Poxviruses Flashcards
poxvirus what type
ds DNA
pox virus structure
- log ds dna
- surrounded by core membrane and 2 lateral bodies (lateral bodies include viral enzymes dna dep rna pol, dna dep dna pol = allow cytoplasmic replication)
- 1 or 2 enveloped lipid membranes
- oval, brick shaped, or phlemorphic
poxvirus host range
- vertebrate and invertebrate animals
- v species specific, some = zoonotic
poxvirus replication important features
- pox viruses replicate in cytoplasm only dna viruses that do this
- pox viruses have 2 diff infectious virulent forms that can be released form infectious cell depending on cell lysis or budding
pox virus infection routes
- through skin by mechanical means (wound contamination, biting insects)
- via resp tract
- via oral route
pox virus infection types
acute infection (no latent, persistent, or chronic infections)
typical routes of infection of poxviruses
- local (skin entry -> skin lesions )
- systemic( resp entry or oral entry) (often fatal)
pox virus genome
- large genome
- variety of immune evasion strategies
- very old
uses for poxvirus genome
- can use as vectors for gene therapy or recombinant vaccines
small pox current status
eradicated but concern for bioterrorism
why could small pox get erradicated
- no reservoir other than man
- vv (variola virus aka causative agent) -> only acute infections no carrier state
- world health organization made coordinated vac program, vac was v affordable bc no patient
- easy surveillance bc dx -> specific rash localization vs chicken pox
poxvirus subfamily differences
- chordopoxivrinae (infects vertebrates)
- entomopoxvrinae (infects invertebrates)
poxviruses we are concerned with
- fowlpox
- myxoma virus
- cow pox (Z)
- ectoromelia
- orf virus (Z)
- pseudo cowpox (Z)
- swine pox virus
(Z) = zoontoic
cow pox effects who
- cows (rarely)
- cats (primarily)
- humans
cowpox genus
orthopoxvirus
orthopoxvirus genus includes
- cowpox
- vaccinia virus
- variola virus (small pox)
cowpox cows
- used to be common rare now
- -> mild lesions on udder and teats dairy cows
cowpox cats get where from who
- common in Eurasia
- get from rodents (virus reserviors)
cowpox cats see what
- single lesion progresses to general skin rash
- crusty lesions
- recover 6-8 weeks unless concurrent infection and or immunosuppression -> dying via pneumonia
- cheetahs usually die of pneumonia
cowpox in ppl where, from who, see what
- usually eurasia
- usually from cats
- localized skin lesions
- lymphadenopathy
- most severe in children -> hospitalization
swinepox genus
suispoxvirus
swinepox transmission
- direct contact
- pig louse
swinepox found where
world wide but low incidence
swinepox effects who
- usually young piglets
swinepox see what
- papules and pustules face, ears, inside legs and abdomen these dry out -> dark scabs giving spotted appearance
fowlpox dx of who
- poultry
- common in backyard chickens
fowlpox caused by what
- variety poxviruses
- all angitenically similar but distinct species
- genus = avipox
dx forms of fowlpox
- cutaneous form
- diphtheric form
cutaneous form of fowlpox general
- proliferative skin lesions, thick scabs
diphtheric form of fowlpox general
diphtheric membranes in upper resp and gi tract
pathogenesis and clinical signs fowl pox infection via biting insects/ wound contamination
- infection via biting insects/ wound contamination -> skin lesions on beak, comb, and wattles -> recover in a few weeks
pathogenesis and clinical signs fowl pox infection via inhalation
infection via inhalation -> diphtheric membranes in pharynx and trachea -> severe resp signs + anorexia -> poor prognosis / fatal
fowlpox diagnosis
- clin signs
- Bollinger bodies in cytoplasm (type of cytoplasmic inclusion bodies)
how to tell infectious laryngotrachietis (GHV-1) apart from fowlpox
- fowlpox = intracytoplasmic inclusions
- herpes= intranuc inclusions
fowlpox control
- manage mosquito population (mosquitos = vectors)
- vac chickens
- recombinant fowlpox vac (combined with GHV1)
- Long lasting immunity post recovery
pseudocow pox effects who -> what
cows -> bovine papular stomatitis
pseudocowpox genus
parapoxvirus
bovine papular stomatitis clinical prsenataiotn
- most infections - unoticed
- important differential diagnosis w/ foot and mouth dx
