Re: Fifty years of leptospirosis research in New Zealand: a perspective

The article which appeared in the Jubilee Issue of the New Zealand Veterinary Journal (Marshall and Manktelow 2002) reviewed one of this country's most important zoonotic diseases. I wish to add three important references concerning its first recognition in livestock and humans in New Zealand. The first field cases of leptospirosis in calves due to Leptospira pomona (now L. interrogans serovar pomona) were confirmed in November 1951 on farms in Westland, not in Northland in 1953 as stated in the review. The seminal year for leptospirosis research was 1951 not 1953. Simultaneously, the association with human disease in New Zealand was also recognized and confirmed (Bruere 1952; Kirschner et al 1952). In that year there was a mini-epidemic of cases in Westland involving both calves and humans. It was fortuitous at the time that Kirschner had established methods for the diagnosis of leptospirosis at Otago Medical School. Despite obvious clinical signs, laboratory diagnosis of leptospirosis was not confirmed at Wallaceville (New Zealand's only animal diagnostic station available to veterinarians in 1951) because of logistic impossibilities in both transport and sample preservation. From calf sera collected in Koiterangi (now renamed Kowhitirangi) in Westland in November 1951, Kirschner confirmed my diagnosis of leptospirosis ...     

Experimental matrix plug production in male cat urine following a natural case of urolithiasis due to matrix plug

Urethral obstruction occurred in a 2-year-old entire long-haired red cat. A suspicion that this was a case caused by matrix plug formation could not be confirmed as reverse flushing using a topical corticosteroid and a trypsin digest appeared to have broken up the obstruction. Nine days later the cat passed a large mucoid mass which, when placed into a simulated urethra produced an obstruction. Histological examination of this plug confirmed that there were no crystalline components and on appearance it was similar to that of natually occurring matrix plugs.     

Bovine spongiform encephalopathy: diagnostic significance of vacuolar changes in selected nuclei of the medulla oblongata

The adequacy of a histopathological diagnosis of bovine spongiform encephalopathy (BSE) based exclusively on observations of neuroparenchymal vacuolation in three specific neuroanatomic nuclei was tested by using a standard coronal section of medulla oblongata cut at the obex. The agreement between the observations and the definitive histopathological diagnosis was assessed in each of 684 bovine brains - 563 confirmed cases of BSE, 20 with changes which did not diagnose BSE conclusively and 101 in which the lesions of BSE were not detected. When the assessment was confined to the solitary tract nucleus and the spinal tract nucleus of the trigeminal nerve a positive result was obtained in 99.6 per cent of confirmed cases of BSE and only 1 per cent of brains in which lesions of BSE were not detected gave a false positive result. Thus an initial examination of the single section, together with an examination of representative areas of the rest of the brain when no unequivocal lesion was found, provided a satisfactory method for the routine diagnosis of BSE.     

Gastric retention associated with a pyloric mass in two horses

Partial pyloric obstruction causing gastric retention is described in 2 young female horses. Gastric retention was confirmed by contrast radiography of the upper gastrointestinal tract. In both horses a large mass was palpated in the wall of the pyloric antrum at exploratory laparotomy. Post-mortem examination of the first case confirmed that this mass was associated with chronic gastric ulceration. Gastric ulceration was not confirmed in the second case but this horse recovered after the pylorus and duodenum were bypassed by gastro-jejunostomy.     

Presentation,clinical pathological and post‐mortem findings in three related Scottish terriers with ligneous membranitis

Ligneous conjunctivitis and gingivitis were diagnosed in three related Scottish terrier dogs presented for investigation of severe conjunctivitis and respiratory signs. Hypoplasminogenaemia was confirmed in one of the three affected dogs. Supportive treatment was not effective, and the dogs died or were euthanased because of the disease. Post‐mortem analysis of two of the dogs revealed multiple abnormalities including severe proliferative fibrinous lesions affecting the conjunctiva, gingiva, trachea, larynx and epicardium and multiple fibrous adhesions throughout the thoracic and abdominal cavities. One dog had internal hydrocephalus and lacked a cerebellar vermis. Ligneous membranitis was confirmed on histopathology. This is a rare condition in dogs but an important differential diagnosis for severe conjunctivitis and gingivitis.     

A Study of Toxoplasma Infection in Chickens and Cats on a Family Farm

Presumptive evidence of toxoplasmosis was obtained following histological and serological studies of tissues from chickens and cats kept on a family farm. This was confirmed by transmission of the infection to experimental laboratory animals and back to chickens. The significance of the low grade serological reaction in one of the persons living on the farm was not clear.     

