Swine Dysentery
Other names |
Blood
dysentery, bloody scours |
|
Causal agent |
Bacterial Brachyspira
hyodysenteriae (formally known as Serpulina hyodysenteriae). 12 serotypes are known |
|
Age group |
Typically affects
pigs from 15 to 70 kg |
|
However, in
acute outbreaks in naive herds it can affect all
age groups from suckling piglets to adult
sows |
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Clinical
signs |
||
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Diarrhoea - with
or without blood, and severity is very
variable. A careful search of the pen normally reveals the presence of blood
and mucus in some places |
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Diarrhoea with large amounts of mucus in
faeces and afterwards with flecks of blood |
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Death of one or
two pigs before other pigs show any signs |
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Rapid loss of
condition in some pigs and pigs look hairy |
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Clinically
affected pigs in a group can reach 50% |
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Reduction in FCR
of 0.6 while disease present with extension of finishing by 20 days |
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On established herds |
Dehydration,
pigs with a painful abdomen and some pigs weak and incoordinated |
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The disease appears
to be cyclic and reappears at 3-4 week intervals |
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Infectivity |
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Pigs may transmit
the bacteria for 90 days |
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Brachyspira hyodysenteriae survives in: |
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Faeces for 61
days at 5•C |
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Soil for 18 days
at 4•C |
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Flies for 4
hours |
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Mice can shed for over 180 days |
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Cats and dogs
can carry for 13 days |
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Incubation period
|
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Incubation
period 10-14 days |
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Common
differentials |
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Colitis |
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Salmonellosis |
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PIA - Haemorrhagic
Porcine Intestinal Adenomatosis - Ileitis |
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Other
Brachyspira spp can cause very similar signs, including the mortality. |
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Post-mortem Lesions |
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Confined
to the large bowel - caecum, colon and rectum |
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Reddening
to haemorrhage of the large bowel |
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Post-mortem findings |
Typical changes in the acute phase include
hyperaemia and oedema of the walls of the large intestine. Colonic submucosal glands may be more
prominent and appear white. The mucosa is usually covered by mucus and fibrin
with flecks of blood and the colonic contents are soft to watery and contain
exudate. The photograph represents a
severe case with extensive haemorrahge into the colon. |
|
Diagnosis |
Isolation
of Brachyspira hyodysenteriae in
the faeces.
Note there are a number of other spirochetes that are normal in the pigs'
large bowel and other may be associated with colitis syndromes. PRC
is available and may be used on faecal samples. Immunohistochemistry can be useful on
tissues samples. |
|
Treatments |
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Acute outbreak |
Treatment
via the water supply is essential for acute cases of swine dysentery as the
affected pigs will not eat and to all animals in drainage contact |
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Follow
by in-feed medication once pigs start to eat,
to all affected pigs and all animals in drainage contact |
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Very
sick and weak pigs respond better using injection antibiotics |
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Water
supply should be supplemented using electrolytes |
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Herd eradication |
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Typical procedures without total depopulation |
Requires
detailed preparation and attention to detail |
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Attempt
in the late spring/summer |
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Reduce
herd size to as small as possible – consider a partial depopulation |
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Have
an effective rodent control programme |
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Drain
all slurry pits |
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All
buildings not containing pigs should be cleaned, disinfected and fumigated |
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Medicate
all remaining pigs as prescribed |
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After
1 week of medication all equipment used for handling pigs, feed and manure
should be cleaned and disinfected |
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Clean
and disinfect floor as often as possible |
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Treat
all farm cats and dogs as prescribed |
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Spread of swine dysentery |
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Pigs Purchased only from Swine Dysentery free
herds |
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Faeces |
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Boots,
clothing, stockpeople |
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Truck
wheels |
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Rats
and Mice |
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Cats |