8. Immunity
FIGHTS INFECTIOUS ORGANISMS
Attacks body’s own cells Rejects and destroys
i.e. Autoimmune disease abnormal cells e.g. cancer cells
The Immune System
Defends the body against
Foreign (non self) antigens
Rejects foreign cells e.g.
Reactions to allergens e.g Organ transplants
Pollens, foods, drugs etc
9. Types of Immunity
I m m u n ity
I n h e r it e d A c q u i r e d N a t u r a l ly A c q u i r e d A r t i f i c i a l ly
21. Vaccines
Vaccines are used to protect against:
Viruses - eg Parvovirus
Bacteria - eg Leptospirosis
Protozoa/Helminths eg Husk
(sets off immune response identical to
natural infection)
22. Types of Vaccine
Live, attenuated e.g. DHP
Killed (inactivated) e.g. Leptospirosis
Heterologous e.g. smallpox
Toxoids e.g. Tetanus Toxoid
Specific Antigen (Sub unit)
36. MEASURING NUMBERS
Mobility
Lack of individual identification
Catch/mark/release
Calculation:
Total population = number marked x total counted
marked counted
Alternatives
41. MALE OR FEMALE?
Males only
First year - 10 male, 10 female, 20 dogs
Result: 60 pups produced
Neuter 9 adult males
Second year- 1 entire male, 9 neutered
males, 10 females, 60 pups
Result: 60 more pups produced
Population 130 dogs
1 very tired but happy male
42. MALE OR FEMALE?
Females only
First year - 10 male, 10 female, 20 dogs
Result: 60 pups produced
Neuter 9 adult females
Second year- 10 males, 9 neutered females,
1 entire female, 60 pups
Result: 6 pups produced
Population 86 dogs
46. DUTY OF CARE
An animal’s needs:
for a suitable environment
for a suitable diet
to be able to exhibit normal behaviour
patterns
to be housed with, or apart from, other
animals
to be protected from pain, suffering,
injury and disease
47. QUALITY OF LIFE
Animal’s feelings
Relationship to welfare
Affected by:
Housing
Exercise
Companionship
Feeding
Measurement
55. SUMMARY
Biosecurity – down to you
Population management – down to
your relationships
Duty of care – your management
Quality of life – needs more work
Editor's Notes
Ideally stop infection getting into shelters. Realistically aiming to minimise the risk of infection Minimise effects of infection i.e. spread within a shelter Incubation e.g. spread of infection at school/one of audience with sore throat. Go thro a period before clin sx Have to accept some admission to shelter will be incubating disease – no clinical signs, therefore cannot detect Excretion Towards end of the incubation period animals will start to shed. Excretion will be millions of organisms per gram of vomit or d+ before think it has an infection i.e. cannot say an individual is healthy, can only say it is clinically well Carriers e.g. Cat flu. Many cats end up excreting virus, may be intermittent. Shedding increases with stress. Major stress = re-homing centre/sanctuary
Direct In an ideal world all new animals would be quarantined; realistically won’t work due to the volumes taken in i.e. shaking hands / sniffing bottoms
i.e. anything a dog or cat comes into contact with Air: Kennel cough in dogs – infectious aerosol. Can sneeze around 3ft, so need at least 4ft distance between kennels across central walkway People behaviour very important in biosecurity: Staff trained Correct procedures
Zoonosis: Disease that can be transmitted from animals to humans All food poisoning organisms: Salmonella, Campylobacter 40% dogs carry Campylobacter, biggest cause of food poisoning in the UK and commonest human zoonosis in Europe. Main source poultry Each yr DT have 2-4 cases with Campylobacter. i.e. don’t wash their hands before making coffee. Moral = make your own coffee NB: If staff infected with Salmonella/Campy, will take home to their families CL Salmonella story, lost 9kg in 3d. Poorly defrostede turkey. Stayed +ve for 5months including daughter having no contact with turkey
Immunity: The power to resist infection or the action of certain poisons Definition of an antigen: a substance which the immune system recognises as foreign or non self Definition of an antibody: a glycoprotein which has the capacity to recognise and bind to foreign molecules
