Virulent systemic feline calicivirus infection: a case report and first description in Ireland.

BACKGROUND: Virulent systemic feline calicivirus (VS-FCV) infection is an emerging disease. It is distinct from classic oronasal calicivirus infection as it manifests with unique systemic signs including severe cutaneous ulcerations, limb oedema, and high mortality, even in adequately vaccinated cats. Devastating epizootic outbreaks with hospital-acquired infections have been described in the United States, the United Kingdom, continental Europe and Australia with up to 54 cats affected in one outbreak and a mortality rate of up to 86%. This highly contagious and potentially fatal disease has not yet been reported in Ireland. CASE PRESENTATION: An 11-month-old male neutered vaccinated domestic shorthair cat was presented with a 10-day history of lethargy, decreased appetite and progressively worsening pitting oedema in all four limbs. The signs were first noted after another kitten from a high-density cat shelter was introduced in to the household. Additional physical examination findings included marked pyrexia, and lingual and cutaneous ulcers. Virulent systemic feline calicivirus was diagnosed based on compatible history and clinical signs, exclusion of other causes, and calicivirus isolation by RT-PCR both in blood and oropharyngeal samples. Negative calicivirus RT-PCR in blood following resolution of the clinical signs further supported the diagnosis. CONCLUSION: This case represents the first known case of VS-FCV infection in Ireland. Given the severity of the clinical signs, and the high risk for epizootic outbreaks, Irish veterinarians should be aware of the disease to ensure prompt diagnosis and implementation of adequate preventive measures, in order to limit the threat that this disease represents for the wider cat population and particularly given the risk of hospital-acquired VS-FCV infection. Virulent systemic calicivirus should be suspected in cats with pyrexia of unknown origin, oedema or ulceration affecting the limbs or the face, and exposure to rescue cats from high-density households.

Obesity and obesity-associated metabolic disease conditions in Connemara ponies in Ireland.

BACKGROUND: Equine obesity combined with insulin dysregulation (ID) is a major risk factor associated with laminitis. Some pony breeds appear to be at increased risk. However, little is known regarding the prevalence of obesity or hyperinsulinaemia as evidence of ID in Irish ponies. OBJECTIVE: To investigate the prevalence of obesity and associated endocrine/metabolic disease conditions in Connemara ponies and to determine if hyperinsulinaemia in these ponies could be predicted by morphometric or metabolic markers. STUDY DESIGN: Cross-sectional study. METHODS: The study population included registered Connemara ponies recruited through public and veterinary social media posts. Ponies underwent a physical examination and information on their management and clinical history was obtained via owner questionnaire. The body condition score (BCS) was measured using the Henneke system; cresty neck score (CNS) and regionalised adiposity were also assessed. Hyperinsulinaemia was confirmed by measuring serum basal insulin concentration (BIC) or insulin concentration after an oral sugar test (OST). Blood glucose and triglyceride concentrations were measured. Characteristics of hyperinsulinaemic and insulin-sensitive ponies were compared by logistic regression. RESULTS: Two hundred ponies were included; 59 ponies (29.5%) had a BCS ≥7, 58 (29.0%) had a CNS ≥2.5 and 135 (67.5%) had regionalised adiposity; 137 (68.5%) ponies had at least one of these abnormalities. Owner-reported history or clinical evidence of chronic laminitis was found in 92 ponies (46.0%). Hyperinsulinaemia was confirmed in 32 ponies (16.0%), including 23 of 91 (25.3%) detected by OST and 9 of 109 (8.3%) by BIC. Hypertriglyceridaemia was observed in 12 of 198 ponies (6.1%) ponies and hyperglycaemia in 11 of 197 ponies (5.6%) ponies. The odds of hyperinsulinaemia increased by a factor of 6.53 (95% confidence interval: 2.95, 15.21) when BCS was ≥7. MAIN LIMITATIONS: The OST was not performed in all ponies. CONCLUSIONS: Increased adiposity, laminitis and metabolic derangements are prevalent in this native Irish pony breed.

Intrathoracic eosinophilic sclerosing fibroplasia with intralesional bacteria in a cat.

