ZOONOTIC DISEASES OF POULTRY: Biosecurity measures at poultry farms for prevention and control
by-DR. RAJESH KUMAR SINGH, (LIVESTOCK & POULTRY CONSULTANT), JAMSHEDPUR, JHARKHAND,INDIA 9431309542, rajeshsinghvet@gmail.com
Poultry farms across the country need to maintain the basic sanitary conditions essential for healthy birds and hygienic products. An integrated biosecurity programme is an application on logical and sound principles specific to an enterprise, monitoring of disease status, evaluation of ongoing poultry farm operations on continuous basis with an objective to contain the diseases at bare minimum level. Some poultry diseases like Avian Influenza are zoonotic in nature, i.e. they may be transmitted to humans, and potentially poses serious public health risks.
Disease outbreaks among farm animals can cause significant economic damage. However, you can limit the impact through preventative and control measures.
You must ensure that you follow biosecurity procedures, such as cleaning and disinfecting premises and vehicles.
During the past two decades, primary breeders of broiler, egg and laying strains have
eliminated vertically-transmitted diseases from their elite and great-grandparent
generations. Unfortunately, infection of grandparent and parent flocks occurs in many developing countries resulting in dissemination of diseases including mycoplasmosis, salmonellosis and reoviral infection. Improved biosecurity and an awareness of the need for
appropriate vaccination programs, reduces the potential losses caused by both catastrophic and erosive infections on commercial-scale farms, village cooperatives and in integrated operations.
Angara disease, virulent infectious bursal disease, highly pathogenic influenza, reoviral
stunting syndrome and swollen head syndrome are examples of emerging diseases affecting flocks in Asia, Africa, and Latin America. In addition, chronic, low-intensity infections such as
coryza, pasteurellosis, and salmonellosis continue to erode profit margins. Prevention of disease depends on a comprehensive program incorporating a sequence of planning, implementing and
control in a repetitive cycle. Strategies to prevent infection are based on the purchase of breeding stock free of vertically-transmitted disease. Vaccination of parent flocks and progeny and
appropriate levels of biosecurity represent the components of disease prevention subject to direct managemental control. The relative importance and contribution of these strategies can be
calculated using simulation studies. These should incorporate projections of risk of infection and compare the production parameters and costs for diseased and healthy flocks.
Objectives of bio-security:
To keep highly contagious diseases like IBD, ND out of the poultry farm. To reduce common pathogens like E. coli and Salmonella.
To reduce or eliminate background immunosuppressive agent such as MD & IBD virus. To reduce contamination by pathogens important to public health safety like Salmonella, Campylobacter.
The components of biosecurity comprise a hierarchy with each of 3 levels influencing the cost and effectiveness of the entire program.
Conceptual Biosecurity:
The primary level represents the basis of all programs to prevent disease. Conceptual
biosecurity includes selecting the location of a complex or operation in a specific area to separate different types of poultry, reduce biodensity, and avoid contact with free-living birds. Siting of
farms in relation to public roads and service facilities such as hatcheries, feed mills, and processing plants has a profound impact on the effectiveness of a program to maintain optimal standards of production. Decisions concerning conceptual biosecurity influence all subsequent
activities relating to prevention and control of disease. Generally, defects in conceptual biosecurity cannot be changed in response to the emergence of new diseases which may result in
severe losses or even failure of an enterprise.
Structural Biosecurity:
The second level of biosecurity includes considerations such as the layout of farms, erection of fences, construction of drainage, allweather roads, equipment for decontamination, bulk feed installations, change rooms, exclusion of rodents and wild birds, and the interior
finishes in houses. Structural biosecurity can be enhanced in the intermediate term with
appropriate capital investment. Remedial action may often be too late to respond to the emergence of a new disease or an epornitic of a catastrophic infection such as highly pathogenic avian influenza.
Major steps:
Fencing of farm perimeter to prevent unwanted visitors restricting the entry of outside visitors & human beings.
Test the water source for mineral, bacterial, chemical contamination and pathogen load. Disinfectant spray with suitable water and power supply for sanitization of vehicles. Suitable location for storage of bagged feed.
Good roads within the farm to ease cleaning and to prevent spreading of microbes by vehicles and footwear.
