Managing common viral infections in poultry Flashcards
Describe the problem-solving approach to ommon presentations?
- Problem identification
- Data collection
- Hypothesis formation
- Diagnosis Testing
- Data analysis and interpretation
- Evidence based intervention
- Monitoring and Evaluation
- Prevention Strategies
How to PE poultry
- Capture & restraint
- BCS
- HEad & neck
- Oral cavity
- FFeathers and skin
- Breathing and Respiration
- Abdomen
- Vent
- Legs and Feet
- Feeding and drinking bhvr
Describe Newcastle disease virus
- Varies in severity
- NOTIFIABLE - VACCINATED against
- Variable STRAINS
What type of transmission for NDV?
HORIZONTAL
What factors influencing SPREAD of NDV?
- Virus characteristics
- Host Factors
- Environmental conditions
- Management practices
- Transmission vectors
- Geographical factors
What are the 5 forms of NDV?
- Doyle’s form
- Beach’s Form
- Beaudette’s form
- Hitchner’s form
- ASYMMPTOMATIC
What CLS vary depending on ?
depending on strain of virus
Describe Doyle’s form
GIT - viscerotropic velogenic Newcastle dx (VVND)
Describe BEach’s form ?
Respiratory and neurological signs - neutropic velogenic (NVND)
Beaudette’s form - describe
less pathogenic form = mesogenic pathotype = live vaccine
Hitchner’s form - describe
mild or inapparent respiratory infections : lentogenic pathotype = live vaccines
Describe asymptomatic form
= enteric form = lentogenic viruses = no obvious CS= some live commercial vaccines
What CLs for Doyle’s form ?
- May appear suddenly, with high mortality
- CS begins with Listlessness, weakness, unusual quietness, prostration, death
- May cause oedema around eyes and head. Green D+, muscular tremors, torticollis, paralysis of legs and wings and opisthonous
What CLS for Beach’s Form?
- Chickens -> sudden onset resp dx followed 1/2 d by neuro signs
- Resp signs == sneeing, coughing etc
- Egg prod dec
Morbidity/ Mortality for Beach’s form?
Morbidity 100% Mortality considerably lower up to 50% in adults and 90% in young
Describe CLS for BEaudette’s form
- Mesogenic strains of NDV usually cause respiratory dx in field infections
- In adult birds drop in prod several weeks
- Nervous signs sometimes
Mortality for Beaudette’s form?
Mortality in fowl low exept in susceptible/ v young birds
T/F Beaudette’s form used as vaccine virus?
TRUE
Describe CLS from Hitchner’s form
- Lentogenic viruses do not usually cause dx in adults
- YOung birds -> serious resp dx & mortality with coinfection with LaSota
Production consieration with Hitchner’s form?
Vaccination or infection of broilers close to slaughter -> colisepticaemia or airsacculitis with resulting condemnation
Are there any pathognomic lesions for NDV?
Not really - gross lesions may be absent
What gross lesions may we see with NDV? (PME)
- haemorrhagic lesions in the intestine distinguishing VVND viruses from NVND
- Lesions prominent in mucosa and proventriculus, ceca, SI
- Haemorrhage in Resp tract
Overall what CLS may ring bells for NDX in your history?
- Resp: coughing, sneezing, nasal disC & resp distress
- Neuro: tremors, twisted necks, paralysis, incoordination
- Digestive: D+ & greenish watery faeces
- General: reduced egg prod, misshapen eggs, lethargy, SD
How do we do Virus isolation to diagnose NDV
- Swab from trachea, cloaca, & oropharynx as well as tissue samples from spleen, lungs and brain
- Samples incoulated into emryonated chicken eggs. NDV causes embryonic death and characteristic leisons in the eggs