Clinical and euthanasia Flashcards
List the main settings of keeping animals that may present a potential risk for public health
- Home
- Pet shops
- Companion animals in pet zoos/open farm
- Occupational risks
- Leisure pursuits
- Farm animal species kept as pets
List significant risks to public/human health from companion animals
- Zoonoses
- Bite injuries
- Transmission of specified diseases
List factors that may increase the risk of zoonoses from companion animals
- Population density of humans and pets is increasing
- Exotic and “novelty” pet species increasing
- Close contact between pet and human esp. children
- Companion and wild animals as reservoirs of disease
- Pet travel and migration of wild animals increasing spread of diseases
Outline the public health significance of dog bites
- Increasing incidence
- Women bitten more than men
- Children 20% of cases (face and hands mostly)
- Adults mainly hands and legs, 10% head/neck
- Loss of tissue function, disfigurement
- Occupation risk
Outline ways in which dog bites can be prevented
- Education
- Appropriate restraint in vet practice
- Legal enforcement of dogs act 1871
What is the purpose of the Dangerous Dogs act 1991?
Protection of people after growing concerns over “status dogs”
Outline the content of the Dangerous Dogs act 1991
- Prohibits certain breeds of dogs
- Prohibits any dog to be “dangerously out of control” in a public place, or place where it is not allowed
- Dogs can be seized
- Owner must be able to prove that dog is not of prohibited type
Outline the contents of the Dangerous Dogs Act Amendment 2014
- Extended definition of out of control to cover all public and private spaces (excl. burglars)
- Extends to attacks on assistance dogs as well as people
- Court to take into account the character of owner/keeper and temperament of dog, plus past behaiour
- Death: 14yr sentence, injury: 5 yr sentence, assistance dog attacked: 3yr sentence
Outline the occurrence of infection following bite injuries
- Severe infections in 20% of reported cases
- Septicaemia can develop quickly
- Infection with commensal flora from human skin and/or animal oral cavity
What pathogen is common in cat and dog bites?
Pasteurella multocida
What pathogen is common in fish bites?
Halomonas vensuta
What pathogen is common in reptile bites?
Serratia mercescens
What pathogen is common in rat bites?
Streptobacillus moniliformis (rat bite fever)
Describe the pathogen that causes cat scratch disease
- Bartonella henselae
- Gram -ve
- Intracellular bacterium
Describe infection with Bartonella henselae
- Transmitted by cat scratch, or flea faeces or saliva of infected cat
- Transmitted between cats via Ctenophalides felis
- Usually self-limiting disease in humans, can become chronic./recurrent, frequently unresponsive to antibiotics
Outline the prevention of cat scratch disease
- Eliminate fleas
- Educate owner about risk
Describe the clinical signs of cat scratch disease
- Lymphadenopathy
- Haemotropic, adheres to RBCs and causes bacillary angiomatosis of lymph nodes (benign tumour-like microvascular proliferation)
Describe the pathogen that causes psittacosis
- Chlamydophila psittaci
- Gram -ve intracellular bacterium
- Aka ornithosis, Avian chlamydiosis
Which species are affected by psittacosis?
- Psittacines and columbiformes mainly
- Also ducks, turkeys, chickens and >450 other bird species
Describe psittacosis in psittacines
- Often chronically infected
- Asymptomatic until stressed
- Shed intermittently throughout life
- Source of infection for humans and other birds
Describe the clinical signs of psittacosis in birds
- Nasal/ocular discharge
- Yellow-green diarrhoea
- Respiratory distress
- Acute infection in young ducks characterised by ataxia, diarrhoea, purulent ocular and nasal discharge
- Chronic cases show emaciation and chronic respiratory involvement
Outline the public health significance of psittacosis
- Zoonotic to humans
- Inhalation of contaminated faeces and dust, mouth-to-beak contact, bird bites
- Occupational hazard in poorly-ventilated abattoirs in particular
Outline the clinical manifestation of psittacosis in humans
- Flu-like illness, pneumonia
- Fatalities and person-person transmission rare
What groups are at particular risk of psittacosis?