Case summary: A 9-year-old neutered female domestic shorthair cat was presented for investigation of a cranial mediastinal mass. Moderate peripheral eosinophilia and mild-to-moderate polyclonal gammopathy were identified. A thoracoabdominal CT scan documented a cranial mediastinal mass encircling the trachea. Ultrasound-guided fine-needle aspiration and core-needle biopsy were performed, but cytology and histopathology were inconclusive. Surgical debulking was performed. Further histological samples identified severe pyogranulomatous and eosinophilic fibrosing mediastinitis, consistent with feline eosinophilic sclerosing fibroplasia. Gram staining and fluorescence in situ hybridisation (FISH) identified numerous Gram-positive coccoid bacteria. Eosinophilia and hyperglobulinaemia resolved after surgery and combined antimicrobial and immunosuppressive therapy. The cat died 3 months later after developing acute haemorrhagic diarrhoea and dyspnoea. Relevance and novel information: Eosinophilic sclerosing fibroplasia is reportedly mainly confined to the gastrointestinal tract in cats. Less commonly, extragastrointestinal cases have been described. Lesions in the mediastinal or sternal lymph nodes have been reported, all in association with evident gastrointestinal involvement. The presence of pleural effusion was variable in these cases. To the authors' knowledge, this is the first report of eosinophilic sclerosing fibroplasia presenting due to lower respiratory signs in a cat. Intralesional bacteria were identified using Gram staining and FISH examination. The presence of intralesional bacteria in the normally sterile mediastinal tissue may support the involvement of penetrating injuries in the pathogenesis of the disease. Eosinophilic sclerosing fibroplasia should be suspected in any cat with abdominal and/or thoracic masses, particularly if associated with peripheral eosinophilia and polyclonal gammopathy.

The comparative performance of a custom Canine NanoString® panel on FFPE and snap frozen liver biopsies.

Formalin-Fixed Paraffin Embedded (FFPE) biopsies would provide a critical mass of cases to allow investigation of canine liver disease, however their use is often limited by challenges typically associated with transcriptomic analysis. This study evaluates the capability of NanoString® to measure the expression of a broad panel of genes in FFPE liver samples. RNA was isolated from matched histopathologically normal liver samples using FFPE (n = 6) and snap frozen in liquid nitrogen (n = 6) and measured using a custom NanoString® panel. Out of the 40 targets on the panel, 27 and 23 targets were above threshold for non-diseased snap frozen and FFPE tissue respectively. The binding density and total counts were significantly reduced in the FFPE samples relative to the snap frozen samples (p = 0.005, p = 0.01, respectively), confirming a reduction in sensitivity. The concordance between the snap frozen and FFPE samples was high, with correlations (R) ranging between 0.88 and 0.99 between the paired samples. An additional 14 immune-related targets, undetectable the non-diseased FFPE liver, were above threshold when the technique was applied to a series of diseased samples, further supporting their inclusion on this panel. This use of NanoString® based analysis opens up huge opportunity for retrospective evaluation of gene signatures in larger caseloads through harnessing the capacity of archived FFPE samples This information used alongside clinical and histological data will not only afford a way to explore disease etiopathogenesis, it may also offer insight into sub-types of liver disease in dogs, which cannot be discerned using more traditional diagnostic methods.

Diagnosis of canine spontaneous hypoadrenocorticism.

Hypoadrenocorticism is characterized by a reduction in mineralocorticoid and/or glucocorticoid production by the adrenal glands. Several subtypes have been described with different clinical and clinicopathological consequences. Most affected dogs have vague and non-specific signs that precede an eventual life-threatening crisis. This review aims to appraise classification, the available data on epidemiology and the clinical and laboratory features of naturally occurring canine hypoadrenocorticism.

Canine hypoadrenocorticism is a relatively uncommon endocrine disease that can present with a wide variety of clinical signs resulting from cortisol or aldosterone deficiency or both. Hypoadrenocorticism should be considered in all dogs with severe illness and typical electrolyte abnormalities but also in those with waxing and waning clinical signs. Multiple clinical and laboratory features are suggestive of the disease and should prompt evaluation of adrenal function. The ACTH stimulation test is the best test for diagnosing hypoadrenocorticism but, in those cases without the typical presentation, evaluation of aldosterone secretory capacity and endogenous ACTH concentrations should be performed to distinguish primary from secondary disease. In this review we discuss the pathophysiology of the disease, the clinical signs and laboratory features that should raise suspicion of hypoadrenocorticism and the performance of the different diagnostic tests.

Free thyroxine measurement by analogue immunoassay and equilibrium dialysis in dogs with non-thyroidal illness.

