POXVIRIDAE Flashcards
Give the target cells of Poxviridae.
Skin cells and or oral mucosa (keratinocytes)
It is the deliberate exposure of infectious smallpox virus contained in the skin lesions of affected individuals.
Variolation
Jenner’s first vaccine for smallpox came from what animal?
Cattle
It is the first viral pathogen of a laboratory animal to be described.
Myxoma virus
Give the difference of Myxoma virus and Rabbit fibroma virus.
Myxoma virus:
- European rabbits: Oryctalagus cuniculus
- Cause of myxomatosis
Rabbit fibroma virus:
- 1932
- Shope
- North American Rabbits: Sylvilagus spp.
Rabbit fibroma virus is the first virus shown to cause _____ ______.
Tissue hyperplasia
What are the 2 subfamilies of Poxviridae?
- Chordopoxvirinae (vertebrates)
- Entomopoxvirinae (insects)
This method allows rapid visualization of poxviruses but not the particular species.
Negative-stain electron microscopic examination
The new virus order that has been recently proposed that would include the Poxviridae, Asfarviridae and other families of large DNA viruses.
Mononegavirales
Give the distinguishing characteristics of Poxviridae. (e.g. shape)
Large, pleomorphic, brick-shaped with an irregular surface of projecting tubular or globular structures.
Parapoxvirus are in what shape?
Ovoid with a regular surface; covered with long thread-like surface tubules in criss-cross fashion resembling a ball of yarn
Give the shape of poxvirus virions of the reptiles.
Brick-shaped but surface structure similar to that of parapoxvirus
Two types of progeny virions produced by poxvirus-infected cells
- Mature virions (MV) - stable
- Enveloped virions (EV) - fragile
The core of virions of poxvirus is in what shape?
Dumbbell shape; 2 lateral bodies
MV type virions are released by?
Budding or after cell lysis
EV type virions are released by?
Exocytosis
Give the main difference of MV and EV virions based on their transmission capabilities.
MV’s are very stable and are thought to mediate transmission between hosts, whereas the more fragile EV’s are best suited to exiting the intact cell and spreading within the host.
What is the symmetry of nucleocapsid core of Poxviruses?
None making them “complex structure”
Poxviridae has double-stranded DNA and is non-enveloped. True or False?
False, enveloped.
Give the mode of transmission of Poxviruses.
Direct contact or indirect contact of infectious material with broken skin and, for some viruses, the upper respiratory tract; transmitted mechanically by biting arthropods
What is the site of replication of poxviruses?
Cytoplasm
Poxvirus DNA replication can usually be detected within ___ hours of infection.
2
Specific cellular receptors for poxviruses have been identified. True or False?
False
Poxvirus infection has been described in how many species and orders of birds?
232; 23
How many proteins does Avipoxvirus encode?
320
Avipoxvirus is transmitted between birds via?
Arthropods especially mosquitoes
Fill in the blanks. These are the choices: chickens; turkey; pigeons; ducks; canaries
Fowlpox virus is highly infectious for _____ and _____, rarely so for _____, and not at all for _____ and canaries.
Chickens; turkeys; pigeons; ducks; canaries
Give the form of fowlpox virus:
- Infection by biting arthropods or mechanical transmission to injured or lacerated skin
- Small papules on the comb, wattles, around the break, occasionally on the legs, and feet
- Papules turn yellowish and progress to a thick dark scab
Cutaneous form
Give the form of fowlpox virus:
- Infection via droplets and involves
- Mucous membrane of the mouth, pharynx, larynx, esophagus, sometimes trachea
Diphteritic or wet form
Recovered birds are immune to subsequent fowlpox virus infections. True or False?
True
Diphtheritic form of fowlpox virus is less difficult to diagnose than cutaneous form. True or False?
False
Fowlpox virus can be isolated via?
Inoculation of avian cell cultures or the chorioallantoic membrane of embryonated eggs
What is the unique feature of fowlpox virus?
Occurrence of near full-length reticuloendotheliosis virus sequences integrated into the virus genome
Fowlpox virus is extremely resistant to desiccation. True or False?
True
Vaccines for poxvirus are typically applied in chickens, turkey, and pigeons by ?
Wing-web inoculation
Describe the typical lesions of fowlpox virus.
Extensive, local hyperplasia of the epidermis and underlying feather follicle epithelium, with accompanying ulceration and scabbing
What is the causative agent of smallpox?
Variola virus
Variola virus enter the body via?
Respiratory droplets or direct contact
Variola virus replicates in?
Respiratory mucosa then spreads vias lymphatics
Give the diseases and/or clinical signs induced by variola virus.
