Poultry and porcine Flashcards
Poultry: What diseases are considered notifiable within the Australian poultry industry ?
Notifiable diseases of poultry in Australia
All diseases that are considered exotic are notifiable in Australia
- HPAI
- ND
- virulent bursal disease (vvIBD)
- salmonella pullorum, enteritids
All exotic diseases are considered notifiable but also including
- Infectious Laryngotracheitis
- Mycoplasma SYNOVIAE
- aVIAN PARAMYXOVIRUS
cONTACT THE EMERHENCY DISEASE HOTLINE
Poultry: Describe the aetiology and epidemiology of Avian influenza
Avian influenza
Disease occurs worldwide but HPAI is notifiable in Australia
- all bird species are thought to be susceptable to virus
- Low pathogenic avian influenza (LPAI), and High pathogenic avian influenza (HPAI)
All highly pathogenic strains involve H5 or H7
- genetic changes are common (antigenic drift, or antigenic shift)
- LPAI - HPAI
- LPAI infections with H5, H7 subtype that have been allowed to spread without adequate control or eradication have ultimately turned into virulent HPAI infections.
Transmission
- in domestic birds throug interaction with wild birds (migratory water fowl)
- 70% of Australias wild water birds have antibodies
- humans have been infected by close contact with infected birds or their excretions. Limited evidence of human to human transmission so self limiting disease.
Poultry: Describe the pathology of Avian Influenza ?
Avian influenza
All highly pathogenic strains involve H5 or H7
There is extreme variation in virulence amongst the strains of AI viruses
AIV may cause
1. subclinical infection (wild water birds natural non clinical host)
2. mild respiratory signs or production drop LPAI
3. acute highly contagious and fatal disease HAPAI
Incubation = from a few hours to 2-3 days
- dependant on dose, route of exposure and human ability to detect early signs
- less virulent strains have a variable incubation period
Poultry: Describe the clinical signs of (LPAI) ?
The clinical signs of LPAI
- respiratory signs
- low mortality (layers 3%, broilers 15%, turkeys 90%)
- significant drop in egg production < 45%, with a recovery usually within two weeks
- difficult to differentiate from other respiratory diseases
- be wary of mutation
Always test for exclusion when dealing with a case of respiratory disease.
Poultry: Describe the clinical signs of HPAI ?
Clinical signs of HPAI
- high morbity and mortality (mortality of 100% in peracute, acute cases)
- severe respiratory signs
- excessively watery eyes
- cyanosis of combs, wattle and shanks
- oedema of head
- ruffled feathers
- sitting on hocks and depressed
- diarrhoea
- nervous signs
- shells may be absent from the last eggs laid
- peracute cases may case sudden death with no clinical signs present
Poultry: When necropsying a chicken suffering from Avian influenza, what do we expect to observe ?
Post mortem of a bird with AI
- There may be no lesions in peracute cases
- subcutaneous oedema - straw coloured or serosanguinous fluid
- conjunctivae, congested, petechiated
- haemorrhagic trachea
- petechiae and ecchymoses - fat serousal surfaces, peritoneum
- ovary haemorhage and necrosis
- pertonitis
- haemorrhage of the gizzard, proventriculis
- enteritis
Poultry: What steps should a veternarian take to confirm a case of AI ?
AI diagnoses
Suspected case
1. First step State Laboratory, 4 hours confirmation of influenza A
( declare as a suspect case of influenza).
- Australian centre for disease prepardness (ACDP)
- PCR
- virus isolation and identification
- pathogenicity test
- serological testing for tracing the source of disease ELISA
- ACDP world leader in AI virus research.
Poultry: What steps are taken in response and control of a AI out break ?
Avian influenza outbreak
AUSVETPLAN
- National response plan
- managed by the commonwealth DAFF
- eradicate through slaughter and movement control
- vaccination as a last resort, when disease spreads out of the control zone
Goal is to return country to freedom from disease and resume international trade.
Poultry: Describe the epidemiology of Infectious Laryngotracheitis (ILT) ?
