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
discuss vesicular stomatitis virus diagnosis, treatment and control
- detection of viral antigen by immunofluorescent antibody staining of vesicle tissue or ELISA on vesicular fluid
- serology
- RT-PCR
- isolation of virus in cell culture
- no specific treatment, idea is to minimize secondary infection
discuss caliciviridae viron structure and genome
- non enveloped icosahedral symmetry
- composed of 180 identical protein molecules
- single molecule of linear +ve sense single strand RNA
- 5’ end capped by a covalently bound protein and 3’ end is poly adenylated
- cytopalsmic replication
what is cat flu
upper resp tract disease caused by feline calici virus and/or feline herpes virus
discuss feline herpes virion structure and composition
- herpesviridae
- double strand DNA virus
- large
- enveloped
what are the clinical signs of acute cat flu disease
- sneezing
- nasal discharge
- dehydration
- anorexia
- pyrexia
- oral ulceration
- ocular signs
feline calicivirus incubation period
2-3 days. cats recover in 7-10 days if disease isnt complicated by secondary bacterial infections
what are the clincial signs of feline calicivirus
- conjunctivitis
- rhinitis
- tracheitis
- pneumonia
- vesiculation and ulceration of the oral epithelium
- fever
- lethargy
- anorexia
- stiff gait
discuss felina viral rhinotracheitis
family: herpesviridae
- envelopled icosahedral
- double stranded DNA virus
- 24-48 hour incubation period
- sudden onset of sneezing coughing and profuse nasal and ocular discharges, corneal ulcers
- acute disease is simialr to calicivirus
- profuse frothy salivation and corneal ulcers more common in FHV while ulcers of the tongue and palate or more common in FCV
discuss diagnosis and treament and prevention of feline viral rhinotracheitis
diagnosis: specific diagnosis often not be necessary but isolation or PCR
treatment: supportive and symptomatic
fluids to correct dehydration, broad spec antibiotics to prevent secondary bacterial infections and nursing care
treatment: inactivated and attenuated vaccines and quaratine for hospital cases
