Mucoid Enteropathy:
Enterotoxemia:
Enterotoxemia is an explosive diarrheal disease, primarily of rabbits 4-8 wk old. It occasionally affects adults and junior stock. Signs are lethargy, rough coat, a perineal area covered with greenish brown fecal material, and death within 48 hr. Often, a rabbit looks healthy in the evening and is dead the next morning. Necropsy reveals the typical lesions of enterotoxemia, ie, a fluid-distended intestine with hemorrhagic petechiae on the serosal surface. The primary causative agent is Clostridium spiroforme , which produces an iota toxin. Little is known about transmission of the organism; it is assumed to be a commensal that is normally present in low numbers. The type of diet seems to be a factor in development of the disease; enterotoxemia is seen less often when high-fiber diets are fed. Because lincomycin, clindamycin, and erythromycin induce Clostridium -related (eg, C difficile ) enterotoxemia due to their selective effect on normal gram-positive bacteria, they are contraindicated in rabbits. Enterotoxemia is a consideration for most antibiotic therapy, and it has been seen after administration of penicillins and cephalosporins. The incidence rate is 40-80% after oral penicillin therapy, which should be considered contraindicated in rabbits. These diarrheas are remarkably similar to those that occur naturally (described above as enterotoxemia). Treatment of colony rabbits is seldom attempted because of the rapidity of death. However, when population size permits, cholestyramine has been used with promising results, both as a preventive and a treatment. Reducing stress of the young rabbits (weaning, etc) and ad lib feeding of hay or straw are helpful in prevention. Adding 250 ppm of copper sulfate to the diet of young rabbits also helps prevent enterotoxemia. Individual animal treatment for enterotoxemia should include supportive fluid therapy. There is little evidence that antibiotics are helpful. Diagnosis depends on history, signs, lesions, and demonstration of C spiroforme . Centrifugation of intestinal contents at 20,000 g for 15 min followed by culture of the supernatant-pellet interface will reveal the organism. For a definitive diagnosis, the presence of iota toxin in the supernatant of centrifuged cecal contents can be demonstrated by in vivo or in vitro assays.
Mucoid enteropathy is a distinct diarrheal disease of rabbits, characterized by minimal inflammation, hypersecretion, and accumulation of mucus in the small and large intestines. While the etiology is unknown, it may occur concurrent with other enteric diseases. Predisposing factors include dietary changes, dietary fiber <6% or >22%, antibiotic treatments, environmental stress, and challenges with other bacteria. Clinical signs are gelatinous or mucus-covered feces, anorexia, lethargy, subnormal temperature, dehydration, rough coat, and often a bloated abdomen due to excess water in the stomach. A firm, impacted cecum may be palpable. The perineal area is often covered with mucus and feces. Diagnosis is based on clinical signs and necropsy findings of gelatinous mucus in the colon. Rabbits may live for ~1 wk. Treatment is unrewarding, but intense fluid therapy, enema removal of mucus mass, antibiotics, and analgesics may be tried. Prevention is the same as for any rabbit enteropathy.
The above research is taken from http://merckvetmanual.com we find this site a mine of information and recommend anyone who is querying an ailment to look here
Mucoid
Enteritis in Rabbits
-
Is there an infectious element linked to Encephalitozoon cuniculi?
As most rabbit
owners will be only too willing to testify, pet rabbits can be very susceptible
to health problems, many of which are difficult to diagnose and costly to treat.
Since the start of CottonTails rabbit and guinea pig rescue in 1993, the major
health issue that has given us most cause for concern apart from dental disease
has been the killer disease mucoid enteritis. Although the condition has also
been referred to as ileus, gastro intestinal (GI) stasis and bloat, there are
important distinctions between these conditions.
It would appear
that GI stasis/ileus develops slowly and it is usually several days before you
suspect there is a problem, but if diagnosed early enough the condition is often
treatable. Bloat, however, happens suddenly and without warning, and the
prognosis for survival is poor, although bloat can even develop as a
complication of GI stasis (1).
Although ingestion of hair (fur ball) was originally thought to be a cause, it
has now been found that fur has gathered due to initial problems with gut
motility, and is not the causative factor (2).
The photo
above shows a young rabbit 15 weeks old that showed typical symptoms of bloat -
he sadly died 8 hours later despite intensive treatment
There have been
several studies of mucoid enteritis carried out in rabbits, and there is general
agreement that it is an extremely serious condition which can affect whole herds
of rabbits, not just individuals. In one study (3)
it was found that there was 60-70% mortality in young rabbits due to mucoid
enteritis in an outbreak over a two-year period. These figures are consistent
with the findings at CottonTails.
