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34 Cards in this Set
- Front
- Back
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What is the morphology of parvovirus?
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Noneveloped
Icosahedral virion 18-26 nm Three capsid proteins: VP1, VP2, VP3 Infectious virions contain 60 protein subunits that are predominantly VP2. |
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What is the virion of parvovirus resistant to?
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Resistant:
pH (pH3 to pH9), Solvents High temperatures (1h @ 50°C). |
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What are the genome characteristics of parvovirus?
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Genome:
Linear, non-segmented. ssDNA, 5.2 kb The ends of the genome have palindromic sequences of ~115nt which form "hairpins". |
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How does the parvovirus enter cells?
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Virus capsid protein VP 2 binds to specific host cell surface receptors
CPV: transferrin receptor (TfR) FVP: transferrin receptors (TfRs) B19: tetrahexosoceramide, a glycolipid (erythrocyte P antigen) |
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What is the major component of the capsid protein for parvoviruses?
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VP2
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What are the adult and fetal cell/tissue tropisms of parvovirus?
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Adult:
Digestive system—crypt cells Hematopeitic system—immunosuppression (panleukopenia) Lymphatic tissue Thymus Spleen lymph node Bone marrow-myeloid series Fetus/neonate Pantropic- Digestive system hematopoietic system Central nervous system (feline)-cerebellum Cardiovascular system (canine)-myocardium |
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Why can parvoviruses infect many different types of tissues in fetus and neonate?
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yes
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How does Parvovirus replication go?
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Virus Entrance:
receptor-mediated endocytosis Virus Replication: Nucleus ssDNA---dsDNA Assembly of progeny: occur in nucleus Virus Release: cytolysis |
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Is FPV, a parvovirus, contagious? fatal? What age of cats are susceptible?
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FPV is a severe, highly contagious disease that is often fatal.
Unvaccinated feral cat colonies and other wild felids serve as reservoirs of infection for the domestic cat population. All ages are susceptible kittens 2 – 6 months of age tend to be more severely effected It occurs worldwide. It is most common in kittens at time of weaning. Young, unvaccinated kittens are most commonly with this disease. The incubation time is about 2 to 10 days. |
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What is the transmission of FPV?
If the virus stable? |
Oral-fecal
Shed in all body secretions Virus is very stable can persist for years Arthropod vectors mechanical transmission Placenta: fetuses in utero Cats can become infected without ever coming into direct contact with an infected cat. Bedding, dishes, hands or clothing of handlers Contact with blood, urine, fecal material, nasal secretions and fleas Pregnant females will transmit the virus to their kittens in-utero |
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What virus is cerebellar hypoplasia associated with?
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Fetuses: the last 2 wks of pregnancy
New born: the first 2 wks of life |
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Why do we only see Cerebellar hypoplasia in newborn cats?
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Because they are growing/dividing, brain is susceptible
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Why do the FPV-infected animals have diarrhea?
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Rapidly dividing intestinal epithelial cells in the crypts of Lieberkuhn are very susceptible to infection:
loss of those cells from villus tips lead to diarrhea. |
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How is Parvoviridae diagnosed?
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Clinical signs
hematological examination Necropy Lab HA: swine or monkey RBC Chromatographic test strip – feces for FPV and CPV Serologic testing Paired serum samples (acute vs convalescent); detects rising antibody titer Viral isolation from feces or affected tissues EM Thymus, spleen, small intestine PCR The IDEXX snap test kit for parvo, one of the most popular ELISA kits |
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What is the most common viral disease of dog enteritis?
What are the symptoms in young and adult dogs and then in newborn puppies? |
Canine parvovirus disease
In young and adult dogs: severe acute leukopenia and enteritis death from dehydration and shock In newborn puppies: multiplying in heart muscle causing myocarditis leading to sudden death of heart failure or permanent scarring of the heart muscle. |
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What four factors make a dog susceptible to CPV infection?
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Season - 3 times more likely b/w July and Sept
Breeds - Rottweilers, Dobermans, Shepherds Sex - intact dogs four times more likely No vaccination - 13 times more likely |
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How is CPV-2 Enteritis transmitted?
What are the clinical signs? |
Canine parvovirus 2
Transmission: Clothing Food pans Cage floors CPV reservoir: Insects and rodents Clinical signs: Lethargy and vomiting - 84-87% (Bloody) diarrhea - 60% Leukopenia (at some time) - 45% Neutropenia (at some time) - 51% Fever (>39.5) - 24% Prone to secondary infection |
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What is the pathogenesis of CPV-2?
