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177 Cards in this Set
- Front
- Back
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5 arboviruses
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Togaviridae
Flaviviridae Bunyaviridae Reoviridae Rhabdoviridae |
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Large granular lymphocytes that non-specifically kill virus-infected cells
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Natural killer cells
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Which Ig is most important for systemic infection and protection against viremia?
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IgG
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Which Ig is more important for localized immunity of mucosa?
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IgA
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Degree to which the measurements of a test result correspond to the true state of the phenomenon being measured-- normally compared to a gold standard.
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Validity
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How should blood be stored when taken for VI?
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EDTA/Heparin
Refrigerate |
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What kind of swabs should be used for collecting a virus isolation sample? Why?
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Dacron
(unbleached synthetic material, so it won't kill the virus) |
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Decribe the ideal tissue block size for soaking in 10% buffered formalin.
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0.5 cm thick and 1-2 cm long
10X more formalin than tissue |
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Is viral isolation a direct diagnostic method, or indirect?
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Indirect (looking at CPE in cell culture)
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Is PCR a direct or indirect method of viral diagnosis?
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Direct (looking for nucleic acids)
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Four methods of direct viral diagnosis.
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Electron microscopy
Ag detection Light microscopy Viral genome detection |
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Three methods of indirect virus isolation.
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Cell culture
Embryonating chicken eggs Susceptible animals |
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Why are two samples needed to detect an antibody titer increase?
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Four-fold increase in Ab titer FOLLOWING acute phase of disease
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Blot test detecting antibodies.
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Western Blot
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Blot test detecting DNA fragments.
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Southern Blot
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Blot test detecting RNA fragments
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Northern Blot
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This test mixes RBC with cell-free virions in a fluid sample and looks for clumping of RBC's together (occurs in a negative test).
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Hemagglutination/ Hemagglutination inhibition
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List some examples of serologic tests
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ELISA
Radioimmunoassay Western Blot Virus Neutralization Hemagglutination Hemadsorption Immunofluorescence Immunoperoxidase Immunodiffusion |
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How do you make a decision when choosing a diagnostic test?
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Type of sample
Analyte (Ab, Ag?) Resources of lab Nature of ure (surveillance vs. animal transport v. herd health, etc) |
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Four porcine DNA virus families.
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Parvoviridae
Herpesviridae Poxviridae Circoviridae |
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Major syndrome caused by porcine parvovirus (PPV)
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SMEDI
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True or false: Pig fetuses infected with porcine parvovirus after 70 days gestation may be born alive but weak.
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True
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How do you definitively diagnose porcine parvovirus?
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PPV antigen by FA in tissue section
Virus isolation in susceptible cells |
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How can one prevent reproductive loss from porcine parvovirus?
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Vaccinate sows with MLV or killed vaccine to prevent virus from passing thru placenta
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Are Parvoviridae enveloped or non-enveloped?
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Non-enveloped
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Major porcine disease caused by Porcine Herpesvirus-1 (PRV-1)...may also be the alternative name for the virus.
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Pseudorabies virus
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Effects of pseudorabies virus in sows.
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Abortion, SMEDI, reduced farrowing rate due to EED.
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Effects of pseudorabies in nursing piglets
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Fever, coma, death, (very high morbidity and mortality)
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Latency and recrudescence are a hallmark of this porcine DNA virus.
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Porcine herpesvirus-1 (pseudorabies)
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Where does the latent porcine herpesvirus-1 hide in the body?
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Sensory ganglia of nerves
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How does pseudorabies affect non-porcine species?
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Fatal CNS signs reminiscent of rabies, but non-contagious
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How is PHV-1 definitively diagnosed?
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Viral antigen detection by FA
Serology: paired samples, 4-fold increase VI in susceptible cells |
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Use of a MLV vaccine for this porcine disease is controversial because it may actually cause latent infection while suppressing clinical signs. This is counterproductive to eradication efforts.
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Pseudorabies virus
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How can management practices be used to control the spread of PHV-1?
