High frequency of cholecystitis in dogs with gallbladder mucocoele in Hong Kong.

The aims of this retrospective study were to characterise the epidemiological, clinical, histopathological, and microbiological findings as well as surgical outcomes in dogs admitted to a specialist veterinary hospital in Hong Kong for surgical management of gallbladder mucocoele (GBM). Inclusion criteria were cases with histopathological diagnosis of GBM and accompanying abdominal imaging, serum biochemistry, bile culture, and liver biopsy histology results. Fifty-six cases met the inclusion criteria. The median age at diagnosis was 12 years (range, 5-16 years). Miniature or toy pure-breed dogs were most commonly affected, including Poodles, Pomeranians, Schnauzers, Bichon frises and Chihuahuas. However, no breed was over-represented compared with their expected proportions among annual hospital admissions. Histological evidence of cholecystitis was present in 84% of cases, including acute cholecystitis in 18%, chronic cholecystitis in 37.5%, acute on chronic cholecystitis in 28% and acute with necrosis in 6%. The most common liver lesions were cholestasis in 64%, along with portal fibrosis in 55%, oedema in 50% and bile duct hyperplasia in 50%. Bile culture was positive in 29.6% of cases. Escherichia coli and Enterobacter species were most commonly isolated. Stentrophomonas maltophili was cultured from one case. Of the 16 cases where bacteria were isolated from bile culture, 94% had evidence of chronic cholecystitis and 81% had evidence of cholangiohepatitis. Fifty dogs (89.3%) survived to discharge including 5/5 dogs with ruptured gallbladders. Of 34 dogs with follow-up data, 21/34 (61.8%) were still alive 12 months later. Gallbladder mucocoeles were frequently associated with both acute and chronic inflammation. High survival rates to discharge were achieved.

Detection of hypoglycin A in the seeds of sycamore (Acer pseudoplatanus) and box elder (A. negundo) in New Zealand; the toxin associated with cases of equine atypical myopathy.

CASE HISTORY AND CLINICAL FINDINGS: During April and May 2014 four horses aged between 5 months and 9 years, located in the Canterbury, Marlborough and Southland regions, presented with a variety of clinical signs including recumbency, stiffness, lethargy, dehydration, depression, and myoglobinuria suggestive of acute muscle damage. Two horses were subjected to euthanasia and two recovered. In all cases seeds of sycamore maple (Acer pseudoplatanus) or box elder (A. negundo) were present in the area where the horse had been grazing. LABORATORY INVESTIGATION: The samaras (seeds) of some Acer spp. may contain hypoglycin A, that has been associated with cases of atypical myopathy in Europe and North America. To determine if hypoglycin A is present in the samaras of Acer spp. in New Zealand, samples were collected from trees throughout the country that were associated with historical and/or current cases of atypical myopathy, and analysed for hypoglycin A. Serum samples from the four cases and four unaffected horses were analysed for the presence of hypoglycin A, profiles of acylcarnitines (the definitive diagnosis for atypical myopathy) and activities of creatine kinase and aspartate aminotransferase.Markedly elevated serum activities of creatine kinase and aspartate aminotransferase, and increased concentrations of selected acylcarnitines were found in the case horses. Hypoglycin A was detected in the serum of those horses but not in the healthy controls. Hypoglycin A was detected in 10/15 samples of samaras from sycamore maple and box elder from throughout New Zealand. DIAGNOSIS: Cases of atypical myopathy were diagnosed on properties where samaras containing hypoglycin A were also found. CLINICAL RELEVANCE: Sycamore and box elder trees in New Zealand are a source of hypoglycin A associated with the development of atypical myopathy. If pastured horses present with clinical and biochemical signs of severe muscle damage then the environment should be checked for the presence of these trees. Horses should be prevented from grazing samaras from Acer spp. in the autumn.

The first case of a bull persistently infected with Border disease virus in New Zealand.

CASE HISTORY: Poor reproductive performance was observed in 62 dairy heifers, with a pregnancy rate of 23% following 57 days mating with one 3-year-old and two 2-year old Belted Galloway bulls that were sourced from separate sheep and beef farms. CLINICAL FINDINGS: The 3-year-old bull was small for its age with small testes. This bull was seropositive for bovine viral diarrhoea virus type I (BVDV 1) using an Ag-ELISA, and positive on PCR for border disease virus (BDV). DIAGNOSTIC INVESTIGATION: Phylogenetic analysis of the BDV isolate from the affected bull indicated that it was part of the BDV 1 group. For 40 of the heifers exposed to the bull that were tested, all of them had a positive VNT (virus neutralisation test) titre to both BDV (titre≥1:4) and BVDV 1 (titre>1:4). On the farm of origin of the affected bull there was no evidence of BDV circulating between cattle. DIAGNOSIS: Persistent infection of a bull with BDV. CLINICAL RELEVANCE: Cattle persistently infected with BDV can act as a source of virus for infection of other cattle. The benefit of testing cattle for bovine viral diarrhoea could be enhanced by using tests that also detect BDV.

