3.4 DNA viruses 2 Flashcards
are herpesviridae enveloped? What is their genome structure?
- Large, enveloped viruses with dsDNA genome
what do herpes viruses require for transmission?
Herpesvirus virions are fragile outside the body- transmission requires close contact- particularly mucosal contact
recovery from a primary acute herpes infection can result in what?
Latency is a unifying aspect of herpesvirus pathogenesis. Recovery from a primary acute infection can result in latent infection
what is the general mechanism of herpesviridae latency? When do we most likely see reactivation?
- Virus genome persists latently in neurons of ganglia or in lymphoid cells with Intermittent reactivation of latent virus
- Often in times of stress
- Winter
do all types of herpes viruses establish latency in the body in the same way/place?
A major difference between the 3 groups of herpesviruses is WHERE they establish latency in the body
what species do herpesviridae effect?
mammals, birds, reptiles
what are the three groups of herpesviridae?
alpha-, beta-, gamma- herpesvirinae
what disease does bovine herpesvirus 1 cause?
Infectious bovine rhinotracheitis
what disease does Equid herpesvirus 1 cause?
Equine abortion
what disease does Felid herpesvirus 1 cause?
Feline rhinotracheitis
what disease does Gallid herpesvirus 2 cause?
Marek’s disease
what disease does Ovine Herpesvirus 2 cause?
Malignant Catarrhal Fever
what is the one reportable herpes virus and what disease does it cause?
Suid herpesvirus 1, causes pseudorabies
Characteristics of Alphaherpesviruses
- Rapid lytic cycle
- Rapid growth and spreading in cultured cells
- Infection of epithelial cells (vesicular lesions)
- Latent infections in sensory ganglia
Characteristics of Betaherpesviruses
- Long reproductive cycle
- Slow infection in culture
- Latent infections in secretory glands, lymphoreticular tissues (lymph nodes and spleen), kidneys
- Restricted host range
Characteristics of Gammaherpesviruses
- Lymphotropic and establish latency in lymphocytes (lymphoid tissue)
- Acute and lymphoproliferative diseases
two common Alphaherpesvirinae
Bovine herpesvirus 1
Feline herpesvirus 1
what disease does Feline herpesvirus 1 (FHV-1) cause? what are the symptoms? Is it more common in a certain age group or setting?
- Feline rhinotracheitis
- Acute upper respiratory disease
- Sneezing, coughing, nasal + ocular discharge
- Conjunctivitis and keratitis
- Anorexia, fever, tongue ulcers
- Common (in kittens <1 year) and widespread
- Common in shelters, households with several cats
what disease is clinically very similar to Feline herpesvirus 1 (FHV-1)?
Clinically very similar to Feline calicivirus
how can we detect Feline herpesvirus 1 (FHV-1)? How can we prevent or treat it?
- PCR panels: feline respiratory diseases
- Vaccination (standard core vaccines)
- Antivirals: Inhibitors of viral DNA synthesis
- Cidofovir, Idoxuridine
what diseases does Bovine herpesvirus-1 (BoVH-1) cause? Can it be deadly?
- Variety of diseases in cattle
- Rhinotracheitis, vulvovaginitis, balanoposthitis, conjunctivitis, abortion, enteritis, and a generalized disease of newborn calves
- Can cause substantial mortality in feedlots and dairy farms
How long does Bovine herpesvirus-1 (BoVH-1) last in the body?
- Life-long latent infection
how do we diagnose Bovine herpesvirus-1 (BoVH-1)? How can we prevent it?
- Diagnosis: PCR on vesicular fluid or scrapings, serology
- Vaccines are available - EU countries have eradicated the disease, Canada and USA have a control program
what is the most important viral cause of abortion in horses?
Equine herpesvirus-1 (EHV-1)
what list is Bovine herpesvirus-1 (BoVH-1) on?
OIE list 2020
what diseases does Equine herpesvirus-1 (EHV-1) cause? what is its global range?
- Most important viral cause of abortion in horses
- Also, respiratory disease and encephalomyelitis
- Equine herpesvirus-1 is enzootic in horse populations world-wide
how do we diagnose Equine herpesvirus-1 (EHV-1)?
Diagnosis relies on history of abortion and characteristic intranuclear inclusion bodies in affected tissue- confirmed by immunohistochemical staining + PCR
what can we characteristically see upon post mortem in cases of Equine herpesvirus-1 (EHV-1)?
Characteristic foci of necrosis in fetal liver
what virus is associated with Marek’s disease?
- Gallid herpesvirus 2 (GaHV-2)
where is Marek’s disease found? what type of animals does it infect?
- Common and widespread (highly contagious), ubiquitous in the environment
- Young chicken (2-5 months)
- Quails and rarely turkeys can also be infected
what cells does Marek’s disease infect? How can we prevent it?
- Infects lymphocytes (T-cells): T cell lymphoma
- Vaccination at hatching or in ovo
what is the pathological process of Marek’s disease? what forms are there and what are their characteristics?
- Aerosol > respiratory epithelium > lymphoid tissue
> viremia > T lymphoblastoid cell proliferation > neoplasia (lymphoma) > infiltrates different organs/tissues: - If infiltrate around nerves (usually sciatic nerve) > classical form
- Form nodules/tumours in organs and nerves > acute form
- Invade iris > ocular (rare)
- Feather follicles > cutaneous form
what will be enlarged in the classical form of Marek’s disease, leading to paralysis?
Enlarged sciatic nerves