This Biosecurity section contains the following sub-sections:
'Biosecurity' is the prevention of disease causing agents entering or leaving any place where farm animals are present (or have been present recently). It involves a number of measures and protocols designed to prevent
disease causing agents from entering or leaving a property and being spread (Defra, 2003). Some diseases are zoonotic i.e they can be transmitted between humans and animals, and therefore there are good public and
occupational health reasons for having biosecurity measures.
Farm to farm movement of infected livestock is the most effective means by which animal diseases such as Foot and Mouth Disease can be spread. Diseases can also be spread by other means, such as wildlife, air or other vectors. Basic biosecurity measures are concerned with minimising the spread through contaminated vehicles, clothing, footwear and equipment.
The biosecurity measures taken should reflect the risk involved. Disease is not always apparent, especially in its early stages. This does not mean that the risk does not exist. Further, disease agents and vectors may still exist even when animals have been removed and hence biosecurity measures still apply.
The two key biosecurity measures are concerned with 1) minimising movement of people, vehicles and equipment where animals are kept and 2) implementing best practice (hygiene and protective clothing) in situations where there is direct contact with animals.
Biosecurity should be an important element within Animal Health Plans.
Defra project OZ0144 explored the issue of Constraints to uptake of adequate biosecurity on UK cattle and sheep farms, with special reference to zoonotic diseases (The University of Reading, 2004). This highlighted the complexity of implementing biosecurity and showed that farmers had a comprehensive and uniform understanding of the meaning of biosecurity at farm level, although there were regional differences in emphasis i.e between the importance of closed herds and disinfection. However, the overall results of the project suggest that little change in approaches to biosecurity has taken place on UK sheep and cattle farms as a result of the 2001 Foot and Mouth Disease outbreak. The study identified a disparity between the major “stakeholders” in implementing biosecurity. Interestingly, whilst auxillary industries highlighted zoonotic diseases as a major concern, these were not seen as the major drivers by farmers and veterinarians. The study also highlighted the requirement for better quantification of the benefits of biosecurity.
The Defra biosecurity web-pages contain a Frequently Asked Questions section.
Typical Ruminant Animal Health Security Measures
The following is a list of typical animal health security measures promoted in the literature for cattle and sheep systems (compiled by Hovi, 2004 as part of Defra project OZ0144)
1. Maintaining a closed herd/flock.
2. Using a 4 week quarantine for purchased stock, including rams and bulls
3. Purchasing animals from herds/flocks with known disease status
4. Preventing contamination of livestock by farm visitors
5. Preventing contamination of livestock by users of public footpaths
6. Preventing contamination of livestock by people and vehicles using public roads
7. Preventing contamination of livestock by delivery and pick-up vehicles.
8. Implementing strict disinfection measures for essential visitors (vets, shearers, AI technicians etc.)
9. Preventing contact of own livestock with stock from neighbouring farms
10. Preventing access of own livestock to contaminated surface water
11. Not using relief/assistant livestock-people who are in contact with livestock from other herds/flocks
12. Minimising access of own livestock and animal feed to wildlife, vermin, pets that may transmit cattle/sheep disease
13. A period of statutory standstill for livestock on farms that have bought/brought in animals
14. Membership of commercial herd/flock health schemes (e.g. Premium Cattle Health Scheme or Sheep and Goat Health Scheme)
15. Establishing disease free zones with neighbouring farms within suitable geographic boundaries.
16. Implementing routine blood or other diagnostic disease screening at purchase.
17. Vaccination
Biosecurity and Organic Farming
Organically managed animals in any one country are part of the national herd or flock and are likely to share the same overall disease status with regard to contagious diseases as the national herd/flock. Similarly, they face the same disease challenges as the rest of the national herd/flock (Hovi, 2004).
Animal health security is not specifically mentioned within the EU Organic Farming Regulation 1804/99. Although the use of animal health plans is included in the UK regulation (Defra, 2006), again this does not specifically mention biosecurity.
Animal movement from farm to farm is partially addressed by the basic organic farming principles that assume closed, sustainable production cycles and require minimisation of animal transport. However, there are allowances for bringing in breeding and/or replacement animals or to reconstitute or expand herds and flocks, allowing for stratified livestock production systems, where animals move from farm to farm regularly.