Facilities for scientific disposal of dead birds.
Safe housing with suitable wild bird and rodent proofing.
Feed, litter and equipment should be stored in section separated from the live bird area to prevent contamination.
A 3 meter boundary of land around buildings must be kept free of all vegetation to inhibit rodent and wildlife activity.
Operational Biosecurity:
The third level comprises routine managemental procedures intended to prevent introduction and spread of infection within a complex or enterprise. These activities can be modified at short notice to respond to disease emergencies. Constant review of procedures, participation by all levels of management and labor and appropriate monitoring of the health status and immunity of flocks contributes to effective operational biosecurity.
Major steps:
Operational manuals incorporating emergency plans should be developed for day to day
activities carried out in feed mills, hatcheries, breeding and grow out facilities.
Proper decontamination and disinfection of equipment, houses, etc. following depletion
of flocks.
In breeder farms, all workers and visitors should shower and use clean farm cloths to prevent cross contamination between facilities.
Marinating a record of visitors, including name, comp[any purpose of visit previous farm visited and next farm to be visited.
In case of breeders, no vehicles, or equipments should be allowed within the farm area from the time of delivery of flock until depletion.
In commercial broilers units a minimum inter flock interval of 2 weeks is recommended.
Effective pest management programme through biological, mechanical and chemical means.
Appropriate disease detection and proper vaccination schedules should be implemented.
In case of small-scale egg production units, follow all-in-all-out, If this is not possible, pullets should obtain from a source fee of vertically transmitted diseases.
Recycled egg packing material, plastic egg trays. etc. Should be decontaminated at the point of entry to the farm.
Routine disease monitoring procedures like post mortem examination of dead birds and periodic serum antibody assays to determine the immune status of flocks is necessary.
General biosecurity measures:
The following managerial factors help to reduce the spread of disease and stress to the
birds.
- Isolation
Isolation of poultry farm from other poultry reduces the risk of infection
Cross infection between farms is reduced at least up to 50% if a barrier of 5km is there.(Practically, isolation is more difficult because of the cost of transportation, feed, egg, bird and supply labour).
- Security fencing
Fencing of farm is very important in restriction of entry of natural predators like jackel, fox, and wolf for security and to protect from theft.
Foot bath at the point of entry into each poultry farm will help in disinfection to a great extent.
Showering in and showering out, that is staff, visitors and vehicles have no other entry to farm other than the shower system.
- Farm and shed
Batch interval before introduction of new flock (15 days to 1 month) Concrete floor for proper and easy cleaning.
Clean thoroughly disinfect with a suitable detergent and disinfectant
Proper curtains to protect the flock from extreme climatic conditions and rain water entry with adequate ventilation
Knowledge of prevention of disease and to check bacterial load from microbiology laboratory
Plant trees not fruit trees and do not allow grasses or weeds to grow around shed put gravel in between sheds.
Distance between 2 different sheds of same type is 30 feet and different type is 100 ft and poultry house to hatchery is 500 feet.
Construct proper drainage system
- Human traffic
Control of human traffic including regular workers, visiting service man particularly weekend veterinarian, who may visit several site in successive.
Do not allow any visitor except on special circumstances like veterinarian.
If possible the visitor should be covering all even boots ;supplied by the farm and disinfected after use.
Record of all visitors to site with name, date of visit, nature of business is must. Staff and visitors having no other entry to the farm other than shower system Keep visitors to a minimum Human transportation of disease-causing organisms is one of the more serious threats to biosecurity.
Post signs at the entrance to the farm indicating that entry to the farm and facilities are restricted.
Lock buildings
Do not be afraid to ask any visitors where they have been. They should not have been on a poultry farm within 48 hours before visiting yours.
Owner should restrict visitors and make sure that any visitor to their farm has a good reason to be there. Visitors should never enter poultry houses unless approved by the farm personnel.
Protective covering such as boots, coveralls, and headgear to any visitors that work with, or have had recent contact with poultry.
Traffic through poultry houses should always flow from younger to older birds.
Keep records of visitors that have been on the farm. If a problem arises, knowing who was there will help in limiting additional flock infections.
- Restricting movement of vehicles
Transport vehicles enter various farms regularly and are at great risk of infections. So, allow vehicles only when necessary.