COMPUTED TOMOGRAPHY OF PRIMARY INFLAMMATORY BRAIN DISORDERS IN DOGS AND CATS

A retrospective study of 22 animals with histologically confirmed, primary inflammatory brain disease was undertaken to determine the value of computed tomography in such patients. The histologic diagnosis was confirmed at necropsy in 18 patients and by surgical biopsy in four. All affected animals had neurologic deficits; the most common presenting complaint was seizures. Abnormalities were identified on computed tomography images in 21 of the 22 patients. The abnormalities included ventricular changes, falcial deviation, edema, focal changes in parenchymal opacity, focal contrast enhancement, periventricular contrast enhancement, and a ring-like pattern of contrast enhancement. Many lesion types identified in this study, such as falcial deviation, changes in parenchymal opacity, and ring-pattern enhancement, have previously been associated with neoplasia. The abnormalities correlated well with the lesion localization predicted by neurologic examination and confirmed by surgery or necropsy. Although computed tomography findings were often judged to be compatible with inflammatory disease, they did not predict the type of pathologic process. The findings suggest that computed tomography is valuable in the evaluation of animals with primary inflammatory brain disorders, but differentiation of neoplasia from non-neoplastic diseases is not always possible.     

Congenital renal dysplasia and psychogenic polydipsia in a Bernese mountain dog.

Congenital renal dysplasia was tentatively diagnosed, based on ultrasound and an intravenous urogram, in a 5-month-old female with polyuria and polydipsia. Creatinine clearance measurement revealed that the renal dysplasia was not the cause of the polyuria. A modified water deprivation test eliminated other differential diagnoses and confirmed psychogenic polydipsia.     

Myotonia in related Chow Chow dogs

A myopathy associated with myotonia was observed in three related Chow Chow dogs. The clinical signs were first noticed at 2 to 3 months of age. They included muscle spasm and stiffness of gait which decreased in severity with exercise. Electromyographic findings and the demonstration of a muscle percussion dimple confirmed the presence of myotonia. Dystrophic changes were observed in muscle biopsies but histochemical techniques did not demonstrate fibre type changes. An inherited aetiology was suspected but not confirmed.     

Canine hemangiopericytoma: 23 cases (1967-1984)

The medical records of 23 histopathologically confirmed cases of canine hemangiopericytoma were reviewed. Ninety-one percent (21/23) of the dogs were 7 years old or older, and 70% (16/23) were female. Seventy-four percent (20/27) of the tumors developed on the extremities. Recurrence rates were 31% (5/16) with surgical excision only, and 60% (3/5) with surgical excision combined with radiotherapy. Tumor recurrence did not appear to be related to mitotic index. Metastasis was suspected in one of the dogs, but was not confirmed.     

Unusual radiographic appearance of lung carcinoma in a cat

A 15-year-old, female Siamese cat presented with multiple cavitary lung lesions on thoracic radiographs. This was confirmed histologically to be a well-differentiated bronchioloalveolar carcinoma. To the authors' knowledge, this radiographic pattern has not previously been reported in association with bronchioloalveolar carcinoma in cats.     

Sarcoptes scabiei infestation in a cat

Sarcoptes scabiei infestation was diagnosed in a cat. Clinical signs included thick, crusty, exudative dermatitis on the feet, caudal aspect of the thighs, and tail. Paronychia and dystrophic nails also were observed. The course of the disease was chronic. Concomitant and potentially predisposing additional health problems were suspected, but were not confirmed.     

The impact of badger removal on the control of tuberculosis in cattle herds in Ireland

In Ireland, the herd prevalence of bovine tuberculosis has remained stable for several decades, and in common with several other countries, progress towards eradication has stalled. There is evidence in support of the potential role of infected badgers (Meles meles, a protected species) in bovine tuberculosis in Ireland and Britain. However, this evidence on its own has not been sufficient to prove disease causation. Field trials are likely to offer the best opportunity to define this role. Building on the earlier East Offaly project, our objectives were to assess the impact of badger removal on the control of tuberculosis in cattle herds in Ireland.

The study was conducted from September 1997 to August 2002 in matched removal and reference areas (average area of 245.1 km²) in four counties: Cork, Donegal, Kilkenny and Monaghan. Badger removal was intensive and proactive throughout the study period in the removal areas, but reactive (in response to severe tuberculosis outbreaks in cattle) in the reference areas. Removal intensity in the removal and reference areas during the first 2 years of the study averaged 0.57 and 0.07 badgers/km²/year, respectively.

The outcome of interest was restriction of cattle herds due to confirmed tuberculosis, where tuberculous lesions were detected in one or more animals. Data were analysed using logistic regression (modelling the probability of a confirmed herd restriction) and survival analysis (modelling time to a confirmed herd restriction).

During the study period, there was a significant difference between the removal and reference areas in all four counties in both the probability of and the time to a confirmed herd restriction due to tuberculosis. In the final year of the study, the odds of a confirmed herd restriction in the removal (as compared to the reference areas) were 0.25 in Cork, 0.04 in Donegal, 0.26 in Kilkenny and 0.43 in Monaghan. Further, the hazard ratios (removal over reference) ranged from 0.4 to 0.04 (a 60–96% decrease in the rate at which herds were becoming the subject of a confirmed restriction).     

Penile haemangiosarcoma in a breeding stallion

A 9‐year‐old Arab stallion was presented for haematuria and a haemorrhagic mass on the urethral process of the penis. Clinical examination and surgical excision suggested a tumour of the penis, histologically confirmed as a haemangiosarcoma. The stallion was successfully treated with surgical excision; however, successful breeding has not been achieved thus far (28 months). To the authors' knowledge, haemangiosarcoma of the equine penis has not previously been described.     

