avian influenza and newcastle disease Flashcards
what are the two notifiable poultry diseases
avian influenza
newcastle disease
pigeon paramyxovirus
what type of viruses are newcastle and influenza
influenza=orthomyxovirus
newcastke disease=paramyxovirus
(both enveloped RNA with glycoprotein spikes H,N and H,N,F respectivley)
what differs between these two virus that makes one harder to vaccinate against than the other
avian influenza has a segmented genome meaning that antigenic shift can occur. as a result there are many strains of varying virulence with no cross immunity between virus subtypes
what type of AIV is of veterinary importance
type A
only virulent strains are notifiable
which subtypes of AIV are of high pathogenicity
H5, H7 subtypes
what are the clinical signs of general avian influenza
depression dulness ruffled feathers cyanotic/necrotic comb/wattle swollen head reduce intake of feed and water cyanosis of shanks tracheal and gi haemorrhage
once suspected what are the next steps takes
- notify DEFRA
- send samples to international reference lab
- PCR of H5/H7 primers (pathogenicity testing)
- subtyping by specialist labs
is AIV stable outside the host
not really. killed by phenol, formailn and UV light
survive 2 weeks in dust and prefers cold wet conditions
how is AIV spread
aerosol, feaces, water/food/surface contamination
what is the control strategy for AIV
STAMPING OUT
What are the 5 groups of Newcastle disease from least to most severe
asymptomatic enteric lentogenic (mild resp) mesogenic (resp, neuro) neurotropic-valogenic (resp, neuro) viscerotropic-valogenic (gut haemorrhage)
what are general signs of NDV
ABNORMAL THIRST
loss of apetite
ruffled feathers
what are clinical signs of neurological strains of NDV
tremors
twisted neck
convulsions
star-grazing
what are the clinical signs of viscerotropic-valogenic strain of NDV
green-yellow diarrhoea
GI haemorrhage
how do you diagnose NDV
serology by PCR
post mortem
How would you vaccinate against NDV
broilers=LIVE VACCINE
1-2 times by spray, water or nasal routes
layers=LIVE OR INACTIVATED
give live 1-4 times 4-8 weeks apart by spray, water or nasal route
give 0.5ml inactivated by IM/SC route
breeders=same as broiler but can give inactivated twice
what bacterial disease is of little significance in chicken but is of high public health importance
salmonella!
what are the clinical signs of salmonellosis in humans
gastroenteritis nausea vomiting diarrhoea fever
What are the 5 vaccination methods of chickens
- Coarse spray
for respiratory diseases. droplets cover birds and vaccine is either inhaled or pecked off feathers - drinking water
blue dye used to ensure chickens have actually drank it - on food
- injection
(mareks only one given SC at day old) - IN OVO
vaccine injected into egg through shell at 18 days of incubation.
SUMMARY OF DISEASES AND SIGNS
Avian influenza=tracheal haemorrhage, cyanosis of comb/wattle, cyanosis of legs
Newcastle disease=abnormal dehydration and thirst, tremors, twisted neck, convulsions OR yellow diarrhoea, gut haemorrhage
Avian pneumovirus=respiratory, swollen head syndrome, loss in egg shell quality and pigmentation
poultry mycoplasmosis=lameness, swollen joints, brest blisters
infectious laryngeotracheitis=gasping, spit out mucus/blood, causeous plug in trachea.
infectious bronchitis=egg peritonitis
infectious bursal disease=muscular haemorrhage, proventricular/bursal haemorrhage
chicken anemia virus=yellow bone marrow
mareks disease=nerve swellings, tumors, splayed legs
