3.3 DNA viruses 1 Flashcards by Mark Sunarich

Important families of DNA viruses

-parvoviridae
-circoviridae
-polyomaviridae
-papillomaviridae

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important viruses in the parvo family

CPV, FPV, PPV (canine, feline, porcine)

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important viruses in the polyma family

APyV

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important viruses in the circo family

BFDV, PCVAD

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important viruses in the papilloma family

CPV, equine sarcoid

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genome structure of parvo and where it replicates. Is it enveloped?

Single stranded DNA genome,
Replicate in the nucleus,
non-enveloped- resistant in the environment
~25 nm (small)

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are canine and feline parvovirus related? How closely?

Canine parvovirus 2 (CPV-2) and Feline panleukopenia virus are genetically closely related
CPV-2 is a host range mutant of Feline panleukopenia virus
–both protoparvoviruses

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1976-1978: CPV-2 caused what?

a worldwide epidemic of myocarditis and gastroenteritis

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is Canine parvovirus 2 resistant to inactivation? is it stable in the environment?

Very resistant to inactivation, stable in the environment

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where are the receptors for Canine parvovirus 2?

Receptors on epithelial cells: gut epithelial cells

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What is NOT a clinical presentation of CPV infection in dogs between 6 weeks and 6 months old?
a. Myocarditis
b. Acute enteric disease
c. Lymphopenia
d. Skin hyperkeratosis

d. Skin hyperkeratosis

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What are target cells of feline panleukopenia virus?
a) Cells of the intestinal crypt
b) Rapidly dividing cells
c) White blood cells
d) All of the above

d) All of the above
note - WBCs and intestinal crypt cells divide quickly

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Which of the following statements is CORRECT about Parvoviruses:
a. Small, double-stranded DNA viruses
b. Replicate in the cytoplasm of actively-dividing cells
c. Enveloped virus resistant to harsh environmental conditions
d. All of the above
e. None of the above
f. All except C
g. All except B

SS DNA, rep. in nucleus, non-enveloped
e. None of the above

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What is the agent associated with Post-Weaning Multisystemic Wasting Syndrome of swine?
a. Porcine parvovirus
b. SMEDI
c. Porcine circovirus 2

c. Porcine circovirus 2

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Which of the following is NOT CORRECT about circoviruses:
a. Non-enveloped virus that is extremely resistant in the environment
b. Replication occurs in the nucleus
c. Porcine circovirus 2 causes a complex disease with multiple syndromes
d. Linear single stranded DNA genome

D. linear stranded DNA
=> circoviruses have a circuloar conformation

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Which of the following statements is NOT CORRECT?
a. Both poliomaviruses and papillomaviruses are non-
enveloped viruses that can be easily disinfected with soap
b. Canine papillomavirus causes “warts” and is usually self- limiting
c. Budgerigar fledgling disease can cause high mortality in diseased birds
d. Equine sarcoid is a skin tumor

a. Both poliomaviruses and papillomaviruses are non-
enveloped viruses that can be easily disinfected with soap
>are both naked, resistant in environment

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where does canine parvovirus replicate? What does it require?

Replicates in the nucleus of the infected cell - needs actively dividing cells because it needs to use the DNA replication machinery (fetal, hematopoietic/ lymphoid tissues, intestinal crypts, cardiomyocytes in neonates)

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how is canine parvovirus released? What is its associated pathology caused by?

Release by cell lysis
Pathology is due to direct destruction of infected cells

pathogenesis of CPV

entry - fecal-oral route
initial replication - thymus, tonsil, retropharyngeal and mesenteric lymph nodes
viremia - days 2-5 post-infection
=>infection of intestinal crypt epithelial cells, bone marrow progenitor cells (high rate of cell division)
=> good antibody response leads to recovery; otherwise, death
=>sheds in feces up to 1 week after recovery

CPV-2 clinical presentation

Acute, generalized viral infection
Usually puppies: 6 weeks to 6 months old
Signs: sudden onset of haemorrhagic diarrhea, vomiting, anorexia and fever, depression, lymphopenia, dehydration
Mortality is higher in puppies than adult dogs
Myocarditis (infection in utero or < 2 weeks old, sudden death)

how do we diagnose CPV?

Based on history, clinical signs, positive SNAP test, post- mortem findings
Identification of viral nucleic acid in feces by PCR (used to confirm Snap test)

how can we treat, control, and prevent CPV?

