oral viruses

Question 1

what is a vesicle

Answer 1

circumscribed epidermal elevations in the skin containing clear fluid and usually less than 5 mm in diameter

Question 2

what is a bulla

Answer 2

circumscribed epidermal elevations in the skin containing clear fluid with diameter greater than 5mm

Question 3

what is a erosion

Answer 3

partial loss of the epidermis that does not penetrate beneath the basal laminar zone

Question 4

what is an ulcer

Answer 4

a loss of epidermis and dermis (and sometimes deeper tissue)

Question 5

list viral vesicular diseases that cause oral lesions in farm animals
which are notifiable in the UK

Answer 5

• foot and mouth (notifiable)
• swine vesicular disease (notifiable)
• vesicular stomatitis (notifiable)
• vesicular exanthema

Question 6

which farm species are susceptible to foot and mouth

Answer 6

• cattle
• sheep
• goats
• pigs

NOT horses

Question 7

which species are susceptible to swine vesicular disease

Answer 7

• pigs only

Question 8

which species are susceptible to vesicular exanthema of swine virus

Answer 8

pigs only

Question 9

which animals are susceptible to vesicular stomatitis virus

Answer 9

• cattle
• pigs
• horses

Question 10

discuss picornaviridae

Answer 10

• 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

Question 11

what are the 6 genera of picornaviridae and what diseases are they associated with

Answer 11

Question 12

what is the distribution of foot and mouth disease

Answer 12

• 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

Question 13

discuss transmission of foot and mouth

Answer 13

• 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

Question 14

what is the host range of foot and mouth disease

Answer 14

• cattle, water buffalo, sheep, goats, llamas, camels, swine
• horses refractory to infection

Question 15

what are the serotypes of foot and mouth. if infected by one serotype will you be able to be infected again by another?

Answer 15

• O
• A
• C
• Asia1
• SAT1
• SAT2
• SAT3

you will not be immune to all serotypes if infected by one - no corss protection

Question 16

what are the clinical signs of foot and mouth disease in cattle

Answer 16

• 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)

Question 17

what are the clinical signs of foot and mouth in pigs

Answer 17

• 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

Question 18

discuss foot and mouth epidemiology

Answer 18

• 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

Question 19

how is foot and mouth disease diagnosed

Answer 19

• 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

Question 20

how is FMDV controlled

Answer 20

• countries free from FMDV: culling, rigid enforcement of quarantine and restriction of movement
• endemic countries: inactivated vaccines are used

Question 21

discuss swine vesicular disease

Answer 21

• 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

Question 22

discuss vesicular stomatitis virus

Answer 22

• rhabdoviridae
• single strand negative sense non segmented RNA genome
• rod shaped enveloped virions

Question 23

cesicular stomatitis virus epidemiology

Answer 23

• 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

Question 24

discuss vesicular stomatitis virus clinical disease

Answer 24

• 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

Question 25

discuss vesicular stomatitis virus diagnosis, treatment and control

Answer 25

• 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

Question 26

discuss caliciviridae viron structure and genome

Answer 26

• 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

Question 27

what is cat flu

Answer 27

upper resp tract disease caused by feline calici virus and/or feline herpes virus

Question 28

discuss feline herpes virion structure and composition

Answer 28

• herpesviridae
• double strand DNA virus
• large
• enveloped

Question 29

what are the clinical signs of acute cat flu disease

Answer 29

• sneezing
• nasal discharge
• dehydration
• anorexia
• pyrexia
• oral ulceration
• ocular signs

Question 30

feline calicivirus incubation period

Answer 30

2-3 days. cats recover in 7-10 days if disease isnt complicated by secondary bacterial infections

Question 31

what are the clincial signs of feline calicivirus

Answer 31

• conjunctivitis
• rhinitis
• tracheitis
• pneumonia
• vesiculation and ulceration of the oral epithelium
• fever
• lethargy
• anorexia
• stiff gait

Question 32

discuss felina viral rhinotracheitis

Answer 32

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

Question 33

discuss diagnosis and treament and prevention of feline viral rhinotracheitis

Answer 33

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