Infectious Laryngotracheitis (ILT)
- Alphaherpesvirus
- younger birds more susceptable
- Persistent infection within the trigeminal nerve
Transmission
- respiratory discharges
- air borne via the wind
- fomites, equipment, personel, mechanical
- intermittently and inapparently shed by latently infected animals
- highly environmentally resistant
New castle disease is decribed into four categories based on the rate it causes death of the chicken under defined conditions, or the amino acid sequence at FO gene cleavage site.
Describe the four categories of New castle disease ?
The four categories of New castle disease
Velogenic
- highly pathogenic or virulent
- viscerotropic high mortality, haemorrhagic enteritis
- neurotropic high mortality and nervous signs
Mesogenic
- moderately pathogenic
- low mortality, respiratory signs predominate
Lentogenic
- only mildly pathogenic
- respiratory disease may be subclinical
Asymptomatic
- sub clinical enteric
Poultry: Describe the epidemiology of New Castle disease ?
Epidemiology New castle disease
- infective for almost all avian species, both domestic and wild
- chickens considered the most susceptable species
Transmission (in descending order of importance)
- movement of infected animals
- equipment, feed stuff and personel
- vertical transmission can occur
- ND virus infections remain for long periods of time on contaminated premises (feathers 255 days, bone marrow muscle 4 for 4 months)
Potential for zoonosis
Most recorded human infections in lab workers who handle the virus or incubators or prepare eviscerate poultry
- person to person transmission not recorded
Poultry: Describe the clinical signs of New Castle disease in chickens ?
Clinical signs of New Castle disease in chickens
During incubation the virus replicates at the site of introduction
- virus is excreted before clinical signs are apparent
- the virulence depends on the virulence and tissue tropism of the virus + age, species, route of exposure, size of dose, external factors eg heat.
The clinical signs
- marked drop in egg production + abnormal eggs (soft, missing shell or pigment, misshappen)
- loss of apetitie, fever, weakness
- swelling and cyanosis of the comb and wattles
- diarrhoea watery, bile stained, bloody or green
- respiratory increased RR and a high pitched sneeze
- nervous = loss of balance, convulsions, somersaulting and stiff wry neck
Poultry: How would you go about diagnosing New Castle disease ?
Diagnosing New Castle disease
Post mortem
- peracute disease may pass without lesions
- oedema interstitual fluid in the neck
- trachea haemorrhage
- diphtheritic memebranes - oropharynx, trachea, oesophagus
- gastrointestinal tract progressively oedematous, haemorrhagic and necrotic
- small petchial haemorrhages on breast muscle
- birds with partial immunity will have less severe lesions
Diagnosis
- screening RT-PCR
- +ve are further characterised by culture in eggs and further molecular analysis
Poultry: How can we prevent or control New Castle disease in chickens ?
New Castle disease in chickens
Prevention
- compulsory vaccination since 2009 (QLD no longer includes broilers)
Control
- National response plan (AUSVETPLAN)
- eradication through slaughter and movement control
Poultry: Describe a chickens respiratory system ?
Poultry: Describe the epidemiology of Infectious Laryngotracheitis (ILT) ?
Infectious Laryngotracheitis
Poultry: Describe the clinical signs of Infectious Laryngotracheitis (ILT) ?
Clinical signs ILT
A highly infectious respiratory disease - notifiable
Characteristic out strectching neck on exhalation - attempt to breath on exhale (tracheal occlusion) long drwan out strangled cry.
high pitched cough
Percute
- high morbidity, mortality >50% sudden
- blood on walls (mucoid, tracheal dischrages
Acute
- mortality 10-15%
- haemorrhagic caseous tracheitis
- respiratory signs
- nasal discharge + infraorbital discharge
- conjunctivitis
Chronic
- low morbidity / mortality
- reduced egg production
- coughing and gasping
Poultry: What would you expect to find in a post mortem of Infectious Laryngotracheitis (ILT) ?
Laryngotracheitis
Post mortem
- mucous membranes uppper third of trachea
- haemorrhagic tracheitis, free blood in lumen + blood clots + mucous
- caseous plugs
- yellow caseous material in mouth, trachea, infraorbital sinus
- yellow cheesy diptheritic membrane (pseudomembrane)
Poultry: Describe how you would go about diagnosing a case of Laryngotracheitis ?
