FMDV/oral cavity disease Flashcards
Clinical presentation of oral cavity diseases
- Protrusion of the tongue
○ May occur due to discomfort in the mouth or due to swelling of the tongue itself - Quids
○ Partly chewed lumps of food may be present called ‘quids’ - due to incomplete mastication and can sometimes be expelled into feed troughs or the floor - Oedema
○ Can occur in the submandibular space - Swelling
○ May be present in the head, lips or mandible - Penetrating wounds
○ Including erosion, ulceration, necrosis and vesiculation of the oral mucosa may be present - Ptyalism
○ Also known as excess salivation or drooling
○ May be present as a result of lesions, obstruction, or failure to effectively ingest, chew or swallow - Anorexia or inappetence
○ Common and can be relative or complete - Bloat
○ With the associated complications for anorexia and gut stasis may also be present
Oral cavity CE
- Suitable restraint (head yokes/bulldog clips)
- Equipment required
- Good light source
- Mouth gag/towel
- Halter/bulldog
- Sedation if necessary
Main viral differential diagnoses for oral cavity diseases
○ BVD
○ MCF (Ovine herpesvirus-2)
○ IBR (BHV-1.1, 1.2 respiratory)
○ Bovine papular stomatitis / orf (parapox virus)
○ Rabies
○ FMD
○ BTV
Main bacterial differential diagnoses for oral cavity diseases
○ Calf diphtheria
○ Actinobacillosis (Wooden tongue)
○ Actinomycosis (Lumpy jaw)
Main traumatic differential diagnoses for oral cavity diseases
○ Choke
○ Drenching gun/bolus
○ Caustic chemicals
○ Teeth
○ Vagal nerve damage
Stomatitis
= inflammation of the oral mucosa
Acute active stomatitis main CS
○ Ptyalism*
○ Dysphagia
○ Repetitive jaw movements
○ Excoriations and ulcers
○ Halitosis = secondary bacterial infection
Stomatitis ddx - non-infectious
= simple stomatitis causes
- oral trauma
- chemical irritants
Stomatitis ddx - infectious
§ IBR
§ Papillomas
§ BVDv
§ MCF
§ BPS
§ Vesicular diseases
IBR CS
□ Grey pinpoint pustules on soft palate
□ Pyrexic
□ Resp signs
Oral papillomas
□ Young animals
□ Pink-white raised with proliferative appearance on lips and mouth
□ Spontaneous resolution
BVDv CS
□ Small ulcers from mouth to rectum
□ Pyrexia and diarrhoea
MCF CS
□ Sporadic
□ Bilateral corneal opacity, nasal and oral discharge
□ Enlarged LN
□ Pyrexic
□ Dysentery
□ Catarrhal inflammation and erosions
BPS
= bovine papular stomatitis
□ Usually asymptomatic
□ Zoonotic
Vesicular dz
□ FMDv: pyrexic, lameness, vesicles on coronary band and mouth
□ VS: restricted to oral mucosa
□ BTV: swollen head, ears and lips
Importance of FMD
- Animal welfare
○ Painful and debilitating disease both short and long term
○ Movement restrictions can lead to overstocking - Social
○ Can be devastating for farmers - Economic impact
Disruption of internal and external market
FMD aetiology
- Disease is caused by infection with a picornavirus family (genus Aphthovirus) named foot-and-mouth disease virus (FMDV)
- The surface-exposed capsid proteins (VP1, VP2, VP3) of the virus determine its antigenicity and the ability of the virus to interact with host receptors and cause disease
- Distinct serotype: A, O, C, SAT1, SAT2, SAT3 and Asia 1
- No cross-immunity between serotypes
FMD transmission
shed in:
- breath
- secretions & excretions
- animal products
contaminates:
- air
- people, vehicles, equipment, feed, roads, etc
- milk, meat, rest of carcase
transmission routes:
- direct contact with aerosols via resp tract
- direct contact and indirect contact with secondary aerosols (resuspension) or via abrasions/ingestion