Outbreaks of pleuritis and peritonitis in calves associated with Pasteurella multocida capsular type B strain.

CASE HISTORY: Three dairy calf-rearing properties experienced high mortality in calves during 2008 and 2009. Affected calves were aged 13-18 weeks (Farm I), 6 months (Farm II), and 2-11 weeks (Farm III), and the mortality rate was 22/175 (13%), 5/80 (6%), and 60/900 (7%), respectively. CLINICAL AND LABORATORY FINDINGS: Affected calves rapidly became moribund, were in respiratory distress, and had a fever (40-41°C). Post-mortem examination of nine calves revealed fibrinopurulent pleuritis, pericarditis, and peritonitis. This was confirmed histopathologically on tissues from three calves, one from each farm; aggregates of small Gram-negative coccobacilli were evident on Gram stain. Pasteurella multocida was cultured from tissues from affected calves on the three farms, and PCR of DNA extracted from tissue samples amplified cap-sular type B-specific DNA. Multi-locus sequence typing (MLST) demonstrated that all capsular type B isolates belonged to the same sequence type (ST), ST62, but did not belong to serotype B:2, the only B serotype classified as causing haemorrhagic septicaemia by the Office International des Epizooties (OIE). DIAGNOSIS: Pleuritis and peritonitis due to infection with P. multocida capsular type B strain. CLINICAL RELEVANCE: Haemorrhagic septicaemia was excluded as a cause of disease from the three farms, however P. multocida was the primary agent in the affected calves. It is possible the agent has been present in New Zealand for some time but not reported, as there had been no transfer of animals between affected farms. Emergence of the syndrome could potentially be a result of factors other than just the presence of the organism, such as changing management. The syndrome described may be of increasing importance in the future.

Use of molecular and milk production information for the cost-effective diagnosis of bovine viral diarrhoea infection in New Zealand dairy cattle.

An increase in veterinary and farmer interest in bovine viral diarrhoea (BVD) in New Zealand over recent years led to requests for cost-effective identification of BVD virus (BVDV) infected herds and individuals. This study was undertaken to determine if the use of real-time reverse transcriptase polymerase chain reaction (RT-PCR) technology and dairy cow production data could identify persistently infected (PI) animals in milking herds. Milk samples were collected from the vats of dairy herds and tested for the presence of BVDV by RT-PCR till four herds were found containing PI animals. Individual serum samples were then collected from every cow in the herd and tested by both RT-PCR and antigen capture enzyme-linked immunosorbent assays (ACE) to identify the PI animals. Individual animal testing found 1/223, 1/130, 2/800 and 1/275 PI's respectively in the four herds. Based on these results a maximum pool size of 400 cows contributing to the bulk tank milk was selected. After removal of the PI from the herds, further bulk milk samples were shown to be BVDV negative by RT-PCR. All the PI animals identified by this method were found in the lowest producing 10-20% of herd. This approach of targeted testing of dairy herds using PCR technology, in conjunction with animal production information, markedly reduced the cost of diagnostic testing for BVDV in dairy herds in New Zealand. Questionnaire follow-up on 81 BVDV-positive herds (15% of those tested) indicated the stratification approach identified milking PIs successfully over 90% of the time and reduced the number of individual tests to 12% of the milking herd.

Does control of bovine viral diarrhoea infection make economic sense?

AIM: To provide an economic analysis of the costs of control or eradication of bovine viral diarrhoea (BVD) against the estimated costs of the disease. METHODS: A decision-tree approach was adapted to an analysis of the costs of bovine viral diarrhoea virus (BVDV) infection and that of three main control options (vaccination, test-and-cull, and increased biosecurity) and their combinations, to the dairy industry in New Zealand. The model was based on an average herd of 322 milking cows. Endemic, epidemic and sporadic effects of BVDV infection were modelled in the herd, to derive an estimate of costs. RESULTS: The cost of BVDV infection to an infected average-sized dairy herd in New Zealand was estimated to be NZ $11,334 (or NZ $35.19 per cow) per annum, and NZ $48,311 over 10 years. Based on these calculations, the estimate of the annual cost of BVDV infection to the dairy industry in New Zealand was in excess of NZ $23 million per annum. While all of the control options required financial input, the rate of return compared with the cost of BVD, when viewed over a 10-year term, was as high as 123%. CONCLUSIONS: All control options offered considerable savings compared with the cost of BVD infection, and control is economically favourable. Uncertainty over the likely efficacy of the control options under field conditions in New Zealand would not allow a firm choice of one option over another at this stage, and more work on determining the efficacy of those control options in New Zealand is needed.