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Purchase animals from clean sources
Request negative test result prior to purchase Isolate new arrivals and test for antibodies 12 days after reciept Restrict contact of pigs with other herds, and restrict human traffic Do not export after outbreak for 3 weeks after CS cease |
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What family does porcine cytomegalovirus belong to?
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Herpesviridae
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This virus causes inclusion body rhinitis
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Porcine herpesvirus 2
aka. porcine cytomegalovirus |
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Age group of pigs most susceptible to porcine cytomegalovirus.
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Young pigs under 2 weeks
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Clinical signs of inclusion body rhinitis include...
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Sneezing, coughing, ocular/nasal discharge, depression, distorted nasal turbinates
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What kind of vaccine is most effective at preventing porcine cytomegalovirus?
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There is no vaccine
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Clinical signs of swinepox
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High morbidity, low mortality
Slight fever, papules on skin, especially on abdomen and inner thighs |
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Characteristic laboratory indicator of swinepox infection.
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Intracytoplasmic inclusions in cultured cells!!!
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How is swinepox definitively diagnosed?
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VI via innoculation of chicken embryos or cell culture
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Are circoviruses enveloped or nonenveloped?
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Non-enveloped
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Which porcine circovirus (PCV) is pathogenic in pigs?
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PCV-2
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Disease caused by porcine circovirus 2
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Postweaning multisystemic wasting syndrome
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Describe the morbidity and mortality for postweaning multisystemic wasting syndrome (PCV-2)
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Low morbidity
High mortality |
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What clinical signs are seen in procine circovirus-2 (PMWS) and in what age group?
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Age 5-18 weeks
Progressive wt loss Dyspnea Enlarged lymph nodes Jaundice |
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Lymphoid depletion and replacement with histiocytic cells is the pathologic hallmark of what porcine disease?
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Porcine circovirus-2, or PMWS
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How is porcine circovirus transmitted?
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Oronasal
Horizontal Transplacental |
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How is porcine circovirus (PMWS) diagnosed?
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Characteristic lymphoid depletion
Lab tests: PCR, IFA, FA, IHC, ELISA, VI |
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This porcine virus is commonly seen in association with other diseases because of the immunosuppression it causes through lymphoid depletion.
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Porcine circovirus
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To prevent procine circovirus in piglets, should they be vaccinated or should the sows be vaccinated?
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Piglets
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What management practices may prevent porcine circovirus outbreaks in nursery piglets?
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Segregated early weaning
All-in, all-out |
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Porcine enterovirus 1 and 9 belong to this family.
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Picornaviridae
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Disease caused by PEV-1
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Polioencephalomyelitis (Teschen/Talfan syndrome)
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Is polioencephalomyelitis an enveloped or non-enveloped virus?
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Non-enveloped.
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How is PEV-1 transmitted?
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Ingestion or inhalation
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Describe the 3 stages of polioencephalomalacia.
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1. Replication in alimentary tract and LN
2. Viremia 3. CNS invasion |
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Describe the CNS signs seen with PEV-1.
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Fever, anorexia, depression, tremors, convusions, coma, death
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How is PEV-1 definitively diagnosed?
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VI from brain, intestinal tract, feces
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Disease caused by PEV-9
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Swine vesicular disease virus (SVDV)
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Natural hosts of PEV-9
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Swine and man
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4 diseases of swine vesicular disease complex.
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Foot and mouth disease
Vesicular stomatitis Vesicular exanthema (VEV, a Calicivirus) Swine vesicular disease virus (PEV-9, a Picornavirus) |
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How is PEV-9 (SVDV) diagnosed?
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Vesicular fluid samples--> CF for viral Ag in fluid
VI in cells or day old mice from whole blood VN to confirm VI |
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Best vaccine form for PEV-9.
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No vaccine
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How is the spread of PEV-9 prevented?
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Quarantine
Movement restriction ID Slaughter Indemnification |
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Porcine reovirus belongs to this family.
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Reoviridae
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Age range of piglets most susceptible to porcine rotavirus
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10-28 day old piglets
(IgA from dam protects youngest piglets) |
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How does porcine rotavirus cause disease?
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Replicates in mature epithelial villi cells, shortens/blunts villi, alters function, causing diarrhea.
