Bird Flu – Suppress the silent Killer of Poultry Economy
What is Avian Influenza or Bird Flu?
Avian Influenza (AI) or bird flu is an ‘infectious viral disease’ that can affect the birds.
This disease can be well very prevented with the complete and suitable scientific
approach. Here are some practical tips to prevent the disease.
What is H5N1?
There are different types of influenza viruses A, B & C but only type A viruses have been
so far isolated from avian species.
The strains of subtypes are determined by antigens H for Hemagglutin the
substance that enables AI virus to bind and infect a specific type of cell; and N for
Neuraminidase is another surface substance to that allows new copies of virus to
escape infected cells and migrate to uninfected cells.
There are 12 H subtypes and 9 N subtypes, and each virus has one of each subtype in any
combination.
Within this type, only a few strains containing H5 or H7 will cause the Highly
Pathogenic Avian Influenza (HAPI) called BIRD FLU
Among them H5N1 and H5N7 are the most pathogenic strains. Recently H5N1 strain has
been reported in West Bengal.
Can AI virus target other species than poultry?
No. However, all birds can be infected by AIV but wild birds especially wild ducks live
near or around the long stored standing stagnant water areas like ponds, small lakes and
temporary rain stored areas are more susceptible to the ‘Bird flu’.
They spread the virus to the domestic birds.
What are the general symptoms of Avian Influenza in poultry farming birds?
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Severe drop in egg production
Swelling of the head, comb, wattles, eyelids and legs
Cyanosis (blueness due to lack of oxygen) of the combs, wattles, and shanks
edema of the head
Respiratory disease, sneezing, coughs, nasal discharge
Neurological signs, watery eyes
Soft shelled and misshapen eggs
In acute cases involving sudden death, clinical signs may not be seen.
Wild birds’ carry the AI virus generally won’t show any signs of illness and are
considered the major reservoir for AIV infections in domestic poultry.
What could be the Mortality % in the flock?
Mortality occurs in a flock as early as 24 hours after the first signs of disease, and
frequently with in 48 hours, or can be delayed for as long as a week.
Mortality rates starts from 10% and go up to 100% which, is possible and have been
reported too.
How AI Transmits?
All avian (bird) species are susceptible to infection by AIV. However, most AIV are
isolated from wild water fowls especially wild ducks.Mostly wild birds especially ducks
and rarely Vectors (flies and insects) carry the AI virus They generally won’t show any
signs of AI illness and are considered the major sources for AIV infections in domestic
poultry. In live bird markets co-mingling of birds from different sources, and their fecal
material are the important sources of AI virus ‘carried to the poultry farms.
Can AI be spread to farm to farm through air?
Airborne transmission of virus from farm to farm probably does not occur under normal
circumstances. The spread of avian influenza between poultry premises is almost always
by mechanical transmission of the movement of contaminated people and equipments.
Wild birds often introduce AIV into domestic flocks through fecal contamination.
The feces of infected birds are the most important source of avian influenza virus (AIV).
Contact with infected fecal material is the most important mode of bird-to-bird
transmission.
Within a poultry house, transfer of the virus between birds can also occur via airborne
secretions. AIV can also be found on the outer surfaces and inside of shell eggs.
What is the favorable environment for the survival of AI virus?
The virus can survive in the manure for up to 105 days, especially in high moisture and
low temperature conditions.
What are the recommendations to prevent the spread of AI virus?
The following practical recommendations can prevent the spread of avian influenza
between poultry premises.
We have outlined these recommendations based on the three key principles.
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Stage 1: Disinfection
Stage2 : Isolation
Stage3: sanitation.
STAGE 1
DISINFECTION MEASURES ON FARMS : FARM PROTECTION
Simple Disinfection (Bio-security) model
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Practice "all in-all out" management of birds, with cleaning between restocking.
Maintain and isolate equipment on the farm, do not share materials or vehicles
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Restrict traffic to essential movements in the poultry farm.
Allow the personnel with a shower and a change of clothes only entering
premises.
Make sure that outsider’s vehicles including service persons’ and visitors
including regular business people are strictly dealt outside the poultry farm.
Anything that enters your premises should be properly and thoroughly
disinfected with broad spectrum disinfectants.
Wash and disinfect all egg trays, carts, and racks. Remove all feathers, feces,
and eggs material.
AIV can be transmitted at egg breaking facilities and processing plants.
Equipments must be thoroughly cleaned and disinfected at these facilities
STAGE 2 : ISOLATION : AVOIDING RISK FACTORS
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Mechanical transmission of AIV by anything that can walk, crawl, or fly from
farm to farm should be strictly prevented by rising the fence height and proper
vigilance.
