Avian Influenza Highly Pathogenic ( ...

Avian Influenza Highly Pathogenic (HPAI) H5 or H7 in Laying Hens

Avian Influenza Highly Pathogenic (HPAI) H5 or H7 in Laying Hen

Observed Clinical Signs Happenings

Egg Drop

  • Egg production declines rapidly
  • Precipitous drops in egg production occur with typical  declines including total  cessation of egg production within six days

Visibly sick birds

  • Many visibly sick birds
  • Depression is common

Behaviour

  • The poultry houses may be unusually quiet because of decreased activity and reduction of normal vocalization of the birds
  • Depression

Mortality

  • High mortality or increases rapidly
  • In most cases, the disease is fulminating with some birds being found dead prior to observation of any clinical signs
  • Typically, the virus spread rapidly among poultry housed on the floor with peak mortality (70-100%)  occurring in 3-5 days of first clinical signs
  • In poultry housed cages, the virus spreads slower through the house with peak mortality taking 10-15 days
  • When death is peracute, no gross lesions may be observed

Dead birds

  • Good body fleshing condition
  • The mortality occurring in 3-5 days of first clinical signs in birds housed on the floor
  •  In birds housed in cages,  the peak mortality taking 10-15 days

Respiratory

  • Respiratory signs spread fast
  • Respiratory signs are less prominent than with Low Pathogenic  Avian Influenza Virus
  • Rales
  • Sneezing
  • Coughing

Nervous

  • If the disease is less fulminating and the birds survive 3-7 days may exhibit nervous disorders:
  • Tremors of head and neck
  • Inability to stand
  • Torticollis
  • Opisthotonus
  • Unusual positions of the head and appendages

Lameness

  • Inability to stand

Head Comb Wattles Face Nostrils Sinuses Mount Beak Ear lobes abnormalities (except eyes)

  • Multifocal necrosis and haemorrhages of comb and wattles
  • Severe edema, necrosis, and haemorrhages of comb and wattles
  • Periorbital  edema may be seen accompanied by petechial-to-ecchymotic hemorrhages
  • Swelling of the head, face and upper neck accompanied by petechial-to-ecchymotic hemorrhages
  • Necrotic foci, haemorrhage, and cyanosis of the non- feathered skin especially wattles and comb

Body Parts (Neck, wings, breast, abdomen, shanks, legs, hocks, feet, joints, vent, and skin, abnormalities), skinny body, retarded growth, weight depression

  • Severe subcutaneous haemorrhages of leg shanks
  • Edematous, haemorrhagic and necrotic lesion in the skin
  • Swelling of the upper neck
  • Subcutaneous edema and may be accompanied by petechial-to-ecchymotic hemorrhages
  •  Necrotic foci, haemorrhage, and cyanosis of the no feathered skin

Feed Consumption Changes

  • Feed intake reduced
  • Significant declines in feed and water consumption

 

Avian Influenza Highly Pathogenic (HPAI) H5 or H7 in Laying Hens in Laying Hens show, exhibit, or manifest any of the following clinical signs happenings:

Observed Clinical Signs Happenings*

ALWAYS

NEVER

SOMETIMES

Egg drop

  •  

 

 

Egg production declines rapidly

  •  

 

 

Egg production drops gradually

 

  •  

 

Mortality above the standard

  •  

 

 

Low mortality or increases gradually

 

  •  

 

High mortality or increases rapidly

  •  

 

 

Dead birds

  •  

 

 

Dead birds in Good bodily condition

  •  

 

 

Dead birds in Poor bodily  condition

 

  •  

 

Visibly sick birds

  •  

 

 

Few visibly sick birds

 

  •  

 

Many visibly sick birds

  •  

 

 

Flock behaviour activity change

  •  

 

 

Decreased flock mobility or activity

  •  

 

 

Increase flock mobility or activity

 

  •  

 

Droppings abnormalities

 

  •  

 

Respiratory abnormalities

  •  

 

 

Spread fast

  •  

 

 

Spread slow

 

  •  

 

Neurological Nervous

  •  

 

 

Lameness or unusual movements, incoordination, reluctance to move

  •  

 

  • *

Eyes abnormalities

 

  •  

 

Head: Comb Wattles Face Nostrils Sinuses Mount Beak Earlobes (except eyes)

  •  

 

 

Body Parts (Neck, wings, breast, abdomen, shanks, legs, hocks, feet, joints, vent, and skin, abnormalities), skinny body, retarded growth, weight depression

  •  

 

 

Feathers abnormalities

 

  •  

 

Feed Consumption Changes

  •  

 

 

Feed intake increased

 

  •  

 

Feed intake reduced or refusal

  •  

 

 

Diet or Feed Changes (Recent Feed delivery, Recent formulation /diet, Other silo or improper storage, another feed brand)

 

  •  

 

Shell quality

 

  •  

 

Internal Egg quality

 

  •  

 

*  Sometimes has not been observed  some of these clinical signs yet or inadequacy of monitoring systems, and even the course time of the disease

 

 

 

Causing Agents
Viral infection. Avian Influenza (AI) virus, family Orthomyxoviridae, genus Influenza virus A. HPAI ("highly pathogenic avian Influenza")
Affected Systems/Organs
Systemic disease (entire body) that affects respiratory, reproductive, digestive, cardiovascular, nervous and integumentary (skin) systems.
Spread
Bird to bird, contaminated water and objects from infected birds. The virus is transmitted by direct contact between infected and susceptible birds or indirect contact through aerosol droplets or exposure to virus-contanminated fomites. The virus is excreted from the nares, mouth, conjunctiva, and cloaca of infected bird into the environment because the virus replication in the respiratory, intestinal, renal, and/or reproductive organs.
Mainly Affects
Liveability and egg production
Solution
Prevention, management, and eradication by slaughter using combination of five following specific components: education, biosecurity, diagnostic and surveillance, elimination of infected poultry.
Suggested Actions
  • Can be confirmed with clinical signs and gross lesions
  • Diagnosis should be confirmed with rapid assays and/or a certified laboratory
  • Veterinary intervention is recommended
  • This is a notifiable disease, veterinary intervention is essential. It is advisable that you run DTECT again to ensure you have answered all the questions correctly. If you suspect that you may have this disease please contact your local authorities immediately.

Impact on Egg quality

0

Impact on Liveability

5


Impact on Production

5

Overall Economic Impact

5



  1. Y.M. Saif.2008.Disease of Poultry. 12th Edition. page 167
  2. David E. Swayne. 2013.  Diseases of Poultry 13th Edition. page 196

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