PRACTICES OF HANDLING DISEASE OUTBREAKS IN POULTRY INDUSTRY
In the last few decades, poultry industry has shown a tremendous growth all over the world. Consumption of chicken has increased due to its versatility as a food, and considered as healthier meat than from other sources. As poultry industry progressed, disease outbreaks and its associated challenges have become more common and costlier to manage. Recently, the Newcastle disease (ND), low pathogenic avian influenza (LPAI) and high pathogenic avian influenza (HPAI) have become endemic, resulting in heavy losses to poultry industry. During the disease conditions, poultry farmers rely more on medication and vaccination for control measures. This is associated with high costs, and more often the success may not be guaranteed. Strict biosecurity measures along with vaccinations are adopted to control some contagious poultry diseases, as vaccination alone is not enough to control diseases in field conditions.
Good poultry producers watch feed and water consumption andegg production at all times, but more important, they observe normalsounds and actions of the flock. They sense immediatelywhen any of these conditions are abnormal and interpret them assigns of abnormal health. When this happens, it should be assumedthat an infectious disease has gained entry and may betracked elsewhere during the investigation period. In a modernpoultry production system, any disease creates serious disruptionin the economical operation of the farm and the plants processingproducts from it. Serious infectious diseases can create havoc. Thefollowing steps should be followed when disease is suspected.
Look for Non-infectious Conditions
Take precautions against tracking an infectious disease that maybe present, but investigate management errors immediately. Ahigh percentage of so-called disease problems referred to laboratoriesfor diagnosis are noninfectious conditions related to management:beak trimming errors; consumption of litter and trash;feed and water deprivation; chilling of chicks; injury from roughhandling, automatic equipment, or drug injection; electrical failures;cannibalism; smothering; overcrowding; poor arrangementof feeders, waterers, and ventilators; inexpensive low-qualityfeed ingredients; ingredients causing feed refusal; improper particlesize of feed ingredients; and rodent and predator attacks. These are conditions that do not require services of a diagnosticlaboratory. External parasites (mites, lice, and ticks) canbe determined by producers if they examine affected birds.
Quarantine the Flock
In the event that no management factors can be found, the nextstep is to set up a quarantine of the pen, building, farm unit area,or entire farm, depending upon its design and programming. Ifthis emergency was anticipated when the farm was laid out andprogrammed originally, the quarantine will be a minor problem.If the basic principle of “a single age in quarantinable units” wasdisregarded in original farm planning, a disease outbreak can bean economic disaster. Separate caretakers should be establishedfor affected birds or at least sick ones should be visited last.
Submit Specimens or Call a Veterinarian
The owner or caretaker should submit typical specimens to a diagnosticlaboratory or call a veterinarian to visit the farm and establishthe diagnosis. Owners should seek professional diagnosis,rather than trying to hide some disease because of possible publicrecrimination. Veterinarians and caretakers can and shouldhelp dispel this apprehension by maintaining high ethical standardsand refraining from discussing one producer’s problemswith others. Yet, there comes a time when all producers must be apprised of a problem. Service workers frequently are requestedto examine the flock, select specimens for the laboratory, and initiatefirst-aid procedures until the veterinarian can be called orvisited. If so, they should wear protective footwear and clothingwhen they enter the house. No other farm should be visited enroute to the laboratory.
Diagnosis of condition
It is important to get a diagnosis as soon as possible. The courseof action will be determined by the nature of the disease. A producershould not procrastinate for any reason when a diseasethreatens, or it may get completely out of hand before a diagnosisis made. It is not always possible to treat a disease or check itsdeleterious effects, but to plan effectively for the future, it is importantto identify any and all diseases that occur. A veterinarianshould also be aware of the owner’s economic plight at suchtimes and render advice and assistance as quickly as informationis available or a judgment can be made.
Special Precautions
In addition to causing serious losses in poultry, some diseases(chlamydiosis, erysipelas, and salmonellosis) are especially hazardousfor humans. When these conditions are suspected or diagnosed,extra precautions must be taken to ensure against humaninfection. The proper government health authorities should benotified of chlamydiosis outbreaks, and all handling and processingpersonnel should be apprised of the disease, hazards, andnecessary precautions.In some states, certain diseases (Mycoplasma infections, avianchlamydiosis, and laryngotracheitis) must be reported immediatelyto the state animal disease control authorities so that properinvestigation and action can be taken to protect the human populationand the poultry industry. Common sense dictates that whena condition suggestive of an exotic disease, such as velogenicviscerotropicNewcastle disease, fowl typhoid, or avian influenza, isencountered, the proper state and federal regulatory authoritiesshould be informed.
