L3: Newcastle Disease (Romero) Flashcards Preview

Poultry Medicine (Fall 2016) > L3: Newcastle Disease (Romero) > Flashcards

Flashcards in L3: Newcastle Disease (Romero) Deck (20)
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1
Q

Newcastle disease is aka:

A

Avian paramyxovirus 1

  • has 9 serotypes
  • a ss RNA virus
2
Q

Membrane of NCD virus contains what glycoproteins?**

A

HN and F

3
Q

Pathotypes of NCD

A

Viscerotropic velogenic (gut hemorrhage, high Mo)
Neurotropic velogenic (resp/neuro signs, high Mo)
Mesogenic (acute resp/nervous signs, low Mo)
Lentogenic (mild resp signs)
Asymptomatic enteric (avirulent)

4
Q

Where did NCD come from?

A

1950: partridges and pheasants imported from Hong Kong

CA outbreaks 1970s, early 200s

5
Q

Pathogenicity assays for NCD by age

A
  1. Eggs: Mean Death Time (MDT)
  2. Day old chicks: Intracerebral Pathogenicity Index
  3. 6 wk old chickens: Intravenous Pathogenicity Index
  4. 6-8 wk old chickens: Intracloacal Inoculation Pathogenicity\
6
Q

NCD: geo distr.

A

Endemic: Asia, Middle east, Africa, Central/S. America
Epizootic: US, UK, Australia, Canada

7
Q

Epi of NCD

A

-virus survives for wks in env.
-incubation period = 2-15 days
-migratory birds and feral pigeons can carry
deaths in 24-48 hrs, continuing for 7-10 days
-almost 100% Mb (90% Mt, depending on strain)

8
Q

Trans. Of NCD

A
  • direct contact

- contaminated env.

9
Q

CS of NCD

A
  • dec. egg production
  • ducks, geese can be asymptomatic
  • edema of head/eyes
  • green/dark watery diarrhea
  • resp/neuro signs
  • depression, prostration
  • asphyxia
  • hemorrhages in comb, head, conjunctiva
10
Q

Necropsy of NCD

A
  • multifocal hemorrhages (ie. In trachea, larynx, GIT, ova)

- hyperemic/necrotic cecal tonsils and lymphoid patches

11
Q

Public health significance of NCD

A

Can cause conjunctivitis in humans (goes away in about a week)
-NOT transmitted by consuming poultry products

12
Q

Vax for NCD

A

At hatchery: in ovo or as spray/eye drops in chicks (live vax)
At poultry house: live vax in drinking water
Layers/repro stock: prime with live vax, boost with inactivated vax at 16-18 wks

High Ab lvls can be transferred to progeny

13
Q

What samples can be collected for dx of NCD?

A
  • feces/cloacal swabs
  • tracheal swabs
  • brain, when neuro signs present
  • LU/SP/LIV/HT
14
Q

Laboratory dx of NCD

A
  • MUST ALWAYS BE CONFIRMED
    1) Ag found in tissues
    2) isolate in SPF embryonated eggs (kills embryo in 3-7 days; test for HEMAGGLUTINATION in 5-7 days)
    3) RT-PCR
15
Q

SPF embryonated chicken eggs are the most sensitive for all APMVs

A

:)

16
Q

ID of avian paramyxoviruses

A

Hemagglutination (HA) activity in chorioallantoic fluid due to 1 of 9 paramyxoviruses or 1 of 16 FLU subtypes

-confirm dx by inhibition of HA or HI with specific antisera and/or monoclonal Ab

17
Q

Ddx for NCD

A
  • HPAI**
  • Fowl cholera
  • Laryngotracheitis
  • Coryza
  • Fowl pox
  • Psittacosis
  • Mycoplasmosis
  • Infectious bronchitis
  • Management problems
18
Q

How to differentiate virulent from non-virulent strains of NCD**

A

Virulent strains have the presence of basic amino acids around the cleavage site of the Fusion (F) protein

19
Q

NCD vax in BROILERS

A
  • maternal Ab interferes with systemic active immunity
  • doesn’t significantly affect local resp. Immunity
  • early vaccinations require boosting; hatchery vax is short lived
  • immune competence is better in older birds
20
Q

Serological surveillance after NCD vaccination

A

ELISA is used to assess humoral response after vaccination or natural infections; provides information on uniformity and strength of humoral response