Atul Kumar1 and Tania Gupta2
1Assistant Professor, Veterinary Public Health & Epidemiology
2Ph.D. Scholar, Veterinary Microbiology
Dr. G. C. Negi College of Veterinary and Animal Sciences,
CSK HP Agricultural University, Palampur (H.P.) – 176062
India is bestowed with the largest livestock population in the world. Rearing of livestock is one of the most important economic activities in the rural areas of the country providing supplementary income for most of the families dependent on agriculture. Livestock rearing not only provide a subsidiary income to the families but is also a source of protein supplement to the family members of the household in the form of milk, eggs and meat. Therefore, along with agriculture, it is crucial for overall food security.
Poultry represents largest domestic stock in the world with estimated global population of approx. approx. 18 billion. Poultry farming is among the most important activities in livestock sector. Poultry production in India has taken a quantum leap in the last few decades, emerging from an unscientific farming practice to one of the most organized, commercial production system with state-of-the art technological interventions. Currently, the total poultry population in our country is 729.21 million (as per 19th Livestock Census) and egg production has increased from 21,101 million eggs during the year 1990-91 to 88,139 million in the year 2016-17. Likewise, there has been steady increase in poultry meat production too and it is estimated to be 3.26 million tonnes during the year 2015-16. Therefore, to ensure the healthy status of industry, it is important that birds should be kept in good health and all the measures to prevent the introduction and spread of harmful biological substances in the poultry population should be carefully designed. So, biosecurity acts as a cornerstone for reaping the maximal benefits out of this profitable enterprise.
The World Organisation for Animal Health (OIE) define biosecurity as the implementation of measures to reduce the risk of the introduction and spread of disease agents. Different measures used by the farm persons to protect their farm from entry and spread of disease is referred to as farm biosecurity. Biosecurity measures play a vital role for quality production of poultry. Both commercial and backyard poultry needs such measures as they have close interaction with humans. Backyard poultry is often characterized by small flocks with low biosecurity measures and it is extremely difficult for backyard farmers to practise sound biosecurity measures, since the birds are being raised outside.
Importance of biosecurity measures
Poultry diseases has expanded greatly with the expansion of poultry population and its industries. The risk for disease outbreak is high which can result in severe economic losses to the poultry industry. A Newcastle or Influenza outbreak in an area involving numerous farms in close proximity can be catastrophic. Introduction of disease in any farm can lead to morbidity and/or mortality among birds. Due to lack of basic management and disease control strategies, disease can spread into and between the farms so it is necessary to implement hygienic measures to prevent the spread of pathogens. Biosecurity measures are simple plans to prevent the entry of pathogens and its spread with the principle of bio-exclusion (i.e. preventing infectious agents from entering the farm) and bio-containment (i.e. preventing infectious agents from exiting). Enforcing biosecurity has become the chief weapon worldwide to fight against fatal disease incidences.
Risk factors for poultry industry
The various factors which can increase the likelihood of occurrence/spread of diseases in poultry industry includes:
- Poor or complete absence of disease control strategies.
- Inadequate managemental practices resulting in emergence of highly infectious disease like Highly pathogenic Avian influenza (HPAI), Newcastle Disease, Salmonellosis, IBD etc.
- The spread of pathogen among poultry flocks through fomites such as contaminated equipment, clothing and footwear etc. is the principle mode that is always neglected. Humans along with infected animals, such as wild birds and rodents, can also act as potential source of diseases for poultry flocks.
- Poultry trading is often viewed as a risk factor for various diseses like HPAI and NCD in the flock. Poultry farmers are therefore advised to avoid visiting live bird markets or other trading places [46,61]. However, this practice persists in many developing countries [8,48]. Poultry farmers are also advised to ensure that the poultry supply source is disease-free .
Risks to Public Health
Many infectious diseases of poultry (e.g. Avian influenza, New Castle disease, campylobacteriosis, salmonellosis, chlamydiosis, West Nile etc.) are zoonotic i.e. they can be transmitted and can affect susceptible human beings. Therefore, there should be some recommendations to limit their risk to humans. This includes separating people especially children from poultry and adopting personal hygienic measures such as hand washing or wearing personal protective equipments like gloves, aprons etc. when handling poultry. The correct approach to combat zoonotic poultry diseases should be holistic, based on the principle of improving personal and community hygiene to prevent all infectious diseases in poultry to eventually mitigate exposure and transmission risk to humans.
Biosecurity measures to be applied
Biosecurity is an integrated approach and it has three major components i.e. isolation, traffic control and sanitation. Isolation refers to the confinement of animals within a controlled environment. A fence keeps the birds in, but it also keeps other animals out. Isolation also applies to the practice of separating birds by age group. Traffic control includes both the traffic onto the farm and within the farm. Sanitation addresses the disinfection of materials, people and equipment entering the farm and the cleanliness of the personnel on the farm. By following these three simple rules, the producer should effectively be able to minimize any preventable disease outbreaks. Thus such biosecurity measures can be achieved by:
- Restricting entry of people: Humans are among the most important determinants in the spread of diseases. Restriction of unnecessary human movement in the farm is an important component of a sound biosecurity programme. Restricting people movement limits the risk of introducing infectious agents into flocks. Therefore, farm manager should not allow visitors without any reason. The entry of all those persons who work with or had recent contact with poultry should be guided with proper protective covering like boots, coveralls, and headgears etc.
- Restricting entry of vehicles: Since many poultry diseases are known to be spread by transportation and thus it is of paramount importance to clean and disinfect vehicles before entry into farm premises. Normally many vehicles enter the farm for various works e.g. for bringing chicks to the farm, feed from mills, etc. Only necessary vehicle should be allowed to enter with proper disinfection at the entry point.
