Birds 1 Flashcards
Lymphoid tissues what are the 2 types and things within
1) Primary
- thymus (T cells)
- Cloacal bursa (B cells)
2) Secondary
- Spleen
- Harderian glands
- caecal tonsils
- GALT - gastrointestinal associated lymphoid tissues
- MALT - mucosal associated lymphoid tissues
- BALT - bronchial associated lymphoid tissues
- CALT - conjunctival associated lymphoid tissues
○ No lymph nodes in birds except for water fowl (have structures that resemble lymph nodes)
Primary lymphoid tissues what are the 2 types and describe their structure and function
1) Thymus -> T cells
§ 7 lobes with lobules (cortical and medullary areas)
2) Cloacal bursa -> B cells
§ Starts growing when hatches, when gets to sexually maturity starts to shrink
□ Largest at 6-8 weeks of age
§ Lots of folds -> with follicles and specialised epithelial cells that present antigens leading to clonal expansion
Secondary lymphoid tissues what are the 3 main ones, location and function
1) Spleen - B and T cells present (not produced just move into)
§ Located underneath the proventriculus
§ In poultry round, other species can be elongated or triangular
2) Harderian glands
§ Underneath the eyeball (ventral aspect)
Lots of Plasma cells -> local antibody response for URT diseases
3) Caecal Tonsils
§ Not all birds have caecal tubes and therefore don’t have tonsil - chickens do
§ Both B and T cells
Vaccination programs what is important and the types based on
○ Timing is important and every bird needs to get the vaccine
○ Different programs depending on the type of production
§ Broilers -> only live average of 45 days, so don’t get diseases of older just younger birds
□ Only vaccinate against -> Infectious bronchitis virus vaccine
® Some use Marek’s disease, Infectious Laryngotracheitis virus and at outbreak Newcastle disease
§ Layer -> live a lot longer and egg production is important (not just clinical but also poor performance)
□ A whole range of vaccines used such as Infectious bronchitis
§ Breeders -> need maternal antibodies to be passed to progeny (antibodies last 3-6 weeks in chick)
□ FAV -> transmitted vertically and can kill progeny but doesn’t affect adults
Vaccination techniques list the main types
1) Mass vaccination
1. drinking water
2. spray vaccination
2) single vaccination
1. eye droplets
2. injections
Mass vaccination what are the 2 main techniques how works and advantages and disadvantages
1) Drinking water -> tricky because the vaccine can get inactivated within the water before get to the end of the shed
□ Generally cut off the water for 2-4 hours depending on season and then release when chickens are thirsty
□ Most farms have medication tanks and dye in the vaccine helps knowing where vaccine is
® Scoring system, scores the birds based on dye on the tongue of the bird
□ Disadvantages -> minerals in the water can inactivate the virus - ILT, Newcastle disease
® Need to add products to the water before give vaccine
2) Spray vaccination -> different size of the droplets (larger droplets for upper respiratory system such as IB)
□ Vaccinated in crates or cabinets - easier when they are young
□ Can do in older birds but need larger equipment
Single vaccination what are the 2 mechanisms and how they work
1) Eye droplet -> individually administer vaccine -> most expensive vaccine due to cost of labour
□ Stressful for the birds so not ideal but generally done at once with multiple procedures to save on labour
□ Again dye the vaccine to check the eyes of the birds
2) Injections
□ Subcutaneous injection or muscle
□ Fowl pox injected via two way needle into the wing
□ New technology can vaccinate the embryos before they hatch - embrex
® Earlier immunity, uniform and fast delivery, reduced stress and labour cost
What are the 2 main types of diseases of the immune system and diseases within
- Neoplastic ○ Marek’s Disease ○ Lymphoid Leucosis - Immunosuppressive ○ Infectious bursal disease ○ Chicken infectious anaemia ○ Others