Avoid the entry of feed truck in premises by holding feed tank at the farm and then distribute to individual houses.
Use of detergent and disinfectant outside and inside the drivers’ compartment. Sanitizing the trucks as they enter the farm by disinfectants.
- Rodent and wild bird control
Rats and rodents are great disease spreaders and have to be controlled and eradicated Make the shed rodent proof.
Wild birds have potential of carrying infectious organisms restrict their entry to farm.
Do not throw away organic material like dead birds, meat used food, feed etc around the shed which attracts crows etc.
No litter should be around the shed and should be transported away from shed. Control movement of all animals in the farm including dogs.
- Equipments:
Entry of equipments from farm to farm only after they are disinfected.
Egg flats from farm to hatchery must be sanitized at hatchery.
Entry and exist of egg flats into the farm and outside farm must be restricted. Disinfect the feeder and waterer
- Water:
Poultry farmers often fail to provide the birds with good quality water.
Both the microbial and chemical quality of the water need to be tested before establishing a poultry farm in a given area.
Microbial contamination of water may happen at the source, for instance in ponds, rivers, open wells and the public water supply system, or during transportation and storage, as well as in the overhead tank or bins. Unhygienic practices on the farm result in the spread of disease.
The microbial load shoots up during flood conditions.
Faecal contamination of water will add to the presence of coliform organisms.
Mineral levels in water depend on soil conditions, and show only minor fluctuations based on the season and the water table.
They lead to hardness in water and affect the taste and palatability.
Quality guidelines for drinking water on poultry farms
The desirable quality guidelines for drinking water on poultry farms are as follows:
Total hardness : 60-180
pH : 6.8-7.5
Nitrate : 10 mg/litre
Nitrite : 0.4 mg/litre
Total bacterial count : 0/ml
Coliform count : 0/ml
Calcium chloride : 60 mg/litre
Sodium : 50 mg/litre
Sulphate : 125 mg/litre
- Feed:
Feed acts as a vector for micro-organisms
Storage of excess feed must be avoided.
Store in feed room above the ground and away from walls. Lumps in feeds must be discarded.
Feed tanks must be swept every month, disinfected twice in month and fumigated
at end of each crop of birds to reduce bacterial count and mold growth. Mould
inhibitors can be used.
Check feed for toxins such as aflatoxins etc.Heat treatment is helpful as it does
not affect the nutritional quality.
- Health monitoring:
10.1) Recognizing sick birds:
It is important to recognize sick birds. It is simple to check flock for dead birds but it requires skill to recognize sick birds. When walking through a flock, take time to scan the birds and spot individuals showing signs of illness, such as:
Lethargy, lack of energy, drooping wings
Loss of appetite
Swelling of the head, eyes, comb, wattles and hocks Purple discoloration of the wattles, combs and legs Nasal discharge
Coughing, wheezing, or sneezing
Lack of coordination or complete paralysis
Muscle tremors or twisted necks
Diarrhea
Sudden or excessive mortality without clinical signs
Decreased egg production, soft-shelled or misshapen eggs for broiler.
Abnormal respiratory sounds, of called a ‘snick’ can be heard. These sounds may
have a variety of characteristics such as a high-pitched ‘squeak’, a sudden’ chuck’
sound, like a cough, or a gurgling or rattling sound.
10.2) Vaccination
10.3) Maintain records:
- a) Flock mortality records will alert the producer of a potential problem, which should
trigger the appropriate response and the first of which will be to find the cause of the - b) Production records
A producer keep daily feed and production record which helps to check for drop in egg production or feed consumption, or a rise or fall in water consumption and it aware the producer to a potential problem. A drop in feed or water consumption can be a sign of an infectious disease.
A significant drop in consumption must be checked and specific diagnostic
actions taken. It included investigations of the watering or feeding system to make sure
that a failure in the supply has not resulted in the consumption drop. In absence of
physical reason diagnostic procedures should be followed such as collection of feed and
water samples.
A drop in egg production or fertility may be an indication of infectious disease. Such drops should be investigated and diagnostic. Veterinarian advice is must.
- Method of rearing:
All in all out system: Only one age group of birds on a farm and farm is populated at one
single time.
Depopulating the farm reduces the major disease threat.
