Poxviridae (Ex2) Flashcards
(42 cards)
1
Q
General properties of Poxviridae
morphology, two types, DNA, location of replication, stability
A
- large, pleomorphic, sometimes enveloped, DNA virus with complex structure
- irregular surface of projecting tubular or globular structures
- extracellular enveloped virus (inner membrane and envelope), and intracellular mature virus (only inner membrane)
- single molecule of linear double stranded DNA
- replication occurs in the cytoplasm
- high resistance in environment and scabs
2
Q
How are poxviruses transmitted?
A
- through broken or lacerated skin
- inhalation of aerosol
- mechanically by biting arthropods
3
Q
Describe the spread of poxviruses in the body
A
- after entry, the virus gains access to systemic circulation via the lymphatics
- a secondary viremia disseminates the virus back to the skin and other target organs
4
Q
Describe the skin lesions caused by poxviruses
including order of lesion development
A
- degenerative changes in epithelium
- rupture of pustules can predispose to secondary bacterial infections
- macule > papule > vesicle > pustule > ulcer or scab > scar and healing
5
Q
Hosts and reservoir of Cowpox
A
Hosts: cattle, cats, humans, zoo animals
Reservoir: rodents
6
Q
What is the genus of Poxviridae that causes Cowpox?
A
Orthopoxvirus
7
Q
Transmission of Cowpox
cattle and cats
A
Cattle: cow to cow in a herd from infected milkers hands or teat cups - infected farm cats - rodent reservoirs Cats: skin inoculation - rodents - oro-nasal route
8
Q
Clinical signs of Cowpox in Cattle
A
- mildly febrile
- papules appear on teats and udder
- suckling calves develop lesions in mouth
- vesicles may rupture, leaving raw, ulcerated areas that form scabs
9
Q
Clinical signs of Cowpox in Cats
A
Primary lesions: lesions on head, neck, or forelimb
- small, scabbed wound to large abscess
Secondary: widespread, develop into discrete, circular, ulcerated papules
- ulcers become covered by scabs
10
Q
Clinical signs of Cowpox in Humans
A
- macropapular lesions on hands and face
- enlarged, painful local lymph nodes
- fever, vomiting, sore throat
11
Q
What is Monkeypox?
What genus of Poxviridae?
A
- in monkeys, a disease characterized by generalized skin eruptions, developing to papules on the trunk, face, palms, and sole
- Orthopoxvirus
12
Q
What is Pseudocowpox?
What genus of Poxviridae?
A
- a viral skin disease that causes mild sores on teats and udders of cows
- referred to as Milker’s Nodule
- Parapoxvirus
13
Q
Transmission of Pseudocowpox
A
- source is the infected cattle
- contaminated milker’s hands, teat cups
- biting insects
- suckling calves are infected
- semen of bulls
14
Q
Describe acute lesions of Pseudocowpox
A
- erythema > papules > vesicle or pustule > rupture > thick scab
- scab becomes elevated due to accumulation of granulation tissue
- scab drops off after 7-10 days, leaving horse-shoe shaped ring of small scabs surrounding a small wart-like granuloma
15
Q
Describe chronic lesions of Pseudocowpox
A
- commences as erythema
- yellow-gray, soft scabs rubbed off during milking
- skin is corrugated
- no pain
- may persist for months
16
Q
Treatment of Pseudocowpox
A
- remove scabs and burn to prevent environmental contamination
- application of emollient ointment before milking
- application of astringent preparation after milking
17
Q
Pseudocowpox in Humans
A
- Milker’s Nodule
- mild skin lesions on hands
18
Q
What are the hosts of Contagious Ecthyma (ORF)?
What is the genus and family?
