“Biosecurity practices in poultry farming and its impact on bird flu”

Siddhartha S. Pathak

Ph.D. Research Scholar

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Biosecurity

“In general, it is a type of programme that is designed to protect life of birds”

In its simplest meaning, it means keeping the poultry away from the germs. Biosecurity is a practice designed to prevent the spread of disease onto the farm. It is accomplished by maintaining the facility in such a way that there is minimal traffic of biological organisms (viruses, bacteria, rodents, etc.) across its borders. Germs can travel more than 100kms from place to place on chicken crates, egg filler flats, trucks, other equipments, on hands of people, in the air, on cloths, on shoes and slippers. They can also be transmitted through carriers like dogs, cats, mice, flies and other insects either mechanically or as an intermediate host (Munegowda, 2005) Biosecurity is the cheapest, most effective means of prophylactic measure for control of diseases. No disease prevention programme will work without it

Types of germs are:

1. Viruses.

2. Bacteria.

3. Fungi.

4. Endo and Ectoparasites.

Control of these Pathogens is considered as an important part of biosecurity program.

Goals of biosecurity.

1. Prevention of the entry of pathogenic organisms into the poultry premises.

2. Reduction of microbial contamination of surrounding areas.

3. Total elimination of pathogenic organisms present within the premises that causes the disease (Munegowda, 2005).

Following steps can be taken to keep germs away from poultry.

• Limit visitors on your farm and restrict their direct contact with the flock.

• Obtain your birds from a disease free source.

• Quarantine new birds for at least two weeks.

• Keep free living birds and mammals away from your flock.

• Obtain feed from a clean dependable source.

• Provide clean, portable water.

• Keep your pets away from flock.

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• Clean and disinfect the shed prior to the arrival of new birds.

• If birds are housed on a dirt flooring, turn over the top soil layer.

• Use disinfected equipments.

• Keep the shed empty for at least two weeks after disinfection.

• Do not mix birds of different ages and species (Teresa, 2001).

Spreading of Infectious diseases.

• Introduction of diseased birds.

• Introduction of carriers birds.

• Through the shoes and clothing of visitors or care takers who move from flock to

flock.

• Contact with inanimate objects that are contaminated with germs.

• Improperly disposed carcass.

• Impure water.

• Rodents, wild animals and free-flying birds.

• Insects.

• Contaminated feed and feed bags.

• Contaminated delivery trucks, rendering trucks and live hauling trucks.

• Contaminated premises through soil or old litter.

• Air-borne fomites.

• Transportation of eggs(Teresa, 2001).

New birds, including day-old chicks should not be put in contact with droppings, feathers, dust and debris left over from previous flocks.

Biosecurity of poultry flocks.

Biosecurity has three major components.

1. Isolation

2. Traffic control

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3. Sanitation (Sreenivasaiah, 2006).

1. Isolation:

It refers to the confinement of animals within a controlled environment. A fence which keep the birds in while keeping other animals out. Isolation also applies to the practice of separating birds by age group. In all-in-all-out management style contributes simultaneous depopulation, which offers time for periodic clean-up of sheds and disinfection.

2. Traffic control:

It includes both the traffic onto the farm and the traffic patterns within the farm. Biosecurity generally requires human traffic, vehicles, rodents and wild birds control by restricting their movement (Munegowda, 2005).

• Grass and bushes can be trimmed for a few feet on each side of the fence. This will

allow detection of burrowing rodents as well as force the predators to approach the fence without the benefit of cover.

• Game bird pens are usually covered with netting. The mesh size of those nets

determines the size of the wild birds kept out.

• Only clean plastic coops have to be used for transfer of poultry. Wooden coops are

difficult to clean.

• Flow of on-farm traffic must be directed from the youngest to the oldest birds and

from resident to the isolation.

• A “clear zone” free of vegetation around the building is ideal to discourage rodent and

insect traffic into the building or pens.

• A different pair of footwear while working in the isolation area and in the resident

bird area is necessary to prevent the mechanical transfer of disease organisms on footwear.

• Footwear should be disinfected at each site. Disinfectant footbaths may help to

decrease the dose of organisms on boots.

• Washing hands thoroughly after handling birds in isolation or birds of different

groups is mandatory.

• Waterers and feeders have to be disinfected on a regular basis. Periodic clean-out,

clean-up and disinfection of houses and equipment have to be planned, at least once a year.

• Simultaneously, rodent and pest control procedures can be taken up when the houses

are empty.