Diagnosis
- CS and history
- post mortem
- caseous plugs die through asphixiation
- mucosal infiltration inflammatory cells
- eosinophilic intranuclear inclusion bodies in epithelial cells (pathognomic for ILT)
- progresses to desquamation of epithelial cells
- PCR
- serotyping swabs from the trachea
Poultry: What could you do to prevent and treat an outbreak of Infectious Laryngotracheitis ?
Prevention and treatment ILT
Notifiable disease
- no treatment available
- vaccination in the face of an ‘outbreak’, only if disease breaks biosecurity
- keep birds cool, provide fresh water, minerals and multivitamins
Biosecurity
- requires intercompany cooperation to limit spread
- flocks to slauhter as soon as possible
- severe movement restrictions
- usual vaccination practice 2-4 wks, 8-10 wks eye drop or drinking water
Poultry: Describe the epidemiology of Infectious Bronchitis (IB)?
Epidemiology IB Infectious Bronchitis
- Coronovirus
- highly contagious
- antigenic drift and shift common
- affects all chickens worldwide
- hardy persistent in the environment
- incubation = 24hrs
Transmission = aerosol droplets, faecal
rarely egg transmission
Poultry: Describe the clinical signs of Infectious Bronchitis (IB) ?
The clinical signs of Infectious bronchitis (IB)
- permanent damage to fallopian tube and shell gland
- decreased egg production throughout life + hatchability decrease
- downgradable table eggs, quality, wtaery yolks and flat sided shell
Respiratory
- rales
- cough, sneezing
- nasal + ocular discharge
- depression
Nephrotropic
- uraemia
- depressed
- cyanosis of comb and wattles
- dehydration but increased water intake
- wet litter
- high mortality
Poultry: In a case of Infectious Bronchitis what would we observe upon postmortem ?
Post mortem IB
- Inflammation and mucous within the respiratory tract
- Nephrotropic
- dark red flesh (dehydration)
- pale swollen kidneys X3 the size
- tubules distended and full of urates
- Layers = egg perionitis and regressed ovarian follicle
Poultry: Describe how you would diagnose a case of Infectious Bronchitis ?
Infectious Bronchitis
Signs and lesions
Isolation of virus
-kidneys, trachea
- chicken embryo inoculation
Antigen typing PCR
Poultry: Describe how you would go about treating/controling Infectious Bronchitis ?
Treatment Infectious Bronchitis
It is difficult to treat once present as it is a virus
- antibiotics if signs of secondary infection
- uraemia increase heat and decrease protein content of fed
- provide electrolytes
Biosecurity very difficult to limit exposure
vaccination attentuated
- water, aerosol, eye drop
- course sprays, Hardarian gland (droplet size)
Layer hens vaccinated every 6-8 weeks through out life
Poultry: Describe the Aetielogy and epidemiology of Mycoplasmosis ?
Mycoplasmosis (bacteria)
Susceptability = chickens, turkeys
- survival fragile organism
- dusty environments will increase severeity of disease (ammonia, dust).
- Chickens = airsacculitis and tracheitis
Transmission = vertical (parent to offspring) and horizontal
Poultry: Describe the clinical signs of mycoplasmosis ?
Clinical signs of mycoplasmosis
M. gallisepticum
Upper respiratory tract infection
- pyrulent type infection, facial swelling and air sacculitis
M. synoviae
- mild upper respiratory tract infection
- predilection for synovial joints and tendon sheaths
- infectious synovitis, lameness, swollen hocks
Clinical signs
- dischrages
- rales
- wet ratty cough
- production drop, decreased eggs and fed consumption
- exudate in respiratory passages
- pneumonia
- air saccultits
Poultry: Describe how you would diagnose and treat a case of Mycoplasmosis ?
Mycoplasmosis
Diagnosis
- isolation - swabs (PCR and typing)
- rapid serum agglutination (RSA)
- ELISA
Treatment
Antibiotics tetracyclines, lincomycin
- hygiene prevent egg transmission
Vaccination live attentuated eye drop
- usually only in longer living stock breeders, layers
- provides life long protection
- provides maternal antibody protection of progeny
Poultry: Describe the epidemiology of Infectious Coryza ?