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Procine rotavirus is synergistic with what secondary bacterial infection?
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Enterotoxic E. coli
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Why are antibiotics indicated with porcine rotavirus?
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Synergistic with enterotoxic E. coli
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Bivalent vaccine given to sows for for porcine rotavirus and...
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TGEV
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Most important preventative measure for preventing porcine rotavirus
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Lactogenic immunity: Early and continuous suckling
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Transmissible gastroenteritis virus of young piglets belongs to this family
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Coronaviridae
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Part of the GI tract that is affected by TGEV. (Regional and histological)
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Small intestine, mature epithelial cells of villi
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Is Coronavirus enveloped or non-enveloped?
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Enveloped
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How is TGEV acqiured?
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Inhaled or ingested
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Important means of spreading TGEV among nursery pigs.
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Fecal shedding
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Clinical signs of TGEV in the piglet.
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Severe diarrhea, vomiting, dehydration, rapid wt loss, coma, high mortality
Feces contain UNDIGESTED MILK!!! |
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Is diarrhea in piglets worse with a reovirus or coronavirus?
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Coronavirus
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Undigested milk in the feces of an affected piglet is a key sign of this viral disease.
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TGEV
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True or false: Only very young piglets are susceptible to TGEV infection.
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False, but the disease becomes less severe as the animal infected is older.
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How do you differentiate colibaccilosis from TGEV on gross pathology?
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Colibacillosis: Distended, normal thickness small intestine, villi not infected
TGEV: Distended, thin, transparent SI with undigested milk curds in feces |
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Why does TGEV cause there to be undigested milk in the diarrhea?
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Causes villous atrophy in small intestine, so can't absorb milk
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How is TGEV infection definitively diagnosed?
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FA epithelial cells of villi
EM of feces |
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Two differential diagnoses for viral porcine diarrhea. How are they differentiated?
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Transmissible gastroenteritis
(seasonal, more severe) Rotavirus diarrhea (year-around, less severe) |
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How is TGEV prevented?
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Vaccinate sows to sensitize IgA production for colostrum
Lactogenic immunity Good hygiene in farrowing facilities!!! |
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Hemagglutinating encephalomyelitis virus is caused by a...
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Coronavirus
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Two diseases caused by hemagglutinating encephalomyelitis virus (Coronaviridae).
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Vomiting and wasting disease
Hemagglutinating encephalomyelitis |
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Clinical signs associated with vomiting and wasting disease (HEV).
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Vomiting, depression, anorexia, dehydration, CONSTIPATION, emaciation
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Clinical signs of hemagglutinating encephalomyelitis (a porcine coronavirus disease)
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CNS signs: Incoordination, tremor, acute encephalitis, convulsion, death
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How is hemagglutinating encephalomyelitis virus diagnosed definitively in the pig?
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Lab tests (VI and FA)
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List four viral CNS diseases of the pig.
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Hemagglutinating encephalomyelitis virus
Porcine enterovirus-1 (poliomyelitis, caused by Picornavirus) Pseudorabies (porcine herpesvirus 1) Hog cholera (flaviviridae) |
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DIsease caused in swine my an orthomyxovirus.
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Swine influenza virus
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Two swine orthomyxovirus strains of recent significance.
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H3N2 swine flu in US herds
Swine-origin H1N1 pandemic flu in humans and other species |
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CS of swine influenza virus, an orthomyxovirus.
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Fever, anorexia, prostration, muscle stiffness, dyspnea, sneezing, coughing, conjunctivitis, nasal discharge
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Describe outbreak patterns, morbidity and mortality with swine influenza viruses.
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Seasonal outbreaks (cold seasons)
High morbidity, low mortality |
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Infection with swine influenza (orthomyxovirus) predisposes a pig to such secondary bacterial infections as...
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Hemophilus somnus
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Pathologic changes associated with swine influenza viral infection.
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Congestion of URT
Swelling of cervical and mediastinal LN Exudate in nasal passages Pneumonia with lung consolidation |
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Definitive diagnosis of swine influenza is made by...
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Virus isolation from nasal secretions and lungs (important for public health!)
