Avian Influenza Low Pathogenic (LPAI) Moderately Virulent of any H 1-16 or N 1-9 subtype in Laying Hens
The moderately virulent clinical group results from infection by Low Pathogenic avian influenza (LPAI) virus of any HA or NA subtype, but also with co-infection by secondary pathogens. The mortality rates are usually less than 5% unless accompanied by secondary pathogens as well as in reproductively active hens, or severely stressed birds. Clinical signs reflect abnormalities in the respiratory, digestive, urinary and reproductive organs. The most frequent signs represent infection of the respiratory tract and include mild to severe respiratory signs such as coughing, sneezing, rales, rattles, and excessive lacrimation. Egg production is decreased and increased broodiness. The generalized clinical signs including huddling, ruffled feathers, depression, decreased activity, lethargy, decreased feed and water consumption, and occasionally diarrhea. The last few eggs laid will have a reduction in calcium deposition within the eggshells. Resulting eggs may be misshapen and fragile with the loss in pigmentation. (1, 2)
High morbidity (percentage of sick birds) and low mortality are typical. Mortality rates are usually less than 5% unless accompanied by secondary pathogens such as Pasteurella multocida or Escherichia coli. (1, 2)
Observed Clinical Signs Happenings
- Egg production declines rapidly
- Low mortality or increases gradually
- Low mortality rates are typical for Low Pathogenicity Avian Influenza Virus
- Mortality rates are usually less than 5% unless accompanied by secondary pathogens.
- Good bodily condition
Visibly sick birds Pattern
- Many visibly sick birds
- Increased broodiness
Flock behaviour activity change
- Decreased flock mobility or activity
- Occasionally diarrhoea
- Respiratory signs spread fast
- Mild to severe respiratory signs
- Mucous-to-mucopurulent nasal discharge
- Excessive lacrimation
Head Comb Wattles Face Nostrils Sinuses Mount Beak Ear lobes,
- Infraorbital sinuses may be swollen
- Mucous-to-mucopurulent nasal discharge
- Ruffled feathers
Feed Consumption Changes
- Feed intake reduced
- Decrease water consumption
- The last few eggs laid will have a reduction in calcium deposition within the eggshells
- Eggs may be misshapen
- Pale or loss of colour in brown-shelled eggs
- Thin-shelled and soft-shelled or porous eggs
- Ungraded or second's eggs increased
- Egg specific gravity score lower (should be above 1.080 (1.068 thin shells)
Avian Influenza Low Pathogenic (LPAI) Moderately Virulent of any H 1-16 or N 1-9 subtype in Laying Hens DOES NOT exhibit or manifest any of the following clinical signs happenings:
- Egg production drops gradually
- High mortality or increases rapidly
- Dead birds: poor body condition
- Few visibly sick birds
- Increase flock mobility or activity
- Respiratory signs spread low
- Neurological Nervous
- Lameness or unusual movements, incoordination, ataxia
- Body Parts (Neck, wings, breast, abdomen, shanks, legs, hocks, feet, joints, vent, and skin, abnormalities), skinny body, retarded growth, weight depression
- Feed intake increased
- Diet or Feed Changes (Recent Feed delivery, Recent formulation /diet, Other silo or improper storage, another feed brand)
- Internal Egg defects
- Causing Agents
- Viral infection. Avian Influenza (AI) virus, family Orthomyxoviridae, genus Influenzavirus A. LPAI ("low pathogenic avian Influenza")
- Affected Systems/Organs
- Respiratory, digestive, urinary and reproductive organs
- 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
- Biosecurity and hygiene programs and an 'All-in/All-out' approach to production. Vaccination with Inactivated H5 and H7 vaccine and a fowl pox-AI hemagglutinin (H5) recombinant vaccine (rFP-AI-H5).
- Suggested Actions
- Can be confirmed with clinical signs and gross lesions
- Can be managed with vaccination programs
- 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
Impact on Liveability
Impact on Production
Overall Economic Impact
- Y.M. Saif.2008.Disease of Poultry. 12th Edition. Page 162, 167-168
- David E. Swayne. 2013. Diseases of Poultry 13th Edition. page 191, 196, 198
- Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition.
- Paul McMullin. 2004. A Pocket Guide to Poultry Health and Disease. First Edition.
- Steven Leeson, John D. Summers. 2008. Commercial Poultry Nutrition. Third Edition.
- Donald D. Bell, Williams D. Weaver. 2009. Commercial Chicken Meat and Egg Production. Fifth Edition.
- Gail Damerow 1994. The Chicken Health Handbook.