- Regular cleaning and sanitation of the farm: Effective cleaning and disinfection is an essential component of good hygiene and thus one of the key biosecurity measures for disease prevention and control. Decontamination of farm floor, equipments, vehicles, water, etc. is essential for reducing the spread of pathogens. Approved disinfectants like chlorine dioxide and peracetic acid can be used in the farm for disinfection or sterilization may be used. Other available disinfectants includes phenols, hypochlorites (chlorine), iodophors (iodine), quaternary ammonium, formaldehyde gas, chlorhexidine, formaldehyde powder and alkali.
- Food and water management: Food and Agricultural Organization recognizes food and water management as a biosecurity hazard to poultry, hence there is a need to account for it. So, provide supplemented food (if possible) or ensure clean containers for food and water
- Restrict animals away from poultry farm: It means restricting access to a farm by employing fences and enclosures which creates a barrier between clean areas where poultry are kept and outside environment and it is the most important biosecurity measures for restricting source of infection away from farm and even from the infected farm to other non-infected farm. Various wild birds– resident fowl or migratory birds can be the carriers of poultry pathogens. Therefore, they should have no contact with the flock through the use of screens or overlying nets.
- Disease prevention by pest and rodents control: Farmers have a documented pest control program to reduce the risk of diseases being carried on to the farm by rodents. Rats, mice, and insects such as flies and darkling beetles can carry and spread microorganisms. These pests annoy and stress the birds and may serve as carriers of diseases. In some cases the pests are simply mechanical vectors. However; in other cases, such as salmonella in rodents and wild birds, they serve as biological vectors. Some pests can travel between poultry houses and even between farms. Wire mesh siding is suggested at all openings into the poultry house to prevent entry of even small birds and rodents.
- Restrict contact with non-commercialized birds: Non-commercial sources of poultry including backyard flocks, fanciers, fairs, poultry shows, and markets, are never fully vaccinated for the major poultry diseases and they are often exposed to many types of unhealthy and healthy flocks of birds. Non-commercial birds have extremely high-risk contacts and their entry should be restricted.
- Avoid visits to live markets and rotinely inspect the flock: Poultry trading is considered as a risk factor for various infectious diseses. Poultry farmers are therefore advised to avoid visiting live bird markets or other trading places. However, this practice persists in many parts of India. Flock should be regularly inspected to check mortality that should be disposed off timely.
- Avoid mixing: One recommended husbandry measure is to separate poultry by age and species or to consider raising one species instead of several, given that mixing species increases HPAIA/H5N1 virus transmission. In large poultry operations, age separation would facilitate the all in – all out strategy whereby sanitary cleaning can be carried out between the complete exit and renewal of flocks. However, age separation would not be feasible in developing countries where farmers keep several ages to ensure meat production throughout the year.
- Disposal of dead birds, biomedical wastes and poultry manure: Dead birds should be disposed off properly and as quickly as possible, to ensure no contact with other healthy birds. This will be helpful in removing the source of infected foci to poultry as well as to the poultry workers. The best way to dispose off dead birds is by rendering, burial or incineration. For appropriate disposal of some biomedical wastes such as syringes, needles, swabs, empty vials, hatchery waste etc., The Bio-Medical Waste (Management & Handling) Rules, 1998 under Environment (Protection) Act, 1986 should be referred. Poultry manure should be left undisturbed for at least 90 days and then can be used as fertilizer. The practices of using poultry manure and other poultry by-products such as feathers in agriculture and aquaculture as fertilizer and in untreated form as food for pigs and fish should be stopped. The use of untreated poultry manure as fertilizer poses a serious risk of infection spread. This can be addressed by composting manure outside the flock area.
- General husbandry practices: Healthy, unstressed birds have an active metabolism and effective immune system to protect them against diseases. Nutritionally balanced diet, maintaining a comfortable living environment and minimizing fear and anxiety in the birds will help the bird’s natural protective mechanisms to function optimally.
- Vaccination and medications: Vaccines aid in preventing disease by stimulating the immune system in such a way that it enhances the immune response when the bird is subsequently exposed to a pathogen. The birds should be provided certain medicines and essential vaccines regularly, which can boost immunity such as vitamins, trace minerals and proteins. Deficiency of these will not only lead to decreased production but there will be more chances of getting infection in flock with low level of immunity.
- Isolation and quarantine of new birds: The most common method of disease transmission is by contact of a susceptible bird with an infected bird. This can occur within the flock or from flock to flock by the introduction of new livestock. It is necessary in a separate place and enclosure so that infectious agents which may be there in the newly introduced birds may be detected before introduction of these birds with other flocks. Poultry farmers are advised to ensure that the poultry supply source is disease-free.
The poultry industry has started attempts to limit its losses due to infectious diseases. However, it is becoming apparent that for achieving the targets it is necessary to switch back to the ‘basics’. Although vaccines and other treatments have been used since last many decades but they too have limitations. To be successful, there has to be a change in the manner in which poultry is raised. The key to future success and expansion will come about through elimination and control of diseases and this can only be brought about by the implementation of effective biosecurity programmes. Biosecurity has become an integral part of the culture of raising poultry and it is critical to the future of the poultry industry too. While there are vaccines and antibiotics to assist, it will be necessary to prevent and eliminate disease agents if the poultry industry is to prosper. Biosecurity will determine the success or failure of the industry in the region. Thus, it must be fully understood and strictly implemented. Basic understanding of how diseases enter into a farm, persist in the farm and gets disseminated from the farm needs to be understood so that control can be approached scientifically. Thus all in all biosecurity is considered as an indispensable tool to mitigate the spread of infectious diseases and therefore, must be approached from a country-wide perspective to be truly effective.