Treatment:
Fluid and electrolytes to replenish what is lost from the diarrhea
Antibiotics to prevent secondary infection

Control and prevention
Disinfection and vaccination

clinical manifestation of feline panleukopenia virus

Usually inapparent in healthy adult cats
Acute disease usually in young cats: dehydration, diarrhea, vomiting, anorexia, fever, high mortality in kittens
Severe and prolonged leukopenia involving all white blood cell elements
Pathogenesis is very similar to Canine parvovirus 2

pathology of feline panleukopenia virus

Pathology: cerebellar hypoplasia
Infection in the 2 last weeks of pregnancy or 2 weeks old kittens
Neonatal death
Congenital abnormalities: cerebellar hypoplasi

how can we diagnose feline panleukemia virus?

* Presumptive diagnosis > Clinical signs ( a young cat with dehydration, diarrhea, vomiting, anorexia) * WBC (leukopenia) * Laboratory diagnosis > PCR (usually labs have feline diarrhea PCR panels) * Antigen detection in feces by ELISA

how can we treat and control feline panleukopenia?

* No effective treatment * Antibiotics may help to prevent bacterial complications * Vaccines: induce protective immunity to prevent the disease (but not infection) * Likely life-long immunity

does porcine parvovirus survive for a long time in the environment? How does it compare antigenically to other parvoviruses? what species does it infect?

* Very resistant in the environment * Antigenically different from other parvoviruses * Infects only swine

what is a major symptom of porcine parvovirus disease?

* Reproductive failure in sows * Return to estrus or infertility

what type of infection is porcine parvovirus and what is the result of this?

* Transplacental infection * SMEDI: stillbirth, mummification, embryonic deaths, infertility

what are the physical/ structural characteristics of a circovirus? where does it replicate?

* Circo= viral DNA has a CIRcular COnformation * Single stranded DNA genome, * Replicates in the nucleus of rapidly dividing host cell * Non-enveloped- resistant outside of the host cell

important circoviruses

Beak and feather disease virus Porcine circovirus 2

characteristics of beak and feather disease. what are clinical signs, and prognosis?

* Infection is often mild or subclinical * Infected psittacine birds may take weeks, months or years before showing any clinical signs, often depending on age of the bird. * In diseased birds clinical sign include necrotic (dead) or abnormally formed feathers. * Once signs are seen, most birds die from secondary infections within 6-12 months.

where do we find porcine circovirus 2? what diseases does it cause?

* Worldwide distribution, ubiquitous in swine * Porcine circovirus associated disease (PCVAD): different disease manifestations associated with PCV-2 (unknown if it is the only cause) * porcine dermatitis and nephropathy syndrome

what does Porcine circovirus associated disease (PCVAD) cause?

-Post-weaning multisystemic wasting syndrome (PMWS) - Reproductive Disease

what is Post-weaning multisystemic wasting syndrome (PMWS); what causes it and what are its characteristics and symptoms?

* Multifactorial disease * Gradual wasting, growth retardation * Pallor, anemia, jaundice, diarrhea, and inguinal lymphadenopathy * Lymphoid depletion -porcine circovirus 2 is agent

what sorts of reproductive disease in porcine circovirus associated with?

* Reproductive Disease Late-term abortions and stillbirths, early embryonic death or decreased reproductive performances

what are the characteristics of polyomavirus? what does it infect? where does it replicate?

Poly= many Oma= tumor Affects mammals and birds Naked (non-enveloped) virus with dsDNA (circular) genome Replicates in the nucleus

what is budgerigar fledgling disease? what does it infect and what causes it? what are signs/ consequences?

Polyomavirus - Budgerigar fledgling disease -Avian polyomavirus (not neoplastic) -Psittacine and passerines -High mortality (sudden death) -Absence of feathers, skin lesions (survivors) -signs of hemorrhage and pale musculature post mortem

what type of genome do papillomaviridae have? what does the name mean? what are its physical characteristcs?

* Papilla (pustule), oma (tumor) * A circular double stranded DNA genome * Non-enveloped small virus (~ 50 nm)

what is the pathology of papillomavirus associated with?

* Pathology is associated with cell transformation - carcinomas in humans

are papillomaviruses species specific?

highly

what do papillomaviruses cause in animals?

* Causes infectious papillomatosis (warts) in animals

what is the prognosis of canine papillomavirus? is it common and how is the infection passed? what happens in severe cases?

* Canine papillomavirus I * Common and usually self-limiting * Puppies acquire the disease after close contact with other carriers * SEVERE cases show compromised eating or respiration may need surgical excision