Infectious Coryza
Avibacterium paragallinarum
- gram negative, bipolar staining non motile rod
- requires special media
Epidemiology
- all ages are susceptable - usually rearing or adult birds
- present in sinus exudate of birds
- carrier birds are a major reservoir
Transmission = inhalation of aerosol or ingestion of contaminated fed and water.
Poultry: Describe the clinical signs of Infectious Coryza ?
Clinical signs Infectious Coryza
Symptoms appear within 24-72 hrs PI
- depression, production drop and decreased feed intake
- swollen face with oclusional discharge
- conjunctivitis - eyelids may close
- morbidity may reach 100%, but mortality usually low
- moves relatively slowly through the flock
- course about two week followed by 2-3 months immunity
Poultry: How would you diagnose a case of Infectious Coryza ?
Diagnosis Infectious Coryza
Post mortem
- acute inflammation of nasal passages and sinuses
- conjunctivitis
- subcutaneous oedema of face
- infraorbital sinuses may be extended with cheesy exudate
Diagnoses
History, CS and lesions are suggestive
- Demonstrate Avibacterium paragallinarum
- smear of exudate
- isolation
- PCR (demonstare a rising titre)
Poultry: Describe how to treat and control Infectious Coryza?
Infectious Coryza
Treatment and control
- Chlortetracycline
- autogenous vaccine
- biosecurity vaccine
- controlled exposure
Poultry: Describe the aetiology and epidemiology of Aspergillosis ?
Aspergillosis = a fungus
Is a mycotic disease usually of the respiratory system in many kinds of birds.
- worldwide and common
- chicks and poults <6weeks
- all species are susceptable
- normal in the environmnet, litter, feed
Under ideal conditions will grow profusely
Transmission
- inhalation of spores
- conjuntiva, contaminated hatchers or chick delivery boxes
Most birds will resist infection but may become overwhelmed by massive exposure
Poultry: Describe the clinical signs of Aspergillosis ?
Clinical signs Aspergillosis
- Environmnet 5-6 days post challenge
- metastases development of secondary malignant growths
- gasping and laboured breathing
- whistle
- depression
- diarrhoea
- conjunctivitis
Poultry: Describe what you would observe in case of Aspergillosis post mortem ?
Post mortem Aspergillosis
- discrete white nodules in lungs, air sacs and trachea
- mycelial growth with sporolation air sacs
- metatatic foci in brain, eye etc
Poultry: How can you diagnose Aspergillosis in chickens ?
Diagnosis Aspergillosis
- signs and lesions
- demonstration of hyphae; fresh preparations or histological sections
- culture (remember this is a common contaminate)
Poultry: What can be done to treat and control Aspergillosis in chickens ?
Control Aspergillosis chickens
- reduce environmental contamination
- antimycotic agent virkon, clinafarm
- smoke generation, liquid fogger
- chlorine dioxide water treatment
- iodine based sanitisers
Poultry: Describe the aetiology and epidemiology of coccidiosis ?
Coccidiosis aetiology
Most ubiquitous and economically significant disease in meat poultry
- common but less significant in layers
- all birds will become infected at some stage in their lives
Aetiology
- Host specific
- There is no cross protection between different strains
- concurrent infection with more than one species is possible
- disease of young poultry (infections are self limiting)
They will become infected - can not be controlled by quarantine, disinfection or sanitisation
Epidemiology
- outbreaks are common 3-6 wks of age
- oocyst is resistant to environmnetal extremes and disinfectants
Transmission = ingestion of sporrolated oocyst
The severity of infection produced is directly proportional to the number of sporolated oocyst ingested.
Poultry: Describe the clinical signs and pathology of Eimeria. acervulina ?
Eimeria acervulina
Clinical signs
Infects upper intestine duodenum
- poor food conversion rate
- loss of pigment due to intestinal malabsorption of pigments
- watery mucoid droppings
- depression
- mortality uncommon
Pathology
serosal lesions are difficult to see - mucosal lesions more visable
- small white discrete nodules
- elongated plaques arranged transversely
- lesions overlap and coalesce in heavy infections
Poultry: Describe the clinical signs and pathology of Eimeria maxima ?
