Introduction
FMD is widely distributed disease through world. It is highly transmissible most of cloven-footed animals such as cattle, sheep and pigs and causes serious damage on the agricultures and economics.
It is categorised by the formation of vesicles
followed by erosions in the mouth, skin between
and above the hoof and on the teats.
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Biology of The disease
Classiffication
Family: Picornaviridae
Genus: Aphtovirus
OIE list A disease
Seven immunologically distinct serotypes:
A, O, C, Southern African Territories (SAT1,
SAT2, SAT3) and Asia1
Within each serotype there are groups which
appears in particular geographical regions.
Over 60 sub-types have been described.(http://www.oie.int/eng/maladies/fiches/A_A010.HTM)
Genome map
The Foot and Mouth viral genome consists
of an RNA strand of approximately 8000 nucleotide
bases . RNA codon is translated to a single
polypeptide which is cleaved by proteases
to produce the protein.(http://www.aleffgroup.com/avisfmd/A010-fmd/tools/0-diag-genome.html)
The appearance of the virus, taken fromhttp://www.aleffgroup.com/avisfmd/A010-fmd/mod0/0124-protein.html
Chemical and physical survival conditions
|
pH |
Active between pH 6.0 ? 9.0 (optimal between pH 7.2-7.6) |
|
Temperature |
Maintained by refrigeration and freezingInactivated above 50 |
|
Disinfectants |
Inactivated by sodium hydroxide (2%), sodium carbonate (4%), and citric acid (0.2%). Resistant to iodophores, quaternary ammonium compounds, hypoclorite and phenol, especially in the presence of organic matter |
|
Other enviromental factors |
Virus can survive for long periods in dark,
moist conditions. |
Incubation 2-21 days (3-8 on average)
Rate of infection can reach 100%.
Mortality range 5% on adults to 75% on sucking
pigs and sheep
Recovered animal carriers 18 ? 24 months
for cattle 1 ? 2 months for sheep
Source
Breath, saliva, faeces and urine (milk and
semen)
Meat and by-products (if pH remains above
6)
Carriers
Mainly Bovidae (cattle, zebus, domestic buffaloes,
yaks), sheep, goats, swine and all wild ruminants
and suidae
Camelidae - (camels, dromedaries, llamas, vicunas have
low receptiveness)
Whole range of animal can infected from hedgehog
to elephant.
Symptoms
Fever (pyriexia)
Lack of appetite (anorexia)
Reduction in milk production
Blisters in mouth, nasal cavities, claws
(causes salivation, depression, anorexia
and lameness.)Drooling
Transmission
The virus can be transmitted directly and
indirectly.
Movement of humans, animals, vehicles, implements
and water (sea) and air especially in temperate
zone (60km overland and 300km by sea) can
spread the disease.
Cattle (often pigs) mainly infected by inhalation
or by excreting large amount of virus through
breathing (the same as the common cold virus,
Rhinovirus, which is in same family).
Test of disease
The virus can now be detected by air samples
from areas with infected animals. It has
been standardised by IVRI (Indian Veterinary
Research Institute). The current method used
to detect the virus requires physical handling
of animal, which is not always desirable.
The test detects the antigen on the viral
protein.
http://www.healthlibrary.com/news/13thjune/foot_mouth.htm)
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Statistics
(NB: Some of the links might not exist anymore)
Livestock Welfare (Disposal) Scheme - Situation at close of Tuesday 22 May
Total number of animals entered for scheme
- 1,693,035
Total number of animals slaughtered - 948,377
Total number of animals awaiting slaughter
- 355,297
Number of animals withdrawn - 155,934
Animals not presented* - 233,427
*Animals withdrawn at a point of collection,
entered on to other schemes or duplicate
applications
|
Species |
Total numbers of animals registered |
Cumulative total - animals slaughtered |
No of applications |
No of animals not presented |
Registered animals awaiting slaughter |
|
Sheep |
1,135,703 | 666,032 | 87,858 |
137,929 |
243,884 |
|
Pigs |
397,273 | 203,019 | 48,037 |
84,126 |
62,091 |
|
Cattle |
155,305 | 78,563 | 16,068 |
11,358 |
49,316 |
|
Deer/ |
4,754 | 763 | 3,971 |
14 |
6 |
|
Totals |
1,693,035 |
948,377 | 155,934 |
233,427 |
355,297 |
http://www.maff.gov.uk/animalh/diseases/fmd/statistics.htm
Map of Outbreaks as reported on 23rd May 2001
http://www.maff.gov.uk/animalh/diseases/fmd/
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Effect on Wildlife
The chance of transmission to wildlife is
low. In the last 60 years only one case has
been reported regularly in wildlife (at Kruger
National Park in South Africa). Deer can
be infected as well as some rodents and foxes
but there is no evidence of wildlife helping
spread the disease.
There are a number of side effects that affect
wildlife. For example, slaughtering sheep
lowers grazing, changing the habitat on moors
and heath land.
Burning livestock can release dioxins into
the air.
