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.

Absence of serological or molecular evidence of Leptospira infection in farmed swine in the Hong Kong Special Administrative Region

Leptospirosis is an important zoonotic disease with several maintenance host species including swine. A cross sectional survey was undertaken between January to October 2020 to investigate the prevalence of leptospirosis in farmed swine in the Hong Kong Special Administrative Region (HKSAR) of China. Serum samples were collected from swine on seven farms (15 swine per farm; ten multiparous sows and five twelve-week-old weaners), while kidney samples were collected from 64 swine submitted for routine post-mortem (26 farms; average 2.4 swine per farm, range 1-6). Microscopic agglutination tests (MAT) to a panel of 24 Leptospira antigens did not reveal any evidence of seroconversion at a titre of 1:100. Polymerase chain reaction (PCR) testing of the kidney samples for Leptospira DNA did not detect any evidence of infection. Bayesian methods were used to compute the probability that the leptospirosis prevalence in farmed swine in the HKSAR was <3%, given none of the 105 swine sampled were positive on the MAT. The results of this study demonstrate no serological or molecular evidence of leptospirosis in farmed swine in the HKSAR. Subsequent statistical analysis supports the conclusion that the prevalence of leptospirosis in farmed swine in the HKSAR is negligible at present.

First case of feline cryptococcosis in Hong Kong, caused by Cryptococcus neoformans

A nine-year-old domestic short hair cat was presented for a nasal planum mass, nasal discharge, hyporexia and weight loss. On physical examination nasal proliferative and ulcerative lesions and submandibular lymphadenopathy were identified. Cytology, histopathology, fungal culture, antigen serology and MALDI-TOF confirmed cryptococcal rhinitis with regional mandibular lymph node involvement due to Cryptococcus neoformans infection. This is the first reported case of cryptococcosis in a feline patient in Hong Kong.

Review of Diagnostic Procedures and Approaches to Infectious Causes of Reproductive Failures of Cattle in Australia and New Zealand

Infectious causes of reproductive failure in cattle are important in Australia and New Zealand, where strict biosecurity protocols are in place to prevent the introduction and spread of new diseases. Neospora caninum ranks highly as an important cause of reproductive wastage along with fungal and bacterial infections. Brucella, a leading cause of abortion elsewhere in the world, is foreign, following successful programs to control and eradicate the disease. Leptospirosis in cattle is largely controlled by vaccination, while Campylobacter and Tritrichomonas infections occur at low rates. In both countries, Bovine Viral Diarrhea virus (BVDV) infection rates as the second most economically important disease of cattle and one that also has an effect on reproduction. Effective disease control strategies require rapid diagnoses at diagnostic laboratories. To facilitate this process, this review will discuss the infectious causes of reproductive losses present in both countries, their clinical presentation and an effective pathway to a diagnosis.

Perspectives on Current Challenges and Opportunities for Bovine Viral Diarrhoea Virus Eradication in Australia and New Zealand

This review outlines the history of bovine viral diarrhoea virus (BVDV) and the current situation in Australia and New Zealand. BVDV has been reported as present in cattle from both countries for close to 60 years. It rates as the second most economically significant disease afflicting cattle, and is highly prevalent and spread throughout the beef and dairy industries. While other cattle diseases have been the subject of government control and eradication, infection with BVDV is presently not. Eradication has been undertaken in many other countries and been judged to be a good investment, resulting in positive economic returns. Presently, Australia and New Zealand have adopted a non-compulsory approach to control schemes, initiated and managed by farmers and veterinarians without the ultimate goal of eradication. Moving towards eradication is possible with the infrastructure both countries possess, but will require additional resources, coordination, and funding from stakeholders to move to full eradication.

Moving past serology: Diagnostic options without serum

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Traditional serology has moved beyond blood as a test medium.

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A number of different samples and tissues are now frequently used in veterinary diagnosis.

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Testing can be robust and accurate and opens up the field to a variety of new opportunities.

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Molecular testing allows direct testing for the agent on a variety of tissues and samples, and pools.

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Pooling of samples can allow for more efficient and cost-effective testing.

Detecting antibodies formed in serum in response to infection is the traditional function of serology. Diagnostic modalities have included complement fixation tests, agar gel immune-diffusion, radioimmunoassay, ELISA and immunofluorescence. More recent technology now allows for the direct detection of pathogens by PCR. This review details the options for diagnostic testing using specimen types other than serum, identifying the advantages and disadvantages of these options and providing evidence for more widespread use of these techniques and specimen types.

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.

