Poxviridae Flashcards

1
Q

How is it possible for poxviruses to replicate in the cytoplasm

A

Unlike other DNA viruses, poxviruses have evolved to encode the enzymes required for transcription and replication of the viral genome

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2
Q

Pathogenesis of contagious ecthyma

A

Macule → Papule → Vesicle → Pustule → Ulcer → Scab

Damage of skin essential to infection

Cellular response with necrosis and sloughing of the affected epidermis and underlying stratum papillare of the dermis

Cutaneous response to infection includes a delayed type hypersensitivity reaction and influx in inflammatory cells

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3
Q

Transmission of contagious ecthyma

A

Scabs that fall off contain less virus

Virus stable in environment

Transmitted on contaminated instruments

Spread rapidly

Infects healthy animals through damaged skin

Oral lesions infect lambs or kids result from nursing

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4
Q

Subfamily of Poxviridae that infects vertebrates

A

Chordopoxvirinae

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5
Q

Venereal form of ulcerative dermatosis

A

Venereally transmitted ulceration of the prepuce and penis or vulva

Rarely, the ulcers may extend to the glans penis so that the ram becomes unfit for natural breeding

Ewes- edema, ulceration and scabbing of the vulva have less serious consequences

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6
Q

Properties of Parapoxviruses

A

Ovid

Covered with long thread-like surface tubules

________________________

Appear to be arranged in crisscross fashion, resembling a ball of yarn

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7
Q

How are poxviruses transmitted?

A

Skin

Respiratory route

Mechanically transmitted

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8
Q

Two distinct infectious pox viruses

A

Intracellular Mature Virus (IMV)

Extracellular Mature Virus (EMV)

______________________

Both forms are infectious

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9
Q

Describe the skin lesions of poxvirus infection

A

Degenerative changes in the epithelium

Rupture of the pustule can pre-dispose to secondary bacterial infection

Ulceration may develop

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10
Q

Clinical signs of lumpy skin disease

A

Fever

Multiple nodular lesions on skin and mucous membrane

Lymphadenopathy

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11
Q

Contagious ecthyma disease in humans

A

Macropapular lesions and large nodular lesions

Healing occurs without scarring

Secondary bacterial infections

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12
Q

Parapoxviruses are what shape

A

Ovoid

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13
Q

Transmission of Ulcerative Dermatosis of Sheep

A

Virus infection through damaged skin or by coitus

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14
Q

Primary lesions of cowpox in cats

A

History of primary skin lesion

Small, scabbed wound to large abscess

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15
Q

Distribution of swinepox

A

Worldwide

Widespread sporadic disease

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16
Q

Prevention and control of sheeppox

A

Notifiable disease!

Ring vaccine, destruction of affected flocks and quarantine of infected premises should be instituted

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17
Q

Type A (ATI) inclusion bodies are induced by what diseases

A

Cowpox

Ectromelia virus

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18
Q

Goat pox virus

A

Reportable

Clinically similar to sheeppox

Young kids suffer systemic disease with lesions on skin, respiratory and alimentary mucosae

Milder form of disease seen in adults

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19
Q

Hosts of Cowpox

A

Cattle, Wild and Domestic Cats, Humans and Zoo Animals

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20
Q

Prevention of pseudocowpox

A

Disinfection, iodophor teat dip

Isolation and treatment of infected cows

Reduce teat trauma, as injuries to skin of teat predisposes to infection

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21
Q

Benign form of sheepox

A

More common in adults and resistant breeds

Only skin lesions occur

No or very mild systemic reaction

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22
Q

Type B (Guarnieri) Inclusion Bodies

A

Slightly basophilic and composed of viral particles and protein aggregates

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23
Q

Describe the structure of poxvirus virions

A

Outer layer encloes a dumbbell shaped core and two lateral bodies

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24
Q

Chronic lesions of pseudocowpox

A

Commenses as erythema

Yellow-grey, soft scurfy scabs which are rubbed off during milking

Skin is corrugated

No pain

Lesions may persist for months

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25
Q

Examples of diseases caused by genus Orthopoxvirus

A

Cowpox

Monkeypox

Varioloa

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26
Q

Monkeypox

A

Genus Orthopoxvirus

Viral zoonosis with symptoms in humans similar to those seen in the past smallpox patients

