Current Findings in the Regional Veterinary Laboratories
JULY 2006
Cattle
A severely jaundiced two-week old Simmental cross heifer calf that was found laterally recumbent and
died within 24 hours of onset was submitted to Dublin. In addition to severe jaundice of muzzle,
conjunctiva, and almost all tissues, a large volume of port wine coloured urine was present in the bladder
and intestinal contents were almost black. Histopathology examination revealed individualisation of
hepatocytes and a severe nephrosis, which together with the severe jaundice and haemoglobinuria is
strongly suggestive of Leptospira icterrohaemorrhagiae infection.
Pallor of the mucous membranes and muscle was observed in a one-month old Charolais heifer calf,
submitted to Dublin with a history of being listless for two to three days before death. A single large
mucosal ulcer of 1.5cm diameter was found in the proximal duodenum. Intestinal contents
throughout the length of the intestine from a point immediately distal to this ulcer were
haemorrhagic indicating a considerable degree of haemorrhage from this ulcer.
Kilkenny examined three three-month old calves from a herd with a history of scour and ill-thrift. All
three were found to be positive for bovine viral diarrhoea (BVD) virus. BVD antigen was also
detected in tissue samples taken from a three-month old calf presented to Athlone. The calf had come
from a group of 26, where some calves had developed high febrile reactions. Initial treatment appeared to
be effective, but four calves had relapsed and died.
Dublin diagnosed severe copper deficiency in a group of suckler calves at grass. Calves were
described as having poor coat condition, poor thrive, and a persistent scour. Four calves from the
group of 40 had died. Post-mortem examination of one of these revealed no obvious gross lesions.
A liver copper level of 0.01mmol/kg was markedly sub-normal (Normal= 0.06- 2.5mmol/kg).
Follow up blood samples from the herd confirmed that serum copper levels were sub-normal in a
high percentage of calves. Copper supplementation and continued monitoring has been
recommended. Athlone also reported copper deficiency in a group of calves in a suckler herd. The
clinical manifestation was ill-thrift, epiphysitis and lameness. Blood serum copper values ranged
from 1.3 – 2.6μmols/l (normal range = 9.4 – 24.0μmols/l).
Cerebrocortical necrosis (CCN) was diagnosed by Kilkenny in a four-month old calf, one of
three in a group to show nervous signs and blindness. The calf was euthanased when treatment
failed. A scan of the brain with a Woods lamp showed strong fluorescence and histopathological
examination of cerebral tissue confirmed the diagnosis. Athlone reported gross lesions of bacillary
haemoglobinuria (BHU) in a five-month old calf with a history of sudden death. The calf also
had pneumonia and Pasteurella multocida was isolated from the lungs. Limerick examined a fourmonth old calf with a history of long-standing ill-thrift. Gross lesions included arteritis and
thrombosis of the aorta, approximately four inches from the heart. The aorta was dilated and had
haemorrhaged into the pleural cavity. There were signs of cardiac failure, which suggested that the
condition had been present for some time. Histopathology suggested bacterial endotheliosis. Postmortem examination of an eight-month old weanling carried out in Limerick showed lesions of
acute verminous pneumonia. Ragwort toxicity was diagnosed in a yearling heifer submitted to
Limerick. Four animals were clinically affected, with signs that included blindness, ataxia,
compulsive walking, recumbency and eventual death.
Pigs
Several weaner pig carcasses received by Cork from one farm where there was a history of
pneumonia, diarrhoea, wasting, and in some cases, sudden death. Salmonella spp, Streptococcus
suis type II and haemolytic Escherichia coli were isolated on different occasions. Histopathology
showed microscopic lesions consisting of depleted mesenteric lymph nodes with histiocytic
infiltration and the characteristic intracytoplasmic inclusion bodies associated with
postweaning multisystemic wasting syndrome (PMWS).
Poultry
Live day-old broiler chicks with clinical findings suggestive of ‘clubbed down’ (figure 1) were
submitted to Cork. They were part of a hatch from a broiler breeder flock of which less than 50 per
cent of each hatch was suitable for rearing. ‘Clubbed down’, (so called because of the appearance of
the feathers that don’t break through their sheaths) was considered to be due to riboflavin deficiency
but, while this is now largely discounted, the suggested implication of viral aetiology has not been
proven. Anecdotal reports indicated that chicks in other flocks were affected also.
The sudden deaths of six-week old goslings from a flock of 250, were diagnosed by Cork as acute
colibacillosis. Gross lesions included pleurisy, pneumonia, pericarditis and peritonitis with thick
layers of fibrin deposited in the thorax and abdomen.
Toxaemia was suspected by Cork as the cause of the death overnight of all eleven hens of a small
backyard flock. The birds had full crops, active ovaries and no visible lesions. At the evening feed
the normal mash had been supplemented with the remnants of a jar of pickled fish and periwinkles
gathered from the beach. No toxin was identified.
Other Species
Cork isolated Rhodococcus equi from a one-month old foal with abscessation of the lungs.
Specimens were submitted to Cork from a three-month old foal that had died following a bout of
diarrhoea. Salmonella typhimurium was isolated and there was a high Strongyloides faecal egg
count. Limerick diagnosed colitis X in an eleven month-old filly that died following a short illness.
The filly had shown signs of abdominal pain, weakness and watery diarrhoea.
Athlone and Kilkenny reported cases of Rabbit Haemorrhagic Disease (RHD). The diagnoses
were made following liver histopathology. Kilkenny also diagnosed coccidiosis in two ten-week old
rabbits with a history of diarrhoea.
Salmonella typhimurium phage type DT2 was identified by Cork in both a racing pigeon flock and a
flock of fancy pigeons. The relevant public health bodies were notified.
High concentrations of lead were detected by the Biochemistry Section of the Central Veterinary
Research Laboratory in the kidney of a swan submitted to Cork. The swan was very thin, and
while ingesta had accumulated in the oesophagus, proventriculus and gizzard, the intestines were
empty. This accumulation of ingesta is considered to be due to weakness in muscles of the
digestive tract. A second swan from the same location had similar lesions, but due to advanced
autolysis, no tissue samples were taken for analysis.
A 25-year old male Lion-tailed Macaque (Macaca silenus) found dead in a wildlife park and
referred to Cork, was found to have haemothorax and collapsed lungs. A further search in the
thoracic cavity revealed two (grape size) pulmonary abscesses. It is believed that vascular wall
erosion caused by the infection may have led to the fatal haemorrhage. No evidence of trauma was
observed. Aerobic bacterial culture of samples collected from the abscesses, liver, and lung resulted
in mixed growth. Histolopathological examination of one abscess revealed a focal granuloma
surrounded by a large number of eosinophils, suggesting possible parasitic aetiology. Acid-fast
micro-organisms (mycobacterium) were not detected on the slides examined.
CAPTIONS FOR PHOTOS
Figure 1 “A chicken with ‘clubbed down’ beside a normally feathered one – photo Sorcha
Spillane”
Figure “Renal adenocarcinoma in a cat – photo Donal Toolan”