Interlaboratory and between-specimen comparisons of diagnostic tests for leptospirosis in sheep and cattle

A study was performed to investigate interlaboratory test agreement between a research and a commercial veterinary diagnostic laboratory on blood and urine samples, and to investigate test agreement between blood, urine, and kidney samples (research laboratory) for leptospirosis diagnosis. Samples were sourced from 399 sheep and 146 beef cattle from a local abattoir. Interlaboratory agreement for real-time quantitative polymerase chain reaction (qPCR) results on urine samples was almost perfect (kappa = 0.90), despite the use of different amplification targets (DNA gyrase subunit B gene vs. 16s ribosomal RNA gene), chemistries (SYTO9 vs. TaqMan probe), and pre-PCR processing. Interlaboratory agreement for microscopic agglutination test (MAT) positivity was almost perfect (kappa = 0.93) for Leptospira borgpetersenii serovar Hardjo subtype Hardjobovis (Hardjobovis) but moderate (kappa = 0.53) for Leptospira interrogans serovar Pomona (Pomona). Among animals that had different titers recorded, higher Hardjobovis and lower Pomona titers were reported by the commercial laboratory than by the research laboratory (P < 0.005). These interlaboratory comparisons can assist researchers and diagnosticians in interpreting the sometimes discrepant test results. Within the research laboratory, the comparison of qPCR results on urine and kidney showed almost perfect agreement (kappa = 0.84), suggesting that the qPCR on these 2 specimens can be used interchangeably. The agreement between MAT positivity and urine and kidney qPCR results was fair (kappa = 0.32 and kappa = 0.33, respectively). However, the prevalence ratio of urine and kidney qPCR positivity in Hardjobovis-seropositive versus Hardjobovis-seronegative sheep indicated that Hardjobovis seropositivity found in sheep may be able to predict shedding or renal carriage.

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.

Osteogenic Intraocular Melanoma in an Alpaca (Vicugna Pacos)

A 10-year-old, female, pregnant alpaca ( Vicugna pacos) presented with a discolored, swollen right eye. The eye did not respond to treatment and was enucleated. Sectioning of the fixed eye revealed an ocular mass replacing the aqueous and vitreous humors, with multiple regions of bone formation. Histopathological, immunohistochemical, and transmission electron microscopy confirmed the tumor was an intraocular melanoma with bone formation. Osteogenic melanoma is a rare variant of melanoma not reported in the eye before.

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.

Malignant catarrhal fever in a swamp buffalo (Bubalus bubalis) calf in New Zealand

Malignant catarrhal fever was diagnosed in a newly imported swamp buffalo calf. This disease is prevalent in deer and cattle in New Zealand and causes sporadic losses in these species. The disease is recognised as a problem in buffaloes overseas and this paper records the first case in a swamp buffalo in New Zealand.

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.

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.

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.

Rickets in alpacas (Lama paces) in New Zealand

Rickets was diagnosed in two weaner alpacas from a flock showing ill thrift and lameness during the winter of 1992. Both animals had abnormally shaped ribs with occasional healing fractures, irregular thickening of growth plates and metaphyseal haemorrhages. The mean serum phosphorus concentrations of the alpacas fell during June and July, even though lambs grazing the same pasture had normal serum phosphorus concentrations and the phosphorus concentration of the pasture was considered adequate. Vitamin D deficiency may also have contributed to the osteodystrophy. The alpacas had a thick fleece during the winter, and diurnal Vitamin D, synthesis resulting from solar irradiation is likely to have been minimal, especially considering the reduced sunshine hours recorded during the 1992 winter. Surviving alpacas recovered after treatment with monosodium phosphate and an oral Vitamin D supplement. It is possible alpacas are more susceptible to deficiencies of phosphorus and Vitamin D than other grazing animals in New Zealand.

A preliminary study of copper supplementation in alpacas (Lama paces)

Supplementing three alpacas with Cu as cupric sulphate (10 mg Cu/kg liveweight) as a single oral dose resulted in no change in the mean plasma Cu concentrations over 30 days while a single oral dose of cupric oxide needles (2.5 g) given to three alpacas caused a small but significant increase in the mean plasma Cu concentrations during days 10-30 following treatment. The mean plasma Cu concentrations of four untreated animals ranged from 4.2 to 5.9 micromol/l over the study. The Cu as cupric sulphate was excreted in the faeces within 5 days while the cupric oxide needles significantly elevated the faecal excretion for over 30 days.

Nematode burdens of alpacas sharing grazing with sheep in New Zealand

Sheep and alpacas of similar age groups (6, 18 and 36+ months) were grazed for 16 weeks on pasture contaminated by lambs. Faecal egg counts, bulked larval cultures, lungworm larvae in faeces, dag scores, liveweight changes and nematode larvae on pasture were measured. Chabertia, Oesophagostomum, Cooperia, Ostertagia and Haemonchus and Trichostrongylus larvae were cultured from both the sheep and the alpacas. For the respective age groups, the alpacas had lower liveweight gains (10, 32 and 47 g/d vs 88, 84 and 120 g/d), peak faecal egg counts (384, 50 and 60 epg vs 1500, 500 and 140 epg) and faecal contamination of the perineum than the same ages of sheep. These results suggest alpacas became less affected with gastrointestinal nematodes than sheep.

Actinobacillosis in an alpaca (Lama pacos)

The death of a 6-week-old alpaca being treated for acute polyarthritis is described. Post-mortem and histological findings included fibrinous mural endocarditis, lung abscessation, acute passive congestion of the liver, embolic suppurative nephritis and chronic nonsuppurative polyarthritis. Actinobacillus suis was isolated from the heart lesion and in pharyngeal swabs from four of six clinically normal alpacas in the same flock.