New castle disease viruses

written by dr abdelaziz

abdelftah

avian poultry consultant of middle east

editor of the poultry disease for the future poultry consultant

Owner of the advisory veterinary lab for the avian disease

digresses – Egypt.

Dr abdelaziz poultry lab @ yahoo.com

tel : 0020123189524

New castle disease viruses

This is septicemic deadly virus of poultry which affect

chicken " especially younger ones" - Turkey – quills – pigeon

and rarely duck. This viruses is belonged to Family called paramoxy viruses

sero type I ( A P M v-1) Paramoxy viruses classified into :

A- paramoxy virus ( pro type . ND viruses ) B- paramoxy virus ( respiratory form )

C- Morbili virus ( measles form )

all paramoxy virus consists from :

N.D is enveloped viruses have -- ve sense single stranded RNA of ( 13 kb)

Have two types of spikes haemoagglutine & Neuromindize ( six genes) which contain .

6 viral structural

F .Protein

N

H . N M . Protein

*The viral (F) .protein brings about fusion between the viral membrane and the cell membrane so the viral genes enters the cell and replicate in it and during replication N.D particles are produced with a precursors glycoprotein ( F) that has to be cleaved to F 1 , F2 glycoprotein.

*in case of Avian influenze , the penetration occur by

areceptor mediated endocytocsis mechanizms which could be affected by the affect of essential oil on the attachment mechanizm of the viruses by the effecting the configuration

of the heamagglutine protein .

Newcastle disease virus virulence is measured by . (1 )The virus has an intra cebral pathogenicity index ( ICPI) in

day old chick (gallus gallus) of (0.7) or greater .

(2 )multiple basic aminoacids either directly or by deduction at the C . terminus of the F2 protein so the virus considered as

septicemic deadly viruses .

A - Classification of the virus acc to its virulence into 1 -lentogenic strain

low in virulence * 2 -mesogenic strain

moderate in its virulence as (komorove & Roakin)* 3 -velogenic strain ( Doyls form & Roakin )

very virulence as (GBtexas & Herts)*B – according To Tissue morphizm

1 -neurotropic viruses 2 -pneumotropic viruses

3 -vesrotropic viruses 4 -panotropic viruses

C- acc to name :

Doyl's form (entiric form ) * *Beach form

Beate detos form * *Hitchner form

*Asymptomatic form

General Clinical signs of N . D viruses infection differs according to

A- immunostatus of bird at time of exposure .

B- the age of the flock Young birds are more affected than aged ones.

c - the degree of exposure of flock to the virus

D – The General healthy condition of the flock at

time of exposure as appearance in case of mycotoxicosis.

The clinical signs: (1 )unusual quietness of birds and the birds huddle with

each other ( 24 hrs ) before the clinical signs become evident

especially at early morning .

(2 )appearance of sudden respiratory manifestation ( rating

sound ) (3)feed and water intake is decreased by increasing

severity which reach to its half amount than normal

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)photo 1(

( normally broiler birds eat about 150 gm per a day at 30 day

which rich to 65 gm peraday in case of N.D infection . (4 )appearance of watery greenish dirrhaee and in some

cases bloody dirrhaee

(5 )coughing , gasping and rating sound which may

appears incase of the in the mesogenic form due to the

appearance of the neuraminidase enzymes and this material

decrease viscosity of the liquid which appears in the

epithelial tissue of the respiratory system which leads to

opening of receptors and going of this liquid downly to lung.

(6 )in neurological form appearance of early neurological

signs as the tortcolitis ( star gasping) which affect the

cerebillium and brain stem producing multi focal glial

nodules and necrosis .

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)photo 3(

(7 )appearance of spasmodic paralysis of Mm .

(8 )appearance of perching reflex as absence of nerves reflex of the toe legs when putten on finger ( but in normal condition when we put of legs on our finger they will catch

down in opposite direction to finger . .

(9 )appearance of lamness ( relactant to stand or move and

appearance of complete paralysis of legs which occur as drop

of first wing then 2nd wing beside the incoordination of

movement of flock and this called ( dragging of legs) .

) photo 4(

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(10 )with increase of severity of virus infection and appearance of viramic stage the mortility is increased which reach to high number then stable at the high level in the second day then decline gradually and feed and water increase again and birds scatter again in the farm and

respiratory manifestion will decreased again.

*and this curve take about 8 days from its beginning but in case of avian flu the curve of mortility is very high and increase to its double every hours and not ended but the curve of mortility of N.D is ended if the N . D is appears only without any secondary bacterial infection or any

viruses infection accompanied .

(11 )in peracute form ( asymptomatic form appears as

many poultry dead from N. D viruses without symptoms and

this occur if the birds has higher degree of immunity against

the viruses.