- this -> NO FOOT LESIONS
- cattle < 2 yrs sm lesions around lips, muzzle, and buccal mucosa, heal in few weeks
- adult cows- teat lesions
- ZOONOTIC (farmyard pox) -> hand lesions
bovine papular stomatitis duration of immunity
- frequent reinfections: short duration of immunity
Orf genus
- parapoxvirus
alt names for orf virus
- ecthyma contagiousum
- ovine range fever
- thistle dx
- scabby dx
orf virus affects who
- lips of young animals
- severe in goats and sheep
- ZOONOTIC
orf virus in enviornment
- highly resistant in environment
orf virus differential diagnosis
- sheep pox and goat pox
- ulcerative dermatosis (related paradox in older animals where orf virus effects younger animals)
Orf virus pathogenesis
- spread via direct contact and fomites
- some environments infection = imitated by scratches from thistles
orf virus clinical signs
- ecthyma contagiosa sheep and goats
- papules and pustules on lips muzzle (lambs or goats) -> encrusting and formation of scabs -> underlying dermis proliferation and tissues w/o scarring
orf virus diagnosis
- clinical signs
- em/ pcr scab material
orf virus control
- live vac (make sure scabs are off before bringing into contact with unvaccinated animals)
- sam amount live vac brushed over light scarifications of skin (skin fairly resistant to infection by viruses so want to make some type wound to get this virus into to establish immune response)
myxoma virus affects who
- rabbits of various breeds
myxoma virus genus
leporipox
myxoma virus spread
- direct contact or biting insects
myxoma virus -> what dx
- natural wild hosts (argenitina, Mexican, Californian rabbit0 -> mild cutaneous fibroma
- aberrant host (European rabbit) -> life threatening systemic viral dx (myxomatosis)
myxoma virus use in countries
- attempt to control rabbit population
myxoma virus vac
- use in endemic areas for pet rabbits (pet rabbits v susceptible)
myxoma virus carrier
- hares rarely show clinical signs can carry the fleas
myxoma virus pathogenesis
primary infection in skin -> replicate in dermis -> infection Langerhands cells that migrate to draining lns (primary viremia) -> infection T cells -> spread via bld and lymph to liver, spleen, other lns, and skin (secondary viremia) -> replication in dermis (secondary skin lesions, high virus titers which means if insects bites their can fx as mechanical vectors and infect other susceptible rabbits)
clinical signs myxoma virus California rabbit
- localized fibromas
clinical signs myxoma virus European rabbit
- lumps/ lrg skin lesions
- edema head and genitals
- conjunctivitis -> blindness
- secondary bacterial infeitons
- death
diagnosis myxoma virus
- clinical signs
- myxoma cells (stelae ct cells lrg nucleus and abundant cytoplasm)
- epithelial cells w/ intracytoplasmic incursion bodies
myxoma virus tx
none
myxoma virus control
- vac in uk (live myxoma-vectored rho vac) hard to get vac in us; flea and mosquito control
ectromelia genus
orthopoxvirus
ectromelia affects who -> what
- mice in mouse colonies kept for research can be endemic in mouse colonies depending on strain
- -> mouse pox = natural mouse pathogen
ectromelia virus infection how
- skin abrasions
- direct contact
- infected material (oral infection)
- other mice (oral infection)
ectromelia virus clinical presentation
- depends on mouse strain
- range from local skin lesions (feet, snout, belly)-> highly fatal
ectromelia pathogeneiss
- primary skin lesions
- primary viremia -> liver and spleen -> replication w/ necrosis and high viral titers
- secondary viremia -> spread via bld stream back to skin -> viral replication at skin -> rash
ectromelia clinical signs susceptible strains
- disseminated infection, rapid death before virus shedding
ectromelia clinical signs intermediate susceptible strains
- develop skin lesions and disseminated infections. can survive long enough to shed virus
ectromelia clinical signs resistant strains
- can spread infection to other mice w/o showing clinical signs
ectromelia diagnosis
- histo: necrosis many tissues + cytoplasmic inclusion bodies
ectromelia prevention and control
- quarantine, import restrictons
- contaminated material and mice
- serologic testing valuable colonies
- vac possible will interfere with ELISA (serologic testing)