Eimeria Maxima
Clinical signs
- poor feed conversion
- loss of weight, poor egg production
- anorexia, depression, emaciation
- water diarrhoea
- occassional mortality in heavy infestations
Pathology
Lesions are pin point discrete, red on serosal and mucosal surfaces
- thickened mucosa
- flaccid fluid filled with yellow orange contents
- diptheritic membrane
Poultry: Describe the pathology and clinical signs of E.necatrix ?
Eimiria. Necatrix
Pathology
The intestine is often dilated to twice its normal size ‘ballooning’
- small white and red plaques on ‘serosal surface’ salt and pepper
- lumen filled with bloody fluid
- alot of haemorrhage is associated with this disease
Clinical signs
Usually a disease of older birds lower reproductive capability
Located jujenum
- highly pathogenic
- bloody diarrhoea
- severe depression, emaciation and anorexia
- anemia
- significant mortality
Poultry: Describe the pathology and clinical signs of Eimeria. tenella
Eimeria. Tenella
Located within the ceca
Pathology
- ceaca appear ballooned with significant congestion
- caecal pouch greatly distended and filled with necrotic material
- cheesy semi solid caecal corse present in recovered cases
Clinical signs
- severe bloody diarrhoea
- anaemia
- depression, emaciation and anorexia
- significant mortality - spectacular sudden jump
Poultry: Describe how you would diagnose coccidiosis ?
Diagnosis of coccidiosis
- lesions
- histopathology
- demonstration of life stages through scraping
- PCR
- Faecal floatation for oocyst
The pathology is generally sufficient for diagnosis
Poultry: What factors could we implement to control and treat coccidiosis in broilers and layers ?
Control of coccidiosis
Broilers
- short lived high performance (no time to develop immunity
- ionophore and chemical coccidials(baycox)
- lesion scoring to test efficiency
Layers
- vaccination
- multi strain vaccines available (no cross protection)
- more expensive than chemicals, but may be used to rest chemicals
- immunity short lived 3 weeks
- natural challenge and controlled exposure
Treatment
Anticoccidial drugs immediate water treatment
- Toltrazuril (baycox)
- Sulpaquinoxaline
- in water supportive treatment eg multi vitamins
Poultry: Describe the digestive system of a chicken ?
Poultry: Describe the epidemiology of Necrotic enteritis ?
Necrotic enteritis = Clostridium perfringens infection
Bacteria
Gram positive, anaerobic, spore forming rod
- commensal organism in the intestinal tract
- causes damage through replication and release of toxin
Common in commercial poultry
- chickens of all ages, turkeys and ducks
- often seen in conjunction with coccidiosis
- diet has a major impact on incidence
It is not adapted to the small intestine - causing damage via releasing toxins into the small intestine.
Poultry: Describe the clinical signs of Clostridium perfringens ?
Necrotic enteritis Clostridium perfringens
Peracute deaths, high morbidity and mortality (50%)
- acute onset
- depressed, hunched, huddled and anoretic
- appearance very similar to E. necatrix and E. maxima
- watery haemorrhagic diarrhoea and caking of litter
Poultry: Describe how you would go about diagnosing a case of necrotic enteritis ?
Diagnosis
Necrotic enteritis = clostridium perfringens
Post mortem
- thin walled friable intestine
- visable lesions serousal surface
- distended ‘ballooning’
- intestinal contents liquid foul smelling
- pseudomembranous diptheritic membrane (difficult to scrape off)
- rapid post mortem autolysis
Conformation
Direct smear
Poultry: What can be done to prevent or treat Clostridium perfrengens ?
Control and treatment
Necrotic enteritis Clostridium perfringens
Antibiotics for atleast three days
Amoxycillin
+ treat concurrent coccidial infections
Prevention
- pre biotics, pro biotics, rganic acids
- feed changes and enzymes
- in fed medication avilamycin, zinc bactitracin
Poultry: Describe the aetiology and epidemiology of Histomoniasis (blackhead) ?
Histomoniasis
Aetiology
- motile protozoan
- very fragile organism
- amoeboid and flagellate stages
Epidemiology
- Worldwide
- most prevalent free range
- chickens, turkeys and ducks
Transmission = Heterakis gallinarum + earth worms
Poultry: Describe the pathology of Histomoniasis ?