A
- sheep and goats, mainly lambs and kids
- Poxviridae, parapoxvirus
19
Q
Transmission of ORF
A
- scabs that fall off from healing lesions contain the virus
- remains stable in environment
- contaminated instruments
- rapid spread in flock
- infection through damaged skin
- oral lesions in suckling kids and lambs from infected teats of mother and vice versa
20
Q
Clinical signs of ORF
A
- first lesions in mucocutaneous junction, accompanied by swelling of lips
- lesions spread to muzzle and nostrils
- anorexia and weight loss
- lesions on teats, secondary bacterial leading to mastitis
- severe cases show lesions in feet, genitals, and ears (infertility, lameness)
- scab falls off in 1-4 weeks, no scar
21
Q
Evolution of lesions in ORF
A
macule > papule > vesicle > pustule > ulcer > scab formation
22
Q
Vaccination for ORF
A
- vaccine prepared from suspension of scabs in glycerol saline, and painted on small area of scarified skin
- should not be used on farms with no ORF
- inspect lamb 1 week after vaccination
- do not offer long-lasting immunity
- vaccinate pregnant ewes
23
Q
ORF in humans
A
- macro-papular lesions and large nodular lesions on fingers, hand, arm, face
- healing without scar
- secondary bacterial infections possible
24
Q
What is the genus of Sheeppox and Goatpox
A
Capripoxvirus
25
Tranmission of Sheeppox and Goatpox
- highly contagious
- enters respiratory tract via aerosol
- also spread through mucus membrane or abraded skin via direct contact
- virus present in nasal and oral secretions for weeks
- can survive in dry scabs for months
- mechanical via biting arthropods
26
Pathogenesis of Sheeppox
- incubation period is followed by a leukocyte-associated viremia
- virus localizes in the skin and other organs
- deposition of immune complexes results in severe necrotizing vasculitis in arterioles and postcapillary venules of the skin
- results in ischemic necrosis of dermis and epidermis
27
Sheeppox Clinical Signs
Malignant form: lambs and susceptible breeds
- marked depression and prostration, high fever, salivation, lacrimation, edema of eyelids, serous nasal discharge
- pox lesions on mucosa, extend to other tissues
- secondary pneumonia common
- cutaneous nodules, heal leaving star shaped scar
Benign: adults and resistant breeds
- only skin lesions occur
28
Goatpox
- reportable
- in Africa, Asia, Europe
- young kids get systemic disease with lesions on skin, respiratory, and alimentary mucosa
- milder form in adults
29
Lumpy Skin disease
| genus/family, transmission, host, signs, control
- Poxviridae, capripoxvirus
- Arthropod vector, direct contact
- fever, nodular lesions on skin and mucous membranes, lymphadenopathy
- live attenuated vaccines
- slaughter affected and in contact animals
30
Transmission of Swinepox
- direct contact with skin injury
- mechanical by pig louse, flies, and insects
- transplacental infection
31
Clinical signs of Swinepox
- transient fever
- typical pox lesions, mostly on abdomen and inner thighs
- exudative epidermatitis and secondary bacterial dermatitis occur often
- lesions may appear in upper respiratory tract and digestive tract
32
Transmission of Fowlpox
- resistant to desiccation
- can survive in scabs
- transmitted through minor wounds
- mechanically by arthropods
- possibly by aerosol
33
What are the forms of Fowlpox?
- Cutaneous form (dry)
- Diphtheritic form (wet)
- Ocular form
34
Clinical signs of Dry form of Fowlpox
- low mortality
- small papules on comb, wattles, and around beak
- lesions can develop on legs, feet, and around cloaca
- nodules become yellowish and progress to thick scab
- sharp fall in egg production
35
Clinical signs of Wet form of Fowlpox
- infection of mucus membranes of mouth, pharynx, larynx, and trachea
- lesions result in pseudomembrane, which can lead to asphyxiation
- poor prognosis
36
Clinical signs of Ocular form of Fowlpox
- conjunctivitis
| - cheesy exudate accumulates under the eue
37
What are Bollinger Bodies?
eosinophilic granular intracytoplasmic inclusion bodies
38
What are Borrel Bodies?
minute spherical bodies obtained by tryptic digestion of Bollinger bodies
- occur inside Bollinger bodies
39
Ulcerative Dermatosis of Sheep
| transmission, signs
- transmitted through damaged skin or coitus
- lesions are ulcers with a raw crater that bleeds easily
- two clinical forms: lip and leg ulceration, and venereal form
40
What are Type-B or Guarnieri inclusion bodies?
- most poxviruses induce the presence of these
| - slightly basophilic and composed of viral particles and protein aggregates
41
What are Type-A or ATI inclusion bodies?
- some poxviruses induce these
| - strongly eosinophilic
42
What is the shape of orthopoxviruses and parapoxviruses?
Ortho: brick shaped
Para: ovoid shaped
