lecture 6 and 7- porcine virology Flashcards by Abigail Brett

what is TGEV? what kind of virus?

transmissible gastroenteritis virus

it is 1 of the 3 porcine coronaviruses

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what is PEDV? what kind of virus is it?

porcine epidemic diarrhea virus

it is 1 of the 3 porcine coronaviruses

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what is SDCV? what kind of virus?

swine delta coronavirus

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what are the 3 porcine coronaviruses?

TGEV (transmissible gastroenteritis virus)
PDEV (porcine epidemic diarrhea virus)
swine delta coronavirus (SDCV)

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true or false: porcine can be infected with coronaviruses during any production phase?

true

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true or false: porcine can be infected with rotavirus during any production phase?

false- they can only be infected during the suckling or weaning phase

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what are the gross lesions of porcine rotavirus / porcine coronaviruses?

dehydrated carcass, watery intestinal contents, thin walled intestines

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what are histological observations of porcine rotavirus / porcine coronaviruses?

stunted intestinal villi and viral antigens in villi

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if diarrhea appears in waves in individual litters or groups of litters in the second half of lactation, is it more likely rotavirus or a coronavirus?

rotavirus

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if there is a sudden outbreak of scour involving large numbers of litters with acute diarrhea and high mortality, is it more likely rotavirus or a coronavirus

coronavirus

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what is the etiology of porcine epidemic diarrhea ?

coronavirus

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how does age impact the mortality of pigs infected with porcine epidemic diarrhea?

suckling pigs have up to 100% mortality, while older pigs have much lower mortality

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how can you clinically distinguish between which porcine coronavirus is the cause of an infection?

you cant

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what is the incubation period of PED?

3-4 days

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which gives more info about virus, detecting protein or genome? why?

detecting for the viral protein gives more info because we can tell if it is actively replicating

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what samples can be taken to test for PED?

feces, oral fluid, small intestine, serum for antibodies

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which of the following tests will NOT detect PED?

RT-PCR
PCR
ELISA
immunohistochemistry
virus isolation
ELISA serological test

PCR- this is an RNA virus so needs to be RT

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can piglets be protected from PED by maternal antibodies in colostrum?

yes

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true or false: mortality rates in SDCV is higher than in PED

false, mortality is lower in SDCV

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how is TGEV related to porcine respiratory coronavirus (PRCoV)

PRCoV is a mutant of TGEV with a deletion of 225 amino acids in spike protein (it replicates in respiratory tract vs GI)

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which animals are at the highest risk of mortality with TGE?

young animals, just like all coronaviruses

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where does rotavirus replicate? is this different from coronavirus?

mature enterocytes, just like coronavirus

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what is the pathology of coronavirus and rotaviruses replicating in mature enterocytes?

infection of respiratory tract –> replication in mature enterocytes –> enterocytes slough off –> decreased enzymes –> water not reabsorbed –> diarrhea

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what body system is most affected by porcine parvovirus?

reproductive

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what family is PPV a part of?

parvoviridae

what is SMEDI syndrome

stillbirths mummification embryonic death infertility

in what animal does parvovirus cause SMEDI syndrome?

porcine (and feline?)

how is PPV transmitted?

- virus secreted in feces and other fluids - sow to fetus transmission in seronegative animals

what are the 3 possible outcomes if a pregnant sow is infected with PPV?

1) early embryonic death and resorption 2) fetal death and mummification 3) survival and seropositivity

if a sow is infected with PPV before day 70 of gestation, will the fetus surive?

unlikely

what kind of placenta do sows have? does this make it difficult for vertical transmission?

epitheliochorial placenta more difficult (lots of barriers)

a female pig returns to estrus with no apparent reason or delay in parturition and has increased numbers of mummified fetuses and smaller litters what virus should be considered?

PPV

PPV vaccines are all....

killed vaccines

what family is pseudorabies a part of?

herpesviridae

how is pseudorabies spread?

direct, sexual, indirect, aerosol, somites

what is the natural host of pseudorabies?

porcine

where does primary replication of pseudorabies occur?

respiratory tract

how does pseudorabies spread within pigs?

blood, lymph, and nerves

what body systems are affected by pseudorabies in pigs?

respiratory, nervous, lymph, reproductive

what are the clinical signs of pseudorabies in a neonate/suckling pig? what is the % mortality?

inability to stand/move, sit like dogs due to posterior paralysis, fever, inapp, V+, other nervous system signs 100% mortality

what are the clinical signs of pseudorabies in a weaner/grower/finisher pig? what is the % mortality?

respiratory signs 5-10% in weaners 1-2% in growers and finishers

what are the clinical signs of pseudorabies in an adult pig? what is the % mortality?

mild or unapparent, gilts and sows might have repro problems

how does the pathogenesis of pseudorabies differ in animals other than pigs?

no blood or lymph transport --> only neurological signs

what is the etiology of mad itch?

pseudorabies

how is pseudorabies diagnosed

immunohistochemistry to demonstrate viral antigens

how has pseudorabies been eradicated?

serologic surveillance, culling, biosecurity, vaccination

what family is swine influenza a part of?