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• Dead birds must be disposed of promptly by rendering/burning/burying/composting

or sending them to a sanitary landfill.

3. Sanitation:

Primarily involves vaccination of birds on farm, cleaning and disinfection profiles adopted at the farm.

General recommendations for floor houses

The following procedures are recommended:

• Litter lifted from floor and dumped as far away as possible.(minimum of 100m)

• Houses swept thoroughly to clean all floors, lighting fixtures, fan blades, Burnt-out

bulbs are replaced and all other bulbs cleaned.

• All permanently installed waterers, feeders and any other equipment must be

scrubbed and cleaned.

• Miscellaneous equipments are removed from the house to permit a thorough job of

disinfection.

• Brooder guards, hand feeders and jugs that will be used for the next flock must be

soaked, Then hand scrubbed and disinfected.

• The sills, trash and debris should be removed, since the organic matter neutralize

disinfectants.

• Ceiling, curtains, walls, partitions, slats, feeders, waterers and other equipments are

thoroughly disinfected.

• The curtains are kept up and fully extended when cleaning and spraying.

Cleaning the feed system

The purpose of these procedures is to reduce the incidence of moldy feed and mold toxin problems. These are especially relevant where automatic feeding system is operative.

1. Feed bin, boot and auger.

1. All feed from the bin, boot and auger removed as soon as possible after the flock is sold.

2. The boot disassembled to ensure thorough cleaning.

3. Insides of the feed bin, boot and auger is washed with a 5 percent solution of sodium hypochlorite.

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2. Feed hopper and feed cart.

1. Feed hopper and feed lines are emptied.

2. All feed from boxes are removed and scraped or brushed away, all material such as caked feed from corners, seams or lips inside and outside of the feed boxes must be removed.

3. All surfaces are washed with a 5 percent solution of sodium hypochlorite.

3. Line feeder.

1. All feed from the feed trough is removed including corners.

2. Line feeders are removed and corners cleaned.

3. Sprayed with 5 percent solution of sodium hypochlorite.

4. Line feeder with feed pans.

1. All feed removed from feeding system.

2. Any mold ring present in the feeders are scraped and removed.

3. The pan is removed and sprayed inside of the cone with 5 percent solution of sodium hypochlorite.

Longevity of Disease Causing Organisms (Finnoff, 2007)

Sl no Disease Life span away from birds1 Infectious Bursal Disease Months2 Coccidiosis Months3 Duck Plague Days4 Fowl Cholera Weeks5 Marek's Disease Months to years6 Coryza Hours to days7 Newcastle Disease Days to weeks8 Mycoplasmosis (MG, MS) Hours to days9 Salmonellosis (Pullorum) Weeks10 Avian Tuberculosis Years

Restarting after cleanout

The checklist of procedures to be followed.

Make sure that all electrical circuits operate properly.

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Fill all light sockets with a clean and operative light bulb.

Run all motors and lubricate them if necessary.

Check for proper tension on feed chains, winch cables and fan belts.

Check all water lines for cracks and leaks.

Inspect thermometers and thermostats to ensure that they are clean, operative and accurate.

Adjust gas brooder stoves so that they light up when needed and the flame is even and blue.

Check the feeding equipment for proper assembly.

Operate all equipment to ensure that it runs smoothly and without abnormal noises.

Health Care and Management.

Control measures for prevention of diseases.

The factors to avoid infection are as follows:

1. Segregation:- Separation of healthy birds from diseased ones

2. Housing birds of different age groups, sex and species separately in different houses.

3. Eliminate chances of introduction of carriers, start with day old chicks separately from the old birds.

4. Keep litter and houses free from dampness.

5. Provide proper ventilation for healthy environment.

6. Adequate exposure of floor to sunlight.

7. Adequate sanitation and disinfection.

8. Enough floor space according to age, size, breed, number and purpose.

9. Adequate drainage of water.

10. Proper disposal of dead birds by burning.

11. Restrict the entry of visitors in and around houses, and arrange footbath of reliable disinfectant at the entrance to farm for proper treatment of feet/shoes.

12. Keep distance of 15m between rearing and laying houses.

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13. Ensure proper cleaning and disinfection of contaminated equipments and appliances.

14. Take judicious sanitary measures to prevent contamination from soil, litter, feed, water, feeder, waterers, feed bags and etc.

15. Keep away rodents, sparrows, wild birds and insects from poultry houses.

16. Provide clean, pure, safe and cool water.

17. Observe the flock daily for any sign of stress, drowsiness, physical discomfort and diseases.

18. Keep distance of 15m between two laying houses.

19. Provide well balanced good quality diet to birds in adequate quantity according to their age, size, breed and purpose.

