ssDNA Circoviridae

Question 1

Circoviridae belong to Class II under the Baltimore Classification System thus classified as _____.

Answer 1

ssDNA

Question 2

Genus _____ and Genus _____ are the two major divisons of Family Circoviridae.

Answer 2

Circovirus and Gyrovirus

Question 3

Genus Circovirus is responsible for _____ _____ and _____ disease virus, _____ circovirus type 1 (nonpathogenic), and Porcine circovirus type 2 (PMWS or _____ _____ _____ _____ _____).

Answer 3

Psittacine beak and feather disease virus; Porcine; Post-weaning Multisystemic Wasting Sydrome

Question 4

Genus Gyrovirus is responsible for _____ _____ _____ virus.

Answer 4

Chicken Infectious Anemia virus

Question 5

Circoviridae are very small viruses, 17 to 22 nm in diameter: Genus Circovirus has a circular, single stranded _____ DNA genome, whereas Genus Gyrovirus has a circular, single stranded _____ negative sense DNA.

Answer 5

ambisense; negative sense

Question 6

The virions of Circovirus are small, 20 to 25 nm, _____, spherical in outline, with _____ symmetry with a T = 1.

Answer 6

non-enveloped; icosahedral

Question 7

Chicken infectious anemia virus has 12 _____-like structures that are less obvious in the other circoviruses.

Answer 7

trumpet-like

Question 8

Virus replication occurs in _____ _____ cells, whereas viral DNA replication occurs in the _____ and requires cellular proteins and other components produced during the _____ phase of the cell cycle.

Answer 8

actively dividing; nucleus; S phase

Question 9

Circovirus virions are very stable, resisting _____degC for 30 minutes and pH range of _____. The virus is stable and can survive on _____ for long periods.

Answer 9

60 degC; pH 3 to 9; fomites

Question 10

EDx for Post-weaning Multisystemic Wasting Syndrome (PMWS): 1st reported in Western Canada in 1991

Answer 10

Porcine circovirus 2 (PCV2)

Question 11

PMWS Host: _____ most common at _____ weeks of age or _____ weeks post-weaning.

Answer 11

Pigs; 4-6 weeks; 2-3 weeks post-weaning

Question 12

PMWS is widespread in most pig populations. The most common transmission route for PMWS is _____, but vertical transmission by _____ infection also occurs in swine.

Answer 12

fecal-oral; transplacental

Question 13

PMWS is found in all secretions, such as _____, _____, _____, _____, etc.

Answer 13

feces, urine, nasal secretions, saliva

Question 14

PMWS is characterized by individual to coalescing foci of _____ inflammation in lymphoid tissues, lungs, liver, kidney, heart and intestines; sometimes with prominent _____ (grape-like) intra-cytoplasmic inclusion bodies in virus infected _____.

Answer 14

granulomatous; botryoid; macrophages

Question 15

PCV2 targets mainly _____, _____ and _____ during fetal life.

Answer 15

cardiomyocytes, hapatocytes and macrophages

Question 16

PCV2 targets mainly _____ in early post-natal life.

Answer 16

monocytes

Question 17

_____ _____ and _____ in peripheral blood is a consistent feature in pigs that develop clinical PMWS. Both _____ and _____ are lost; there appears to be no direct effect of PCV2 on lymphocytes, but lymphopenia cause is unknown. Marked lymphocyte depletion and granulomatous inflammation is seen in the lymph node parenchyma, leading to formation of Langhans giant cells.

Answer 17

lymphoid depletion; lymphopenia; B cells and T cells

Question 18

PCV2 inhibits the pig’s leukocytes from producing _____.

Answer 18

IFN alpha

Question 19

PMWS infection (transplacental) during the first and second trimesters results in _____ _____ and _____ or aborted fetuses with severe _____ congestion.

Answer 19

fetal death and resorption; cardiac

Question 20

Infection during the last trimester with PCV2 has minimal effect on the fetus. True or False

Answer 20

True

Question 21

Subclinical infection is most common in the case of PMWS/PCV2. True or False

Answer 21

True

Question 22

Morbidity rate of PMWS: _____%

Answer 22

10-30%

Question 23

Common clinical signs with PMWS infection: lethargy, progressive weight loss, cough, dyspnoea, slow growth, lymphadenopathy (_____/_____), diarrhea, skin discolouration, congenital tremors, less commonly _____

Answer 23

inguinal/mandibular nodes; icterus

Question 24

_____ with Porcine parvovirus (PPV), Porcine reproductive and respiratory virus (PRRSV), SIV, Mycoplasma hyopneumoniae, and/or a variety of opportunistic bacteria may cause severe disease and more pronounced lesions.

Answer 24

Co-infection

Question 25

PMWS may be characterized by interstitial pneumonia; Immunoperoxidase stain can be used to diagnose _____ _____ in lung samples.

Answer 25

Lymphohistiocytic infiltrates

Question 26

White necrotic foci in the _____ and multifocal necrosis in the _____ are both common findings with PMWS.