Echocardiographic results and clinical considerations in dogs with right atrial/auricular masses

The case records of 26 dogs with pericardial effusion were examined. Sixteen dogs with confirmed right atrial/auricular masses were found. Eighteen masses were identified, of which 16 were confirmed as hemangiosarcomas. Eleven dogs had an abnormal mass detected during the echocardiographic examination, and tumor location was correctly predicted in nine of the 11 dogs. Six of seven tumors, which were not detected during the echocardiogram, were located in the right auricle. Pericardial effusion was apparently not necessary for the echocardiographic detection of a right atrial/auricular mass. Of ten dogs with pericardial effusion due to causes other than a cardiac mass, one abnormal mass-like lesion was seen during echocardiographic examination.     

Retrobulbar rhabdomyosarcoma in a neotropical peregrine falcon (Falco peregrinus cassini)

A mild swelling of the left periorbital was detected on a routine physical exam of a healthy captive adult peregrine falcon. Despite treatment, the swelling did not subside and within twenty‐five days was causing significant exophthalmia and medial deviation of the left globe. A retrobulbar fusiform cell sarcoma was diagnosed with histopathology, then light microscopy and immunohistochemical staining confirmed the diagnosis of a rhabdomyosarcoma.     

Congestive heart failure in two pet rabbits

This case report describes congestive heart failure with pleural effusion in two middle-aged, pet house rabbits. Both had a history of acute onset dyspnoea, weakness and weight loss. Bi-atrial enlargement was seen on echocardiography in both rabbits. One rabbit had atrial fibrillation and ventricular premature complexes identified on electrocardiography. There was a radiographically evident pleural effusion in both rabbits and thoracocentesis was undertaken in one rabbit. These findings were confirmed on post-mortem examination. The aetiology for the underlying heart disease was not found, but the potential types of cardiomyopathies are discussed.     

CT characteristics of primary splenic torsion in eight dogs

Splenic torsion is a rare potentially life‐threatening condition characterized by rotation of the spleen around the gastrosplenic and phrenosplenic ligaments leading to occlusion of venous drainage and arterial supply. This retrospective study describes the CT characteristics for dogs with surgically confirmed splenic torsion from 2013 to 2018 using the submissions to a large multinational teleradiology database. Eight dogs had the splenic torsion confirmed with surgery. Seven of eight cases had histology confirming congestion, hemorrhage, and necrosis, and one had concurrent myelolipoma infiltration. The CT characteristics included an enlarged (8/8), rounded (7/8), folded C‐shaped spleen (8/8) with a difference of median parenchymal attenuation between pre‐ and postcontrast of +1.15 HU (Hounsfield units). Other common features included a mainly homogeneous parenchyma on pre‐ and post‐contrast images (6/8), lack of subjective and objective vascular and parenchymal contrast enhancement (6/8) and free peritoneal fluid (6/8). A “whirl sign” was seen in the majority of cases (7/8) alongside a strongly hyperattenuating center (95‐416 HU) on the precontrast images (5/7), which has not been previously described in the veterinary literature. Gastric position was normal in all cases. More variable CT characteristics of the confirmed torsions were attributable to suspected partial torsion and myelolipomatous infiltration. Overall, primary splenic torsion confirmed with surgery showed consistent characteristics on CT.     

Detection and confirmation of reptilian adenovirus infection by in situ hybridization.

Adenovirus infections are documented in at least 12 different species of reptiles. In contrast to their mammalian and avian counterparts reptilian adenoviruses are not well characterized as to their pathogenic potential and their ability to cause primary disease. In the diagnostic setting, fresh tissues are often not available for virus isolation, and the confirmation of reptilian adenovirus infections is dependent largely upon electron microscopy for the identification of intranuclear viral inclusions associated with histopathologic changes. The diagnosis of adenovirus infection in 2 different species of snake was confirmed by the application of DNA in situ hybridization. Using an aviadenovirus specific oligoprobe, adenoviral DNA was observed in the nuclei of hepatocytes, Kupffer cells, endothelial cells, and enterocytes. Electron microscopy of the liver confirmed the presence of intranuclear viral particles morphologically consistent with an adenovirus. DNA in situ hybridization on formalin-fixed tissues can serve as a suitable alternative to electron microscopy in the diagnosis of reptilian adenovirus infections. Both affected snakes had other concurrent diseases, suggesting that the adenovirus may not have been the primary pathogen.     

Ulcerative duodenitis with luminal constriction in two horses

Proximal enteritis was diagnosed on the basis of clinical signs of disease in 2 Standard-bred yearlings from the same farm. Large volumes of fluid were repeatedly obtained during gastric decompression. The horses did not respond to treatment with IV administered fluids, antimicrobial agents, cimetidine, and metoclopramide. Postmortem findings confirmed severe focal chronic active duodenitis with stricture formation. An etiologic agent was not identified.