Evaluation of two commercial enzyme-linked immunosorbent assays for detection of bovine viral diarrhoea virus in serum and skin biopsies of cattle.

AIM: To assess the ability of two commercial bovine viral diarrhoea (BVD) virus (BVDV) antigen-capture enzyme-linked immunosorbent assays (ELISAs) to detect virus in serum and skin biopsies. METHODS: Thirty cattle persistently infected (PI) with BVDV were identified using routine diagnostic laboratory testing. Additional ear-notch skin biopsies and blood samples were collected from these animals to confirm the diagnosis, and from 246 cohorts, to determine their BVDV status. Skin biopsies were soaked overnight in buffer and the eluate collected. All sera and eluate were tested using two commercially available ELISAs for detecting BVDV antigen, and a subsample of positive and negative sera was tested using a polymerase chain reaction (PCR) test. A study was also performed to ascertain the risk of cross contamination occurring during the collection and processing of skin biopsies. RESULTS: Both serum and skin samples tested using either ELISA resulted in the detection of all cattle identified as PI and no non-infected cattle were incorrectly classified as infected using either method. Agreement between all assays (ELISAs, whether performed on serum or skin, and PCR) was 100%. No cross-contamination of skin samples between animals was evident using routine biopsy methods. CONCLUSIONS: Viraemic cattle infected with BVDV were accurately identified using either of the two commercial ELISAs evaluated on either serum or skin samples. CLINICAL RELEVANCE: Either skin biopsies or serum samples can be collected from cattle to determine their BVDV status. This should overcome problems in accurately identifying the infection status of young calves in which colostral antibodies might interfere with the antigen-capture ELISA.

A triad of bovine inherited diseases (abstract).

Three inherited diseases of cattle seen in the past 2 years were described. Familial acantholysis of Angus cattle was seen in 9/54 calves born to cows inadvertently mated to a full sibling bull. Sloughing skin from the joints, nose and palate were seen at 1 day of age, confirmed as suprabasilar clefts on histopathology. A 2-year-old Charolais steer was noted at ante-mortem slaughter inspection with a whole body tremor and nystagmus. Histopathologically, eosinophilic plaques expanded white matter throughout the brain, consistent with a syndrome of 'progressive ataxia' of Charolais cattle. Two calves born from Red Devon cattle had marked hyperkeratosis, microtia and periocular reddening with deep fissuring of the keratin, characteristic of congenital ichthyosis.

Polyglucosan body disease in a mixed-breed dog.

AIM: To describe the histopathology of a previously unrecorded canine disease and deduce the cause of the lesions. METHODS: Formalin-fixed tissues were processed into paraffin wax and epoxy resin for light and electron microscopy of variously stained sections of liver, brain, heart muscle and kidney. RESULTS: Periodic acid Schiff (PAS) -positive bodies in liver and myocardium were typical of a polyglucosan body disease. Neurons contained coarse granular material that stained similarly to the polyglucosan bodies. CONCLUSION: The nature, distribution and histochemistry of lesions observed are consistent with a putative diagnosis of Glycogen storage disease type IV, an inherited metabolic defect associated with a deficiency of glycogen-branching enzyme not previously reported in dogs.

Detection of Sarcocystis neurona in the brain of a Grant's zebra (Equus burchelli bohmi).

