1. Using biodiversity in husbandry practices for disease
control
Cheryl Lans
November 24, 2006
Culling (stamping out) for the control of contagious diseases is one of the
earliest methods used by the veterinary profession and originated in
Britain in 1892.
For trade-related reasons culling has been preferred to vaccination which may mask
symptoms or produce carrier animals. Therefore vaccination does not necessarily stop
contamination of the environment with the infectious agent; however it can reduce the
spread of the infectious agent.
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2. Culling has been criticized for the following reasons:
1. for the emotional impact it has on the owners, on meat consumers and rural
populations,
2. for being indiscriminate – healthy, valuable and disease-resistant animals in
affected areas are also killed,
3. it is hugely expensive [but not necessarily more expensive than vaccination in a
capitalism-friendly political environment].
4. it can contribute to the spread of the target disease.
5. it has a negative impact on biodiversity (including the genetic breeds favoured
by small scale and organic farmers, and wild species that may be affected in
future epidemics).
6. biodiversity is also affected when local people turn to “bushmeat” to replace their
culled poultry in their diets.
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3. Underlying assumptions of culling
 The most basic assumption behind stamping out is that a disease-free
existence is optimal and can be achieved.
 A second related assumption is that given enough resources a disease can be
eradicated and this will be more cost effective than having lost productivity
from sub-clinical and clinical infections, medication costs and lost
opportunities for international trade. However “enough resources” rarely
exists in practice and very few diseases have actually been eradicated. For
example the SARS outbreak (in 30 countries and with approximately 8500
deaths) cost between US$10 billion to US$30 billion (Robertson, 2002). It is
unlikely that these resources can be continuously spent on each new serious
outbreak without a long term economic impact

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4. A third assumption is that eradicating a disease justifies any resulting loss in
biodiversity. This assumption may be linked to the fourth assumption.
 The fourth assumption is that scientists can genetically-engineer more
productive species than those that originally existed.
 The most important assumption is that cheap food and cheap protein are
universal goods that should be achieved whatever the environmental costs.
First there is already sufficient food, but it is poorly distributed and post-
harvest losses and wastage are immense. Given the current obesity pandemic
and the linked increase in famine and desertification it is obvious that there
are environmental limits to the provision of cheap food that have not been
overcome. The cost effectiveness of living within environmental limits?
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5. Avian flu
1. Millions of economic resources have gone into vaccination, outreach and
research programs, in order to prevent new pandemics. While it is encouraging
to see an increase in scientific jobs, these resources must have been diverted
from other uses.
2. Millions of birds have been killed. These birds have more genetic diversity than
the industrial poultry being protected.
3. Organic practices are being curtailed (animals have to be kept indoors) although
there is no scientific evidence that organic practices increase the spread of the
disease. However there is mounting scientific evidence that animal welfare
increase in organic systems.
4. Exotic diseases can be dealt with on a case-by-case basis and these regional or
country specific diseases do not normally cause great perturbations.
5. Medicinal plants exist that could be used for disease control (Lans et al., 2006).
The following plants, usually immersed in the drinking water, are used to control clinical
signs of unspecified respiratory disease in poultry globally:
Three of these species (Allium sativum, Andrographis paniculata and Nicotiana glauca)
and species of three other genera (Citrus, Euphorbia and Mahonia) have anti-influenza
activity. A further seven species (Curcuma longa, Eryobotrya japonica, Momordica
charantia, Ocimum sanctum, Plantago major, Ricinus communis and Zingiber officinale)
demonstrate activity against other viruses.
Momordica charantia
www.finerareprints.com/.../vanhoutte/11124.jpg
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6. Computer simulations
Most computer simulations model the spread of the disease in a target population as it
is. For example scientists working with the Models of Infectious Disease Agent Study
(Midas) research network have concluded that immediate treatment with vaccines and
antiviral drugs as well as quarantines and other standard public health measures would
prevent a pandemic.
Simulations could be used to change the underlying assumptions of livestock husbandry.
For example industrial agriculture and globalized trade are considered to be best
practice and most efficient. It should be possible to model organic agriculture and local
food provision as best practice based on the increased hardiness of livestock raised
organically and the reduced food miles of local food.