Answer 26

liver; kidney

Question 27

Co-infection of PCV2 with _____ _____ result in aborted fetuses, mummies or stillborn fetuses, especially in the early trimesters.

Answer 27

Porcine Parvovirus

Question 28

Co-infection of PCV2 with _____ _____ result in aborted fetuses and interstitial pneumonia.

Answer 28

Porcine Arterivirus (PRRS)

Question 29

Co-infection of PCV2 with _____ _____ result in enzootic pneumonia of swine, characterized by chronic bronchopneumonia.

Answer 29

Mycoplasma hyopneumoniae

Question 30

PMWS DX via clinical signs, characteristic _____ of samples (blood, tonsils, lymph nodes, spleen, ileum), serological assays (antigen detection is not of much value since most pigs are seropositive for PCV2), or detection of PCV2 nucleic acids via _____.

Answer 30

histopathology; PCR

Question 31

_____ vaccines: new generation developed utilizing non-pathogenic PCV-1 as a genetic backbone for expression of the immunogenic _____ protein of PCV-2

Answer 31

Chimeric; capsid

Question 32

_____ or _____-expressed vaccines: virus-like particles that include the capsid protein of PCV-2

Answer 32

inactivated or baculovirus

Question 33

Piglet Vaccine Schedule for PCV-2: either one or two doses with the first dose at _____ weeks of age and the second dose at _____ weeks of age

Answer 33

3 and 6 weeks

Question 34

Sow Vaccine Schedule for PCV-2: _____ and _____ weeks antepartum (occurring not long before parturition)

Answer 34

2 and 5 weeks

Question 35

PDNS or _____ _____ and _____ _____, is associated with PCV-2. It is sporadic, reported in older piglets with _____ skin lesions, necrotizing vasculitis, and necrotizing and fibrinous _____.

Answer 35

Procine Dermatitis and Nephropathy Syndrome; necrotizing; glomerulonephritis

Question 36

Chicken Infectious Anemia or CAV is a member of genus Gyrovirus and family Circoviridae, first siolated in Japan in 1979. It is a highly contagious disease of young chickens, _____ weeks of age. Older chickens are more resistant to clinical disease.

Answer 36

2 to 4 weeks

Question 37

CAV is shed in feces and feather dander. Horizontal transmission occurs via _____ or _____ exposure. Vertical transmission is possible through the _____. The virus is environmentally stable and contaminated fomites for long periods.

Answer 37

inhalation or oral exposure; egg

Question 38

The principal sites of CAV replication are _____ in the bone marrow, precursor _____ in the cortex of the thymus, and dividing _____ and _____ cells in the spleen.

Answer 38

hemocytoblasts; T cells; CD4 and CD8 cells

Question 39

Replication in hemocytoblasts leads to _____ while replication in the T cells leads to _____.

Answer 39

anemia; immunosuppression

Question 40

The _____ protein of CAV virus induces apoptosis and causes destruction of infected lymphocytes.

Answer 40

apoptin

Question 41

Chickens infected with CAV typically have watery blood which clots slowly as a result of thrombocytopenia due to presence of _____ and _____ anemia.

Answer 41

immunosuppression and aplastic anemia

Question 42

Birds with CAV are vulnerable to secondary _____ and _____ infections.

Answer 42

bacterial and fungal

Question 43

CAV replication in the _____ of chickens may be regulated by _____, allowing more efficient vertical transmission in the egg.

Answer 43

oviduct; estrogen

Question 44

Chicks infected with CAV present with anorexia, lethargy, depression, reduced weight gain, pale skin, mucous membranes and muscles, and subcutaneous and skeletal _____. PCV is low, indicating anemia:

Answer 44

hemorrhages;

Question 45

Induced thymic and fibricial bursa _____ is pathognomonic of CAV.

Answer 45

atrophy

Question 46

_____ blood and long bones such as the femur with pale, asplastic _____ _____ is pathognomonic of CAV.

Answer 46

"watery"; bone marrow

Question 47

CAV DX: clinical signs, blood examination (_____ _____, anemia revealed by low RBC count, thrombocytopenia, "watery", slow to clot), histopathology, necropsy, serology (ELISA, neutralization test, FAT test), virus isolation, PCR, qPCR

Answer 47

low

Question 48

Immunity to CAV is complex. The presence of antibodies in breeders greatly reduces vertical and horizontal transmission. The aim of vaccination is to protect the progeny of vaccinated breeders from early infections by means of _____-derived antibodies.

Answer 48

maternally

Question 49

_____ vaccines are available for vaccination of antibody-negative breeder flocks before the start of egg production.

Answer 49

Live

Question 50

Administration of CAV vaccine by _____ or addition to drinking water depending on the type of vaccine.

Answer 50

injection

Question 51

Due to the __________ between CAV and other immunosuppressive viruses such as _____ disease virus, control of the latter is also important.

Answer 51

synergism; Marek's