Disease is a complex linkage between the host, the pathogenic organism and the environment. The spread of disease is mainly due to nature of livestock industry (mobility of animals, birds, milk, egg and feed) and people contact. Biosecurity is a strategic plan to control and prevent the spread of disease. The term was first used by Agricultural and Environmental communities from late 1990s in response to the threat of biological terrorism. The definition of biodiversity is dynamic per the place i.e. for individual farm, region or a nation. The meaning of biosecurity can apply to different levels i.e. a single premise, geographical region, an entire country or different parts of several neighboring countries.
FAO broadly defines biosecurity as- “Biosecurity is a strategic and integrated approach that encompasses the policy and regulatory framework that analyze and manage risk in the sector of food safety, animal life and health and plant life and health including associated environmental risk”.
There is a famous saying: “Do not bring germs to livestock and do not bring livestock to germs.” The concept of organic farming is not possible without biosecurity. There are two basic components of biosecurity- Bio-exclusion and Bio-containment; the former implies preventing the introduction of disease to farm and the latter means to prevent the spread of disease from farm to farm and within the farm.
Key points of biosecurity
- Prevention of disease
Prevention of disease can be done through the components of biosecurity.
- Disease control
It emphasizes in reducing the consequences of disease with the use of epidemiological tools.
- Determinants of disease
These are the various factors that influence the spread of disease. The determinants include any group of variables such as specific disease agent, housing environment that may directly or indirectly influence the distribution and frequency of spread of disease.
- Assessment of risk
It deals with the use of statistical tools and techniques to find out the probability of exposure, occurrence and spread of disease and its consequences. Assessment of risk is important to co-relate some specific factor with disease.
- Host immunity
The immunity of host determines the infectivity of any infectious agent. The least immune host is more easily infected depending upon the dose and virulence of the infectious agent. Such weak members of a population will tend to decrease the infectious dose 50 (ID50).
- Epidemiological factor
It implies determination of origin of disease whose cause is known and investigation of disease whose cause is either unknown or poorly understood. Epidemiology helps us to better understand how climate and environment affects the interaction between host and pathogen. The assessment of economic effects of disease is also equally important as the measurement of disease i.e. measures of morbidity and mortality.
Basic concept of biosecurity at farm level
Farm should be established farther from public roads, especially which have low density of animals. Isolation includes perimeter fencing as well as limiting the use of vehicles in farm area. Isolation of sick animals and quarantine of new or returning animals helps to maintain the entire herd health program.
- Traffic control
Personnel and vehicles which are not directly involved with the farm should not be allowed to enter the farm haphazardly. Housing design, farm layout, movement of vehicles, equipment and animals should be considered as well.
Sanitation assuredly is a measure of biosecurity as it addresses disinfection of materials, equipment and people entering the farm. Personal cleanliness, proper disposal method, water quality, feed storage and delivery system are some of the factors which should be considered and checked at regular time interval.
Developing a biosecurity plan for livestock sector
Biosecurity is a set of habits, design to subdue the risk of introducing diseases or contamination of farm environment.
Following points are to be considered:
- Site selection is a vital part for a farm. Place having enough grazing area and easy market accesses, sufficient air circulation and sunlight and area having low density of animal population are desired.
- Shed should be prepared perthe location of the farm with a view to keep the manure pit in distance from the shed.
- Good fences be like good neighbors. Boundary fences are to be checked routinely and repaired if required.
- Quarantine practice is essential.
- New animals should be brought from sources with good herd health program along with their health certificate.
- Management of the shed is also as important as disease control. So, limited number of animals as per the capacity of the shed should be kept maintaining suitable temperature, ventilation, sunlight and bedding.
- Different age group animals should be kept in different sheds. It is wise keep same age animals and of same breeds.
- A training program to the farm staff about biosecurity and personal hygiene is necessary to keep the farm secure.
- Sanitation is a must. The shed should be cleaned thoroughly before the intake of animals in the farm. Unwanted equipment and the equipment which are not disinfected should not be entertained within the farm premises.
- Prevention of stock feed from contamination is another important aspect of biosecurity.
- Animals should be provided with healthy, clean and microbes free water.
- Carcass requires proper disposal as they can be a hazard to farm environment and invites the migratory animals like dog, fox, etc.
- Contractors, visitors are mostly unware of farm biosecurity. A designated parking area with wash water facility is essential with properly visible hoarding board.
- Disinfection of equipment, sheds, mangers, containers and other materials is necessary.
- A regular surveillance of farm animals is also important to see the symptoms of diseases if present and culling of diseased animal.
- Diseased animals should be isolated from rest of the herd and better not to take for grazing.
- Chemoprophylaxis and vaccination program should be launched with the advice of veterinary doctor.
Furthermore, biosecurity program can be completed in three levels i.e.
- Bio–exclusion to limit the level of exposure of animals to pathogen below the threshold level for infection
- Surveillance to estimate prevalence of disease and their severity in a population.
- Bio–containment to reduce the consequences of diseases which includes immunization and quarantine.
A biosecurity program is needed for every veterinary sector either large or small which drawsthe prevention methods exploited to protect the animals, workers and owners. It is difficult to find a single plan that fits all facilities, but the risk of disease transmission can be reduced by exercising standard personal hygiene and prevention strategies. Assessment of biosecurity protocols at regular time interval is required to tackle with the emergence of new infectious diseases. A biosecurity plan is only productive when the entire unit is working within the program.
Merck Veterinary Manual. 1991. S. E. Aiello (ed.). Merck and Co. Inc. White House Station, USA (8th Edition)
Brennan ML. and Christley RM., (2012). Biosecurity on Cattle Farms: A study in North-West England. PLoS One. 2012; 7(1): e28139
Wilson, S-J., (2014). Developing an on-farm biosecurity plan for your grazing enterprise. Livestock Biosecurity Network. Canberra.
Chakrabarti, A. 1993. A Textbook of Preventive Veterinary Medicine. Kalyani Publishers, India