Rather than model the target population as it currently is, the simulations will change
the practice of animal husbandry in the target population to organic (including the use
of medicinal plants), and reduce the level of international food-related trade and then
investigate whether these modifications have any effect on the spread of disease.
http://www.nigms.nih.gov/Research/FeaturedPrograms/MIDAS/
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7. Example of a Methodological Approach
1. Map the spread of avian flu against industrial food trade routes to see if there is
any correlation.
2. Document the location of the ~ 100 people who have died of avian flu – whether
they were close to industrial operations or trade routes or whether they were
involved in backyard operations.
3. Document through literature study the symptoms of the people who died and
those who recovered and if possible what they were treated with.
4. Compare the costs of disease control in the past when it was largely tax-payer
funded to the current privatized provision (pharmaceutical companies recovering
their research costs).
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8. Researchers in the United Kingdom postulate that human
commerce routes, rather than bird migratory routes,
are responsible for the spread of avian influenza.
Source: Eilat-Guide
http://bioterroreurope.wikispaces.com/European+Union
5. Create computer models of alternative husbandry strategies and trade practices
and examine their impact on disease spread:
o Simulation 1: This simulation will investigate what would happen if all the
industrial food production including slaughter plants was
compartmentalized close to airports and ports. The costs and benefits of
this approach will be examined in 3 representative countries (Europe,
Asia, Americas)
o Simulation 2: This simulation will investigate what the economic impact of
requiring all industrial food producers not in compartmentalized areas to
adopt organic or modified organic principles. The impact if any this would
make on new disease emergence and spread will then be investigated.
o Simulation 3: This simulation will assess the potential economic impact of
a restricting all food production to small or medium scale, localized and
fully in compliance with the principles of ecosystem health and use of
biodiversity. This simulation will estimate the costs and benefits of this
approach.
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9. References
Bano S, Naeem K, Malik SA. 2003. Evaluation of pathogenic potential of avian influenza
virus serotype H9N2 in chickens. Avian Dis. 2003; 47(3 Suppl):817-22.
Bennun, Leon. 2006. Reality takes wing over bird flu. BBC News February 17, 2006.
http://news.bbc.co.uk/2/hi/science/nature/4721598.stm
Capua I, Terregino C, Cattoli G, Toffan A. 2004. Increased resistance of vaccinated
turkeys to experimental infection with an H7N3 low-pathogenicity avian influenza
virus. Avian Pathol. 2004;33(2):158-163.
GRAIN, 2006. Fowl play: The poultry industry's central role in the bird flu crisis.
http://www.grain.org/go/birdflu
Jeffrey Robertson, 2002. The Economic Costs of Infectious Diseases. Research Note no.
36 2002-03, Foreign Affairs, Defence and Trade Group. 13 May 2003, Parliament of
Australia.
Lans, C., Khan, T., Martin-Curran M., McCorkle, C.M. Ethnoveterinary Medicine: Potential
solutions for large-scale problems. Book chapter submitted for publication in a Mosby
textbook entitled "Veterinary Herbal Medicine" edited by Susan Wynn, DVM and to be
published in 2006
Simon J. Barteling and Paul Sutmoller, 2002. Culling versus vaccination: challenging a
dogma in veterinary (FMD) science. Report of the Session of the Research Group
of the Standing Technical Committee of EUFMD. Appendix 15. EUFMD Research
Group Meeting 2002 - Çesme, Izmir
http://www.fao.org/ag/aga/agah/eufmd/reports/rg2002iz/Research%20Group%20Meetin
g%202001%20-%20Maisons%20Alfort.htm
Swayne DE, Beck JR. 2005. Experimental study to determine if low-pathogenicity and
high-pathogenicity avian influenza viruses can be present in chicken breast and thigh
meat following intranasal virus inoculation. Avian Dis.49(1):81-5.
Walbridge, Rob. 2006. Terrorist ducks and free-range sleeper cells.
http://organics.bc.ca/modules/news/article.php?storyid=109
Walton, Dawn. 2006. Scientists hand Ottawa a blueprint for a mass cull of bison. Globe
and Mail March 21, 2006.
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