Current Findings in the Regional Veterinary Laboratories
February 2004
Cattle
Samples submitted to Kilkenny from cows with a history of abortion or infertility showed a positive
titre to Salmonella dublin at the “O” antigen in six percent of samples and showed a positive titre to
the “H” antigen in only two percent of samples. Testing for Leptospirosis showed a low positive
result in 33% of cases and a moderate or high positive in 12% of cases. Testing for Neospora
caninum gave an inconclusive reading in two percent, a low/moderate reading in four percent and a
high reading in another four percent of cases. A herd of 120 dairy cows in the Cork region had 18
abortions in November 2003 which were not submitted for examination as the abortions were
ascribed to a severe respiratory outbreak that had occurred in the herd and had affected most of the
cows that had aborted. However an aborted foetus of eight months gestation length submitted in
February, the dam of which had not had respiratory illness, had histological lesions with inclusion
bodies suggestive of infectious bovine rhinotracheitis (IBR) virus infection and in addition bovine
viral diarrhoea (BVD) virus was detected on PCR test and Arcanobacter pyogenes was isolated on
culture. Athlone reported abortion in cows due to Neospora -both animals in the same herd were
one month from term and both had positive titres. Kilkenny found that Bacillus licheniformis was
isolated in 13% of aborted bovine foetuses, Arcanobacter pyogenes was isolated in 9% of cases and
Listeria monocytogenes was isolated in 1% of cases. Anoxia/hypoxia was diagnosed in 25% of
stillbirths submitted. Four cases of atresia ilei and two atresia coli were referred to Cork. All had
distended abdomens with severely dilated meconium-filled intestinal loops and in one calf the
diaphragm had ruptured. These common congenital defects are probably genetic in origin. Kilkenny
had three cases of atresia jejuni in calves. One case was presented as a three-day-old calf with a
history of being off form on the previous day. The abdomen of this calf was slightly distended and
its eyes were slightly sunken. The abomasum, duodenum and first half of the jejunum were
distended with golden brown liquid. The second half of the jejunum, the colon and rectum were
empty and of small calibre. There was no interruption of the mesentery at the junction of the full
and empty parts of the jejunum. There were strands of fibrin on the serosal surfaces of the
intestines. A diagnosis of atresia jejuni with peritonitis was made. Another one-day-old calf seen by
Cork had pulmonary consolidation affecting approximately 80% of the lungs. Pasteurella spp were
isolated and the established histological lesions of characteristic pneumonic Pasteurellosis would, in
consideration of the age of the calf, indicate that the disease process had occurred in utero!
Kilkenny found that 21% of neonatal enteritis samples tested were positive for Rotavirus, 16% were
positive for Campylobacter jejuni jejuni , 11% were positive for Cryptosporidia , 1% positive for
Clostridium sordelli and Salmonella typhimurium was isolated in one case. Coccidiosis was
identified in 16% of specimens examined in Kilkenny. Three per cent had a severe burden, 8% had
a moderate burden and 5% had a light burden. Thirty two per cent of blood samples examined with
the Zinc Sulphate Turbidity Test (ZSTT) gave a reading of less than ten units, 26% gave a reading
between 10 and 20 units and only 42% had what was deemed an adequate level of immunoglobulins
in their system (>20 units). Cork had a typically classical case of Escherichia coli K99
enterotoxaemia in a one day old calf, the first such case this year. The calf had an acceptable
concentration of immunoglobulins but as the dam was unvaccinated specific antibodies were
obviously low or absent. Athlone reported neonatal enteritis in dairy calves with rotavirus,
coronavirus and E.coli present in the faeces. Dublin diagnosed meningitis in a two-day-old calf that
displayed nervous signs before death. A Zinc Sulphate Turbidity test result of eight units revealed
inadequate immunoglobulins absorbed. Rotavirus and cryptosporidia were the two most commonly
identified pathogens found in faecal samples submitted to Limerick from calves with enteritis.