Inherited / innate immunity e.g. horses don’t get foot and mouth, cats don’t get canine distemper, dogs don’t get FeLV NB: Be aware that immunity not immediate i.e. even if vaccinate on entry to sanctuary, may still succumb to disease
Naturally acquired immunity results from an attack of some disease from which the animal has recovered. The bodies defence in this case is the production of antibodies and cellular immunity which destroy the foreign agent. A young animal may acquire passive immunity via the placenta in utero and/or through the colostrum of its dam These acquired antibodies are known as maternally derived antibodies. (MDA)
Artificially acquired : again there are two varieties, active or passive. Active Immunity This is produced by inoculating an animal with a vaccine (ie dead or modified bacteria or virus) or with a toxoid. The vaccine or toxoid stimulates the immune system to produce antibodies and to generate a ‘memory’ so that if the disease is encountered a rapid response is mounted. Vaccine: Here the immune response is mounted to the invading organism Toxoid: This is specific to tetanus (for the horse owners in the audience). Tetanus is a bacterial infection. The bacteria produces toxins (poisons). It is these poisons which cause the clinical signs of tetanus. Therefore the vaccine aims to stimulate the immune system to bind to the poisons to prevent the clinical signs of tetanus. Similarly, in the case of acute injury e.g. a cut, tetanus anti-toxin is administered to bind to any poisons before they can cause the clinical signs of tetanus. Passive immunity This attained by injecting animal blood serum drawn from the body of an immune animal into that of another. The serum contains antibodies which enable the animal to resist infection. This gives immediate immunity but is not long lasting; it can be used in the face of infection NOTE: Ensure delegates understand the difference between active and passive immunity
Feeding: Well fed better immunity Pregnancy: decreases immunity. Huge draw on body Stress decreases immunity. Take dog off streets into sanctuary, can’t choose what to do so stress levels ^^^ Drugs e.g. steroids NB: Study done a couple of years ago re stress and cortisol levels. Suggested HAC as so high. Smell other dogs but cannot see and cannot get away.
Level of immunity needs to be ABOVE the level of infection i.e. need to keep level of infection BELOW level of immunity. Do this by proper management and proper cleaning
If are able to/cannot manage, as level of infection increases, exceeds immunity and disease results This will be a process of progression: incubation period excretion clinical signs of disease i.e. trying to avoid levels of infection exceeding levels of immunity. Otherwise potential exponential rise of infection Greater the stress, greater the immune system is suppressed and individuals become more prone to infection. Therefore HOW WE MANAGE ANIMALS IN SHELTERS IS CRITICAL
What is passive immunity: MDA T1/2 every 9 days approx Neonatal period is the only time in life when whole protein can be absorbed through the gut and into the body. Gut only permeable for 24-36hrs. Antibodies in first milk (colostrum only)
Emphasise importance of management and cleanliness. Higher the level of infection, more rapid the onset of disease. What does this mean? Lower levels means greater time lag before infection happens; may be the difference between being able to vaccinate and stimulate immunity. At least should reduce severity of clinical signs if not prevent altogether
NB: Immunity gap: period when maternal immunity too high to allow vaccine to stimulate immune system, but too low to prevent against infection
Most diseases are caused by either viruses or bacteria. Viruses - minute in size,need cells of the host to replicate. Bacteria - larger in size, multiply by division. In addition some diseases are caused by Protozoa and Helminths (larger organisms) such as lungworm in cattle (also known as husk).