- indirect contact via ingestion or secondary aerosols
FMD pathogenesis
- Pre-viraemia - the period from when an animal is 1st infected with FMDV until virus is 1st detected within the intravascular (i.e. blood)
- Viraemia - the period during which FMDV can be detected within the intravascular compartment. This period typically coincides with the clinical phase of the disease
- Post-viraemia - the period following viraemia starting with the 1st negative assay on blood (determined by VI or detection of viral RNA) which includes
a. Resolution of clinical signs
b. Short-term persistence of infectious virus, antigen and/or RNA in specific tissues
c. Persistent infection (carrier state)
d. Chronic long-term sequelae including hirsutism, heat-intolerance (panting) and thyroid dysfunction, have been reported in recovered cattle
FMD clinical signs
- Incubation period - 2-12d
- Salivation, characteristic ‘smacking’ jaw movements
- Vesicles and ruptured lesions (muzzle, inside the mouth, feet)
- Abortion
- Anorexia
- Lameness
- Recumbency
- Low head carriage
- Dullness
FMD CS in cattle
- Often severe
- Depression, anorexia, possibly recumbency
- Profuse salivation
- Sudden death calves (myocarditis)
- Abortion
- Milk drop (usually before onset of other clinical signs)
FMD CS in small ruminants
- Often less severe than cattle
- Vesicles on the tongue, dental pad, along the coronary band and/or interdigital space, anorexia, possibly recumbency
- Vesicles can be difficult to see
- Sudden death in lambs/kids
- Animal may develop secondary infection
Abortion
FMD cattle ddx
○ Vesicular stomatitis
○ Bovine papular stomatitis
○ Bluetongue
○ Bovine viral diarrhoea
○ Mucosal disease
○ Infectious bovine rhinotracheitis
○ Actinobacillus ligneresi
○ Trauma, chemical burns, photosensitisation
○ Rinderpest (eradicated)
FMD small ruminant ddx
○ Bluetongue
○ Parapox virus (orf)
○ Peste de petitis ruminants (PPR)
○ Oral trauma
○ Trauma, chemical burn, photosensitisation
○ Laminitis, foot-rot, abscesses
FMD diagnosis
Penside:
- vesicular fluid, epithelium suspensions
- Very rapid
- Highly specific
- Side-cow test
- Not recognised confirmatory test
- Sensitivity varies between serotypes
Virus isolation (VI) cell culture:
- vesicular fluid, epithelium
- highly specific
- can take up to 4d
Antigen ELISA:
- vesicular fluid, epithelium
- Can determine serotype
- Less sensitive than VI or RT-PCR, so not applicable to blood or swab samples
Serology - antibody detection:
- clotted blood
- Confirms FMD in the late stage of the disease once the virus has cleared
- Not useful in acute stages of diseases
- Ab from previous infection/vaccination can make interpretation difficult
RT-PCR:
- More sensitive than ELISA or VI
- Doesn’t need live virus
- Usual methods don’t determine serotype
FMD diagnostic priority:
- Vesicular fluid sample is best if you can get it; otherwise, epithelium from a recently ruptured vesicle is best
- Even a swab sample from a recently ruptured vesicle can yield virus
- Blood samples should always be taken
FMD - in the case of an outbreak
Suspicion of FMD or any signs of a notifiable vesicular disease in a susceptible animal must be notified immediately to the local AHVLA Office. The duty Veterinary Officer (VO) will then discuss the clinical signs and health status of the suspect animal over the phone with the person reporting the suspicion. Based on these discussions, the duty VO will either rule out FMD or request a VO attend the premises to undertake a full disease investigation.