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27
Q

Distribution of contagious ecthyma

A

worldwide

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28
Q

Clinical signs of swinepox

A

Erythematous macule → Papule → Vesicle → Pustule → Ulcer → Scab

Transient fever

Exudative epidermitis (Greasy pig disease) and secondary bacterial dermatits

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29
Q

Pathogenesis of psudocowpox

A

Lesions are characterized by hyperplasia of squamous epithelium

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30
Q

Two forms of sheeppox virus

A

Malignant form

Benign form

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31
Q

Routes of transmission of fowlpox virus

A

Transmitted within a flock through minor wounds and abrasions in mouth, comb, wattles, or skin as result of fighting, pecking and other injuries

Mechanically transmitted by mosquitos, lice and ticks

Possible aersol route

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32
Q

Malignant form of sheeppox

A

Lambs and susceptible nonnative breeds

Marked depression and prostration

High fever, salivation, lacrimation

Edema of eylids

Serous nasal discharge that becomes mucopurulent

Days after infection pox lesions develop in respiratory, digestive and urinary tracts

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33
Q

Pseudocowpox disease in humans

A

Milkers Nodule

Cause mild skin lesion

Lesions on hands - dairy farmers and vets treating infected cows

Lesions vary from multiple vesicles to a single indurated nodule

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34
Q

Enveloped/Non-Enveloped virions are taken up by cells more readily and appear to be more important in the spread of virions through the body of the animal

A

Enveloped

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35
Q

Transmission of Sheep Pox

A

Highly contagious

Enters respiratory tract and transmission is commonly by aerosol route

Can also occur through MM or abraded skin

Virus present in nasal and oral secretions for several weeks after infection

Virus survive months in dry scabs

Mechanical transmission by biting arthropods

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36
Q

T/F: Sheep Pox and Goat Pox are strains of the same virus

A

False

________________

Genetic sequencing has now demonstrated them to be separate viruses

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37
Q

Primary transmission of monkeypox in humans

A

Results from direct contact with blood, bodily fluids or rashes of infected animals

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38
Q

Deadliest form of fowlpox disease

A

Diphtheric form - wet form

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39
Q

Clinical signs of contagious ecthyma

A

Mucocutaneous junction - swelling lips

Animal may find it difficult to take food

Lesions in genitals, coronets and ears

Scab drops off (1-4 wks) tissue heals without scarring

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40
Q

Economic importance of Cowpox

A

Losses to farmers due to inconvenience in milking because of soreness of teats and mastitis resulting from secondary bacterial infections

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41
Q

Clinical signs of cowpox in humans

A

Macropapular lesions first observed on hands and face

Develop into vesicular and then ulcerative lesions

Enlarged painful local lymph nodes

Fever, vomiting and sore throat

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42
Q

Extracellular Mature Viruses (EMV) are released from cells by

A

budding

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43
Q

Transmission of lumpy skin disease

A

Arthropod vector - most common

Direct contact

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44
Q

Epidemiology of pseduocowpox

A

Reported from most countries

45
Q

Lip and leg ulcerative form of ulcerative dermatosis of sheep

A

Formation of ulcers around the mouth and nose or on the legs

Face lesions occur on the upper lip, between the border of the lip and nasla orifice, on the chin and on the nose

Foot lesions are seen anywhere between teh coroent and the carpus or tarsus

46
Q

Cutaneous form of fowlpox

A

Small papules on comb, wattles and around beak

Lesions occassionally develop on legs, feet and around cloaca

Nodules become yellowish and progress to thick scab

Sharp fall in egg production

47
Q

Reservoir host of Cowpox

A

Rodents

48
Q

Vaccination for sheeppox

A

Commercial and subunit vaccine available

Killed vaccine elicit temporary protection

Live attenuated vaccines offer excellent protection

49
Q

Swine pox is transmitted mechanically by

A

Haematopinus suis - pig louse

50
Q

Transmission of Cowpox in cattle

A

From cow to cow in a herd is through infected milkers hands or teat cups

51
Q

Monkeypox infection in monkeys

A

Disease characterized by generalized skin erruptions, developing to papules on the trunk, face, palms and soles