The rules regulating the origin of bought or brought-in stock on organic farms are not adequate to constitute barriers to disease, unless individual certification authorities implement such barriers for animals coming from conventional farms (Hovi, 2004). There is no requirement for routine quarantine and testing procedures for incoming animals, although Council Regulation 1804/1999 Annex Paragraph 3.1.3 states “…..The inspection authority or body may apply, depending on local circumstances, special measures, such as screening tests, and quarantine periods”.
Hovi (2004) surmises that the reasons behind the apparent absence of animal health security in the organic regulation may be consequent of the expected benefits of closed herds/flocks and the assumed smaller health risk emanating from organic herds. With regard to the latter, there is little evidence of differences in the prevalence of endemic disease or resistance to exotic epizooties than that found in non-organic herds and flocks. Hovi (2004) argues that, given current understanding, the external disease challenges facing organic livestock farms are likely to be the same as those facing similar non-organic conventional farms in the same locality.
Apart from closed herds, there are other specific characteristics of organic livestock farms that may contribute to their relative health security risks:
· A requirement for maximisation of pasture use for ruminant and the requirement to maintain free-range systems for poultry and pigs expose organic animals to added health security challenges. This may be particularly true for pigs and poultry given the exposure to a potentially contaminated environment and wild disease hosts as compared with biosecure contained systems (see also Zoonoses).
· Vaccination use in organic farming is based on risk assessment and therefore not in such widespread use as in non-organic farming.
· The potential for immuno-suppressed animals in organic farming consequent of sub-clinical infections with diseases such as BVD which are more likely to be contained by vaccination in non-organic herds (Hovi, 2004).
There are a number of Defra publications that offer guidance on biosecurity issues for farmers, all of which are available at the Defra web-page Disease control: Biosecurity.
Leaflet “Better Biosecurity Provides Peace of Mind, Healthy Stock and a More Viable Business” provides summary information on the benefits of biosecurity, how disease spreads, how to stop it and animal movement onto farms.
Defra (2003) Booklet “Biosecurity Guidance to Prevent the Spread of Animal Diseases” provides biosecurity guidance on entering or leaving places where farm animals (including poultry) are kept of have been kept. This guidance applies to everyone who enters a farm or premises with farm animals, or enters land used for grazing or keeping farm animals.
Defra also provide disease and species specific biosecurity information, such as the Fact Sheet Biosecurity – Preventing the introduction and the spread
of foot and mouth disease and Biosecurity and preventing disease in poultry.
Exotic, new and re-emerging diseases
An outbreak of an Exotic Notifiable Disease is where the Chief Veterinary Officer of Defra has confirmed the presence of such a disease, for example Foot and Mouth Disease, Classical Swine Fever, Avian Influenza, Newcastle Disease. In the event of an outbreak a Press Release would be issued immediately and details posted on the Defra website. Details of Exotic Notifiable Diseases can be found on the Defra website.
Recent studies suggest that major animal disease threats to UK include new outbreaks of mostly viral diseases, including as rabies, FMD, classical swine fever, Newcastle Disease, avian influenza, enzootic bovine leucosis, and equine viral arteritis, all of which have appeared before. Amongst diseases which would be entirely new to UK, the viruses responsible for blue tongue, West Nile virus, African swine fever, swine vesicular disease, and yet-unknown emergent diseases are among the most likely threats in the near future. Biological features shared by many of these new disease threats include the existence of wild animal reservoirs (and usually a degree of wild animal impact) and their zoonotic potential (Waage et al., 2005)
The recent outbreaks of FMD generated considerable information and modelling on rapid disease spread which highlight the role of aerial spread and satellite creation through long distance movement of animals. However, the extremely rapid spread of this disease is not necessarily typical for new introductions into UK. Other existing or potential UK animal diseases, such as bovine TB, TSE and rabies, are known to move more slowly.
Climate change, growing and changing trade and markets and social issues associated with changing values and land-use are the main new factors likely to influence the pattern and spread of new and re-emerging diseases associated with non-native species of animal and plant. Defra project “A New Agenda for Biosecurity” (SD0301) (Waage et al., 2005) consider the biosecurity issues associated with the introduction of non-native animal and plant species into the UK.