A five-week-old calf submitted to Kilkenny with a history of respiratory distress had a patent
foramen ovale. The lung showed pneumonia with 20% consolidation of the lung. The heart was also
enlarged and rounded. A three-week-old calf that was found dead was submitted to Kilkenny. It had
pale mucous membranes and was dehydrated. There was widespread dilation, haemorrhage and
congestion in the small intestine. The intestinal contents were very bloody. The abomasum, large
intestine and rectum appeared normal. Faecal examination identified a heavy coccidial burden. A
diagnosis of Intestinal Haemorrhagic Syndrome and heavy Coccidia burden was made. A six-weekold calf submitted to Kilkenny with a history of acute respiratory distress showed severe
consolidated pneumonia of 80% of the lungs. A tracheitis was also present with a mucohemorrhagic
discharge. Mannheimia haemolytica and Haemophilus somnus were isolated on bacterial culture.
Two two-week-old calves submitted to Kilkenny with a history of pneumonia had Haemophilus
somnus isolated from one and Salmonella dublin from the other. Both calves had extensive
pneumonia, involving about 60% of the lung substance. RSV was diagnosed by Dublin in a threemonth-old weanling calf. A ten-week-old calf was submitted to Kilkenny for PME. It had a history
of scour and stomach problems. There were lesions in the lung, intestine and abomasum. Some
loops of small intestine were adherent to each other. There were many lesions in the liver (see
photograph), ranging from 1 - 12 cm. in diameter. They consisted of light brown necrotic tissue
surrounded by a narrow rim of red tissue. Many of the lesions were circular but some of the larger
ones were irregular in shape. No significant bacteria were isolated on either aerobic or anaerobic
culture. Histological examination confirmed a necrotic hepatitis. Thrombosis of the blood vessels
was seen in the necrotic areas and occasional fungal hyphen were seen. A diagnosis of fungal
hepatitis with peritonitis and pneumonia was made.
Despite the time of year, adult lungworm were observed by Dublin in the bronchi of an outwintered
weanling which was one of two casualties in a group of ill-thrifty six-month-old weanlings which
had been housed three weeks before dying. Sarcocystis encephalitis was diagnosed in an eightmonth-old bullock by Dublin. At the start of the month Cork confirmed ragwort poisoning (see
photograph) in a group of 40 yearlings from which five had died. The source was identified as
contaminated silage and that was immediately withdrawn. Although the exposure to the
contaminated silage was long-standing there were only two more deaths by the end of the month
and the clinical appearance of the remaining yearlings suggests that the regenerative powers of the
liver may be such that most will overcome the poisoning. A nine-month old pedigree Charolais bull
that had died suddenly was found by Limerick RVL to have died from shock resulting from the
perforation of a large abomasal ulcer, with leakage of the contents into the peritoneal cavity. Dublin
diagnosed lead poisoning in an 18-month-old heifer, which was one of three dull depressed animals,
two of which died. A broken tractor battery was found in the field. Athlone reported Paramphistoma
or Rumen Flukes present in a sample from a two-year-old bovine submitted from an abattoir. These
parasites may be present in huge numbers in rumen and reticulum of adult ruminants where they
seem to have little pathological significance. However in the young grazing ruminant they can
cause an afebrile enteritis as the young flukes feed in the duodenum before migrating to the
forestomachs. A two-year-old Friesian bullock presented to an abattoir for slaughter was identified
as a BSE suspect and was returned to the farm of origin. The history was that the animal was born
with nervous signs. The animal had required special care in order to get it to a weight and size
suitable for slaughter. On examination of the brain Limerick RVL could find absolutely no trace of
a cerebellum. The animal was negative for BSE.