( in layers )

1 -Sudden drop in egg production reach to zero and may

lasts for 4-8 weeks .

2 -Affect on egg quality egg" shell discoloration which

considered as one of the first signs of N.D include the

reproductive tract of the breeders hen and this sign more

appear in brown egg layers . and if the infection is severe the

shell become fragile and abnormalities occur in shape size

and after signs of N.D disappear the egg production is

decreased also for about 4-8 weeks later

( P.M lesions )

(1 )N .D viruses leads to profuse bleeding as it leads to

analysis of R.B.C s. (2 )appearance of pin point necrotic focii scattered on

epidural fat of the leg muscles

3 -severe viramea which leads to bloody appearance of the

musculture of the bird Mm and the bird takes ( feverished

appearance )

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(4 )bleeding into the tracheal mucosa ( hommorragic

trachitis as in case of acute form of N . D viruses

(5 -)appearance of pink swollen eye and swollen eye lids

with abnormal fluid and faschial oedmae appearance – foamy

nasal discharge and accumulation of liquid in trachea.

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)photo 8(

6 -lung is congested and appearance of cloudy air sac and exudates present on lung and wipe pipe and acute inflammation of air passages and this called trypling air sacs which called the pneumonia

7 -appearance of profuse intestinal and muscular himmorrage called the viramea and appearances of pin point hemorrhagic ulcers called ( Doyls form ) which scattered through the intestinal tract and when this lesion appears confirm that the viruses present in the farm for about 4 : 7 days and this is important in using the emergency vaccination to be of value or

not .

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)photo11(

8 -appearance of bluish & reddish necrotic raised area at

the lymphoid tissue especially blind sac (cecaltonsils)

9 -appearance of homorrhage on the tips of gizzard and

around the surface.

10 -appearance of the petchal hommorrhage on the sub pleral

fat and heart fat .

) photo 12(

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11 -clocal lesion : Appearance of multiple

randomly distrubited well

demarcated hommorragic

erosions and ulcers and this

ulcers present on the mucosa of

cloacae with overlying fibrin

accumulation . To differentiate the fibrin from

digestea by washing the lesion

the digesta go out but fibrin is

still appears.------------------------------------------------------------

------------Lesion in layers:

Appearance of necrotic

foccii on ova.Hommorrage on the ova. Shelless egg.

Colour of eggs is changed

especially in brown egg

breeds which turned to

colourless eggs.

) photo 14(

) photo 15(

Diagnosis of the virus: 1 - isolation and identification of the virus .

( a ) samples taking from infected flock . take the swabs from trachea ( 10 sample) and 10 swabs from

clocae at age of 22 – 28 days of age for PCR . taking of blood samples from the jugular vien for serology and

H.I Test which is used for antibody number against N.D viruses

infection ( ANON 1971 ) molecular Basis of viral virulence ( Rott and klent) it is

possible to use the nucleotide sequencing technique to asses

whether or not an isolate has the genetic make up to be highly

pathogenic for poultry( Collins 1993 )

according the HI. test the minimum protection level is mean

antibody an of log 20 ( anon 1971)

(schmit 1955) studied the relationship of HI. titrc and

the protection capacity as HI titre up to 16 failed to

resist the challenge infection adequate antipathy (HI)

titre of 2 3 or greater which is the minimum standard to

give protection to N.D viruses for birds less than (18 w)

and ( 25 ) or greater for birds above 48 weeks or older.

Epidemiological group meaning It is a group of bird is deemed to the same epidemiological

group if the following criteria are present as :

a- All birds in the group are vaccinated at the same day . B- all birds in the group were vaccinated using the same

vaccine ( same lot / batch no )

C – all birds in the group are of the same age. D – all birds in the group are of the same spp.

E– biosecurity measured are the same . Immunity and vaccination against the N. D virus :

A- maternal antibody of N . D viruses Chicks from vaccinated parent Stock contained high level

of maternally derived antibody which ranged from 285.51

– 289.43) at day old and then degrade gradually below

protection level within 15- 20 days after hatching and

maternal derived antibody decline about half every 5 days

( Allan etal 1978) as 2 fold decay in maternally derived

antibody every (5) days . Maternal antibody neutralize the introduced vaccine antigen

rendering the vaccine ineffective ( awang et al 1992)

immunoresponse was nil at high titre of maternal antibody. B- humeral Immuroresponse against N . D ( I9M & 19 G)

Maternal antibody neutralize the introduced vaccine .

antigen rending the vaccine ineffective ( awanget el 19)

Immunoresponse wall be nil at high titre of maternal

antibody.