Marek’s disease what birds affected, clinical signs and aetiology
- Only chickens are affected, fairly rare due to vaccine
- Insignificant in terms of the poultry industry
- Sulkies particularly infected
Signs - Usually 3-4 months (point of lay)
- Paresis/paralysis - unable to walk or lameness
○ wing, leg, neck
○ respiratory, GIT - if these nerves are affected - Non-specific signs
Aetiology - Herpesvirus
- Three serotypes -> evolving and increasing in virulence over the years
○ serotype I -> pathogenic, a spectrum of virulence
○ serotypes II & III (HVT) -> ubiquitous but avirulent
List 6 diagnostic techniques for mareks disease
- Age - 3-4 months of age
- Clinical signs (paralysis)
- Gross lesions (nerves, skin & eye)
○ Swelling and discolouration of the nerve, sciatic nerve is a good one, generally only one side of the neuron - Histopathology
○ Made of lymphocytes (T cells) -> mature and immature - polymorphic -> lymphomatous infiltrations of nerves/skin/organs
§ Lymphoid leucosis -> stain with B cell markers not T cell so how to tell the difference - Immunohistochemistry (T cells)
- PCR
What are the 4 steps in the pathogenesis of mareks disease
- Infection by inhalation
- Acute phase - growth of virus in lymphoid tissue (bursa, thymus), degenerative lesions -> premature bursal/thymic atrophy
- Latent phase, virus carried in lymphocytes, inflammatory lesions in nerves
- Proliferation of lymphoid cells, lymphoma formation, lymphomatous infiltration of nerves and viscera. Malignantly transformed cells are T-cells through both T and B cells participate in lesions
What are the 5 main factors affecting development of the disease
- Virus pathogen virulence and pathogenicity
- Environment, degree of exposure
- Host - age at first exposure, genetic resistance/susceptibility
- Sex - females are more susceptible than males
- Immune status - vaccination protects against development but not infection
What is transmission and control of mareks disease
MDV Transmission
1. Very early in life - first day
2. Horizontal
○ Complete virus produced only in feather follicle epithelium so excreted in feather dander, keratin
○ Infectious within the environment for a long time - can never eradicate it
3. No vertical
Control
- No treatment!
- Hygiene, age separation, pest & insect control, genetic selection do not provide total protection
“Vaccination” -> injected to back of neck at 1 day old, or the embryo injection machine
Lymphoid leucosis what age, clinical signs, transmission and mechanism
- Naturally occurs in chickens
- Usually > 5 m
- Clinical Signs - non-specific
○ Reduced weight, weakness & anorexia
○ Egg parameters, hatchability & fertility
○ Non-specific mortality
Transmission - Virus generally comes from the parents
○ Chicks hatch with viraemia and shed from all systems (respiratory, gastrointestinal, reproductive)
Mechanism - Affect B cells within the cloacal bursa and B cells become tumour and metastasise to other organs
Lymphoid leucosis describe 6 ways to diagnose lymphoid leucosis
- Age -> < 5months
- Lesions
○ Cloacal bursa ALWAYS affected
○ B cells involved - Histopathology
○ Doesn’t generally affect skeletal muscle, eyes or nerves unlike Marek’s disease
○ Lymphoblast’s not lymphocytes - Immunohistochemistry
○ B cell marker staining works - different to Marek’s disease - PCR
○ Need to determine which PCR -> such as Lymphoid leucosis PCR - Serology
○ Detect antibodies however with immunotolerance some birds infected don’t produce antibodies
Lymphoid leucosis pathogenesis and cause
Pathogenesis
1. Infection in ovo leads to disease about 4-5months
2. Neoplastic transformation occurs initially in the bursa of fabricius
3. Nodular tumours are evident from about 14 weeks and metastasize from bursa to other organs
LL Virus
- A member of the avian leucosis/sarcoma viruses (ALV)
- Other members cause:
○ myelocytomatosis
○ Myeloblastoma & erythroblastoma
Haemangioma, nephroblastoma, fibrosarcoma, osteopetrosis, etc.
