...Anthrax

موضوع: ...Anthrax السبت أبريل 04, 2009 3:35 pm

Anthrax

In the UK, all cases of unexplainable sudden death have to be reported
to the Divisional Veterinary Office, so that a decision can be made
whether the animal is to be tested for anthrax as sudden unexplained
death is the most common presentation of anthrax in cattle.

However, although the number of cases of sudden death has increased
there have been no cases of anthrax in cattle for over three years.
However, it is important that owners and stock people are aware of
anthrax, as contact with animals or animal products is, despite the
recent American outbreak, still the most important cause of human
anthrax.
Clinical Signs
• Sudden death (often within 2 or 3 hours of being apparently normal) is by far the most common sign
• Very occasionally some animals may show trembling, a high
temperature, difficulty breathing, collapse and convulsions before
death. This usually occurs over a period of 24 hours
• After death blood may not clot, resulting in a small amount of bloody discharge from the nose, mouth and other openings
Diagnosis
• On the clinical signs described above
• Rod-shaped bacteria surrounded by a capsule are visible in blood smears made from surface blood vessels
• Post-mortem examinations should not be undertaken on suspected
anthrax cases (including any cow that has died suddenly for no apparent
reason) until a blood smear has proved negative)
• If a carcass is opened accidentally, the spleen is usually swollen
and there is bloodstained fluid in all body cavities Suspected anthrax
cases are covered by the Anthrax Order 1991 (which replaced the Order
of 1938). Any suspicion of the disease must be notified to the DEFRA
Divisional Veterinary Manager (DVM), who if they see fit will instigate
a veterinary enquiry to determine whether anthrax is present on the
farm. Usually the DVM will arrange a visit (often by the ownerپfs own
vet) to take a blood sample to look for bacteria with capsules. The
animal or carcass must not be moved before this has been done, fines
will be levied if movement does occur. If the tests prove negative, the
veterinarian will send in a certificate stating this and nothing
further will happen. If anthrax is still suspected then orders banning
movement and requiring disinfection will be instigated.
Treatment
• Due to the rapidity of the disease treatment is seldom possible
• High doses of penicillin have been effective in the later stages of some outbreaks
Prevention
Infection is usually acquired through the ingestion of contaminated
soil, fodder or compound feed. Sterilisation of meat and bone meal used
in animal feed (and more recently its complete removal from cattle
feed) has been the main factor responsible for the rarity of anthrax in
the UK over the last few years.