20. Never make reuse of old litter.

21. Proper deworming of birds.

22. Vaccination of birds at proper time and age regularly.

23.Keep feed from aflatoxins.

24. Make use of antiperching panel to prevent contamination of water by birds feet.

25. Spraying insecticides to kill parasites or make provision of sodium fluoride dust bath for birds.

26. Daily raking of litter and mixing lime and super phosphate if needed to prevent dampness and bad smell.

27. Never take chance to experiment chicks from new source.

28. Prevent stressors.

29. Use coccidiostats in feed regularly but change the brand of coccidiostats at regular interval to keep effective against all strains of coccidia.

30. Avoid prolonged use of antibiotics to maintain natural immunity.

31. Avoid overcrowding and provide sufficient number of feeders and waterers.

32. Carry out fumigation of incubators before setting the eggs.

33. Avoid abrupt changes in feed and weather.

34. Never mix two vaccines together and give one week rest after first vaccination.

35. Do not vaccinate birds in stress.

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Bird flu (Fowl plague/Avian influenza).

It is a dangerous disease since it can kill all poultry on a farm. It can spread rapidly to other farms, to the whole country and may cause 100% mortality (Swayne, 2008).

Introduction:-

AI is a diseases causing extremely high mortality in fowls and is called fowl plague. AI virus is actually type A influenza virus . Type A influenza virus capable of causing the AI are of two sub types

1. Virus of low virulence(LPAI).

2. Virus of high virulence(HPAI).

HPAI (Highly pathogenic Avian influenza) the term has been used for these viruses. thus fowl plague was caused by highly pathogenic strains of AI viruses. the viruses of low virulence could be antigenically indistinguishable from those of high virulence .

It is a zoonotic disease which can make humans sick and even to die. There is no treatment for this disease, it can be prevented by vaccination.

Distribution

Avian influenza viruses are distributed through out the world in many domestic birds, including, chickens, turkeys, ducks, geese, guinea-fowl, pheasants, and quails, and also in the feral bird population, ie., in wild birds however, the number and frequency of isolations from other species have been overshadowed by the presence of these viruses in waterfowl ,particularly ducks. Ducks have yielded more viruses than any other group.

Moreover, though the ducks may be infected, they do not suffer from the clinical disease because of the marked resistance these birds show even to strains that are highly virulent for chickens and turkeys. Ducks therefore act as reservoirs and carriers of avian influenza and spread the virus to chickens and turkeys, which suffer the disease clinically.

Etiology

Influenza type A viruses; Othyomyxoviridae. The virus is further classified into subtypes based on:

1. The glycoproteins hemagglutinin(H) and neuraminidase (N) present on the virus-15 H subtypes (H1-H15) and 9 N subtypes (N1-N9). H5N2, H7N1 and H7N7 have been reported to be highly pathogenic causing high mortality in chicken.

2. The ability of the virus to cause disease – Highly pathogenic Avian influenza (HPAI)-can cause up to 100% mortality and low pathogenic Avian influenza (LPAI)-causes a

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mild disease with lower mortality; LPAI subtypes, especially H5 and H7,have the ability to mutate to HPAI after circulation in a poultry population.

HPAI is an OIE List A disease. Avian influenza is classified as HPAI if it conforms to these criteria:

1. Any influenza virus that is lethal for six ,seven or eight of eight 4-8-week- old susceptible chickens within 10 days following intravenous inoculation with 0.2ml of a 1/10 dilution of a bacteria-free , infective allantoic fluid.

2. The following additional test is required if the isolate kills from one to five chickens but is not of the H5 or H7 subtype : growth of the virus in cell culture 1 with cytopathic effect or plaque formation in the absence of trypsin. If no growth is observed, the isolate is not considered to be an HPAI isolate .

3. For all H5 and H7 viruses of low pathogenicity and for other influenza viruses, if growth is observed in cell culture without trypsin, the amino acid sequence of the connecting peptide of the hemagglutinin must be determined .If the sequence is similar to that observed for other HPAI isolates ,the isolate being tested will be considered to be highly pathogenic .

Avian influenza virus is an enveloped RNA virus. The viral genome is composed of eight segments of single-stranded RNA of a negative-sense (i.e., the virus RNA is complementary to the messenger RNA ). Proteins are associated with the RNA genome to form the “nucleoprotein-RNA-polymerase complex”. The matrix surrounding the genomic complex is enveloped in a lipid membrane. The surface of this lipid membrane of the virion that is envelope, is covered by two different surface “projections” or “spikes”.

