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equine assay data sheet
Equine GI / diarrhea PCR panel
Test code:
P0015 - Equine GI / diarrhea PCR panel includes qualitative
detection and differentiation of:
Diarrhea in
adult horses can be acute (<1 month) or chronic (>1 month).
Causes of acute diarrhea in horses include Salmonella, Ehrlichia
risticii, Clostridium difficile and Lawsonia intracellularis. An
acute, fatal diarrheal disease of unknown etiology is known as
colitis. Chronic diarrhea is often not due to microbial
infection.
Salmonellosis is the most commonly diagnosed infectious cause of
diarrhea in adult horses. Many infected horses are subclinical
and become carriers of the pathogen. The disease most commonly
occurs sporadically but may become epizootic depending on the
virulence of the organism, level of exposure, and host factors.
Infection usually occurs via contamination of feed or water or
by contact with animals actively shedding the bacteria. Other
factors such as stress due to surgery, transportation or change
in feed can play an important role in pathogenesis. GI disorders
(colic) and treatment with broad-spectrum antimicrobial drugs
can also lead to diarrhea. Salmonella typhimurium (group B), S.
agona (group B), S. anatum (group B), S. newport (group C), and
S. krefeld (group E) are the most common serotypes associated
with diarrhea in adult horses.
Potomac
horse fever is an acute diarrheal syndrome caused by Ehrlichia
risticii. Horses suffering from this disease may develop
lethargy, anorexia, fever, mucous membrane injection, ileus,
colic, diarrhea, and laminitis. Any combination of these signs
may be present but only rarely will a horse develop all symptoms
together. Colitis is present in all cases but diarrhea only
develops in <60% of affected horses.
Clostridium
difficile is a strictly anaerobic, spore-forming bacterium that
is a frequent cause of gastrointestinal disease in humans,
horses, and pigs. Nosocomial diarrhea due to C. difficile has
been reported in humans and horses and is often associated with
administration of antimicrobials, but non-antimicrobial
associated cases also occur. In the past, diagnosis of C.
difficile involvement in diarrhea relied on both anaerobic
culture of the organism from feces and demonstration of the
presence of toxins A and/or B in fecal material; with toxin
production differentiating the pathogenic and non-pathogenic
strains of the organism. However, culture is difficult due to
the fastidious nature of C. difficile and frequent overgrowth by
other enteric bacteria. The cell cytotoxin test was considered a
"gold standard" for identification of C. difficile toxins, but
its turnaround time is slow. PCR detection of the
toxin-producing genes sidesteps both the slowness of direct
cytotoxin detection and the difficulty of culturing C.
difficile. Thus PCR is a specific, sensitive and fast technique
for detection of this bacterium.
Lawsonia
intracellularis is the causative agent of proliferative
enteropathy (PE) or ileitis in horses, swine and other domestic
animals. This agent causes proliferation of intestinal cells,
resulting in enteric disease which is sometimes fatal. The
disease is responsible for serious economic loss to animal
production worldwide. L. intracellularis is an obligate
intracellular bacterium. Animals suffering from chronic PE may
have clinical or sub-clinical effects on weight gain, feed
conversion and fecal consistency. Diarrhea is a common symptom.
Besides culture detection, which is slow, insensitive and
difficult, some immunofluorescence tests using a monoclonal
antibody directly on feces have been described, but this method
lacks sensitivity. Diagnosis can also be based on histological
examination of clinically affected necropsy samples. Currently
no serological test is available for detection of L.
intracellularis. PCR is a useful detection technique for L.
intracellularis in both tissue and fecal specimens.
Although the
etiology of <50% of cases of diarrhea in horses can be
determined, treatment of most horses and foals with diarrhea is
similar. Thus therapeutic management is possible despite a lack
of a definitive diagnosis. It is however important to identify
the causes of diarrhea so as to prevent further outbreak.
PCR
detection of pathogens included in this panel offers a useful
technique for quick, sensitive and specific identification of
the disease-causing agent. The ability to detect multiple
pathogens from one specimen minimizes the inconvenience and cost
of collecting, handling and shipping multiple specimens.
Utilities:
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Help confirm the pathogen causing GI symptoms and diarrhea
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Selection of appropriate treatment regimen
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Shorten the time required to confirm a clinical
diagnosis
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Help ensure that horse populations are free of listed GI
pathogens
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Early prevention of spread of listed GI pathogens
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Minimize personnel exposure to listed GI pathogens
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Safety monitoring of biological products that derive
from horses
Specimen requirements:
Rectal swab, 0.5 ml feces or bacterial culture.
Contact Zoologix if advice is needed to determine an appropriate specimen type for a specific diagnostic application. For specimen types not listed here, please contact Zoologix to confirm specimen acceptability and shipping instructions.
For all
specimen types, if there will be a delay in shipping, or during
very warm weather, refrigerate specimens until shipped and ship
with a cold pack unless more stringent shipping requirements are
specified. Frozen specimens should be shipped so as to remain
frozen in transit. See shipping
instructions for more information.
Turnaround time:
3 business days
Methodology:
Qualitative
multiplexed real time PCR
Normal range:
Nondetected
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