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Comparisons to 1967
The two outbreaks are very different. When
the source of the current outbreak of the
current outbreak was confirmed, the disease
had been incubated for several weeks, whereas
in 1967 the disease was quickly identified
and dealt with immediately.
There are also larger scale animal movements
nowadays which helped the disease spread
over a larger area much faster.
Another factor is that the infection is mainly
is sheep, whereas in 1967 it was mainly in
pigs and cattle, which are easier to trace.
The current strain also doesnft show clearly
in sheep making diagnosis difficult.
The policy in 1967 was to slaughter infected
and potentially infected animals, the same
as the present policy, but there is now a
stronger argument for using vaccination.
In 1967 it was decided that a vaccination
policy was not only more expensive, but would
not guarantee protection due to the many
strains of the disease. It would lead to
more frequent infection and would mean accepting
the disease as endemic instead of eradicating
it.
There is now a better understanding of vaccination
and the way it can be used, making policies
such as firebreak vaccinations a possibility,
instead of simple protective vaccination.
Methods like these seem more humane in the
eyes of a critical public that is taking
an increasing interest in scientific fields,
especially those that concern animal welfare.
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Disease control measures
Necessity for control
The Foot and Mouth disease needs to be controlled
because it can cause death to young animals
and causes reduction in production of milk,
affecting the livestock industry. Also exporting
of meat will be affected because many countries
will not import meat from an infected country.
Prevention and control
- Advice to general public to stay away from farmland and animals unless necessary.
- Animal movement control through construction of border fences and surveillance of trucks, etc where roads and railways pass through these borders.
- Slaughter of infected, recovered, and susceptible contact animals.
- Sterilisation of premises and infected materials (implements, cars, clothes, etc.).
- Destruction of cadavers and susceptible animals products in the infected areas.
- Quarantine measures. The incubation period is 2-21 days (average 3-8 days) so animals passing out of infected areas would presumably need to be held in quarantine for at least 14 days before the disease could be reliably tested.
- Vaccination - Inactivated virus vaccine containing
an adjuvant.
Immunity: 6 months after two initial vaccinations, 1-month apart, depending on the antigenic relationship between vaccine and outbreak strains.
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Social and Economic Effects
The policy for foot and mouth disease is
largely chosen for economic reasons rather
than scientific reasons. The method of slaughtering
is far cheaper than vaccination, which would
take a lot longer and would have to be carried
out three times a year for every farm animal.
The National Farmerfs Union is also against
vaccinations, worrying that it may further
delay Britainfs return to the export markets.
But the slaughter policy has a traumatic
effect on those who have to deal with it
first hand. Vets, farmers and slaughter men
are finding it emotionally difficult to watch
the killing, especially in those farms that
are uninfected but happen to be near to an
infected area.
The public is becoming increasingly knowledgably
and critical of MAFF, losing their faith
after such clumsy handling of the present
epidemic, with the wrong farms being targeted
through map reading errors and other serious
errors. With the recent BSE and E. coli outbreaks, MAFF canft afford to lose any
more public confidence.
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References
Office international des epizooties (http://www.oie.int/eng/en_index.htm) [accessed 23rd May 2001]
AVIS (http://www.aleffgroup.com/avisfmd/) [accessed 23rd May 2001]
Department of Agriculture, Food and Rural
Development (http://www.irlgov.ie/daff/AreasofI/FMD/default.HTM) [accessed 23rd May 2001]
MAFF surveillance & control (http://www.maff.gov.uk/animalh/diseases/fmd/default.htm) [accessed 23rd May 2001]
European Commission for the control of foot
and mouth disease
(http://www.fao.org/WAICENT/FAOINFO/AGRICULT/AGA/AGAH/EUFMD/fmd/default.htm) [accessed 23rd May 2001]
Braun U. Pusterla N.& Schicker E. UCDAVIS
(http://www.vetmed.ucdavis.edu/vetext/INF-DA_Fadavma2.html) [[accessed 23rd May 2001]
Foot and mouth (http://www.foot-and-mouth.org.uk) [accessed 22nd April 2001]
Simple test (http://www.healthlibrary.com/news/13thjune/foot_mouth.htm) [accessed 23rd May 2001]
Preslar D. Federation of American Scientists ahead iliad (http://www.fas.org/ahead/disease/fmd/index.html) [accessed 23rd May 2001]
Byrne S. (2001) RTE news online (http://www.rte.ie/footandmouth/news.html) [accessed 7th May 2001]
Guardian unlimited (http://www.guardianunlimited.co.uk/footandmouth/) [accessed 7th May 2001]
Mann M. & Newman C. (2001) Foot-and-mouth eunder controlf (http://www.ft.com) [accessed 20th April 2001]
Brown D. & Clover C. (2001) The daily telegraph (http://www.telegraph.co.uk) [accessed 20th April 2001]
Stephen H. (2001). Burning issues. Journal of BBC wildlife. Vol.19 No.4, 34-37
Monbiot G. (2001). Up in smoke. Journal of BBC wildlife. Vol.19 No.5, 26-27
Written by Arian Silver and Suiren Kin