These surface spikes are glycoprotein , and have haemagglutination and neuraminidase activity. The surface spikes are of two different shapes : 1) haemagglutinin (HA), and 2) neuraminidase(NA).HA is a rod-shaped trimer (made up of four subunits ) So far, Only type A influenza viruses have been isolated from the birds .

The haemagglutinin is responsible for the attachment of the virion to cell surface receptors (sialyl-oligosaccharides), and is responsible for the haemagglutinating activity of the virus. Antibodies against the HA are very important in neutralization of the virus ,and protection against infection. Neuraminidase enzyme activity is responsible for the release of new virus from the cell, by its action on the neuraminic acid in the receptors .Antibodies to NA are also important in protection,by restricting the spread of virus from infected cells (Perkins et al, 2002).

Disease forms:

1. Highly pathogenic avian influenza(HPAI).

Severe and generalized clinical signs.

2. Low pathogenic avian influenza(LPAI).

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Mild and respiratory clinical signs(Joseph, 2006)

Transmission:

The virus may enter the poultry farm through various ways.

• Purchase or gift of one or more domestic birds.

• Human beings coming from live bird market/slaughter house/laboratory that was

infected or contaminated to the healthy farm.

• Dogs bringing infected carcass.

• Migration of wild birds from affected farm to healthy farm.

• Ducks going and coming back from rice fields.

• Any domestic poultry that must find its own food out side the farm.

• Contact with water ponds.

• Contact with infected manure.

• Spread of avian flu between healthy and infected farm

PATHOGENESIS:

Incubation period: 2-5 days. The avian influenza virus adsorbs to glycoprotein receptors containing sialic acid on the cell surface. The virus then enters the cell by receptor-mediated endocytosis .

• The tissue tropism of a virus is involved in its pathogenicity.

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• The basis for tissue tropism is receptor specificity. Receptor recognition by the viruses is an important factor in both tissue tropism and pathogenicity.

• Infectivity depends on post-translational cleavage of the haemagglutinin molecule .That is, on a spilt or division (cleavage) of the haemagglutinin molecule after it has been formed /synthesized (post-translational). This cleavage is brought about by host proteases, and takes place at the cleavage site.

• Tryspsin –like enzymes can cleave if only a single amino acid arginine is present at the cleavage site, whereas other host proteases require multiple basic amino acids.

• The HA of low to moderately virulent influenza viruses have only a single basic amino acid arginine at the cleavage site.

• The highly pathogenic viruses possess HA with multiple basic amino acids at the cleavage site. Therefore HA can be cleaved by proteases found throughout the body.

• These viruses, Therefore invade and replicate in many tissues and organs ,resulting in the production of infective virus throughout the body ,generalized disease, and death.

• Bacteria provide proteases capable of cleaving the haemagglutinin of these low or moderately virulent viruses in the absence of multiple basic amino acids. This enables them to replicate and spread widely in the host.

• Tissue culture cells infected with influenza virus undergo apoptosis (programmed cell death). (Perkins et al, 2002).

Clinical signs:

Disease appears suddenly, and many birds will die:

Either rapid mortality without clinical signs. Or with minimal signs of depression, low appetence, Ruffled feathers and fever.

• Some birds show weakness and staggering gait.

• Sick birds often sit or stand in a semi-comatose state (sleepy) with their heads

touching ground.

• Younger birds may show neurological signs.

• Hens may at first lay soft shelled eggs, but soon stop laying

• Combs and wattles are swollen, turn dark red to blue and may have pin point

haemorrhages at their tips.

• Professed watery diarrhoea.

• Birds are excessively thirsty.

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• Laboured and fast respiration.

• Haemorrhages at un feathered area, especially at shanks.

HPAI in chicken

Depression decreased appetite, decreased egg production, nervous signs, swollen blue combs and wattles, coughing sneezing, diarrhea and sudden death(Sims, 2008: Tiensn, 2005).

LPAI in chicken

Mild respiratory disease, depression, decreased egg production.

Morbidity and Mortality

In outbreaks of highly Pathogenic Avian Influenza (HPAI) mortality can be up to 100%.low Pathogenic Avian Influenza (LPAI) in chickens may even go unnoticed

Diagnosis.