Orthomyxoviridae

how many types of swine influenza are there? what do we care about

4 (A-D) type A* infects animals and humans, (type D infects cattle)

how many subtypes of HA and NA are there? (regarding type A influenza viruses)

HA (18) NA (11)

what does HA bind to on host cell

sialic acid residues

what is significant about the receptor types of HA in pigs and quail?

pigs can bind to both the avian 2-3 sialic acid receptor (gut and lung) and human 2-6 linked sialic receptor (non-ciliated epithelium of human airway) this makes pigs a mixing pot for human and avian influenza strains, leading to reassortment and antigenic shift

what are 2 requirements of reassortment/antigenic shift

1) virus must be segmented 2) multiple virus strains must enter one cell

which strain of influenza persists the longest?

H1N1

what family is PED, SDCV, and TGE a part of?

Coronaviridae

what is the structure of PED, SDCV, and TGE (given they are a part of Coronaviridae)?

enveloped, positive sense

what is the replication strat of PED, SDCV, and TGE (given they are a part of Coronaviridae)?

ssRNA + (viral genome acts as mRNA)

if you delete 225 amino acids from the spike protein of _______, you get PRCoV

TGEV

what is the structure of PPV?

naked, positive sense

what is the replication strat of PPV?

ssDNA (cellular DNA pol --> dsDNA --> cellular RNA pol2 --> mRNA)

what kind of cells are required for parvoviral replication in sows?

mitotically active stem cells

what is the structure of pseudorabies?

enveloped

what is the replication strat of pseudorabies?

dsDNA (cellular RNA pol2 --> mRNA)

what is the structure of swine influenza?

enveloped, negative sense

what is the replication strat of swine influenza, given it is orthomyxo?

ssRNA- (virion RdRp --> mRNA)

what is PCV

Porcine Circovirus

what family is PCV a part of

Circoviridae

how many PCV strains are there? which is most significant for us to pay attention to?

4 (PCV1-4) PCV2 - most prevalent across the world and has both field observation and experimental reproduction

which PCV strain is spread worldwide in both domestic and wild boar populations

PCV3

what influences the clinical significance of PCV2? 4 things

1) difference between PCV2 isolates 2) co infection 3) immune modulation 4) host susceptibility

what are the 4 possible outcomes of PCV-2 infection? explain the clinical signs of each

1) subclinical infection (no signs, some decreased gain) 2) systemic disease (sig weight loss, ill-thrift, sometimes resp/GI disorders, lymphoid depletion) 3) reproductive disease (abortions/mummifications) 4) dermatitis and nephropathy syndrome (dark red papules and macules on skin- usually on hind and perineal area)

on histo, which virus shows depleted lymphoid with multinucleated giant cells and lots of viral proteins (when clinical)

PCV2

what cells do PCVD (derm) target during fetal life and postnatally?

fetus- cardiomyocytes, hepatocytes, macrophages postnatally- macrophages

how to diagnose PCV2?

- clinical hx - post mortem findings - immunohistochemistry on lymph tissue - PCR - qPCR

what is the structure of PCV (naked or enveloped)

naked

what is the replication strat of PCV?

ssDNA (cell DNA pol --> dsDNA --> cell RNA pol2)

what are 3 things that make the PCV vaccine worth administering

1) can be given during gestation 2) cross-protection between PCV2 strains 3) decreases clinical disease (not infection)

what is PRRSV?

porcine respiratory and reproductive syndrome virus

what family is PRRSV in?

Arteriviridae

what is the structure and repro of PRRSV

enveloped positive sense RNA virus

how many strains of PRRSV is there? which broad ones are the American and which are the European strains

lots of strains! but... PRRSV-1: European PRRSV-2: American

PRRSV replication lends itself to genetic variability through_____ and ____ , causing numerous straight

point mutations and recombination RNA virus so more mutations!!

what type of cells does PRRSV target?

macrophages (alveolar, tissue, and lots more)

where is PRRSV found during chronic phase?

peripheral lymph nodes and tonsils

what are the clinical signs of PRRSV

-repro problems - respiratory disease - cutaneous - rarely neuro - blue ears

is persistent infection common in PRRSV?

yes - chronic for as long as 5 months

does PRRSV target the innate or adaptive immune response? what does this result in?

innate- results in delayed immune response

would RT-PCR be useful in diagnosing PCV (porcine circo) and PRRSV?

PCV- NO its a DNA virus so PCR must be done PRRSV- yes!! :) RNA so RT-PCR

is the vaccine for PRRSV helpful in preventing disease

yes

virus transmission involving inanimate objects such as needles is

iatrogenic

during herpes virus infection you may observe

intermittent virus shedding

common viruses that cause porcine respiratory disease

pseudorabies (Herpes) swine influenza (Orthomyxo) PCV2 (Circo) PRRSV (Arteri)

common viruses that cause porcine reproductive disease

PPV (Parvo) Pseudorabies (Herpes) PCV2 (Circo) PRRSV (Arteri) swine influenza --> fever causes aboriton NOT disease

common viruses that cause porcine GI disease?

Corona! (PED, TGEV, SDCV) sometimes PCV2-SD (Circo)

lecture 6 and 7- porcine virology Flashcards

(93 cards)