Main points:
* Contact tracing
* Establishment of protection and surveillance zones
○ National authorities must establish a protection zone with a of at least 3km and a surveillance zone with a minimum radius of 10km around the site of infection
○ Restrictions on the movement of susceptible animals in and out of the areas
○ Conditions for the dispatch of products from the susceptible animals from these zones
* Culling of infected animals
* Emergency vaccination
* National livestock movement ban
* Restriction of movement of animal products
* Cleansing and disinfection of premises
* Surveillance
What is the impact of FMD on trade?
- The OIE has a disease-free status list related to certain diseases, including FMD. That serves as a guideline for countries when deciding on their import policy
- Outbreak = the whole country loses its FMD-free status
- Until the free status is recovered, other countries can ban live animals and animal products from the affected country
- Several scenarios to recover the free status, depending on whether or not vaccination is used to control the outbreak
- The shortest period in which disease-free status can be recovered is 3m after cull of the last infected animal
Bluetongue (BTV) - aetiology
- Orbivirus genus of the Reoviridae family
- 24 serotypes worldwide
- BTV3 and BTV8 are the most important ones in the UK and Europe
- Generally, VP2 and VP7 are the target proteins for diagnostic tests and vaccine production
BTV CS in cattle
- Fever up to 40C
- Nasal discharge
- Swelling of the head and neck
- Conjunctivitis (runny eyes)
- Swelling in and ulceration of the mouth
- Swollen teats
- Saliva drooling out of the mouth
- Abortion
BTV epidemiology
- All orbiviruses are arthropod-bourne, distributed by Culicoides spp.
- Cattle are the reservoir and amplification hosts
- Endemic in tropical regions of the world where vectors are active year-round
- Incursive disease can occur in regions that don’t normally experience infection and may be caused by windborne movement of infected Culicoides with subsequent insect breeding in the summer before ‘die-out’ in autumn and winter
- Epidemics occur in temperate climates dependent on seasonal temperature, moisture and wind
- During the European BTV8 outbreak between 2006-2008, morbidity rates ranging from 0-32% were reported. Mortality ranged between 0-17% in sheep and 0-4% in cattle
BTV CS in sheep
- High rectal temp
- Eye and nasal discharges
- Drooling as a result of ulcerations in the mouth
- Swelling of the mouth, head and neck
○ Farmers reported that the 1st clinical sign was ‘hanging head over the water trough’ as the animals were trying to soothe their mouths with cool water - Lameness with inflammation at the junction of the skin and the coronary band
- Difficulty breathing
- Abortion
BTV - diagnosis
- Clinical exam
- Virus identification (cell culture & RT-PCR)
- Serologic testing (competitive ELISA & AGID)
- PM
– erosive, haemorrhagic gingivitis
– gums contain erosions and multifocal haemorrhage
– cyanosis and multifocal haemorrhagic ulcerative glossitis
-l blue colour of lingual mucosa
– brain parenchyma markedly compressed and replaced due to excessive fluid in ventricles
– folded meningeal membranes
BVD - tx
- NSAIDs
- Supportive care for recumbent animals (rehydration with isotonic fluids, antibiotic treatment ONLY if it’s necessary for 2ndary infection)
BVD - prevention
- Limiting vector exposure during peak beating times (from dusk to dawn)
- Methods of controlling vector biting, i.e. application of synthetic pyrethroid, have shown limited efficacy
- Modified and inactivated vaccine in some parts of the world; vaccines don’t offer cross-protection, i.e. vaccinating animals against BTV8 won’t protect them from infection with BTV3
Other vial causes of hypersalivation and stomatitis
- Rabies
○ Clinical signs include excessive salivation, behavioural change, muzzle tremors, vocalisation, aggression, hyperaesthesia and/or hyperexcitability and pharyngeal paresis/paralysis
○ The British Isles have been rabies free since rabies was eradicated in 1922 - BVD (mucosal disease)
○ Presentation of acute GI ulceration, including of the oral cavity and death
MCF
= Malignant Catarrhal Fever
* Sporadic disease affecting single cattle but occasionally severe outbreaks can occur in a group of cattle
* It’s caused by a virus transmitted from pregnant or recently lambed sheep or goats to cattle
MCF CS
○ Affected cattle are profoundly depressed with a high fever (40.5-42C
○ Complete loss of appetite