Lymphoid leucosis what are the two types of transmission and control
Exogenous and Endogenous Viruses Transmission
Exogenous
1. Transmitted through the egg via parents -> progeny
2. Horizontal via infectious virus
Endogenous
1. Genetic -> viral DNA integrated in gamete DNA -> can start to produce virus
Control
- No vaccine
- Eradication via selection for genetic resistance and detection of carrier hens
○ Carrier hens -> detected via vaginal swabs, carrier birds culled from breeder flock
Infectious bursal disease (IBD) what birds does it affect, virus character and the 3 diseases forms
- Only in chickens but is very significant worldwide
- Very hardy virus, cooking chicken the virus is still viable
- Disease forms
a. Immunosuppression, <3 wo
§ Succumb to other diseases
b. Clinical disease, 3-6 wo
c. Severe form, any age
Infectious bursal disease (IBD) what are the 3 main mechanism forms and the weeks involved
1) inapparent form (<3 weeks)
2) acute form (3-6 weeks)
3) very severe form
Inapparent form for infectious bursal disease what are the clinical signs and lesions
○ Subtle clinical signs
§ Mortality apparently due to other diseases
□ Trying to control multiple bacterial infections and cannot control - THINK THIS
§ Poor vaccination response due to the virus affecting the B lymphocytes
○ Lesions -> cloacal bursa may be very small for its age
Acute form of infectious bursal disease clinical signs, lesions and onset
- Clinical signs ○ "sick chicken" -> chicken hunched over, fluffed up, low acitivty ○ Polyuria causing running droppings - Lesions ○ Bursa is swollen ○ May see haemorrhage in skeletal muscle - Immunosuppression - Rapid onset (IP 2-3d) and course Mortality up and then back to normal
Very severe form of infectious bursal disease where presnt, what caused by, clinical signs, affected tissues and age
- “EXOTIC TO AUSTRALIA”
- Caused by vvIBDV (very virulent)
- Clinical signs & lesions as acute form
- Also affects other lymphoid tissues eg. thymus
Affects any age eg. >6 w
Infectious bursal disease what are the 4 main diagnostic techniques
- Rapid course
- Bursal lesions* - swelling, oedema, haemorrhage, atrophy
- Detection of Virus
○ RT-PCR -> RNA viruses
○ AGP - Serology (ELISA) - mainly for monitoring
Infectious bursal disease what are some control methods
- Hygiene does NOT eliminate the virus but can reduce level of infection - all in - all out
- Biosecurity
○ Source of feed - not contaminated
○ Insect control - beetles can carry the virus - Passive antibody* - MATERNAL ANTIBODIES ARE THE BEST
○ How done in Australia
○ Different strains in different areas so need to strain type to ensure vaccine has local strain
Vaccination of Non-breeder Flocks - NOT IN AUS - If the risk of vIBDV is high
- Passive antibodies interference
○ “antibody profiling” - 1-3 live, moderately virulent vaccines
Chicken infectious anaemia (CIA) what caused by and significance
Caused by a Gyrovirus (A type of Circovirus)
○ Very resistant
Significance
- Clinical disease
○ Poor growth and performance,
- Immunosuppression -> secondary infections such as E.coli, Staphylococcus etc.
- Vaccine contamination with other vaccines -> have to be recalled
○ Especially important for specific pathogen free (SPF) chickens
Chicken infectious anaemia transmission, diagnosis and control
Transmission - Vertical (if affected during lay) ○ As soon as develop antibodies no longer sheds the disease that’s why vaccinate the mother - Horizontal - Signs only in progeny Diagnosis - Gross lesions ○ Thymus atrophy (most common but non-specific) and pale bone marrow (DIAGNOSIS) - CIA PCR - ELISA Control - Vaccination of the parent flock "prior to the point of lay"
Circovirus what leads to and present
- Leads to immunosuppression in not just chickens such as pigeons, parrots
- Cause inclusion bodies
List some immunosuppressive conditions
- Infectious bursal disease
- Chicken Infectious Anaemia
- MD, LL & RET
- Pigeon circovirus infection
- Psittacine Beak & Feather Disease
- Polyomavirus
- Mycotoxicosis
- Nutritional deficiencies
- Stress
List some common signs to look for in a avian consult for a diseased animal
(a) Fluffed up, the head tucked under a wing.
(b) Inactive.
(c) Not calling or responding to calls.
(d) Eyes closed.
(e) Movements of the head are slow.
(f) Posture is unusual.
(g) On bottom of the cage.
(h) Breathing noticeable or audible. Bobbing of the tail - indication of respiratory distress
(i) Vent is soiled - dirty bottom
(j) Any discharge from the nostrils.
(k) Singing birds stops singing or change in voice.
○ Via the syrinx -> deep in the chest
(1) Not eating or not passing normal droppings.
