| Many animals are now kept in intensive
conditions, and perhaps a combination of this and other factors
has been implicated in some recent outbreaks of animal disease,
some of which appear to have also endangered human populations.
To briefly note some of these problems, with the apparent causes:-
- BSE (bovine spongiform encephalitis) appears to be implicated
in CJD (Creuzfeld-Jacob disease) which affects humans. Both
are degenerative diseases of the central nervous system (and
scrapie in sheep may in fact be the pre-cursor of this) and
the condition is caused by a virus which has a very long incubation
time before any symptoms are apparent. It is thought that ground-up
remains of infected sheep were added to cattle feed. When these
apparently healthy cattle were slaughtered, and some marrow,
spinal or brain tissues from these animals were used for human
food products, leading to the CJD cases. It is now believed
that these food-chains have been broken in two ways, as animal
protein is no longer used in cattle food, and marrow and brain
tissues are no longer used in human foods
- Foot and Mouth disease. This is a contagious disease which
affects pigs, cattle and sheep (but seldom humans). In a recent
outbreak in the UK many millions of animals were slaughtered.
For any farm which had an outbreak, all animals on all adjoining
farms were slaughtered, and there were strict regulations about
access to land, disinfection of vehicles in the affected areas,
etc. and the disease was finally brought under control. The
causes are not really known, but it appears that the disease
was spread by unnecessary stock movements, some of which were
intended to cheat the subsidy systems. The disease is endemic
in many parts of the world, where it is thought of as the equivalent
to tonsillitis - the animal is quite ill, but then recovers.
- Bovine Tuberculosis. This is a cause for concern in some parts
of the UK. The government proposes a cull of all badgers in
these areas, as a similar form of TB is endemic in badgers,
and it is thought that they infect the cattle.
- Swine Vesicular disease. This appears to break our every year,
with several herds of pigs culled, and this seems to be kept
under control
- Chicken influenzas. Some influenzas of chicken are infectious
for humans, and there seem to be outbreaks of new strains of
the virus every year, perhaps originating in the far east
- E. coli. There seem to be regular E. coli outbreaks, which
can be very dangerous for humans if large quantities enter the
food chain. E. coli is an intestinal bacterium which is found
in nearly all species, and poor hygiene at the slaughterhouses
and butchers is often blamed for this
- Mastitis. This is an infection of cows teats which is widespread,
and which is treated with direct injections of anti-biotics,
which inevitably are then present in small quantities in milk
and milk products.
- Calves and cows are now seperated soon after birth. The cows
give milk until the next calf is born, often without a pause.
Cows are almost invariably fertilised by artificial insemination.
- Salmonella. There have been several outbreaks of this disease
in recent years, apparently due to poor hygeine during the handling
of food. Often it is caused by reheating 'once-cooked' foodstuffs.
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