oral viruses Flashcards
what is a vesicle
circumscribed epidermal elevations in the skin containing clear fluid and usually less than 5 mm in diameter
what is a bulla
circumscribed epidermal elevations in the skin containing clear fluid with diameter greater than 5mm
what is a erosion
partial loss of the epidermis that does not penetrate beneath the basal laminar zone
what is an ulcer
a loss of epidermis and dermis (and sometimes deeper tissue)
list viral vesicular diseases that cause oral lesions in farm animals
which are notifiable in the UK
- foot and mouth (notifiable)
- swine vesicular disease (notifiable)
- vesicular stomatitis (notifiable)
- vesicular exanthema
which farm species are susceptible to foot and mouth
- cattle
- sheep
- goats
- pigs
NOT horses
which species are susceptible to swine vesicular disease
- pigs only
which species are susceptible to vesicular exanthema of swine virus
pigs only
which animals are susceptible to vesicular stomatitis virus
- cattle
- pigs
- horses
discuss picornaviridae
- virons are spherical
- non enveloped
- icosahedral symmetry
- genome is single molecule of positive sense RNA
- acts as mRNA, translated into a single polyprotein which is later cleaved to yield individual proteins
- replicate in the cytoplasm of host cells
what are the 6 genera of picornaviridae and what diseases are they associated with
what is the distribution of foot and mouth disease
- worldwide
- endemic in africa, south america, parts of europe and asia
- north and central america, UK and irelandm Japan, australia, new zealand, scandinavia and the caribbean are all free of FMD currently
discuss transmission of foot and mouth
- predominantly by respiratory infection
- ingestion of contaminated food or direct inoculation are also effective
spreads rapidly in a previously free country as highly contagious and lack of local immunity
what is the host range of foot and mouth disease
- cattle, water buffalo, sheep, goats, llamas, camels, swine
- horses refractory to infection
what are the serotypes of foot and mouth. if infected by one serotype will you be able to be infected again by another?
- O
- A
- C
- Asia1
- SAT1
- SAT2
- SAT3
you will not be immune to all serotypes if infected by one - no corss protection
what are the clinical signs of foot and mouth disease in cattle
- incubation = 2-8 days
- fever
- loss of appetite
- marked drop in production of milk
- in 24hrs, profuse salivation, drooling
- vesicles develope on tongue and gums
- vesivles may also be found on teats and coronary band of the feet leading to lameness
- smack lips leading to rupture of vesicles and subsequently uncerative lesions
- secondary bacterial infection
- preganant cows may abort (consequence of fever, does not cross placenta)
what are the clinical signs of foot and mouth in pigs
- lameness is the first sign
- fot lesions can be sever and very painful
- vesicles within mouth are less prominent than in cattle
- large vesicles that quickly rupture often develope on snout
discuss foot and mouth epidemiology
- extremely infectious virus
- rapid replication cycle - high yield virus
- large volumes of aerosols virus still stable
- short incubation period
- virus excreted up to 4 days pre-clinical signs + mild clinical picture in some hosts
- virus persists in pharynx in carriers
- transmitted by animals/contaminated items/people/environment/windborn
how is foot and mouth disease diagnosed
- laboratory diagnosis essential
- samples from vesicular fluid, epithelial tissue from edge of vesicle, blood in anticoagulant, serum and pharyngeal fluid
- detection of foot and mouth antigen in tissue and fluid samples by ELISA
- PCR for the detection of viral nucelic acid
how is FMDV controlled
- countries free from FMDV: culling, rigid enforcement of quarantine and restriction of movement
- endemic countries: inactivated vaccines are used
discuss swine vesicular disease
- similar to other vesicular viruses
- picornaviridae eternovirus
- non-enveloped
- RNA
- pigs natural hosts
- milder desease = febrile illness
- notifiable as to prevent confusion with foot and mouth
- UK free from currently
- lesions seen on coronary bands and less on snout, lips and tongue
- ELISA or virus isolation distinguish from other vesicular diseases
- in UK, culled
discuss vesicular stomatitis virus
- rhabdoviridae
- single strand negative sense non segmented RNA genome
- rod shaped enveloped virions
cesicular stomatitis virus epidemiology
- endemic in central and south america and souther USA
- affects horses and cattle but also pigs
- virus enters the body through breaks in the mucosa and skin (esp minro abrasions and bug bites)
- vesicles develop at site of infection
- virus isolated from mosquitoes, midges, black flies, house flies and mites
discuss vesicular stomatitis virus clinical disease
- incubation period of 1-5 days
- fever and excessive salivation first sign in horses and cattle
- lameness is the first sign in pigs
- vesicles, blisters on oral mucous membrane produces excess saliva
- vesicular lesions on teats, coronary bands, snout
- lesions usually heal within 7-10 days
