Expert opinion
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Swine dysentery - Summer, the season for eradication
Swine dysentery is one of the most damaging diseases in
pig production and really should be eradicated. Brachyspira
hyodysenteriae
find it difficult to
survive in hot, dry conditions, making summer the ideal time to attempt an
eradication programme.
At a recent conference on Colonic Spirochaetal
infections in Animals and Humans in the beautiful and historic city of Prague,
the continued presence and isolation of Brachyspira hyodysenteriae was discused.
Brachyspira hyodysenteriae is
still common in most European countries. Swine dysentery can be a severe disease
damaging the large intestine (colon) of the pig and the associated diarrhoea,
containing blood and mucus, can lead to mortality, a loss of bodyweight and a
negative feed conversion efficiency.
In a German survey of nearly 5000 samples, the infectious organism
was found in 26.4% of diarrhoeic samples and worryingly, 5.5% of normal samples
or potential carriers.
Fortunately, reports from Germany and Spain showed there
was little antimicrobial resistance build up to the pleuromutilin treatments,
tiamulin and valnemulin, which are commonly used for swine dysentery eradication
but there was some to lincomycin and especially tylosin.
In the Czech Republic
however, a different picture was painted, with a steady increase in resistance
to all antimicrobials including the pleuromutilins. Once Brachyspira are resistant to all the main antibiotics,
the only real alternative is to completely cull out the herd, which is an
expensive procedure.
The more common approach is to use partial depopulation
of all the stock above weaning age and blanket medicate the breeding herd to
kill the organism, as well as moving away manure and slurry, cleaning and
disinfecting the farm, controlling rodents and improving biosecurity to prevent
re-infection.
The summer sun can help with the environmental control (see
graph). When temperatures go above 20°C, the survival time of B.
hyodysenteriae drops dramatically, below 10 days, decreasing the chances of
reinfection.
Graph: Survival time of Brachyspira hyodysenteriae in faeces and
slurry |
 |
In England, we have a saying 'make hay while the sun
shines' but also now is the season to consider carrying out a swine dysentery
eradication programme, while nature is on our side.
Has anybody had some good
experiences of swine dysentery eradication programmes?
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