- Vets
- Poultry processing workers
- Bird keepers
- Young, elderly, immunocompromised, pregnant women
Outline the prevention of psittacosis
- Eradication in birds not possible
- No vaccine
- Can be reduced with antibiotics but is resistant and intracellular (difficult)
- PPE when processing ducks and turkeys
- Regular clear out of faeces from pet birds, good ventilation
- Rehome or cull vulnerable birds
- Where suspected, quarantine and treat all birds in consignment with oxytet
Is psittacosis reportable?
Yes, report to the CCDC in Cambridgeshire
Describe the agent that causes rabbit fever (tularaemia)
- Francisella tularensis
- Gram -ve bacterium
- Type A in USA, Type B everywhere else
What are the reservoirs of tularaemia?
- Rodents
- Other small mammals
- Rabbits in particular
What are the possible routes of transmission of tularaemia?
- Aerosol
- Ectoparasites
- Bites, scratches, wounds, open sores
- Consumption of contaminated food/water
Describe the typical symptoms of tularaemia in humans
- Fever
- Diarrhoea
- Vomiting
- Ulcers
- Haemorrhage
- Pneumonia
Compare the susceptibility of dogs and cats to tularaemia
- Cats more susceptible
- Dogs relatively resistant
Outline the prevention and treatment of tularaemia
- Vaccines available for humans but not animals
- Antibiotics including aminoglycosides, fluoroquinolones
- Ectoparasite control in endemic areas important
- Prevent consumption of contaminated water
- Educate “at risk” groups
What are some at risk groups for tularaemia?
- Outdoor workers
- Vets
- Walkers
Describe the pathogen that causes ringworm
- Dermatophytosis
- Microsporum in cats
- Trichophyton in horses
- Fungal
What are the common reservoirs of ringworm?
- Dog
- Cat
- Horses
- Rabbits
- Rodents
- Cattle
Outline the control and treatment of ringworm
- Generally self limiting
- Common zoonosis
- Systemic or topical antifungal agents used e.g. itraconazole, chlorhexidine washes also effective in severe cases
- Decontamination of environment and equipment
Describe the pathogen that causes bordetellosis (kennel cough)
- Bordetella bronchiseptica
- Gram -ve
- Strict anaerobe
Describe bordetellosis in humans
- Purtussis-like disease
- Whooping-style cough
Outline the prevention and treatment of bordetellosis
- Prevention with vaccine (but can be ineffective and short-lived)
- Treatment usually supportive
- In severe cases may treat with tetracyclines
What is the consequence of bordetellosis in the presence of other pathogens?
- Synergy
- In particular with Mycoplasma and canine respiratory coronavirus
Outline the public heath risk of Helicobacter pylori
- Causes GI disease, ulcers, stomach cancer in huamns
- High prevalence in humans (esp. older)
- Significance of zoonotic link unclear (some found in cat faeces, saliva and dental plaques but may be reverse zoonosis i.e. from humans to cats)
Outline the public health significance of Campylobacter
- Frequently found in cats and dogs
- C. jejuni shed by dogs over 1 yr old, C. upsaliensis present in all ages
- Zoonotic link unlcear
- C. upsaliensis occasionally causes infections in humans but may be that humasn and animals are exposed to common source e.g. chicken
Name the canine hookworks
- Uncinaria stenocephala
- Ancylostoma caninum
Outline the public health risk of Uncinaria stenocephala
- Endemic in UK
- 30% of dogs infected, 70-90% of foxes
- Mild dermatological signs in humans
Outline the public health risk of Ancylostoma caninum
- Mostly tropical and subtropical
- Cutaneous larva migrans
- possible spread to UK due to climate change and pet travel
Outline the prevention methods of canine hookworm
- Humans: personal hygiene, limit possible contact of larvae to skin esp. abroad (beach towel, footwear)
- Animals: house in conditions which prevent build up of infective large (dry, well maintained)
- Dogs: routine de-worming with pyrantel
Outline the public health risk of Salmonella
- Food-borne infection risk greater than that from companion animals
- Dogs and cats can shed in faeces/saliva
- All reptiles/amphibians presumed to carry Salmonella
Outline the control of salmonellosis
- Antibiotic treatment not recommended (resistance) so difficult to eradicate
- Hygiene measures e.g. wash hands after handling, do not use kitchen for washing, disposal of bedding
Outline reptile associated salmonellosis
- 27% of salmonella cases in <5yo children linked to reptiles
- ASPHA and PHE ensure screening of frozen mice imported as feed
- 50% of mice +ve for Salmonella
- Source of contamination from reptile feed to human food
Describe the pathogen that causes Lyme disease
- Borrelia burgdorferi
- Gram -ve spirochaete bacteria
What animals act as reservoirs of Lyme disease?