○ The eyes are severely affected with corneal opacity causing blindness
○ Affected cattle avoid bright light and sudden exposure to sunlight causes the eyelids to close
○ Copious mucopurulent nasal discharges
○ Crusting on the surface of the muzzle
○ Marked enlargement of all lymph nodes
○ May be an exudative dermatitis which affects the inner thigh and udder/teats
MCF diagnosis
○ Based upon clinical signs and confirmed by demonstration of MCF virus/antibodies and/or characteristic PM findings
○ Identification of the agent
§ Virus isolation from peripheral blood leukocytes or lymphoid cells
§ PCR
○ Serological tests
§ Immunofluorescence
§ ELISA
§ Immunoblotting
MCF tx
○ No treatment and affected cattle must be euthanised immediately for welfare reasons
BPV
= bovine papillomavirus
* Pathogen bovine papilloma virus resulting in wart like proliferations around the muzzle, neck and trunk
* Self-limiting
○ Autogenous vaccination possible but rarely used unless it impacts the ability of the cow to eat or be milked
* It’s a zoonotic disease (minor)
BPV issues
○ Interfere with suckling and milking
○ Secondary bacterial infections
BPV transmission
○ Abrasions, direct contact +/- flies
BPV CS
- initial lesions are erythematous macule and papule that may become papillomatous, or may undergo central necrosis and become crusted
Orf
- Pox virus
- Can remain infective in the environment for many months in dried scabs
- Contagious pustular dermatitis virus (also referred to as CPD, Orf, Scabby Mouth, Contagious Ecthyma) most commonly results in proliferative lesions following trauma of the coronary band and lips/gums
- The proportion of the flock affected can be high, but mortality in uncomplicated cases is low
- Public health implications - zoonotic
Orf CS
- non-pruritic ulceration around the lips and teats of lambs and ewes
- These commonly have secondary bacterial infections present
- This can result in lambs being unable to suck (hence decreased growth rates, cross suckling or very noisy lambs), which in turn is a risk factor for mastitis in the dam
Orf tx
○ Largely unsuccessful except for lambs with superficial secondary bacterial infection of scabs, which show a good response to either IM procaine penicillin or oxytet injections and topical oxytet spray for 3-5 consecutive days
Orf control
○ Vaccination but only in endemically affected flocks
○ The vaccine is a live attenuated vaccine (so care with admin)
○ The vaccination doesn’t provide colostral antibody protection for lambs
Actinobacillus
- Wooden Tongue
- Signalment
○ Mainly adult cattle - Infection method:
○ Commensal of the URT and GIT
○ Breaks in buccosal mucosa
Actinobacillus presentation
○ Painful, sometimes fever
○ Stomatitis, glossitis, cellulitis evolving in pyogranulomatous infection
○ Swollen tongue, often protrudes, hard to touch
○ Submandibular swelling, enlarged LN
○ Salivation and reluctant to eat/drink
○ Rapid BCS loss
○ Can also affect skin, oesophageal groove, rumen wall, etc
○ Subclinical cases: 3% lesions in slaughterhouse survey
Actinobacillus diagnosis
○ Painful pyogranulomatous lesions exuding yellow-white pus
○ Deep incisional biopsies (‘sulphur granules’)
Actinobacillus tx
○ Early initiation often leads to successful outcome
○ Antibiotics: Gram-negative, facultative anaerobes
§ Procaine penicillin and dihydrostreptomycin
§ Streptomycin and dihydrostreptomycin and NSAID
§ TMPs
§ Daily IM >10d
Actinobacillus prevention
○ Isolate cases and review feeding
Actinobacillus complications
○ Laryngeal and pharyngeal paralysis
○ Vagal indigestions: enlarged rumen
○ Secondary to hardware disease, actinobacillosis (rumen/reticulum)
Actinomycosis
- Lumpy jaw
- Signalment
○ Usually younger animals due to erupting teeth
Actinomycosis presentation
○ Hard, immobile lesion (differentiate from local abscess)
○ Often unilateral
○ Chronic infectious disease (slow process)
○ Swelling
○ Abscesses
○ Fistulous tracts
○ Fibrosis
○ Painful
Actinomycosis infection method
○ Opportunistic commensal of the oral cavity
○ Mucosal damage allows access to bony structures via lymphatics
Actinomycosis prevalence
- Low incidence in UK
Actinomycosis pathology
○ Pyogranulomatous inflammation = suppurative tracts that permeate the medullary spaces leading to osteomyelitis and multiple foci of bone reabsorption and proliferation
Actinomycosis diagnosis
○ Clinical signs
○ Microscopic exam of thick pus and yellow granules
Actinomycosis tx
○ Early treatment often successful
○ Antibiotics: Gram-positive anaerobe, procaine benzylpenicillin, daily IM >10d
○ NSAIDs?
