiratory disease in cats
Acute upper respiratory tract infection
* Sneezing
* Hypersalivation
* Conjunctivitis
Can lead to ulcerative keratitis
Secondary bacterial infections can result in pneumonia
feline viral rhinotracheitis
Accounts for 40% of respiratory disease in cats
Acute upper respiratory tract infection
* Sneezing
* Hypersalivation
* Conjunctivitis
Can lead to ulcerative keratitis
Secondary bacterial infections can result in pneumonia
porcine herpesvirus 1
“Aujeszky’s disease” in pigs
“Pseudorabies” in other species
* PHV-1 is the only one of these alphaherpesviruses that can infect other species but it is not zoonotic (not people)
* Pseudorabies eradication has been successful in US swine herds, but wild pigs may still be infected
Aujeszky’s Disease
Porcine herpesvirus 1
* Aerosol transmission (nose-to-nose contact)
* Virus replicates in the epithelium of the oropharynx and tonsils
* Spreads to regional lymph nodes and brain via the cranial nerves
* Becomes latent in the trigeminal ganglia
* Reactivated in times of stress
* Large amounts of virus are shed in nasal secretions, milk, and semen
* Mortality can reach almost 100% in suckling pigs
* Neurologic signs predominate in young pigs
* Infections of sows can result in abortion with hepatic necrosis and intranuclear inclusions in the fetus
* Pseudorabies in other species manifests as severe neurologic disease and pruritis (itchiness) and death within a few days
gammaherpes viruses similarities
- Infect lymphocytes
- Produce latent infection in lymphocytes
- Can cause neoplastic transformation
- dont cause disease in HOST species
malignant catarrhal fever
gammaherpes virus
Types:
* Ovine gammaherpesvirus 2 (Sheep associated)
* Alcelaphine gammaherpesvirus 1 (Wildebeest) associated
* Caprine gammaherpesvirus 2 (Goat associated)
There is no clinical disease in natural reservoir hosts
Severe disease can occur in susceptible hosts
Transmission between susceptible hosts does not occur
Species affected:
* Cattle
* Deer
* Giraffes
* Pigs
* Bison
malignant catarrhal fever clinical signs
Vasculitis (hemorrhage) and primary necrosis of epithelium
Corneal edema (blue eyes)
Mucopurulent nasal discharge
Gastrointestinal and bladder hemorrhage
Neurologic disease
Cutaneous disease
Fatal lymphoproliferative disease