Viremia leading to fever, malaise, and widespread pustular rash
What vaccine provides strong, long-lasting immunity for Variola virus?
Smallpox vaccine or Vaccinia virus
What are the diagnoses for Variola virus?
PCR, electron microscopy, viral culture
Give the transmission mode of sheeppox and goatpox.
Environmental contamination to small skin wounds; infective scabs; respiratory droplets; biting arthropods
Give the transmission mode of Lumpy skin disease virus.
Biting insects (reservoir host is African Cape Buffalo)
Give the clinical signs of Lumpy skin disease.
Fever followed shortly thereafter by the development of nodular lesions in the skin; edema
Give the pathogenesis of sheeppox, goatpox, and Lumpy skin disease (Capripoxvirus).
After an incubation period of 4-12 days, increase in temp. and respiratory rate, edema of the eyelids, lacrimation, and mucous discharge from the nose; appetite loss.
1-2 days later, skin nodules (papules) will develop on the skin and in the subcutis
Lesions will persist for 3-4 weeks
(Cell-associated viremia preceding the appearance of lesions and marked lympadenopathy.)
— Blood monocytes are important in spreading virus to secondary sites of infection
Myxoma virus (Leporipoxvirus) causes ?
Localized benign fibromas in its natural hosts, wild rabbits in the Americas (Sylvilagus spp.)
In contrast, it causes a severe generalized disease (myxomatosis) in European rabbits (O. cuniculus)
What are the characteristic early signs of myxomatosis in European rabbits?
Blepharoconjunctivitis and swelling of the muzzle and anogenital region, giving animals a leonine appearance.
Infected rabbits become febrile and listless, often die within 48 hours of onset of clinical signs
Describe the Rabbit fibroma virus (Leporipoxvirus).
Large wart-like tumors of the face, feet, and legs of affected North American Slyvilagus spp; first virus to shown to cause tissue hyperplasia; also affects squirrel
Bovine papular stomatitis virus (Parapoxvirus) has higher incidence in animals less than ____ years of age.
2
Site of development of lesions of Bovine papular stomatitis virus (Parapoxvirus).
Muzzle, margins of the lips, oral mucosa, less frequently teats
Give the transmission mode of Bovine papular stomatitis (Parapoxvirus).
Direct contact
Give the diagnostic method for Bovine papular stomatitis (Parapoxvirus).
Electron microscopy
Give the characteristic lesions of Pseudocowpox virus (Parapoxvirus).
Ring or horseshoe-shaped scabs
Transmission mode of Pseudocowpox virus (Parapoxvirus).
Cross-suckling of calves, improperly disinfected teat, flies
Pseudocowpox virus (Parapoxvirus) can infect the unprotected hands of people working with affected cattle, causing _____ _____.
Milker’s nodules
Orf is an old english word for ?
Rough
Orf virus (Parapoxvirus) usually affects the?
Mucocutaneous junctions of muzzle and lips, lesions within the mouth affecting the gums, palate, tongue especially in lambs and kids
Spread of infection of Orf Virus (Parapoxvirus) is via?
Direct contact; exposure to contaminated feeding troughs and similar fomites including wheat stubble and thorny plants
What are the synonyms of Orf Virus (Parapoxvirus)?
- Contagious ecthyma of sheep
- Contagious pustular stomatitis
- Contagious pustular dermatitis
- Scabby mouth
- Sore mouth
The lesions of Org Virus duration ranges from ?
4 to 9 weeks
Comparative genetic analyses indicate that swinepox virus is most closely related to the ______ and less so to _____ or _____.
capripoxviruses; yatapoxviruses or leporipoxviruses
Swinepox is most severe in pigs up to ____ months of age.
4
During the ear of smallpox eradication, many outbreaks of poxvirus disease in swine were caused by _____ _____ infection.
vaccinia virus
What are the clinical signs of Swinepox virus (Suipoxvirus)?
- Pox lesions on skin of abdomen;
- Transient low-grade fever may precede the development of papules that within 1-2 days become vesicles and then umbilicated pustules 1-2 cm in diameter
Swinepox virus pocks crust over and scab by ____ days.
7
Healing from swinepox virus is usually complete by ____ weeks.
3
Swinepox virus is transmitted most commonly between swine by the bite of the pig louse: ______ ______.
Hematopinus suis
What is the reservoir host of Cowpox virus?
Rodents
Give the pathogenesis of Myxoma virus.
Dermal cell replication likely dendritic cells —> spreads to local macrophages and epidermal cells and to draining lymph node —> lymphoid depletion —> extensive loss of cortical and paracortical lymphocytes —> spreads to blood leukocytes to distal tissues including the spleen and other lymphoid tissues, testis, lungs
