Oorsig / Review
like fungi . Flotation and special staining is best . Immunofluoroscopy probably best . Size 6 micrometer - as far as I remember RBC are 7 micron ??
WG - 15 Jan 2017
I find that the test strips usually show positive for Crypto - it is often present in calves without signs so may or may not have been the cause / only cause in this case . It is also probably present on most / all farms .
RL - 26 May 2018
To answer your questions I have noted the following :
Cryptosporidium is easily missed if only a single section of small intestine is submitted ( organisms are most concentrated in the distal jejunum and ileum ).
• Poor fixation procedures of intestine for histopathology is probably the greatest cause of “ missed diagnosis ”. Ensure you keep your intestine tubes intact , maximum of 2cm in length and gently wash out the ingesta from the lumen with 10 % buffered formalin before sinking in your formalin pot for fixation . If you do not flush out the ingesta with formalin and simply place the intestine segment directly into formalin the formalin takes time to penetrate through the ingesta and by then you have post mortal autodigestive change of the superficial villous mucosa and that ’ s exactly where the crypto sit and they are therefore destroyed . Placing long sections of intestine ( 6cm plus ) directly into formalin is a BIG no no .
• Be careful of labelling any E . coli isolate as a primary cause unless you have done pathogenicity typing of the isolate . Many turn out to be commensals / contaminants merely riding on the back of the Crypto .
• Before you implement the use of any E . coli vaccine ( including autogenous vaccines ) ensure you have pathogenicity typed your isolate . E . coli vaccination is only of benefit where you are dealing with pathogenic strains .
• Have diagnosed in roan antelope calves ( very high mortality ) from Free Sate but that was only last week – and things are starting to pump down here in KZN so will expect outbreaks in other antelope in the not too distant future .
RL - 27 June 2018
Be very careful about taking action on a Crypto test strip without having confirmatory pathology i . e . histological evidence of severe villous atrophy with villous epithelial colonization by Cryptosporidium and moderate proprial inflammatory infiltrates . Crypto is commonly associated with other extremely virulent enteric pathogens and you don ’ t want to be missing those . If the farmer really wants to waste money - take action on a screening strip test without any supporting clinical or laboratory data .
My 5 cents worth
HYGIENE & IMMUNE STATUS
MvdL - 14 Feb 2014
In an ideal world these calves would have received adequate colostrum . The big dairy beef operators who raise thousands of veal calves work from the assumption that the bull calves have received little or no colostrum & they do not test for TSP . Where did the colostrum go ? To the heifer calves . They make it work by raising them in individual hutches , meticulous attention to detail & strict adherence to cleanliness , particularly the milk feeding equipment . And they have a few secrets they won ’ t share too . The use of bleach alone is inadequate , but commonly seen used for cleaning . Hot water & detergent are essential to remove the fat layer in buckets , bottles & nipples . You are maybe not dealing with a large enough number of calves , but nipples are very effectively washed in a laundry machine . They can then be placed in a disinfectant till next use .
TS - 13 Jan 2017
Crypto in a dairy = problems . They are much more resistant to treatment than cocci – variable results are obtained with Diclazuril ( Vecoxan ). The disease is usually self-limiting but can cause havoc for a while . It will be advisable to , if at all possible , treat and then move the calves to a different calf-rearing venue ( even if only temporary ) away from adult cow traffic ( they can act as reservoirs ). Disinfect the original calfraising area with 10 % formalin ( nasty !).
WG- 15 Jan 2017
Control of Crypto relies on hygiene and colostrum which is essentially the same as for most / all causes of calf diarrhoea . Regular monitoring of IgG or TSP will tell you if the colostrum programme
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