An 8-yr-old intact male Grant's zebra (Equus burchelli bohmi) was referred to the Veterinary Medical Teaching Hospital of the University of California-Davis after being found in the owner's pasture obtunded and in lateral recumbency. The animal was hypothermic, weak, and unwilling to rise. There was no evidence of trauma, and the zebra had seemed normal the preceding evening. There was no extensor rigidity, and cranial nerve reflexes were normal. Flexor and extensor reflexes were weak upon initial examination. A complete blood count and serum biochemistry analysis revealed a mild leukocytosis, hyperfibrinogenemia, hypoglycemia, hyponatremia, hypochloremia, hypocalcemia, and hypoalbuminemia. Urinalysis was normal, and a urine toxicology screen for alkaloids was negative. No toxic substance was found in the hay or pasture grasses although the owner reported the presence of yellow star thistle and mushrooms in the pasture. The cerebrospinal fluid cytologic and biochemical analyses were normal, but antibodies to Sarcocystis neurona were detected. The zebra died despite aggressive supportive therapy over a 4-day period. The necropsy demonstrated severe gastrointestinal nematodiasis that could account for hypoalbuminemia and electrolyte abnormalities. Histopathologic examination of the nervous system revealed focal areas of perivascular cuffing in the brainstem that were comprised mainly of lymphocytes, monocytes, and plasma cells. Immunohistochemical staining identified the presence of S. neurona merozoites associated with the lesions. This zebra probably died from severe endoparasitism that resulted in malabsorption, weakness, and recumbency rather than from encephalitis associated with S. neurona merozoites. Equine protozoal myeloencephalitis has not been reported previously in nondomestic equids.

Polioencephalomalacia in cattle in New Zealand fed chou moellier (Brassica oleracea).

Polioencephalomalacia was diagnosed clinically in 26 heifers from a herd of 99 grazing chou moellier (Brassica oleracea). Clinical signs included ataxia, recumbency, blindness and aimless walking. Characteristic polioencephalomalacic autofluorescence was seen under long ultraviolet radiation of four fresh brains examined in the veterinary clinic and two formalin-fixed brains sectioned and examined in the laboratory. Haemorrhage and malacia were noted grossly and microscopically in the cranial colliculus, thalamus and hippocampus of two brains sectioned in the laboratory, while multifocal vasculitis was seen in one brain. High sulphur concentrations of 8500 mg/kg DM in the chou moellier and a recent change in grazing management were the most likely causes of the outbreak.

Antibody responses of grazing alpacas (Lama pacos) in New Zealand to intestinal nematodes.

Alpaca (Lama pacos) were grazed for 10 months (October 1992-June 1993) on pasture with sheep or on pasture which had been recently grazed by sheep. The alpaca, of various age groups, totalled 94 at the beginning of the experiment and during the course of the experiment 32 progeny (cria) were born, 10 in spring 1992 and 22 in autumn 1993. Serum levels of specific antibodies to excretory/secretory antigens of the third larval stage (L3) of Cooperia curticei, Ostertagia circumcincta or Trichostrongylus colubriformis and somatic antigens from adult T. colubriformis were determined at monthly intervals by ELISA. Faecal egg count and live-weight were determined monthly and fleece-weight was measured at shearing. Three days after the birth of the cria, serum antibody levels ranged from 0.46-0.85 optical density units for the L3 antigens and averaged 0.22 for the adult T. colubriformis antigen. These levels declined to 0.1-0.24 and 0.06 respectively by 2-3 months of age. Subsequently, antibody levels increased steadily to reach maximal adult levels at approximately 23-26 months. Antibody levels were negatively correlated with FEC, but positively correlated with live-weight at 7 months although at 15 months antibodies and live-weight were negatively correlated. A positive correlation was found between weight and FEC. Fleece-weight showed no correlation with antibody level, a positive correlation with weight and a negative correlation with FEC. The relationships among antibody responses, FEC, live-weight and fleece-weight observed for alpaca in this experiment suggest that antibody responses might provide a useful indicator of alpaca immuno-responsiveness and has potential for use as a parameter for selection of alpaca with reduced FEC.

Cryptococcosis in a North Island brown kiwi (Apteryx australis mantelli) in New Zealand.

A case of disseminated cryptococcosis in a North Island kiwi (Apteryx australis mantelli) caused by Cryptococcus neoformans var. gattii (serotype B) is reported. This is the first case of cryptococcosis to be reported in a kiwi and is also the first isolation of C. neoformans var. gattii from a veterinary source in New Zealand. The kiwi is an example of a ratite bird and as such has a lower body temperature approximating that of a mammal. As a consequence, the kiwi and other ratitis (e.g. emus) would be expected to show an increased susceptibility to cryptococcosis compared with other birds. There has been only one other isolate of this variety of C. neoformans in New Zealand and this was isolated from the sputum of a human male with leukaemia who was from the Gisborne area of the North Island, a region adjacent to Hawkes Bay where the case of kiwi cryptococcosis occurred. Some months prior to the development of the infection in the bird, a mulch of Eucalyptus leaves/twigs had been spread throughout the kiwi enclosure and this is considered to have been the probable source of the yeast. Neither Eucalyptus camaldulensis nor Eucalyptus tereticornis were among the species from which the mulch material originated and it is suggested another species may be the environmental host(s) of C. neoformans var. gattii in New Zealand.