Live vaccines are non-harmful strains of a disease that have had their ability to cause disease modified (reduced). They create a quicker immune response and immunity lasts longer. Killed vaccines have been rendered inactive. Immunity generally doesn’t last as long and more frequent boosters are required. Some vaccines would not be safe to have live components so killed vaccines have to be used. Heterologous vaccines: Some vaccines use components similar to the disease but not exactly the same to give cross protection against the diseases e.g. cowpox was used to vaccinate against smallpox in humans (smallpox is now officially eradicated from the world). Early distemper vaccines were actually measles vaccines (the 2 diseases come from the same family). Shope Fibroma virus cross protects against Myxomatosis. Toxoids: As mentioned before: tetanus is a bacterial infection. The bacteria produces toxins (poisons). It is these poisons which cause the clinical signs of tetanus. Therefore the vaccine aims to stimulate the immune system to bind to the poisons to prevent the clinical signs of tetanus. Similarly, in the case of acute injury e.g. a cut, tetanus anti-toxin is administered to bind to any poisons before they can cause the clinical signs of tetanus. Specific Antigen: Some vaccines are genetically engineered and have a specific piece of the virus which stimulates immunity e.g. FeLV. i.e. these are a purified form of vaccine – it is only the part of the virus that stimulates the immune system that is used in the vaccine.
Live vaccines: small, non harmful dose of the infectious agent. Will replicate in the body (hence the marked response) but will not cause disease. 4 main differences between live and killed vaccines (as listed): Greater stimulation of immune system: more dramatic response Much more rapid response i.e. rapid mobilisation due to replication of vaccine Generally single dose, but young e.g. puppies/kittens special case Immunity generally lasts longer
Killed vaccine: inoculate (inject) with a dose of the killed organism e.g. Nobivac Lepto 2. As the organism is killed and it does not replicate in the body there is: A less dramatic response A slower response Generally 2 doses are required to achieve the required level of immunity (irrespective of the age of the individual) More frequent boosters e.g. Lepto 2 must be given annually to maintain immunity cf Nobivac DHP, live vaccine, repeat every 3 years Safety Before a vaccine is brought to market, we need to prove 2 things: that it works (is efficacious) and that it is safe. In order to prove safety we have to administer multiple doses to ensure that there are no adverse reactions. For killed vaccines we have to give TWICE the dose. For live vaccines we have to give TEN TIMES the dose because they replicate in the body.
4 main differences between live and killed vaccines; reiterate as per diagram Greater stimulation of immune system: more dramatic response Much more rapid response i.e. rapid mobilisation due to replication of vaccine Generally single dose, but young e.g. puppies/kittens special case Immunity generally lasts longer
Remove all faeces: organic material and disinfectant = nice smelling shit Clean thoroughly: smooth, impervious surfaces. Will dilute infectious material Pressure hose: useful BUT too often and will destroy material i.e. don’t do every day but as part of routine. NB: Coat oils on floor/walls – if poorly cleaned will remain in situ. Start to look soiled with grease/fat so pressure wash monthly. Disinfect: Need to mix with water to work properly. Follow correct dilution. Look at defra.gov.uk for approved disinfectants. Do not make stronger – not necessarily better. Equally weaker will be ineffective. May find 2 dilution levels – everyday use and in face of infection. If have outbreak often good to change disinfectant e.g. Trigene / Virkon. NB: Commercially made disinfectant have detergents to get into nooks and crannies. Hydrogen peroxide and chloride NOT a good substitute. Leave 20-30 mins to allow to work – won’t be effective if remove as soon as apply DRY: Essential part to complete the process. Most organsims hate drying. E.g. use sqeegee. I.e. bateria/virusesd prefer warm and wet
Walls between kennels need to be solid. Free flow of air means that disease particles not only enter central corridor but can spread from dog to dog via this route
Kennels have pop hatches which allow air to blow in from kennels to central corridor
Consider fans in central corridor pushing air through the kennels and to the outside i.e. cleanest air in central corridor
Hand washing
Ideally wash hands between each animal. Not practical in sanctuary situation, but should at least be done between blocks