Nursing Care
Nursing care plays an important role in the outcome of a diseaseoutbreak. Additional heat should be supplied to young chicks thatbegin huddling because of sickness. Clean and fresh (or medicated)water should be available at close range. Temporary, moreaccessibly located waterers are sometimes necessary during sickness.If water founts normally are located where chickens mustjump onto some raised device or turkeys must cross through hotsunlight to reach them, the sick will not have the energy or initiativeto seek water. They will soon become dehydrated, an earlystep on the road to death.The same principles are true for feed. Sick birds can be encouraged
toeat if the caretaker will proceed through the house,stirring feed and rattling feed hoppers or adding small quantitiesof fresh feed. Some antibiotics appear to stimulate feed consumptionwhen included in the diet; however, any additive thatproves distasteful to the bird should be removed immediately.Sometimes birds become so depressed and moribund that thecaretaker must walk among them frequently to rouse them so thatthey will eat or drink.Hopelessly sick and crippled birds should be killed in a mannerto preclude or control the discharge of blood or exudates
Use of drugs
No drugs should be given until a diagnosis is obtained or a veterinarianconsulted. If the wrong drug is given, it can be a wasteof money, or it may be harmful or even disastrous. If an infectiousdisease is found and corrective drugs are indicated, theyshould be used very carefully according to directions.Strict regulations govern the use of drugs in mixed feeds forfood-producing animals. Feed manufacturers must have FDAclearance to include drugs in mixed feeds. When treated flocksare to be marketed, a specified period (depending on the drugused) must follow cessation of treatment to allow dissipation ofdrug residues from tissues before slaughter. If the flock is producingtable eggs when treated, the drug must be one permittedfor use in laying flocks, or eggs must be discarded during, andfor varying lengths of time after, treatment, which is a costlyalternative.If the flock is producing hatching eggs when it becomes infectedand there is danger that egg transmission of the infectiousagent from dams to offspring may occur (salmonellosis, mycoplasmosis,and avian encephalomyelitis), eggs should not be usedfor hatching until the danger has passed. It should also be kept inmind that in fertile eggs, residues of drugs used to treat breedersoccasionally may cause abnormalities in some embryos.
Disposition of the Flock
The flock should not be moved or handled until it has recovered,unless the move is to a more favorable environment as part of thetherapy. After treatment, if any, has been completed and the flockappears to be completely healthy, it may be marketed or movedto permanent quarters if such a move is part of the managementprogram. Some healthy carriers may remain. If the flock ismoved to another depopulated farm, this will present no problemexcept that occasionally a disease may flare up from stress ofhandling and moving. If the recovered flock is moved to amultiple-age farm, carriers can introduce the disease into susceptibleflocks already there. If the recovered flock is already in permanentquarters having multiple ages, newly introduced flocksmay be exposed and contract the disease, a common occurrenceespecially with respiratory and litter-borne diseases.
Biosecurity refers to the management practices aimed at excluding or reducing the transmission and spread of diseases to animals, humans or an area from the disease causing agents. “Bio” refers to life, and “security” indicates protection. Biosecurity is the key factor for better chicken health and profitable poultry production. It is accomplished by maintaining the poultry shed in such a way that there is a nominal traffic of biological organisms (viruses, bacteria, rodents, etc.) across its borders. Biosecurity is the most cost-effective means of disease control management and defined as ‘informed common sense’. Biosecurity is based on two fundamental principles: bio-exclusion,“preventing the introduction of a disease agent onto a farm” and bio-confinement, “preventing the spread of a disease agent onto a farm” (Figure-1). Thus, biosecurity has become the huge factor for minimal loss for poultry stakeholder and emerged as a phenomenon for poultry farming.
Major Routes of Disease Transmission
Disease transmission at a farm is an important factor in biosecurity studies. Some studies have stated that about 90% of diseases are transmitted from one farm to another farm through contaminated people, poultry farm equipment’s and farm vehicles. There are some examples of direct transmission through ovarian transmission (Mycoplasma gallisepticum), egg shells penetration (Salmonella spp.), water borne disease (Escherichiacoli) and airborne transmission (Mycoplasma gallisepticum). But the chances are very low through airborne transmission. Stability of poultry disease in the environment is also a major factor for disease transmission. The routes of disease transmission details are given in Table-1.
Farm Standards for Complete Biosecurity
Biosecurity measures depend upon the farm modality and standards (Figure-2). The farm standards redefine the easy steps for bio-security which is described as follows.
- The poultry production area must have well developed fence or boundary, defining biosecurity zone.
- If there is mixed farming or grazing area, there must be well defined grazing areas for other animals that must not be linked with poultry production system.
- Provision for separate clothes and boots for visitors.
- Footbath area should exist in farm entrance for individuals, vehicles and all other entries.
- Well-developed drainage system.
- Poultry house must be designed or maintained in such a way that minimal entry of wild birds and access to vermin is observed.
- Routine biosecurity procedures.
- Drinking water and cooling water supplied in poultry shed must meet poultry water standard.
- Only commercial poultry should be kept in production areas not other species.
- Better storage facility for feed.
- Separate weighing machine for the production areas.
- During rearing period, minimum 15-30 days gap for broiler flock, 1.5-2 months gap for layer flock and 1.5-2 months gap for breeder flock should be maintained.
Routine Biosecurity Procedure
Routine biosecurity measures to maintain the poultry farm are discussed as follows.
- Farm workers should wear neat and clean clothes, and boots.
- Hand sanitizer should be used prior to house entry and upon exit.
- Farm workers should not entertain or contact with outside farm birds.
- Visitors on farms should be discouraged, especially contract persons like veterinarians and service providers. Visitor guidelines should be properly mentioned outside and inside the farm.
- Avoid allowing pets, wild birds and livestock inside the farm.
- Spraying disinfectants inside the farm should be done thrice a week; in diseased condition once or twice a day depending on the nature of disease.
- Spraying of disinfectant in vehicles of visitors should be strictly done.
- Treated water should be used if there is provision of surface water or during diseased condition.
- Before entry of chicks, farm should be properly disinfected and fumigated.
- Hatched eggs should be properly disinfected.
- Workrooms should be maintained clean.
- Sharing farm equipment’s like poultry birds in cages should be avoided. Effective way of cleaning and disinfection of equipment must be taken care between farms.
- Routine maintenance of farm should be conducted whenever possible.
- Litter delivery and collection of used litter – trucks carrying new or previous litter must be cleaned and disinfected between production areas.
- Other delivery vehicles (e.g. gas, chicks, prepared flocks, eggs and feed) and drivers should not be allowed to enter in farms.
DR RAVINDRA KUMAR, IVRI