(m) Excessive stretching of wings, and legs or shivering.
(n) Body weight of the bird is declining.
Handling of birds what is important to remember in terms of problem areas and support
- Parrot beaks hurt - so want to have control of
○ Control head (long cervical vertebrae) gently stretch the head than support their body close to chest - Birds of prey can cause damage with their feet.
- Pigeons need body support.
- Fowl, control wings and support body.
- Swans and other long neck species, control the neck.
- Use a towel NOT gloves
- Need to move their chest to breathe -> don’t push against chest
- Rough handling of a tame bird can cause significant trust issues.
- Often owners don’t know how to handle their birds -> get the bird from the cage yourself
- Cause minimal stress.
- Handle the bird as little as possible
What is important part of history taking in consults
- Sometimes it is helpful to have clients fill out questionnaires before their initial consultation - SAVE
- Often a bird is stressed from the car ride into the clinic and from the waiting room, so consultation should always start with history taking and observation before touching the bird
- May need to put bird into oxygen chamber before consult if very stressed/sick
What is a check list for taking history
- age,
- details of why the bird was bought in
- information about diet
- how the bird is kept, is it an aviary bird?
- Has it been hand reared and how? Is it a breeding bird?
- what is the birds daily routine?
- what environment factors may be significant.
- Is the bird in contact with other birds
- Previous medical history
- Detailed history of husbandry
○ cage location, sleep at night, available perches, toys to play with, branches to chew, access to UV light, what is the substrate at the bottom of the cage?
What examination besides of the bird is important for a consult and what is involved
Examination of cage and environment - very important
- encourage owners to bring in the cage (uncleaned) with the bird (or take a picture of the cage)
○ Generally not communicable diseases as not exposed to other birds more about husbandry
- It’s a good idea to talk to the owner and get the history giving the bird time to relax and settle in the cage, a bird that comes in already fluffed up may be very sick, but birds will try and hide their illness.
Examination of the bird what are 5 important things to look out for when you need to put the bird back into the cage
- If bird is breathing and panting rapidly and doesn’t turn to bite when loosen grip.
- If the bird doesn’t bite at something presented to the corner of the mouth.
- If the bird doesn’t grasp the hand or has a weak grasp with its feet.
- If the birds eyes are closed during the examination
- If in doubt put it down.
List and describe 7 equipment that is important during a bird consult
1) fresh towels
2) scales to weight the bird - needs to go down to 1 gram, weigh throughout the treatment
3) training perch - the examine on
4) stethoscope - focal light source, needles and syringes
5) mouth gag - to prevent biting down
6) grinder - grind down beck and nails
7) crop tubing- giving water/food, medication
What advice give to owners of sick birds while transporting
- Warmth
- Low light
- Small cage - restricts movement
- Quiet room
- Monitor droppings
- Isolate
When transporting - As above
- Remove water bowls
- Get owner to bring in food and any existing meds so bird can be offered its normal diet if it has to stay.
Describe the unique bird anatomy and physiology for the respiratory system, integument and skeleton
- respiratory system, no diaphragm, air sac system (9 air sacs in most birds), tubular lung tissue attached to ribs and rigid tracheal rings.
- integument – thin skin covered with feathers used for flight, temperature regulation, protection and display
○ Cannot do normal skin tenting -> all papery skin - large keel bone resulting in a small abdominal area
- Large pectoral muscles for flight
- Skeleton – medulla-cortex ratio, pneumatic bones (don’t inject into bones - femur and humerus), no teeth, back bone mainly fused
Describe the unique bird anatomy and physiology of the digestive and urogenital system
- Digestive system – crop, proventriculus and gizzard (with back and forward movement of food) and cloaca
○ Food moves in both directions, blockage will not see large loops of bowl - Urogenital system - Internal gonads and egg layers with 1 developed uterine horn.
○ Kidneys attached to the backbone and pelvis, main waste product is uric acid and no bladder.
What is important to do when clipping bird wings nails and giving microchips
- Clip last 10 primary flight feathers
- Don’t clip just one side
Nails - Why long?
○ Nutritional
○ Fungal/bacterial
○ Mites
Microchips - Rarely anaesthetise a bird -> no more painful than injections with the small microchips
- Shallow left breast