- Deer
- Wild mammals
- Birds
- Rodents
What is the significance of rodents in Lyme disease?
Ticks need rodents in the first stage of their life cycle and ticks are the source of Lyme disease transmission
Describe Lyme disease in humans
- Variable incubation time (4-32 days), up to 8 weeks to develop antibodies, may have no recollection of tick bite
- Early disease characteristic - expanding “bulls eye” skin rash (erythema migrans)
Describe Lyme disease in dogs
- Sudden lameness (2-5 months after tick bite)
- Severe pain, swollen joints, depression, lethargy, kidney failures, seizures
- Chronic form of disease rarer in dogs cf humans
Outline the control of Lyme disease in dogs
- Vaccine available (efficacy disputed)
- Doxycycline effective when used within 4 weeks
- DEET repellent and prompt removal of ticks
Outline the public health significance of Lyme disease
- Most significant vector borne infection in UK/Northern Europe
- Prompt antibiotic admin important otherwise end up with debilitating condition
- Suitable clothing as well as DEET and prompt removal of ticks can help prevention in humans
Describe the characteristics of type 1 decision making
- Instant
- No analysis
- Intuitive
- Use past experience
- Quicker, cheaper
- Orone to error
When would it be appropriate to use type 1 decision making in a clinical scenario?
- Pattern recognition
- Symptomatic treatment
Describe the characteristics of type 2 decision making
- Slower
- Analytical
- Conscious
- Serial/rational
- Multiple pieces of evidence
- More accurate
- May be costly
- Slower
When would it be appropriate to use type 2 decision making in a clinical scenario?
- Gathering of evidence
- Where a definitive diagnosis is required
- Where there is time to establish the full clinical picture (i.e. not emergency scenario)
What is meant by shared decision making?
Communication between vet and client in order to come to a fully informed decision that both parties are happy with
What is meant by Evidence Based Veterinary Medicine?
Use of best relevant evidence in conjunction with clinical expertise to make the best possible decision about a veterinary patient
What may affect test results?
- Prevalence of the disease in the population tested
- Incorrect labelling
- Incorrect calibration of machines
- Storage of samples or test reagents
- Experience/skill of person carrying out test
- Recording of results
What is meant by paternalism with regards to clinical decision making?
Where the vet makes the decision
What is meant by autonomy with regards to clinical decision making?
Where the client makes the decision
What is meant by anchoring bias?
Latching onto the first/one thing we hear in conversation
What is meant by availability heuristic bias?
Overestimation of the important of the evidence available
What is meant by choice supportive bias?
Decisions made remain “good” even where there are issues
What is meant by recency bias?
Last decision influences next decision
What is meant by confirmation bias?
Exploration/hearing of information that confirms preconceptions
Outline some of the laws set out for euthanasia
- Is not an act of veterinary surgery but must be human
- Not obliged to kill healthy animal
- RSPCA inspectors can use pentobarbitone to euthanase wild animals
- AWA 2006: welfare of animal is first priority
- Need owner consent unless delay would adversely affect animal’s welfare
Outline some reasons for euthanasia
- Welfare
- Chronic disease
- Acute disease
- Convenience
What is the definition of euthanasia?
Killing to relieve suffering, welfare reasons
Compare euthanasia and killing
- Euthanasia is for welfare reasons
- Killing is for non-welfare reasons e.g. food production, fur production, lab animals
What is culling?
Killing of wild, food, feral and zoo animals (not for welfare reasons)
What are the requirements for informed consent for euthanasia?