Pathology Histomoniasis
Histomonads released in caecum and invade submucosa - extensive inflammation and necrosis
- reach the liver via hepatic portal system
- divide multiple in caecum and liver - forming grossly visable necrotic lesions
- concurrent infection with coccidiosis, contributes with the spread to liver
Poultry: What clinical signs would you observe with Histomoniasis infection ?
Clinical signs of Histomoniasis
Symptoms appear 7-12 days post infection
- depression, drowsiness
- drooping of wings
- anorexia
- sulphur yellow droppings
- morbidity 1-10% (chickens may reach 10-20%
Poultry: Describe what we would observe in a post mortem of Histomoniasis ?
Post mortem Histomoniasis
Caeca
- unilateral or bilateral
- small ulcers which may rupture
- caecal cores concentric rings (onion rings)
The onion rings may be used to differentiate from E. tenella
Liver
- distinctive depressed areas of necrosis
- circumscribed raised ring
- more prevalent in turkeys than chickens
Poultry: Describe how you would go about preventing or traeting Histomoniasis ?
Histomoniasis
There is no effective treatment
- may provide antibiotics for any secondary infections
The best method is prevention
- limit access to earthworms
- aggressive parasite control
- seperation of turkeys and chickens
Poultry: What is the cause of Dysbacteriosis ?
The cause of dysbacteriosis
Non specific bacterial enteritis - imbalance of normal bacterial population
- non infectious
- production limiting
- nutritional interaction; dietary changes or abrupt feed interuptions
Wheat based diets have a high starch content - microbial population becomes imbalanced
- change in PH
- encourage anarobes
- damage to microvillous linning
- Increased susceptability to clostridial overgrowth and enteritis
Poultry: What are the clinical signs of Dysbacteriosis ?
Clinical signs of Dysbacteriosis
- litter becomes wet
- diarrhoea, unformed very fluid
- feathering becomes dirty
- foot pad lesions
- increased water consumption
Poultry: Describe how you would go about diagnosing a case of Dysbacteriosis ?
Diagnosis Dysbiosis
Post mortem
- intestine contains high volumes of liquified contents
- intestine friable
- contains undigested fed
- voluminous caecae, often with gas bubbles
May progress to clostridial enteritis, necrotic enteritis
Poultry: Describe how you would treat an outbreak of dysbiosis ?
Treatment Dysbacteriosis
Review rations to correct starch imbalance or remove indigestible ingredients
- probiotics, prebiotics
- organic acids
- review coccidiosis + clostridium control
- improve husbandry especially floor conditions
Amoxil - may help to reduce anaerobic bloom
Poultry: Describe the aetiology and pathology of Colibacillosis
Colibacillosis = E.coli infection
Aetiology
- invariable a secondary pathogen, requires a predisposing cause
- gram negative
Epidemiology
E.coli is a normal gut and environmnetal inhabitant
Secondary infection occurs due to a primary disease allowing a point of entry
- Primary APEC (no virulent cause, Secondary
- poor husbandry
- injury scratches foot pad dermatitis
- poor management air or water quality
Most common cause of death in broilers and layers
Infection = oral, inhalation or injury routes
Poultry: Describe the clinical signs of an E.coli infection in chickens ?
Clinical signs Colibacilosis E.coli
The clinical signs vary depending on the particular strain of E.coli and site
- respiratory signs, coughing, sneezing
- depressed
- huddled
- inapetance, poor growth
- characteristic smell
- diarrhoea and pasty vent
Predisposition = Abnormally open naval
Poultry: Describe how you would go about diagnosing E.coli ?
Colibacillosis, E.coli
Clinical signs + history
Conformation through postmortem
- femoral head necrosis
- cellulitis
- airsacculits, pericarditis, perihepatitis, peritonitis
- arthritis
- omphalitis (yolk sac)
Describe the Aetiology and clinical signs of yolk sac infection ?
Yolk sac infection = E.coli
Unhealed navals due to early or late hatching
- unhygienic hatchers / equipment
- poor husbandry
- < 2 days of age
The clinical signs