Isolated
incidents of mucoid enteropathy can often be attributed to stress of one sort or
another, especially the sudden change of diet and environment of young rabbits
as well as inadequate diet, coccidiosis, and conditions causing the rabbit to
stop eating such as pain after surgery and dental disease. However, the
outbreaks described by various authors and also experienced at CottonTails
appear to be different and would indicate the involvement of an infectious
element of some kind or some unknown "trigger" for the release of
Clostridium botulinum toxin, the presence of which we have had confirmed at post
mortem. Coccidiosis was not found to be a contributing factor in those animals
examined at CottonTails.
From personal
observations, the onset of symptoms was usually very sudden, with loss of
appetite, few or no droppings being passed, lying stretched out or huddled in a
corner with obvious abdominal pain, and behaving in an abnormally quiet or
withdrawn manner. A decrease in normal abdominal sounds or frequent gurgling was
found, with subsequent development of palpable hard areas within the intestines
and often accompanied with the onset of bloat/and or diarrhoea and passing of
mucus.
The day
immediately before onset of symptoms the rabbit would appear to eat and behave
normally. The next day it would be seriously ill and deeply distressed. However,
it is likely that the illness develops for some time before any obvious outward
signs become apparent, making this condition very difficult to treat as often by
the time it is noticeable it is then too late for the rabbit to be saved.
The first
mucoid enteritis outbreak experienced at CottonTails occurred in 2002 when a
group of 25 rabbits was brought in. They were part of a herd of over 100 rabbits
of mixed sexes, breeds and ages, all previously running free in a garden. Most
of the females were pregnant or had young litters with them. As a result we had
an exceptionally high number of young rabbits at the centre during this time.
Several of the rabbits also had dental disease, and most were thin with wounds
consistent with fighting. However, they all had good appetites and appeared to
be otherwise fit and well.
Prior to the
outbreak, no sudden changes had been made to diet or environment to explain the
onset of the symptoms apart from when they initially arrived. The rabbits were
all fed a vet-recommended measured diet of Burgess Excel, with the addition of
fresh vegetables as appropriate for age and tolerance, and good quality hay and
fresh water (from a drinking bottle) available at all times. Care was taken to
avoid overcrowding, and litters were kept separate, usually with their mothers.
Symptoms did not coincide with timing of vaccinations or neutering, nor was
there a pattern of infection based on hutch location as symptoms appeared in
rabbits several hutches apart (in one case
From the
information gathered during this and another 2 outbreaks as well as random
isolated cases, it would appear that the average duration of the disease from
the point of first symptoms to either start of recovery or death was 12 hours to
9 days, giving an average of 5 days. Of the total number of rabbits in the
centre at the time, 20% were affected, most of which being rabbits less than 5
months old or nursing mothers, with a mortality rate of up to 60%. Very few
adult rabbits became ill, and they had a much better recovery rate than the
young rabbits, with 70% making a full recovery compared with 40% for those
younger than 5 months. The incubation period varied from 6 days to 4 months,
making quarantine an impractical solution for future disease management.
The affected
rabbits were given intensive treatment: administration of Metacam for pain
relief (plus Tagamet syrup in some cases to prevent possible inflammation of the
stomach); Prepulsid to stimulate stomach emptying (not now available);
Metaclopromide to stimulate gut motility (very effective but if a severe
blockage is present, rupture of the stomach can occur); subcutaneous fluids to
prevent dehydration (not effective in cases of shock, so some individuals
received i.v. fluids); syringe feeding of Critical Care to those individuals
willing to eat; Questran (Cholestyramine which absorbs enterotoxins (4));
subcutaneous administration of broad spectrum antibiotic Baytril in some
individuals to rule out infection; Kaogel in cases of diarrhoea; Vitamin B
injection in some individuals in an attempt to stimulate appetite. Gentle
massage of the abdominal area was also carried out in those rabbits that would
tolerate it. An incubator was used for individuals whose body temperature
dropped significantly below normal (usually an indication that death was
imminent). Personal observations indicated that recovery or death was not
significantly influenced by medications, apart from the obvious relief that
Metacam provided.
By the time the
third major outbreak occurred 2 years later, E. cuniculi, the protozoan parasite
infecting the renal and nervous system of rabbits had been officially recognised
as a serious problem, possibly affecting at least 50% of pet rabbits (5).
As a result, one of the affected litters that demonstrated the additional
symptoms of hind leg weakness and white eye spots was tested for E. cuniculi and
was indeed found to be positive.
With this in
mind, it was decided to treat all rabbits under 5 months old with Panacur
(orally, at a dose of 20mg/kg/day) to ensure that they were free of the
parasite, on the basis of the suspicions that E. cuniculi could be an important
factor in turning what would ordinarily be an isolated occurrence of GI stasis
into an infectious outbreak, if only in respect that infected animals would have
a lower resistance to disease. Panacur (fenbendazole, metabolised into the
active form, oxfendazole) works by inhibiting an essential part of the
feeding/infective apparatus of microsporidian parasites such as E. cuniculi (6).