52
Q

Diseases caused by genus capripoxvirus

A

Sheep pox

Goat pox

Lumpy Skin disease

53
Q

Clinical forms of ulcerative dermatosis of sheep

A

Lip and leg ulceration

Venereal

54
Q

Orthopoxviruses are what shape

A

Brick shaped

55
Q

T/F - Poxvirus can survive in dried scabs for many months or years

A

True

56
Q

Transmission of swinepox

A

Direct contact associated with skin injury - virus can survive in scab for years

Mechanical transmission by pig louse, flies and insects

Transplacental infection of neonatal pigs

57
Q

Clinical signs of pseudocowpox

A

Infection generally mild

Multiple lesions per teat

Acute lesions vs chronic lesions

58
Q

Control of lumpy skin disease

A

Live attenuated vaccine available

Slaughter of affected and in-contact animals

59
Q

Distribution of Sheeppox and Goatpox

A

Endemic in Africa, Asia and parts of Europe

60
Q

Characteristics of fowlpox virus

A

Extremely resistant to desiccation

Can survive in exfoliated scabs for long periods

61
Q

Etiology of Ulcerative Dermatosis of Sheep

A

Infectious disease of sheep caused by a virus antigenially similar to the ectheyma virus

62
Q

Hosts of lumpy skin disease

A

Cattle - all ages and types susceptible

63
Q

Bollinger bodies

A

Eosinophillic granular intracytoplasmic granules inclusion bodies

64
Q

Distirbution of Cowpox

A

Endemic only in Europe and Asia

65
Q

Are enveloped or non-enveloped virions of poxvirus infectious?

A

Both

66
Q

Poxviruses replicate primarily in the

A

Cytoplasm

67
Q

Diagnosis of poxviruses

A

Clinical signs

Sampling material

Electron microscopy

Histopathology

Inoculation in embryonated egg

Serological assay

Detection of pox nucleic acid by PCR

68
Q

Secondary lesions of cowpox in cats

A

7-10 days after primary lesion appears

Develop into discrete, circular, ulcerated papules

Ulcers become covered by scabs

69
Q

Vaccination for contagious ecthyma

A

Suspension of scabs in glycerol saline and is painted onto a small area of scarified skin inside the thigh

Does not offer long-lasting immunity

70
Q

Treatment of pseudocowpox

A

Removal of scabs

Burn the scabs to prevent environmental contamination

Application of an emollient ointment before milking

Application of astrigent preparation after milking

71
Q

Control of swinepox

A

Eradication of lice from piggery

No vaccine

72
Q

First virus to be grown in embryonated egg

A

Fowlpox virus

73
Q

Acute lesions of pseudocowpox

A

Erythema → Papules → Vesicle/Pustule → Rupture → Thick Scab

Scab elevated due to accumulation of granulation tissue

Scab drops (7-10 days) leaving horseshoe shaped ring of small scabs

74
Q

Type A (ATI) Inclusion Bodies

A

Cowpox and Ectromelia virus

Strongly eosinophilic

75
Q

Antigenic characteristics of poxviruses

A

Group specific nucleoprotein (NP)

76
Q

Most common form of fowlpox disease

A

Cutaneous form - dry form

77
Q

Hosts of Contagious Ecthyma

A

Sheep and goats

__________________________

Primarily in lambs and kids

78
Q

T/F: Parapoxviruses do not multiply in chicken embryo

A

True

79
Q

Properties of Poxviruses

A

Large, sometimes enveloped, DNA viruses

Complex structure - pleomorphic, brick shaped

Irregular surface of projecting tubular/globular structures

80
Q

Hosts of swinepox

A

Pigs

___________________

Benign with low mortality and low morbidity in older pigs

81
Q

Transmission of pseudocowpox

A

Source of infection is infected cattle

Contaminated milkers hands and teat cups

Biting insects can transmit

Calves infected when suckling

Semen of bull

82
Q

Pathogenesis of Sheeppox

A

Systemic disease

Incubation period is followed by leukocyte associated viremia

Virus localizes in skin and other internal organs

Immune complexes results in severe necrotizing vasculitis develop in arterioles and postcapillary venules of the skin

