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Some Facts about the disease
Foot and Mouth Disease (FMD) is an acute, highly contagious picorna
virus infection of cloven hoofed animals. The virus (FMDV) is sensitive
to environmental influences, such as pH less than 5, sunlight and
desiccation, however it can survive for long periods of time at
freezing temperatures.
FMD is present in many countries of the world, except for North
and Central America (north of Panama), Australia, New Zealand, Great
Britain and Scandinavia. The European Union (EU) countries are generally
free of FMD. FMD was last reported in 1929 in the U.S.A., 1952 in
Canada, and 1954 in Mexico.
The disease is highly contagious and may spread over great distances
with movement of infected or contaminated animals, products, objects,
and people. Pigs are mainly infected by ingesting infected food.
Waste feeding has been associated with outbreaks. Cattle are mainly
infected by inhalation, often from pigs, which excrete large amounts
of virus by respiratory aerosols and are considered highly important
in disease spread. Large amounts of virus are excreted by infected
animals before clinical signs are evident, and winds may spread
the virus over long distances.
People can be infected through skin wounds or the oral mucous
by handling diseased stock, the virus in the laboratory, or by drinking
infected milk, but not by eating meat from infected animals. The
human infection is temporary and mild. FMD is not considered a public
health problem.
The incubation period is 2-21 days (average 3-8) although virus
is shed before clinical signs develop. The rate of infection (morbidity)
can reach 100%, however mortality can range from 5% (adults) to
75%(suckling pigs and sheep). Recovered cattle may be carriers for
18 to 24 months; sheep for 1 to 2 months. Pigs are not carriers.
Clinical signs in cattle are salivation, depression, anorexia
and lameness caused by the presence or painful vesicles (blisters)
in the skin of the lips, tongue, gums, nostrils, coronary bands,
inter- digital spaces and teats. Fever and decreased milk production
usually precede the appearance of vesicles. The vesicles rupture,
leaving large denuded areas which may become secondarily infected.
In pigs, sheep and goats the clinical signs are similar but milder.
Lameness is the predominant sign.
The whole of Great Britain has been declared a 'controlled area'.
This bans the movement of animals susceptible to the disease. 'Additionally
infected areas' are declared to a minimum of 8 km around infected
places.
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