○ Bone deformation remains
Calf diphtheria pathogen
○ Fusobacterium necrophorum
○ A GI and URT commensal
○ Causes an infection due to mucosal injury, usually related to either erupting teeth, abrasive feed, bolusing
○ Can also be co-infection with Pasteruella multocida and Truperella pyogenes
Calf Diphtheria signalment
○ Young pre-weaned calves
○ Usually dairy
○ Can occur up to 3y
Calf Diphtheria CS
○ Halitosis
○ Cough
○ +/- pyrexia
○ Difficult swallowing
○ BRD
Calf Diphtheria 2 forms
○ Necrotic stomatitis (oral form) - describes the necrotic ulceration of the cheek and/or tongue
○ Necrotic laryngitis (laryngeal form) - describes the ulceration of the larynx
Calf diphtheria - difference between the 2 forms
Necrotic stomatitis
- pyrexia: not usually
- halitosis: +/- present
- coughing: not usually
- laryngeal palpation: NAD
- internal oral exam: deep ulcer in cheek mucosa
- tx: 3-5d course of AB (penicillin, tetracycline, TMPS), NSAIDs
- prognosis: good
Necrotic laryngitis
- pyrexia: yes
- halitosis: yes, fetid odour
- coughing: yes +/- dyspnoea, tend to make a roaring sound
- laryngeal palpation: painful +/- palpable external swelling
- internal oral exam: oedema, erosions and inflammation of the larynx, can also affect the tongue
- tx: 2-3w course of AB (penicillin, tetracycline, TMPS), NSAIDs, +/- tracheostomy if really bad
- prognosis: guarded to poor
Non-infectious causes of stomatitis
○ Traumatic injuries such as drenching gun and bolus applicator
○ FB e.g. sticks, root veg
○ Caustic substances on farm
§ Chemical dips
§ Caustic soda
§ Formalin
Tx of non-infectious causes of stomatitis
○ Remove any decaying food material
○ Broad spec antibiotic e.g. amoxicillin (5d)
○ NSAIDs (3d)
Hypersalivation due to obstruction
- Common in cattle - usually seen if root crops are fed (potatoes, turnips, apples, fodder beet etc)
- Emergency
Hypersalivation due to obstruction CS
○ Profuse salivation and bloat*
○ Distress, extended neck, coughing
○ Obstruction at certain sites
§ Oropharynx, thoracic inlet, heart base
§ May palpate if cervical / passage of a stomach tube
Hypersalivation due to obstruction diagnosis
○ Based on history and clinical appearance
Dental diseases
- Uncommon in ruminants
- Impaction: prevention of eruption
- Malocclusion
○ Tooth root abscess
○ Periodontal disease - Fractures of the mandible
○ Rare
○ Can attempt to wire them - Always examine the oral cavity in clinical exam
