Oral microbiology

what are vesicles?

• circumscribed epidermal elevations in skin containing clear fluid <1cm

what is a bulla

• a circumscribed epidermal elevation in the skin containing clear fluid >1cm

what is acantholysis?

• death and loss of stratum spinosum cells

what are 3 notifiable vesicular viral diseases that are notifiable?

1. foot and mouth disease

2. swine vesicular disease

3. vesicular stomatitis

what are 4 viral vesicular diseases?

1. foot and mouth disease

2. swine vescicular disease

3. vesicular stomatitis

4. vesicular exanthema

What animals are susceptible to FMD?

• cattle

• sheep/goats

• pigs

what species is resistant to FMD?

• horses

what species is susceptible to swine vesicular disease virus?

• pigs

what species are resistant to swine vesicular disease virus

• sheep, goats

• cattle

• horses

what species are susceptible to vesicular stomatitis virus?

• cattle

• pigs

• horses

what species is resistant to vesicular stomatitis virus?

• sheep, goats

what species is susceptible to vesicular exanthema of swine virus?

• pigs

what species are resistant to vesicular exanthema of swine virus?

• cattle

• sheep, goats

• horses

what is the order of FMD and swine vesicular disease virus?

• picornaviridae

what is the structure of picornaviridae?

• icosahedral symmetry

• single genome molecules of +ve sense RNA

• replicate in host cytoplasm

how is FMDV transmitted?

• by respiratory infection

• ingestion of contaminated food/direct inoculation is also a route

why is FMD a notifiable disease in UK?

• it can spread very rapidly in a previously free from country

what is the host range of FMDV?

• cattle, buffalo, sheep, goats, llamas, camels and swine

• also wild mammals

how many serotypes of FMDV are there?

• 7

is there cross protection between serotypes of FMDV?

• no

what are clinical signs of FMDV in cattle?

• initial fever + appetite loss, note reduced milk

• then profuse salivation and vesicles on the tongue and gums

• may be lame - due to vesicles on feet

• may see ulcerative lesions due to ruptures vesicles

• may have secondary bacterial infection - mucopurulent nasal discharge

• may have abortion - due to fever!

what are FMDV clinical signs in pigs?

• lameness is first sign

• foot lesions can be severe and painful

• less prominent lesions in mouth, but may see on snout → rupture

how does FMDV present in sheep, goats and wild animals?

• mild clinical signs → foot lesions and lameness

• can be reservoirs of the disease

what is so dangerous about FMDV epidemiology?

• virus shedding for up to 4 days before signs develop

• carriers exist (not pigs)

How do we diagnose FMDV?

• lab diagnosis is essential

sample:

• vesicular fluid, epithelial tissue from edge, blood in anticoagulant, serum and pharyngeal fluid

then:

• detect FMDV antigen in tissue and fluid samples in ELISA

• PCR for viral nucleic acid

how do we control FMD?

• exposed and affected animals are culled

• inactivated vaccines are used

what kind of animals are affected by FMD?

• even toed ungulates

what is the main symptom of swine vesicular disease virus?

• lameness

what happens if there’s a positive test for swine vesicular disease virus?

• diseased, susceptible and in-contact animals are culled

structure of vesicular stomatitis virus?

• Rhabdoviridae

  • single strand, negative sense RNA genome

    • rod shaped, enveloped virion

pathogenesis of VSV?

• virus enters body and breaks through mucosa and skin → minor abrasions and arthropod bites

• vesicles develop at side of infection

what are clinical symptoms of VSV?

• fever and excessive salivation in cattle and horses

• lameness in pigs

• vesicles, blisters on oral mucous membrane → excess salivation

• lesions on teats, coronary bands, snout

when do lesions of VSV usually heal?

• within 7-10 days

how do we detect VSV

• immunofluorescent antibody staining of vesicle tissue or ELISA on vesicular fluid

how can we use serology for VSV?

• demonstrating rise in antibody titre by ELISA

how do we treat VSV?

• no specific treatment, try to minimise secondary infection

How do we respond to VSV?

• movement restrictions

• quarantine for 30 days after last case

what is calicivirus virion structure?

• non-enveloped, icosahedral

• linear, +ve sense, ss RNA

is VES a current threat?

• no it’s an extinct disease but virus is present in marine mammals and some fish

what are the 2 kinds of cat flu?

1. FCV - feline calicivirus

2. FHV - feline herpes virus

what is the structure of FHV?

• dsDNA

• large

• enveloped

what are acute clinical signs of FCV/FHV?

• sneezing

• nasal discharge

• dehydration - be wary of this!

• anorexia

• pyrexia

what are more specific signs of FCV and FHV?

• oral ulceration - FCV

• ocular signs e.g. chemosis, keratoconjunctivitis, corneal ulceration - FHV

what kinds of disease does FCV cause?

• acute

• sub-acute disease

incubation period of FCV and recovery is how long?

• 2-3 days

• 7-10 days if not complicated by secondary infection

what are FCV signs

• conjunctivitis, rhinitis, tracheitis, pneumonia and vesiculation and ulceration of oral epithelium

what is feline viral rhinotracheitis?

• large enveloped virus with icosahedral nucleocapsid and dsDNA genome

feline viral rhinotracheitis:

1. incubation period

2. symptoms

3. what is the acute disease similar to?

4. what symtpom is more commin in FHV than in FCV

1. 24-48hrs

2. sneezig, coughing, profuse nasal and occular discharge as well as corneal ulcers = suddenly onset

3. feline calicivirus

4. profuse frothy salivation and corneal ulcers

what symptoms are more common in FCV than in FHV

• ulcers of tongue and palate

how do we diagnose cat flu (rhinotracheitis)

• virus isolation or PCR

how do we treat cat flu (rhinotracheitis)

• supportive fluid and symptom

• fluid therapy

• borad spec antibiotics to prevent secodnary infection

how do we prevent cat flu

• inactivated and attenuated vaccines

what is pemphigus vulgaris?

• an autoimmune disease of the oral, skin and mucosal surfaces

what does pemphigus vulgaris cause?

• separation of the epidermal cells from the underlying tissue as the antibodies are directed against intracellular layers above basal cell layer

what are some toxicity related diseases that may give crusting and skin lesions with ulcers?

1. primary photosensitisation due to plant ingestion

2. secondary to liver disease

3. phenylbutazone toxicity in horses - oral ulcers