- In small animal practice often have a form
- Not always the case in large animal, ideally witness to this consent
- Owner must be >16yrs
- Over the telephone consent need a witness and consent form countersigns
Outline the guidelines for the euthanasia of dangerous dogs
- Need to request destruction order from court
- Unless the dog is a genuine threat to human safety
- Various legislation involved
Outline the guidelines for euthanasia in equine sports
- May need to act without owner consent, trainer second best under BHA rules
- Record circumstances
- Confirmation from another vet ideal
- Ensure adequate insurance of self
- Ensure identification of correct animal
Outline the legislation regarding wildlife casualties
- Legislation differs depending on species
- Contact DEFRA, local Animal Health Office, English Nature for advice
- Regional differences
- Wildlife and Countryside Act 1981 states suffering animal can be taken for treatment, if treatment not possible then may be killed
- AWA 2006 also covers wild animals
- RSPCA inspector cannot give consent for euthanasia
What should the method of euthanasia lead to in all cases?
- Rapid unconsciousness
- Cardiac and/or respiratory arrest
- Loss of brain function
- Should be painless
- Minimal stress and anciety
What are the different methods of euthanasia broadly?
- Hypoxia
- Pharmacological
- Physical
Outline euthanasia via hypoxia
- Slaughter
- Indirect or direct
- Inhalation: CO, CO2, nitrogen
- Unconsciousness: electrical stunning, non-penetrating captive bolt, CO2
- Killing: exsanguination, electrocution, potassium chloride injection
What are the injectable agents that can be used for euthanasia?
- Sodium pentobarbital
- Potassium chloride
Outline the use of sodium pentobarbital for euthanasia
- Rapid onset
- Pentobarbitone or somulose (secobarbital/quinalbarbitone and cinchocaine hydrochloride)
- Often brightly coloured solutions
- IV admin
- Non-selective CNS depression
- Method of choice for SA, many exotics and some horses if not entering food chain
- Persists for long periods in carcass
Outline the mechanism of action of sodium pentobarbital
- Non-selective CNS depression
- Affects synaptic transmission by enhancing GABA-mediated inhibition
What are the effects of sodium pentobarbital’s action on the cerebral cortex?
In cerebral cortex leads to unconsciousness and anaesthesia
What are the effects of sodium pentobarbital’s action on the respiratory centre?
Leads to apnoea and subsequent cardiac arrest
Outline the use of potassium chloride
- Cardiotoxic
- Used for euthanasia of livestock/wildlife species where carcasses may be consumed
- Reduces toxicosis for predators/scavengres
What is a disadvantage of potassium chloride euthanasia?
Injection is painful and must be used only after induction of unconsciousness e.g. non-penetrating captive bolt or general anaesthesia
How is potassium chloride administered?
- IV
- Intracardiac
Which inhalational agents can be used for euthanasia?
- Sevoflurane
- Isoflurane
- Carbon dioxide
- Nitrogen
- Carbon monoxide
What is the mode of action of inhalational agents in euthanasia?
Induce CNS depression and hypoxaemia
Compare the use of sevoflurane and isoflurane in euthanasia
- Sevoflurane is non-irritant
- Isoflurane has pungent odour and may cause animal to hold breath, leading to delayed onset of unconsciousness and more drug required
Outline the use of common inhalational anaesthetic agents in euthanasia
- Usually small exotics and wildlife <5kg
- Use vapours (liquid phases are irritant)
- Closed receptacle containing gauze/cotton wool soaked with anaesthetic agent
- Induction box
Outline the use of carbon dioxide for euthanasia
- Is an anaesthetic agent
- Laboratory animals, food production animals e.g. pigs
- No longer recommended (caustic)
Outline the use of nitrogen for euthanasia
- Induces hypoxaemia
- Used mainly in food production, e.g. poultry
Outline the use of carbon monoxide for euthanasia
- Induces hypoxaemia
- Laboratory animals mainly
- Used in some shelters for aggressive animals
What is commonly used for the euthanasia of fish?
Tricaine methane sulfonate (TMS or MS222)
Describe the use of TMS or MS222 for the euthanasia of fish
- powder made into solution and buffered with sodium bicarbonate to pH 7.0-7.5
- May or may not premedicate with medetomidine
- Fish pale with sedation
- Leave fish in solution for at least 10 mins after cessation of opercular movement
- Not appropriate for fish intended for consumption
What is tricaine methane sulfonate and what is its mechanism of action?
- Benzoic acid derivative
- Causes CNS depression
- Used in the euthanasia of fish