Sligo is currently investigating a suspected outbreak of malignant catarrhal fever on a mixed
sheep/suckler farm in Co. Donegal, where 15 cattle have died to date. Initially, affected animals
showed severe pyrexia and acute onset nervous signs, including trembling, inco-ordination and
aggression before proceeding to lateral recumbency and death in 24-48 hours. Later in the outbreak,
the disease showed a longer course, with more classical signs suggestive of MCF evident (Photo 1,
Photo 2). These animals ran very high temperatures (>107F), had ocular and nasal discharges,
blepharospasm/photophobia, generalised lymphadenopathy and in some cases, diarrhoea. One
affected animal had marked ocular opacity (Photo 3). At post-mortem examination of one animal,
marked generalised lymph node enlargement (See pre-scapular lymph node, Photo 5), severe
ulceration of the hard palate and muzzle, and generalised lymphadenopathy were noted. This
animal had mild ocular opacity, which was more obvious at PME when the head was skinned than it
had been during clinical examination, because of the difficulty of opening the eyes due to
blepharospasm (Photo 4). At the point when the RVL was notified, 12 animals had already died
over a two-week period. On a farm visit it was apparent that the sheep and cattle enterprises were
conducted in close proximity to each other, with lambing ewes within a short distance of cattle,
although there was no direct contact. Contact with periparturient sheep is a known risk factor for
MCF, and in this case any such contact would have been indirect (via fomites). The results of
histopathological and viral examination of tissues 1, are awaited.
Recent infection with Leptospira hardjo was confirmed by Dublin by detection of antibodies in the
majority of a representative group of cows (including titres of 1/400) in a herd which submitted two
aborted foetuses and dam sera. There was also the possibility of zoonotic illness being associated
with this infection. Athlone reported Johnes Disease in a dairy herd. A number of animals were
showing clinical evidence of disease. Faecal staining, faecal culture and serology were all positive.
Sheep
Campylobacter spp. were isolated by Dublin from two flocks experiencing abortion outbreaks with
indicative white spots visible in the liver of the foetuses from one of the flocks. Toxoplasma
abortion was diagnosed by Dublin in another flock based on histological observation of
characteristic non-suppurative encephalitis lesions in the foetus. Fibrinopurulent acute pleurisy and
interstitial pneumonia and peritonitis was found by Dublin in a two week old lamb, which was one
of four that died suddenly and from which, Pasteurella spp. was isolated. Heavy concentrations of
sarcocysts were observed by Dublin in the myocardium of two ewes that died within 10 days after
lambing, one of which also had localised lung lesions associated with lungworm parasites. A threeyear-old pedigree ram with a history of bloat and constipation was submitted to Limerick RVL
following unsuccessful treatment. Intussusception of the ileum had lead to the blockage, with a
large accumulation of fluid anterior to the lesion. More typical of the season of the year were
observations of liver fluke by Dublin in ewes carrying twin lambs that died suddenly. Athlone
confirmed sheep scab in two flocks. Live Psoroptes ovis mites were present in samples submitted
for examination.
Other Species
Cork received two five-week old Bordeaux Mastiff pups, the dam and sire of which originated in
Moscow. There had been three deaths in a litter of eight. The clinical signs were paralysis of the
hind legs with pain on touch, head tilt, anisocoria in one, and inappetence. Lesions consistent with
protozoal infestation and present in all organs sampled - brain, spinal cord, liver, heart, lung and
kidney were found on histology. Testing is ongoing but to-date serology in the dam for Toxoplasma
gondii gave a titre of 1/128 on a latex agglutination test marketed for human, feline and porcine sera
and with which a titre of 1/64 is deemed positive in cat and pig. Serology for Neospora caninum
(undertaken at the Veterinary College UCD) showed a titre of 1/800.
Salmonella arizona was identified by Cork as the cause of death in juvenile terrapins. There were
several deaths in a large batch recently imported to a pet shop. Public health disciplines were
informed and the remaining terrapins were destroyed. Enquiries by the relevant authorities indicated
that only the one batch had been imported to the state.
Fungal Hepatitis
Photo 1
Photo 2
Photo 3
Photo 4
Photo 5