Volume 22 • Issue 04 • 2018
Crypto may have been present for some time
but perhaps never received the attention that
it receives now. The past 3 years I have paid
specific attention to the diagnosis of Crypto with
smears, histopath, bacteriology and antigen ID
with Vetdiagnostix. The correlation between the
different diagnostic techniques was high with
Crypto being present with E coli & Salmonella
(I suspect secondary) in 91% of the cases. E coli
was involved on its own was in very few cases
and we had it identified and had a vaccine made. affected. That same pen/ run may not have any
problems for the following batches or year.
One of the questions has been: Why the sudden
increase in Cryptosporidium? A group of us at
Onderstepoort investigated all calf diarrhoea
cases, during the early 1990’s, as calf diarrhoea
was also common then. Jaco van der Lugt
[Pathologist] co-ordinated it, Truuske Gerdes
looked for viruses, Laura Lopez for protozoa
and I did the bacteria, and we asked others, e.g.
toxicologist, if there was an indication of anything
else. Most of the cases during that time were due
to viruses. Effective vaccines for the viruses have
since become available. There were very few
cases due to Cryptosporidium at that time. LW - 26 May 2018
MH- 27 Nov 2017
What has changed in the meantime? There has
been a worldwide increase in cases in man, and
these are related to water and food contamination,
raw sewage in water sources and HIV. Chlorination
of water does not kill Cryptosporidium. Better
diagnostic sensitivity of tests, as well as more
awareness of Cryptosporidium being a possible
diagnosis. Change in weather patterns resulting
in both floods [which spread contamination] and
drought [which concentrates the cysts].
Cryptosporidium is very resistant in the
environment. It is resistant to chlorination
of water. There are many different species of
Cryptosporidium, and many of them infect
multiple host species. It is also very infective,
as only a few cysts can cause disease, and many
millions of cysts are shed during the acute
phase. Cysts are also shed for many months after
recovery.
AO - 27 Nov 2017
Just to confirm when we observe Crypto in the
ostrich industry – 80% cases during mid to late
summer. Any rain or leaking water sources.
Pica/ vices by chicks. High water consumption
causes high frequency and volume of urination =
increase risk of soil pica or vice.
Any small stressor triggers it. You can have 4
batches next to each other with only one being
Jo'D - 25 May 2018
Is both diseases a problem on the same farm(s)?
Or is a farm hammered by either Crypto or E.coli?
Which wildlife species show clinical disease with
Crypto? And which have shown mortalities?
Management/production system on these farms?
I am not aware of any Crypto outbreaks this
side of the Magaliesberg but E.coli seems to be a
problem all over.
We see Crypto and E coli in both calves and lambs.
Sometimes both, sometimes one of the 2.
Confirmed by Vetdiagnostix, IDEXX and Vetpath
over the last few years. We are in the Eastern
Free State, on the border of Lesotho. Intensive
lambing systems and extensive systems, summer
and winter. (Also see Rick Last under Dx)
CONCURRENT INFECTIONS
EdP - 27 Nov 2017
The commercial E. coli vaccine unfortunately did
not work. We found that quite long ago that the
results with the commercial vaccine was very
poor and then initiated the process of having an
autogenous vaccine produced. The results that
we see lately are promising. The vaccine has been
produced for many clients. The vaccine is not a
silver bullet as it seems that the crypto is still the
instigator and many other factors also play a role
in the outcome of your treatment regime.
PR - 27 Nov 2017
More related to vaccination against E.coli. How
much of an effect would a non-autogenous
(commercial) vaccine have and how are the
commercial E.coli vaccines strains chosen? And
also more focused on sheep.
MH - 27 Nov 2017
E. coli is a normal commensal of the intestine,
and it is also found in the environment. Only a
very few strains possess virulence factors, and
they can cause disease. The virulence factors
are mainly of two kinds: attachment to the
intestinal wall and toxins. A variety of virulence
factors have been found and are being found by
scientists, as this is a dynamic area of research.
The attachment factors and toxins can be general,
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