Sunday, August 30, 2020

Newcastle disease-

  • Newcastle disease






Newcastle disease

Newcastle disease(ND)


occurance: world wide ,very common ,very virulent.
newcastle is a notifiable disease.


species affected:all species ,one of the most common respiratory disease of poultry.

age affected : all ages of poultry.

causes: newcastle disease virus is single strain , non segmented , RNA virus ,envelope and belong to paramixoviridae family .



there are three pathotypes
1-lentogenic (mild disease)
2-mesogenic (moderate disease)
3-velogenic(sever morbidity  and mortality)

newcastle is air borne disease spreads by inhalation or by ingestion virus.


incubation period : 2-15 days 


symptoms: twisted neck , immunosuppretion ,paralysis ,incoordination and central nervous signs following the initial respiratory signs which are diagnostic of newcastle disease virus .
watery eye and blug in the eye is seen with lentogenic strain .

coughing , gasping  and sane mortality are seen with mesogenic strain .
egg production and quality of egg are affected .
it may produce "torticollis" paralysis , bloody diarrhea .

high morbidity and mortility  occur with velogenic strain .


special note
VVND (viscerotropic velogenic newcastle disease )

It is a notifiable disease , it is a very common viral  disease of poultry.
most poultry are vaccinated several times against this virus.

causes :
this disease was named after a town in England where it was first seen .

single strain ,RNA virus , non segmented , envelope and belong to paramixovirus.

three pathogen strains exist 
1-lentogenic (mild disease )
2-mesogenic (moderate disease )
3-velogenic(high morbidity and mortality )



species affected :
all species of birds of all ages are susciptable  to this acute to chronic disease .

it is the most common of respiratory diseases .


mode of transmition 
air borne disease (inhalation or ingestion )
free flying birds may be infected with lentogenic strains.


clinical signs 

coughing , gasping  and sane mortality are seen with mesogenic strain .
egg production and quality of egg are affected .
it may produce "torticollis" paralysis , bloody diarrhea .

high morbidity and mortality  occur with velogenic strain .

brown broiler eggs convert into white egg

incubation period 

2-15  days



exotic , rarley occur in commercial poultry in the united state .

outbreaks in pet bird population are more frequent .


prevention
vaccination in one day age in the hatchery using a course spray machine .

multiple live and killed vaccine are given to broiler in area with VVND .

pullets and often layers multiple live and killed VDV vaccine 

B1+B2 +lasota strain are normally used.

A recombinant  NDV vaccine 




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