Clean out vegetation in and around poultry houses that can be shelter for possible
carriers’ especially wild birds.
Prevent and remove accumulation of long standing stagnant water. This is a great
attraction to migrating waterfowl or wild birds.
Implement a vector control program for insect, mammalian, and avian vectors.
These vectors are important because they can mechanically carry infected feces
from one house, pen, or premise to another.
Rodent control and preventing their traffic between houses on a single premise are
essential.
Educate your employees about the dangers of wild and water fowls and advise
them to avoid visiting live bird markets or other poultry premises. If it happens to
be entered the premises after a bath or proper bio- secured measures.
Advise your employees to avoid handling dead, wild and free-flying birds they
find. Any such birds found in and around the premises must be treated cautiously.
Handle them with gloves, place in a plastic bag, and seal it and should be
disposed in the deep pit.
Finally, a complete change of fresh clothes and shoes that are properly disinfected
and a shower should happen before entering poultry premises.
STAGE 3: SANITATION: PROTECTION WITH IN
Removing organic material
The first and foremost action is removing the organic material from the poultry house.
Organic material can make the disinfectant ineffective and greatly increases the
resistance of avian influenza viruses to disinfection.
Hence, organic material must be removed before disinfection by any method which is
effective. Cleaning protocols should include critical inspection.
All the manures should be sprayed with broad spectrum disinfectants twice daily and
should be removed at least once in a week completely.
Scrape the sides and corners of the buildings to remove all residual organic material that
might harbor virus or can be disinfected with fire guns.
Practical tips for the better sanitation
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Spraying an anti viral disinfectant across the poultry house is a practical and
effective method. Apply the disinfectant to all surfaces twice, allow the
disinfectant to dry between applications.
Avoid open sun drying of feed raw material as they can attract wild and freeflying birds.
Droppings of the wild birds’ flying over the poultry house should be cleaned with
broad spectrum disinfectant when they happen in the farm premises and water
tank should be sanitized.
At the same time a vector control program should be instituted, followed by
removal of manure, cleaning of all surfaces followed by a second application of
anti-viral spray.
All dead birds to be disposed properly in the tightly closed plastic bags and into
the deep pit.
Disinfectants that can be used to protect the farm from AI virus
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Glutaraldehyde combinations
Acid combinations
Formaldehyde
Iodine containing solutions
Any reputed broad spectrum disinfectants can be used in the rotation method.
What is rotation program?
Any chemicals will have residual activity of particular period. On the continuous usage
the micro pathogens will develop resistance to the particular medicines or chemicals by
understanding their mechanism of action. This is called drug resistance. To avoid this we
have to rotate the medicines periodically or at different sites of action.
FREQUENTLY ASKED QUESTIONS ABOUT BIRD FLU
Can we have chicken meat?
Any one can have chicken meat freely without any psychological barrier. However, better
to have cooked meat heated up to 100ºF at least for 30 min. Our, Indian cooking system
is quite efficient to kill the AI virus.
Who are vulnerable for AI virus?
People live near the water as water fowls and wild birds are the potential carriers of AI
virus and also the personnel who are working in the poultry farm or in close contact with
the birds.
If we take precautionary measures as mentioned above very well we can avoid AI
infection and the disease spread.
How and when AI occur?
As we have discussed the incubation period is more 105 days for AI virus and the
favorable environment for AI in India is onset of winter and early summer.To control the
AI occurrence thrush should be given on the effective Bio-security programs through at
the year in the farm houses. However, from the beginning of October month onwards our
bio-security with vigilance program should be on the high alert. If so India can be free
from the AI mania.
What should I do if we find dead birds or huge mortality in a flock?
Our advice is to avoid handling dead, wild and free-flying birds they find. Any such birds
found in and around the premises must be treated cautiously. Handle them with gloves,
place in a plastic bag, and seal it and should be disposed in the deep pit.
Immediately should contact nearby veterinary centers and veterinarians and proper care
Can I vaccinate my flocks for AI?
Since vaccines strains specific and are not cross-protective for the 15 virus subtypes that
can infect poultry. Its’ difficult to predict the strains as highly pathogenic sub types arise
by mutation through re-assortment and recombination. Since there is no way to predict
which type will infect a flock, vaccines can be used as a part of complex AI prevention
program.
What should I do if I suspect avian influenza in my birds?
You should contact your veterinarian if you observe any of the signs of AI, especially if
they are accompanied by a drop in feed consumption and/or a significant drop in egg
production. Because the signs of AI are so variable, it is important to get the help of an
expert for diagnosis. And the action should be taken under veterinarian’s supervision.