Avian Intestinal Spirochaetosis in UK Layers
 

On Sun, 30 Jul 2006 22:23:21 +0100, "Mike"
wrote:

Brachyspira pilosicoli infection (a form of Avian Intestinal Spirochaetosis
or AIS) of caged hens causes chronic soft to watery brown droppings, a 10%
drop in egg production and 8% increase in mortality over
the laying period. Newly published research by three UK vets records just
how widespread spirochaetosis may be in the UK laying flock, both in caged
and free-range birds.

In a small survey of six caged-hen flocks with depressed production, one
flock had pale eggs, thought to be associated with high avian pneumovirus
(ART/TRT) titres and only B. innocens was isolated. In the other
5 flocks, B. pilosicoli were cultured and only one of these flocks, with the
most severe performance drop, showed rising IB titres as well. It is
important to carry out a number of tests to obtain a correct diagnosis, as
it may involve more than one causal agent.

Avian intestinal spirochaetosis may be more widespread than previously
thought, especially in free-range flocks where B. intermedia appears to
dominate. Caged flocks can be infected but B. pilosicoli appears to be more
common. Calculations of the potential losses to the UK laying industry if
30% of laying flocks are affected could amount to over £4.1 million/year.

Treatment of laying hens is limited to two antibiotics in the UK, because of
the necessity for a zero withdrawal period in eggs. Both tiamulin and
chlortetracycline have been used separately and in combination to control
these spirochaete infections and tiamulin has been shown to be effective
where chlortetracycline resistance occurs. Both are antibiotics and must be
used under veterinary supervision. It is important to treat early on in the
infection to obtain the best results, before chronic caecal damage occurs
and production is adversely affected.

The full report is online at:
http://www.octagon-services.co.uk/ar...oultry/AIS.htm

it includes...

Photo: B. pilosicoli bacteria sticking to caecal epithelial cells.

Table: Comparison of Brachyspira infections in free-range and caged flocks
with sub-optimal performance.

Graph: Treatment of a caged flock infected with B. pilosicoli with tiamulin
and chlortetracycline.





"As I was walkin' - I saw a sign there
And that sign said - no tress passin'
But on the other side .... it didn't say nothin!
Now that side was made for you and me!"
Woody Guthrie

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..........among his own relations...
............and in his own house