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Is Orthomyxoviridae a family of enveloped or non-enveloped viruses?
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Enveloped
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Number one swine pathogen, as listed by USDA
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Porcine reproductive and respiratory syndrome virus (PRRSV), an arterivirus
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Signs caused by PRRSV (arterivirus) include...
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Respiratory diseases of growing pigs
Reproductive failure in sows |
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Is Arteriviridae a family of enveloped or non-enveloped viruses? DNA or RNA?
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Enveloped
Positive sense ss-RNA |
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3 modes of transmission of PRRSV.
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Aerosols
Direct contact Semen |
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This porcine virus may have a reservoir in Mallard ducks.
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PRRSV (Arteriviridae member)
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Major factor affecting control of PRRSV in large herds.
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Persistently infected, asymptomatic individuals, up to 156 days
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PRRSV causes this syndrome in nursing pigs
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Respiratory disease
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PRRSV causes fever, anorexia, pneumonia, and listlessness in this age group of pigs.
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Grower-finisher pigs
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Major syndrome that PRRSV causes in sows.
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SMEDI
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Where in the pig's body does PRRSV replicate?
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Alveolar, epithelial, tonsilar macrophages
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True or false: Not all strains of PRRSV are equally virulent.
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True
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Gross pathology for this porcine viral disease includes nasal turbinate rhinitis and loss of cilia, tan colored lungs that fail to collapse, and lymphadenopathy
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PRRSV
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What is the concern with available vaccines against PRRSV?
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None protect against heterogenous strains.
Also, MLV's for PRRS van revert to virulent phenotypes. |
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Major disease caused by Caliciviridae in the pig.
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Vesicular exanthema virus
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Only vesicular disease of swine currently seen in the US.
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Vesicular stomatitis
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Family to which hog cholera virus belongs.
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Flaviviridae
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Classical Swine Fever Virus is also called...
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Hog cholera virus
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Clinical signs caused by hog cholera virus
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Septicemic disease with generalized hemorrhage, constipation, CNS signs, muscle tremors, reproductive failure
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Incubation period for hog cholera virus (CSFV).
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5-10 days
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Pathological signs of HCV/CSFV.
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MARGINAL INFARCTS in spleen and gall bladder
Enlarged LN Submucosal petecchial hemorrhages in kidney, LN, bladder, larynx Congestion of lungs, liver, bone marrow BUTTON ulcers of colonic mucosa |
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Button ulcers of colonic mucosa and marginal infarcts of the spleen are key pathological signs of this virus...
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Classical swine fever virus
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Definitive diagnosis of classical swine fever virus is made by...
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Viral antigen detection: FA, IHC of pancreas
Anbtibody testing by FA, VN, or ELISA in blood |
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True or false: Hog cholera is a notifiable and reportable disease in the US.
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True
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What kind of vaccination is most effective in the US against hog cholera virus?
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No vaccine in US
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African Swine Fever Virus is grossly indistinguishable from...
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Hog cholera/ classical swine fever virus
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Asfarviridae is a family of what kind of viruses: DNA or RNA?
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DNA
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Is African Swine Fever Virus enveloped or non-enveloped?
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Enveloped
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Natural reservoirs for African Swine Fever Virus.
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Warthogs, forest hogs, bush pigs
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Is African Swine Fever Virus more stable or less stable than other enveloped viruses?
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More stable
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Incubation period of African Swine Fever Virus
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5-15 days
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CS of African Swine Fever Virus
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Fever,
depression, ocular discharge, cough, diarrhea, dehydration Chronic disease course much longer. |
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How is African Swine Fever Virus spread among wild pigs?
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Via ticks
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Where does African Swine Fever virus replicate in the pig host?
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Initially in draining LN
Then after viremia, in lymphoid organs and vascular endothelium |
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How is African Swine Fever Virus definitively diagnosed?
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VI from blood, spleen, lung, LN
Hemadsproption of pig RBC ELISA |
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How is African Swine Fever Virus prevented and controlled in the US?
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No US vaccine
Quarantine and slaughter Control meat export, burning of waste food from airplanes and ships arriving from endemic countries |
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True or false: Equine papilloma vuris causes sarcoids.