Samples

1. Live birds :- Tracheal swabs and cloacal swabs or faeces; dead birds – organs and faeces.

2. Serology :- Clotted blood samples or serum

3. Procedures :- Identification of the Agent

Serological tests

1. ELISA/AGID.

2. HI.

3. IFI.

4. RT-PCR.

Differential diagnosis:

1. Virulent New Castle disease.

2. Duck plague.

3. Acute poisonings.

4. Other diseases which cause swelling of combs and wattles(Acute Fowl Cholera and other septicaemia diseases, Bacterial infection of comb and wattles)

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Avian flu should be suspected in any disease out break in poultry that persists despite the application of preventive and therapeutic measures for other diseases.

Prevention and control.

1. Isolation of affected birds

2. Wild birds should not allowed to come in contact with domestic birds

3. Strict bio-security measures

4. Recovered birds acts as carriers and hence they should not come in contact with healthy birds.

Vaccination.

The following types of vaccines are used against avian influenza

1. Conventional vaccines.

2. Recombinant vaccines.

3. Heterologus avian influenza vaccines.

4. Protection by H sub type vaccine.

Biosecurity measures to be taken when there is no out break of avian influenza .

Principle I: Keep the poultry in good condition.

Poultry in good condition’s resist better to disease.

a) Have a good access to clean water and adequate food

b) Have access to adequate housing.

C) Receive deworming products and vaccination.

If the poultry is not in good condition:

a) More likely to catch diseases.

b) They produce fewer eggs, less meat.

Principle II: Keep the poultry in protected environment.

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Principle III: Control the entries on to your farm.

• Every one coming from a place where there are sick poultry, can carry the virus on

their cloths, sandals:

o Family members: Coming back from neighbours, from the local market,

paddy fields,

o Family relatives: Coming back from special occasions(Wedding, New year).

o Neighbours.

o Middle man coming to bye or to sell poultry but also pigs, cattle or other

agriculture products.

o Paravets coming to treat or vaccinate your animals, they may have also visited

other infected farm.

• New chicks, ducklings, Piglets bought from a middle man, or from a neighbours farm,

or from the market.

• Purchase of animal feed, Equipment etc.

• Entry of motor bike, Bicycle or other vehicles in farm yard.

• Dogs or cats that brings dead animals.

• Manure purchased from another farm.

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Principle IV: Quarantine measures.

Biosecurity measures to be taken when there is out break of avian influenza

Principles I: Keep the poultry in good place.

Principles II: Do not buy nor accept new animals on to the farm.

Principles III: Decrease and control entries from humans.

Principles IV: sweep the farm yard, clean the animal buildings, the equipments, the motor bike more regularly.

Principles V: Store the manure(IBRD, 2006).

Steps to be taken when there is high suspect mortality on the farm.

Only the laboratory can confirm that it is or that it is not Avian Flu.

• The former and the paravet must act before getting the result from the laboratory. If

you wait for the laboratory result, the situation will become impossible to control.

• When you observe suspect mortality on your poultry, the farmer and the paravet must

work together.

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Their objective must be:

1) To eliminate the virus from that farm as soon as possible.

2) To avoid contamination of other farms.

3) To avoid infections of human beings.

4) To report immediately to the village and commune leaders and to the

district veterinary officer.

5) to write down information about the events.

• The farmer must inform the para vet

• The paravets must:

• immediately visit the farm and give the appropriate advice to prevent the disease from

spreading.

• Then inform the district veterinary office as soon as possible.

• Do not wait for lab reports for acting.

• Do not wait for DVO staff to come before acting.

• If the disease is confirmed to avian flu, the district vet and paravet should ensure that the control measures are maintained (East, 2007).

Cares to be taken on dead birds and other contaminated objects.

• Never through dead birds in river.

• Never eat them.

• Dead bird should put immediately in bags.

• The DVO staff may come and take some specimens from these birds.

• All dead birds and other contaminated objects must be destroyed properly as soon as

possible during the day through burning and burying.

Protection of human beings.

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• It is a zoonotic disease mainly transmitted through faeces or direct inhalation of virus

that are spread by infected birds through breathing.

• In non infected poultry farms, only one person should take Care of poultry, That

person should be adult in good health.

• The pregnant woman and young children should avoid the contact with the animals.

• Do not eat animals dead of disease.

• Each time when u touch the animals or their products, you should wash your hands

with soap.

• People should not eat raw blood.

• People should ware mask, gloves, glasses etc.

• In infected area any contact with poultry and poultry products must be avoided.

• The only people who have to be in contact with poultry should be farmers, paravets

and vets and they should wear protection.

• Advice should be sought from local doctors (WHO, 2006: Webster et al, 2003).

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