83
Q

Borrel Bodies

A

Occur inside bollinger bodies, minute spherical bodies obtained by tryptic digestion of bollinger bodies

84
Q

Chicken pox is caused by what virus

A

Human Herpesvirus 3 - Varicella zoster virus

85
Q

Transmission of cowpox in cats

A

Skin inoculation, probably through a bite or skin wound

86
Q

Bollinger bodies andn borrel bodies are seen in what pox virus

A

Fowlpox

87
Q

Enveloped poxvirus show a (high/low) environmental stability.

A

High

88
Q

Diseases caused by genus Suipoxvirus

A

Swinepox

89
Q

Diseases caused by genus parapoxviruses

A

Pseudocowpox

Contagious Ecthyma / Orf

Bovine Papular Stomatitis Virus

90
Q

Diphtheric form of fowlpox

A

Caused by droplet infection

Involves infection of mucous membranes of mouth, pharynx, larynx, and sometimes trachea

Lesions result in a necrotic pseudomembrane which may cause death by asphyxiation

Prognosis is poor

91
Q

Pseudocowpox

A

Genus parapoxvirus

VIral skin infection that causes mild sores on the teats and udders of cattle

Commonly referred to as milkers nodule in humans

92
Q

Bollinger and Borrel bodies are seen in what type of pox virus infection

A

Avipoxvirus

93
Q

Secondary transmission of monkeypox in humans

A

Human to human contact, resulting from close contact with infected respiratory tract excretions, with skin lesions of an infected person or with recently contaminated objects

94
Q

Lumpy skin disease distribution

A

Enzootic in sub-saharan Africa and Middle East with recent incursion in Iraq

95
Q

Diseases of genus Avipoxvirus

A

Fowlpox

Turkeypox

Canarypox

Avipox

96
Q

Clinical signs of monkeypox in humans

A

Invasion period - fever, intense headache, lymphadenopathy, muscle pain

Skin erruption period - rash from amculopapules to vesicles, pustules followed by crusts

97
Q

Transmission of cowpox in humans

A

Caused by direct contact to cats

98
Q

Host of fowlpox

A

Highly infectious disease of poultry and turkeys

99
Q

Control of fowlpox

A

Vaccination

Control mosquito population and other biting insects

100
Q

Distribution of fowlpox

A

Worldwide

101
Q

Why do enveloped poxviruses show high environmental stability?

A

Due to their low lipid content, they are less sensitive to organic solvents/disinfectants compared to other enveloped viruses

102
Q

Histopathological characteristics of poxviruses

A

Type B (Guarnieri) Inclusion Bodies

Type A (ATI) Inclusion Bodes

103
Q

Three forms of fowlpox disease

A

Cutaneous Form - Dry Form

Diphtheric Form - Wet Form

Ocular Form

104
Q

Form of pox virus that contains two membranes

A

Extracellular Mature Virus (EMV)

105
Q

Ocular form of fowlpox

A

Conjunctivitis

Cheesey exudate accumulates under the eyelids

106
Q

Hemagglutinin is produced by what poxvirus

A

Orthopoxvirus

107
Q

Eitiology of Fowlpox

A

Genus Avipoxvirus

108
Q

Diagnosis of pseudocowpox

A

Horseshoe shaped ring like lesion are pathognomic

Isolation and detection of the virus by various diagnostic laboratory methods from vesicular fluid or from teat skin

109
Q

Clinical findings of cowpox in cattle

A

Incubation period of 3-7 days

Mildly febrile

Papules on teats and udder

Sucking calves may develop lesions in mouth

Vesicles may be evident or may rupture