Pox Viruses Flashcards
Entomopoxvirinae
pox viruses of insects
Chordopoxvirinae
Pox viruses of vertebrates
Basic structure of pox viruses
Large, sometimes enveloped DNA viruses with complex structures
Two distinct infectious particles
Intracellular mature virus (IMV)
Extracelluar enveloped virions (EEV)
Intracellular mature virions
only have an inner membrane. Released by lysis
Extracellular enveloped virions
have an envelope and inner membrane
released by budding
Genome of Pox virus
single molecule of linear double-stranded DNA
encodes proteins that counteract host adaptive and innate immune responses
Replication occurs
in the cytoplasm
Pox virus antigenic characteristics
Specific nucleoprotein, exposed following alkaline digestion of virus
production of hemaggulation only by Orthopoxviruses
Envelope properties
High environmental stablility, long infectious period.
less sensitive to organic solvents/disinfectants due to low lipid content
Methods of transmission
Damaged skin
Respiratory route
Mechanically by biting arthropods
spread by lymphatics
Most pox are host specific except ____
Orthopoxviruses
Orthopoxviruses: hosts
Cowpox
wide host range
Rodents are reservior
Cowpox: cattle transmission
cow to cow by milker’s hands or teat cups
infected farm cats
rodents
Cowpox: cattle Clinical findings
papules on teats and udder, suckling calves may have them on mouth
May rupture into ulcers
Cowpox: Cats Transmission
skin inoculation by bite or would
oro-nasal route
Cowpox: Cats Clinical signs
single primary skin lesions, followed by widespread secondary lesions as ulcerated papules
Cowpox: Humans Transmission
contact with cats most common
Cowpox: humans Clinical signs
papular lesions on hands and face, may ulcerate
enlarged, painful lymph nodes
fever, vomiting, sore throat
Monkeypox: Monkeys
generalized skin lesions
Monkeypox: human transmission
direct contact with infected animal fluid (monkey, gambian rat, or squirrel)
contact with infected respiratory excretions
Monkeypox: human clinical signs
Invasive period- fever, headache, lymphadenopathy, muscle pain
Skin eruption period- rash of macropapules and vesicles
Parapoxviruses
Pseudocowpox
contageious Ecthyma/Orf virus
Pseudocowpox condition
viral skin disease, causes mild sores on teats and udder of cows
Milker’s nodule- human infection
Pseudocowpox transmission
contaminated milkers
biting insects
calves get infected by suckling
semen of bulls
Pseudocowpox pathogenesis and CS
lesions of hyperplasia of squamous epithelim
high morbidity of mild infection
up to 10 lesions on 1 teat
Pseudocowpox acute lesions
thick, elevated scab, falls off, leaving Horse-shoe shaped ring of small wart-like granuloma
Pseudocowpox: chronic lesions
erythema, yellow/grey scabs that rub off at milking
corrugated skin, no pain
Pseudocowpox: Treatment and prevention
removal and burning of scabs, apply emollient ointment before milking, astringent prep afterwards
disinfection, teat dip, reduce teat trauma, isolate infected
Pseudocowpox: humans
Milker’s nodule
lesions on hands
Contagious Ecthyma: Hosts
Orf virus
Sheep and goats
Contagious Ecthyma: transmission
scabs from lesions, long infectious period
primary infection by damaged skin.
Contagious Ecthyma: Pathogenesis
cellular necrosis and sloughing of epidermis
lesion forms scab
immunity last ~8 months
Contagious Ecthyma: Clinical signs
first lesions develop at lip corners followed by lip swelling
continues to muzzle and nostrils
anorexia and weightloss
lesions also seen on udder, feet, and scrotumm
Contagious Ecthyma: Vaccination
developed from suspension of scabs.
should not be used on farms that do not have a problem
1-2 years of immunity
Contagious Ecthyma: vaccinate lambs at ____ and pregnant ewes ____ before lambing
lambs: 6-8 weeks
Ewes: 7-8 weeks before lambing
Contagious Ecthyma: Human infections
from handling infected animals
large nodular lesions on fingers, hands, arms, face, and penis (wash your hands, boys)
lasts about 4-9 weeks
Capripoxvirus
Sheep pox
goat pox
Lump skin disease (cattle)
Sheeppox and goatpox: Transmission
Highly contagious, long infectious period
by respiratory tract
damaged skin by contaminated materials
mechanical by biting arthropods
Sheeppox: Pathogenesis
systemic disease
leukocyte-asso. viremia
immune complexes = severe necrotizing vaculitis (Type III hypersen.) = ischemic necrosis of dermis
Sheeppox: 2 forms of disease
Malignant form
Benign form
Sheeppox: Malignant form
depression, prostration, high fever, salivation, lactrimation, edema of eyelids, mucopurulent nasal discharge.
lesions develop, spread into visera.
scar into star shaped w/o hair or wool
Mortality -50%, up to 100% in lambs
Sheeppox: benign form
more common in adults
only skin lesions develop or mild systemic reaction
Sheeppox: Prevention
Reportable- prohibited importation from infected areas
vaccines provide temp. protection
Goatpox
Reportable, similar to sheeppox
kids suffer systemic disease on skin and viscera
Flat hemorrhagic form had high mortality case
Lumpy Skin Disease: transmission
most common by arthropods
also direct contact
Lumpy Skin Disease: Clinical signs
in all cattle ages and breeds
fever, multiple nodular lesions on skin and musoca. lymphadenopathy
Lumpy Skin Disease: Control
Vaccine
cull infected animals
Suipoxvirus
Swinepox
Swinepox
pigs (duh)
typically low mortality and morbidity
high mortality in young pigs
Swinepox: transmission
direct contact with skin injury, long infectious period
Mechanical via Haematopinus suis.
Transplacental infection
Swinepox: Clinical signs
transient fever, pox lesions
Exudative epidermitis (Greasy Pig Disease) as a 2nd disease
congenital pox lesions in vicera
Swinepox: Control
Pest control
no vaccine
Avipoxvirus
Fowlpox
Fowlpox: hosts
highly infectious disease of poultry and turkeys
Fowlpox: Transmission
long infectious period
direct contact to wounds
Mechanically
possibly aerosol route
Fowlpox: 3 forms
Cutaneous form (dry form) Diphtheritic form (wet form) Ocular form
Fowlpox: Cutaneous form characteristics
Most common form, low mortalility
small papules on comb, wattles, and around beak (sometimes on legs and cloaca)
Drop in egg prod. Recovery in about 4 weeks
Fowlpox: Diphtheritic form characteristics
by droplet infection
infection of muous membranes of mouth, pharynx, larynx, and trachea
necrotic pseudomembrane lesions, death by asphyxiation
Fowlpox: Ocular form
Conjunctivitis
cheesy exudate accumulates under eyelids
Avipoxvirus: inclusion bodies
Bollinger bodies- eosinophilic granular intracytoplasmatic
Borrel bodies- minute spherical bodies obtained by digestion of Bollinger bodies
Fowlpox: control
Vaccine
control mosquito population
Ulcerative Dermatosis of Sheep
unclassified poxvirus
Infectious disease of sheep
Ulcerative Dermatosis of Sheep: features
transmitted by wound infections or by coitis
Lip and Leg ulceration
Veneral form, ulceration of gentials
Diagnosis of Pox virus
clinical signs Sampling material Electron microscopy Histopathology inoculation of embryonated egg (pox lesions on CAM) serology and PCR