This curve refers to the normal declination of the

broiler bird immunity at the age from 25 until 27

day and then go normally to rise from day 28 and

this period is very dangerous in the virus infection

23 24 25 26 27 28 29 30

Imm

unity

Days

Blockage mechanism phenomanah of Newcastle virus By . dr abdelaziz Abd elftah

This phenomanah characteristic to N. D viruses as

appearance of the competition between the field viruses of

N.D and the adapted viruses of the vaccine which used

against N. D.

Once one of them reach to the target cells in the receptors

specialized for N . D will block it and prevent the other

virus to enter .

This phenomanah is useful in making emergency

vaccination against N . D but this occur under certain

condition as . When the virus of vaccine enter the cells at first

before the filed virus the birds will survive and the

field virus fail to be pathogenic and appears of good

immune system . But when the opposite occur and field virus enter the cells

befor the virus of vaccine so the bird will dead.

And this depends up on the days of infection and the delay

of diagnosis .

Emergency vaccination of N .D is useless as

incubation period reach from ( 1-3 days) but under stress

and environmental problems and appearance of mycotoxin

in feed or other stre ssfull condition the immune system of

the bird will be weak and the infection takes only 24 hrs to

appears . virus in when present in the intestinal tract or in

respiratory tract is very weak and emergency vaccination

will be usefull but once enter the blood and go to the

viramic stage ( which takes 4 days ) the emergency

vaccnation will make the so called ( virus challange ) and

will be deadly to birds.

From our field experience if you have a good

common sense in the first diagnosis of N.D by clinical signs

and Hi test & serology and isolation through the first 24 hrs

the vaccinator is will be useful .

But if you delayed in diagnosis of the case and appearance

of decreasing of feed intake and water and appearance of Respirotory manifestation and greenish dirrhaee.

The vaccination is forbidden.

SO

SO

SO

How to deal with the case affected by N. D

viruses and we delayed in its diagnosis :

You must let the viruses to take its severity period photo

and then the bird will recovery from itself and you must in this

period concern on using:1 -liver and kidney support derivatives.

2 -giving of immuostimulator drugs to bird .3 -good hygenic ventilation control.

You must take care from the using of the antibiotics &

injection ( espercilly in the respiratory manifestion which

appears as atrap for the farmers and veterinarian. From our expereience we spray on birds piperment oil

and ecupltus derivatives and iodine prepartion at night to

decrease the respiratory manifestion problems and to decrease

the incidence of enterance of other avian ( flu & IB) in affected

area with N. D infection period .

SO

Vaccination control : Each vaccine againist N . D should contain not less

than ( 10 6 EID / ml) ICPI

ND 6/10 0.25 VG / GG 0.3

HB 0.2

Cloned 58 ( Hitchner ) 0.2 Lassota 0.4

Cloned lassota 0.4

PATHOGENATYICPIVSTRAIN

Apath0.0-0.16PHyl Mv 0.4

Apath0.15Ulster st. Apath0.15VH

Lentogenic0.2HB

Lentogenic0.35VG/ G.A

Lentogenic0.4Lassota

Type of vaccine Live vaccine :

A- lentognic form

each vaccine should not contain less than ( 106 EID so ml )

Colone HB1lossota

ICPI 0.4ICPI 0.2ICPI 0.4 Protect chicks w or without maternal

immunity

*No adequate protection

*Gives local immunity

Highly affect on protecting chicken

wout maternal antibody

respiratory tract only Respiratory tract

Predlication site the respiratory tract and

mesentry

Colone HBIlossota

Causes minimal vaccinireaction

even app in one day .

Mild respiratory reaction

Cause sever systemic distress which resulting in

increase the moritility and

delayed weight if given at early ages

Vaccination w lassota is preferable

at age of 18 days old chicks not less than as maternal

immunity at age of 4 days will be 26

and at age of 9 days 25 and at age

of 18 days 23 Injection of live viruses as lassota leads to a wide range

Of affection in the flock as 1 -high antibody 2 -stress response

3 -neutralization ( antibody free)

B- mesogenic form :

1 -Using of komorove which used as awing stab

a administration . 2 -You must give good and sufficient primary dose

of N. D before using of komorove by ocular

technique by sufficient time . to take good result

from using of komorove but if the primary

vaccination . has been failed and we use komorove

which gives sever post vaccination reaction and

sever range of bad effect.

3 -mesogenic strain ( is preferable to not applied

before 10-12 weeks )

2 - killed ( inactivated vaccine ) (Good in decreasing of susceptibility of birds to N. D

viruses. (A )When injected sub/cut or intramuscular work

immediately but reach to its peak of action after is days of

injection . (B )it is preferable . to vaccinate both live and killed vaccine

to reach the so called hyper immunization procedure .

Using of killed and live vaccine to induce hyperimmunizatiom

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Unvaccinated birds

ylno eniccav eviL

delliKylno eniccav

(noitazinummirepyh ) gnisu eniccav dellik dna eviL