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It is similar to cat, but lacks cerebellar hypoplasia
Leukopenia Myocarditis: Focal myocardial necrosis with fiber loss Intranuclear basophilic inclusions in cardiac muscle cells Prominent pulmonary edema |
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What are some bacterial and viral differentials for enteritis in dogs?
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Parvovirus
Distemper virus Coronavirus Rotavirus (<2weeks) Salmonella Campylobacter Clostridium Yersinia Neorickettsia Histoplasmosis |
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How do you make a viral diagnosis?
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Direct virus Isolation:
fecal suspension treated with chloroform inoculate feline kidney cells incubate 3-5 days EM FA: Immunofluorescence antibody staining |
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What are characteristics of the CPV vaccine?
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Attenuated or Inactivated vaccines are available:
by itself or as component of combined vaccine (DA2PPv) Avoiding maternal antibody interference |
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What is the most common and important cause of infectious infertility in pigs?
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Porcine Parvovirus Disease (PPV)
Porcine parvovirus is a fairly tough virus that multiplies normally in the intestine of the pig without causing clinical signs. It is associated with SMEDI (stillbirth, mummification, embryonic death, infertility) |
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What is the pathogenesis of parvoviruses?
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Parvoviruses infect a wide variety of birds and mammals.
The pathology is shaped by their dependence on cellular functions for replication. The viruses have broad cell tropism, but since require cells in late S or early G2 phase for replication, they tend to infect rapidly dividing tissues, most commonly: the fetus the intestinal epithelium the haematopoetic system |
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Which canine adenovirus is more potent? 1 or 2?
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1 - it causes hepatitis.
2 causes respiratory colds (I think) |
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What are the structural features of adenoviruses? Is it enveloped or naked?
What kind of genome does it have? Is it larger or smaller than Parvovirus? |
Non-enveloped
Icosahedral virion, 70-90 nm Genome: 30-42 kb. (CPV is 5-7kb) Linear; dsDNA |
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What are adenoviruses resistant to?
How does this relate to the route of transmission? |
Stable non-enveloped viruses
Resist to ether bile detergents trypsin acid This explains the oral transmission between dogs. |
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What are the three classes of viral genes expressed in adenoviruses?
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Three classes of viral genes are expressed sequentially:
Immediate early ( E1A) Early gene (E1B, E2A, E2B, E3, E4, some virion proteins) Late genes (virion proteins) Transcription of virus genome It is regulated by virus-encoded trans-acting regulatory factors Multiple protein products Alternative intron splicing: (Sharp, 1977) |
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Where will the adenovirus replicate inside the cell?
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nucleus
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How does the adenovirus (only 30 kb in the genome) produce so many genes?
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Intron splicing
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Does adenovirus have a very unique cellular receptor?
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Not really - it's very common. They use a common host receptor (MHCII) to get into the cell.
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What is the mechanism of adenovirus replication?
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Entrance-
Fiber binds to cell receptor cellular receptor: MHCII, Integrin Car (Ig-like) Cell tropism: epithelial cell Replication Nucleus Release cytolysis |
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What is the transmission route of CAV-1?
What is the incubation period? What are the three expressions of this strain? |
Canine Adenovirus Type 1
Transmission-horizontal Ingestion or inhalation Urine, feces, saliva, nasal secretion, eye secretion from infected dogs Infected by attenuated CAV-1 vaccine Incubation period: upto 2 wks Hepatic form Hepatocelluar destruction Endothelial cellular destruction Hemorrhages Encephalitis Immune complexes Blue eye—corneal edema (opacity) Kidneys (glomerulonephritis) viruria Kennel cough-- |
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What are the clinical signs of canine adenovirus 1?
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Puppies <6 months of age
Peracute disease with no signs, or 3-4 hours of signs before death Acute disease Mild disease Severe infection is rare Fever Depression Anorexia Vomiting/bloody diarrhea Petechiation on gums Pale mucous membranes Jaundice Conjunctivitis/serous ocular discharge Rarely convulsions Blue eye |
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What is the pathogenesis of CAV-1?
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Infection of Nasopharyngeal, oral and conjunctival routes leads to infection of tonsils and/or Peyer's patches which passes to multi-system infection through viremia then again through viremia to the liver, kidney, lungs, spleen and CNS.
This can result in: haemorrhagic swollen liver, ascites + oedema of gall bladder wall |