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False. Bovine papilloma virus is associated with sarcoids.
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Is papilloma virus enveloped or non-enveloped?
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Non-enveloped
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Locally aggressive, fibroblastic benign skin tumors of horses
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Sarcoids
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Virus that causes equine sarcoids.
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Bovine papilloma virus 1, 2, and 5
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Three equine alphaherpes viruses.
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EHV-1 (equine abortion)
EHV-3 (coital exanthema) EHV-4 (rhinopneumonitis) |
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Three equine gammaherpes viruses
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EHV-2 (Pharyngitis and URT infection)
EHV-5 (URT infection) |
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These equine herpes subtypes are seen only in donkeys.
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EHV-6 and EHV-8
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Three criteria for an emerging disease, one of which must be met.
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1. First emergence in this species
2. Change in organ tropism 3. Change in geographic area |
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Are herpesviruses enveloped or non-enveloped?
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Enveloped
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How long is EHV-1 shed (in reproductive form)?
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15 days
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Three major tropic organs for EHV subtypes.
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Respiratory
Reproductive CNS |
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Major feature of all herpesviruses.
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Latency and recrudescence
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WHat about EHV-1 causes abortion in the pregnant mare?
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Ischemic necrosis following damage to BV
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Duration of acquired immunity against EHV-1 in vaccinated dam.
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3-6 months
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Vaccination against EHV-1 prevents...
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Abortion
(Not latency, not recrudescence) |
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Posterior paresis and bladder atony are seen with which eqine viral disease?
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EHV-1 myeloencephalopathy
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Does EHV-1 directly infect neurons?
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No
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This form of EHV infects young horses, causing acute bronchopneumonia.
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EHV-4
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This virus causes cotial exanthema in the horse.
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EHV-3
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How are EHV infections definitively diagnosed in the horse?
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Blood/nasal swab for PCR, VI
Paired sera for Ab titer Differential ELISA between EHV 1 and 4 Viral Ag detection |
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Why does it do no good to isolate EHV antibodies from the CSF in a neurologic horse with suspected myelotropic EHV-1?
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Ab generated against all EHV subtypes filter into CSF
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Describe the challenges of EHV vaccination.
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Robust but transient immunity
Poor CMI response |
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How is spread of EHV prevented in an outbreak?
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Segregation
Isolation Subdivision of susceptible groups Stress reduction Disinfection Sampling Hygiene |
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EEE,WEE, and VEE all belong to this family of viruses.
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Togaviridae
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WNV belongs to this virus family.
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Flaviviridae
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How are the equine encephalitises transmitted?
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Mosquitos
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This equine encephalitis has a rodent-mosquito cycle.
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VEE
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EEEV and WEEV have an incubation period of how long?
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5-15 days
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VEEV has an incubation period of how long?
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2-6 days
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Amplifying host of VEEV.
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Horse
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Describe the two phases of equine encephalitis.
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Primary viremia at 2-5 days
Secondary CNS replication at 6-8 days |
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Clinical signs of equine encephalitis.
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Hyperexcitability, CNS signs, depression--> starvation--> coma and death
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Least fatal of the equine encephalitises.
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Western
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Pathologic changes associated with equine encephalitis.
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Severe inflammatory response in gray matter
Mild to severe hemorrhages or necrosis Neuronophagia, perivascular cuffing, gliosis |
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Definitive diagnosis for equine encephalitis is made by...
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VI (EEE from brain, WEE rarely, VEE from blood or serum)
RT-PCR Paired serology |
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Which equine encephalitis is marked by a prolonged viremia?
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Venezuelan
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How are equine encephalidites prevented/controlled?
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Quarantine and surveillance
Insect abatement Vaccinations (MLV and inactivated) |
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West Nile Virus is transmitted by...
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Mosquitoes
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WNV causes CNS signs only in these two species.
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Horses and humans
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CS of WNV
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Muscle fasiculations
CNS signs Most recover |
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How is WNV definitively diagnosed?
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VI or serology
CSF for Ag and Ab detection RT-PCR |