- Cleaning and disinfection:
Disinfection is the process or act of destroying pathogenic microorganisms.
A disinfectant is an agent that destroys pathogenic organisms, and that can be applied on
inanimate objects or used as a footbath.
Phenol, cresol, chlorine compounds and iodophors can be used for disinfecting surfaces
as well as the egg room, feeders, drinkers, buildings and footwear; liquid formalin at 5
percent level, or formaldehyde gas by fumigation, will also serve as an effective
disinfectant.
Sun-drying may be practised for washed equipment; for cement surfaces-dry heat in the
form of flame is recommended.
Copper sulphate as a 0.5 percent solution is effective against fungi.
Quarternary ammonium compounds are good disinfectants when used according to
directions. However, they are not effective in hard water.
They can be used for disinfecting surfaces, washing egg rooms, feeders and drinkers and
other equipment.
- Insect control:
Counter measures against insects are part of maintaining a sanitary environment, as insects
play a significant role in transmitting disease-producing micro-organisms, tape worms,
etc.
Flies sit on the birds, irritate them, prevent them from taking water and feeding normally, causing stress which results in reduced egg production especially where cage rearing is practised. Insect or fly control measures include:
Avoiding stagnation of water in and around the farm premises.
Provision of proper drainage facilities, attending immediately to leaky drinkers,
water lines, etc.
Use of insecticide sprays or dusting at required intervals,
Treating the birds and checking the feed and water quality to avoid watery
droppings.
Keep the surroundings clean by covering the area with treated soil devoid of vegetation or by growing grass lawns.
- Dead bird disposal:
The main principle involved in the prevention and control of current and emerging diseases is the scientific disposal of dead birds.
Mortality is inevitable on every poultry farm, and it varies with the prevailing disease and sanitary conditions on the farm.
When birds die, their carcasses remain as a source of infection for pen-mates and other birds on the farm (or other farms).
All carcasses should be removed from the pen as soon as possible.
Diseased and ill birds also discharge infectious material into the environment and act as
reservoirs for disease-producing organisms.
It is essential to eliminate ailing birds from the flock rather than jeopardize the health of
the remainder of the flock.
The habit of throwing dead birds on to the nearest manure pile or into an open field is
dangerous and unscientific for the following reasons:
The smell of the carcasses attracts street dogs and cats, which consume the infected
carcasses and harbour the enteric organisms infectious to poultry. Because of their free
movement, these animals are capable of carrying contaminated material or a portion of a
carcass to neighbouring farms, with disastrous results;
Vultures and other wild birds invade the carcasses and become potential carriers of the
disease-causing agents from one farm to another or even from one country to another
country if they migrate;
The carcasses lure insects and flies, which act as transmitters of infectious agents;
The disease agents carried by rain water contaminate other water sources;
The surrounding area of the farm is contaminated with feathers and bones, causing soil
pollution; On decomposition, the carcasses may emit a foul smell and cause air pollution. The disposal of carcasses of birds dying from known or unknown causes, should be
carefully attended to.
There are many methods for the efficient disposal of carcasses such as burying, pit
disposal, incineration, septic tank disposal, or composting.
In general, the following points should be observed while disposing the carcasses: Remove the dead birds from the flock as soon as possible;
Do not deposit carcasses in or near a flowing stream;
Take the necessary precautions to prevent spillage of infectious material from the
carcasses during transportation from the farm or post-mortem room to the disposal site; Take sound bio-security measures at the disposal sites to prevent disease transmission. Moreover, with the present concern for the environment, the poultry industry needs to
pursue efforts to protect the environment.
Therefore, all methods that allow for environmentally safe and scientific ways of disposing of carcasses should be considered.
- Litter removal
After the pen is emptied, deep litter and caged layer droppings should be removed to a
field far from the poultry shed, and spread to dry in the sun.
It should be disposed off as soon as possible for manure or other purposes and not
allowed to remain accumulating for a long period.
Composting is better, since the heat produced will destroy the pathogens.
- Personal hygiene of worker
Use of clean and separate clothing meant for farm premises only.
Hand sanitizers and cleaning tubs must all time be available in the shed. Separate workers for different age groups and different farms are must. Sick persons kept away from the farm.
