AVIAN MYTH BUSTERS
Time to clear up some myths
By Dr. Colin Walker B.Sc. B.V.Sc. M.A.C.V.S (avian health)
Myth 1.
‘Air sac disease’ can be diagnosed
in the droppings:
Microscopic examination of
droppings is a useful diagnostic step but it is important that
fanciers realize this test’s limitations.
Last week at the clinic we had an unusual situation. We had a fancier
ask us to diagnose if his birds had air sac disease (ie. an infection
of the air sacs) by examining his birds droppings. He seemed to
think this was quite possible and stated that this had been done
elsewhere. Let me state here quite categorically that this is just
not possible.
In the droppings we can diagnose
parasitic problems such as worms and coccidia and in very fresh
samples Hexamita. We can also get an impression (particularly
with special stains) of the bacteria present and also detect
the presence of yeasts. If the birds are not well, for any reason,
so that their ability to resist disease is reduced, bacteria
capable of causing disease will take advantage of this, increase
in number and the bacterial population in the bowel will change.
Any health problem (and included in this list is air sac disease)
or indeed any management or environmental error (eg cold damp
loft, poor diet, over tossing) can lead to these changes. Any
vet who examines droppings microscopically and based on this,
diagnoses air sac disease is just not being honest. And if a
vet suggests that antibiotics for this condition should commence
after only doing this test, lets face it, it’s time to
get a new vet. The two principle causes of respiratory infection
in pigeons are Chlamydophila and Mycoplasma. Chlamydophila is
diagnosed usually in a live bird either by a Chlamydia immunocomb
test (which detects Chlamydia antibodies in the blood stream,
costs about $50.00 and takes about 5 hours to do }or alternatively
a Chlamydia PCR (that measures Chlamydia DNA in the blood stream,
costs about $40.00 and takes about 10 days to do). With Mycoplasma,
although symptoms displayed by the birds and changes visible
on microscopic examination of a throat swab may be suggestive,
usually an autopsy combined with histopathology (microscopic
examination of tissues) is required.
Myth 2.
‘Fungal problems in grain can be detected
by simply culturing the grain’
When grain is cultured for fungi the fungal spores on the grain
will grow and the grain will go mouldy. This does not necessarily
mean the grain is bad and condemning the grain based on this test
is simply not correct. The test is just not valid. Mould spores
(the fungal equivalent of a seed) are quite commonly found in samples
of grains and legumes and occur naturally in these samples. Often
the mould is present as inert spores that would not become active
unless they come in contact with moisture. The presence of mould
in itself is not the important factor but whether or not the mould
has been active and is of a species that would give rise to fungal
toxins (called mycotoxins). To measure mycotoxin levels is a laboratory
procedure. Expect to pay about $100.00 for this test or ask your
local grain merchant whether the grain he is supplying has had
this test. If any one offers to test grain for a lower amount simply
ask yourself why is it so cheap. Probably the grain is simply being
cultured and the results are just not of any real use to you. If
fanciers need further information I suggest you contact the experts
at Agrifood on 1800 801 312. Ask to speak to Don Patterson.
Myth 3.
‘That Streptococcus (a bacteria) can
be diagnosed by microscopic examination of droppings or culturing
of droppings’
This one is a beauty. Streptococcus
is regarded as a normal inhabitant of the bowel in pigeons. It
is therefore found in the droppings of both healthy and sick
birds. Finding it in the droppings therefore means nothing. Any
vet who finds it here and diagnoses your birds as having Streptococcus
infection is simply ‘pulling your
leg’. Streptococcus can cause disease however it only becomes
a problem when it invades the bowel wall (leading to a green watery
diarrhea) or enters the blood stream. Once in the blood stream
it can infect a variety of sites. To diagnose Streptococcus one
needs to therefore identify the bacteria elsewhere in the body
(ie. not in the bowel) or associate it directly with bowel wall
inflammation.
Correct diagnosis leads to the correct medication being supplied
and an understanding of the biology of the current problem. This
means we know how the problem came about and what measures we need
to adopt to prevent it happening again. Incorrect diagnosis leads
to inappropriate use (usually overuse) of medication and an inability
to understand the current problem properly.
Assess the advice you are given. If your
birds become unwell don’t
ask the old fella at the club, your neighbour or your mate. Your
local veterinarian will be helpful but often the best person to
contact is a fully qualified avian veterinarian. There are currently
approximately 24 avian vets available throughout Australia. Victoria
has 4, Queensland has 7, and New South Wales has 8. If fanciers
wish to contact me at the clinic I can always put them in touch
with their closest one.
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