Unfortunately, although a 4 week course of Panacur has been shown to eliminate
the parasite (given via their pelleted food) (7),
there is no evidence to suggest that it can reverse neurological damage already
done. However, if some of the symptoms are due to inflammation and/or the immune
response itself, elimination of the parasites along with anti-inflammatory drugs
such as Rimadyl may be helpful.
Controversially,
there is evidence to show that Panacur and its derivatives can cause bone marrow
failure in a very small percentage of dogs, cats, birds and reptiles, and it has
been reported that 3 unrelated rabbits may also have suffered the same side
effect (8).
If this proves to be the case, we may need to review our policy of
administrating Panacur prophilactically, but for the present time there would
appear to be more advantages than disadvantages in following current procedures.
However, Intervet have conducted a safety study to address the concerns of bone
marrow problems and initial studies have shown no evidence of any changes to
haematological or biochemical parameters, and have launched a new product
specially for rabbits for E. cuniculi prophylaxis. This is in the form of a
paste and the recommended prophylactic regime will be a 9 day course 2-4 times
yearly. It will also be recommended at high risk times such as when a rabbit is
acquired, prior to mixing with new rabbits and prior to mating. From personal
communication with Intervet it would appear that the Panacur paste is ideal for
rabbits over 1.25kg, and therefore treatment of baby rabbits under this weight
would still be best with 10% Panacur in order to achieve a higher degree of
accuracy for the 9 days required.
Since the
policy of administrating Panacur to all rabbits under the age of 5 months was
initiated, CottonTails has had no further outbreaks of mucoid enteritis-type
illness. There have been isolated individual cases as one would expect in a
rescue centre where animals often arrive in poor condition and then have to
undergo changes in diet, environment, neutering and vaccination. Personal
observations would indicate that either the Panacur itself or the elimination of
the parasite has had some influence on this result.
In a personal
communication with the small animal vet adviser for Intervet (the manufacturers
of Panacur), it was suggested that the preventative effect we have witnessed may
be due to the eradication of intestinal worms, on the basis that a heavy
infestation with Passalurus ambiguous in young rabbits can be a contributory
factor to the enteritis complex of diseases that occur around weaning. As there
has been no evidence of worm infestation in any of the affected rabbits, and
none were found at post mortem it seems unlikely that this is the case.
Another factor
that may be involved in the infectious element of mucoid enteritis could be
bacterial infection leading to gastric ulceration, similar to Helicobacter
pylori in humans (9).
Personal observations showed that all rabbit fatalities examined from the mucoid
enteritis outbreaks had erosion of the stomach lining as seen by visible small
circular areas. This was also found in a study that showed 7% of the rabbits
examined had gastric ulcers (10).
It is known that gastric ulceration in rabbits can develop from pain and fear
due to catecholamine (epinephrine) release, and also with reduced gut motility
such as repeated episodes of stasis (1).
As the broad spectrum antibiotic Baytril was given by subcutaneous injection to
some rabbits during the outbreaks had no obvious effect, it would appear that if
a bacterial infection was involved it may not be sensitive to this particular
antibiotic.
The possibility
of a virus has been suggested in a study looking for viral agents in rabbits
with enteropathy in
There have been
comparisons made with mucoid enteropathy in rabbits and that of equine grass
sickness in horses, whereby evidence showed that the origin of the disease in
two particular cases involved soil-borne botulinum neurotoxin (12).
This study showed for the first time that green grass blades can contain
Clostridium botulinum toxin and put forward the hypothesis that equine grass
sickness is a clinical form of botulism, a soil-borne disease. The relevance of
this finding to rabbits is in the large quantities of hay used routinely as an
important food source.
To add even
more confusion to the situation, recent national and international research into
gut-related problems in rabbits have identified a condition known as
dysautonomia (13, 14,
15, 16),
a very serious disease affecting the autonomic nervous system. However, this is
not thought to be the cause of the outbreaks at CottonTails. As the symptoms had
some similarities, some of the rabbits suffering from mucoid enteritis were
taken to Katherine Whitwell, a leading authority on dysautonomia in rabbits and
hares, for her opinion, but as the recorded symptoms and crude evidence did not
indicate the presence of dysautonomia, further laboratory tests were not carried
out.
It would appear
that, as yet, the cause of mucoid enteropathy-type outbreaks is still not known.
Whether there could be some involvement of E. cuniculi can only be speculated,
with infected rabbits perhaps being more vulnerable to disease. What is clear,
however, is that research is urgently required if more rabbits are not to be
lost to this killer disease.
This research is taken from http://www.cottontails-rescue.org.uk/