OBJECTIVES: Measurement of free T4 by analogue immunoassay (fT4a) is popular but its ability to differentiate hypothyroidism from non-thyroidal illness (NTI) is unclear. The aims were to assess fT4a concentrations in dogs with NTI and to explore diagnostic agreement with total T4 and free T4 measured by equilibrium dialysis (fT4d). METHODS: fT4a was measured in dogs classified with mild, moderate and severe NTI. Total T4 and fT4d were measured in a subgroup of these dogs. RESULTS: 146 dogs were included of which 84, 35 and 27 had mild, moderate and severe NTI, respectively. Median (range) fT4a concentrations (pmol/L) were significantly lower (P = 0.023 and P < 0.001) in dogs with severe (3.86 (3.86-23.60)) compared with moderate (11.10 (3.86-34.70)) and mild (15.25 (3.86-48.60)) NTI. Overall, 49 (33.6% [95% CI, 26.4-41.6]) dogs had low fT4a concentration. All thyroid hormones were measured in 74 dogs. Agreement was substantial between total T4 and fT4a (κ=0.79 [95% CI, 0.65-0.92]) and fT4a and fT4d (κ =0.63 [95% CI, 0.47-0.79]) but moderate between total T4 and fT4d (κ=0.49 [95% CI, 0.32-0.66]). Of 42 dogs with low total T4 concentration, five (11.9% [95% CI, 5.19-24.99]) and 18 (42.9% [95% CI, 29.12-57.80]) had fT4a and fT4d within reference interval, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: fT4a and fT4d cannot be used interchangeably. Measurement of fT4a provides limited further diagnostic information over measurement of total T4 in dogs with NTI. This study raises concerns regarding the ability of fT4a to differentiate NTI from hypothyroidism in dogs with low total T4 concentrations.

Insulins for the long term management of diabetes mellitus in dogs: a review.

The year 2021 marked the centenary of the isolation of a therapeutic form of insulin and its successful use in dogs. This was a landmark moment that subsequently and rapidly led to the commercial manufacture of insulin for use in humans. The impact of insulin was almost miraculous as those destined to die from their diabetes mellitus returned to life. Over the past 100 years, insulin formulations have been modified to attempt to provide a predictable and prolonged duration of action while avoiding the development of hypoglycaemia. This has led to an ever-growing variety of insulin types in human medicine, many of which have subsequently been used in dogs. The purpose of this review article is to provide an overview of available insulin types and their application to the chronic management of canine diabetes mellitus.

A Preliminary Study of the Effect of Hyperadrenocorticism on Calcium and Phosphate Concentrations, Parathyroid Hormone and Markers of Bone Turnover in Dogs.

Reports on the effects of hyperadrenocorticism (HAC) on bone turnover in dogs are largely confined to radiographic studies. The aim of this study was to more accurately assess bone turnover in dogs with HAC by measuring circulating total and ionized calcium and phosphate concentrations, both intact and whole parathyroid hormone (PTH) concentrations and markers of both osteoblastic (osteocalcin) and osteoclastic [carboxyterminal cross-linked telopeptide of type 1 collagen (ICTP) and urine aminoterminal telopeptide of type 1 collagen (NTX) activity]. Dogs with HAC and a control group were prospectively enrolled for comparison. Results from 49 dogs with HAC were compared with 39 dogs from a hospital control population. Plasma intact and whole PTH concentrations were determined using a human immunoradiometric assay. Serum osteocalcin and NTX concentrations were measured using human enzyme linked immunosorbent assays. Serum ICTP concentration was measured using a human radioimmunoassay. Total calcium concentrations in dogs with HAC (2.67 ± 0.25 mmol/L) were not significantly different than in the control group (2.67 ± 0.14 mmol/L). By contrast, phosphate concentrations were significantly (P = 0.0143) higher in dogs with HAC (1.46 ± 0.30 mmol/L) compared to the control group (1.28 ± 0.33 mmol/L). The median intact PTH concentration in HAC dogs was 9.25 (range, 1.34-95.45) pmol/L, which was significantly (P < 0.0001) higher than in the control group [median, 3.88 (range, 2.01-10.31) pmol/L]. Whole PTH concentrations were also significantly (P < 0.0001) higher in the HAC group [median, 4.61 (range, 0.56-125.16) pmol/L] compared to the control group [median, 1.83 (range, 0.88-6.81) pmol/L]. Serum osteocalcin and urine NTX concentrations were not significantly different between the two groups of dogs. The median ICTP concentration in dogs with HAC was 2.98 (range, 1.15-6.62) ng/mL which was significantly (P < 0.0001) lower than in the control dogs [median, 7.30 (range, 3.68-21.25) ng/mL]. Both whole and intact PTH concentrations are increased in dogs with HAC compared to a hospital control population. This does not however appear to be associated with a decrease in bone formation (as assessed by osteocalcin) or an increase in bone resorption (as assessed by ICTP and urine NTX).

Pan-European Study on the Prevalence of the Feline Leukaemia Virus Infection - Reported by the European Advisory Board on Cat Diseases (ABCD Europe).

Feline leukaemia virus (FeLV) is a retrovirus associated with fatal disease in progressively infected cats. While testing/removal and vaccination led to a decreased prevalence of FeLV, recently, this decrease has reportedly stagnated in some countries. This study aimed to prospectively determine the prevalence of FeLV viraemia in cats taken to veterinary facilities in 32 European countries. FeLV viral RNA was semiquantitatively detected in saliva, using RT-qPCR as a measure of viraemia. Risk and protective factors were assessed using an online questionnaire to report geographic, demographic, husbandry, FeLV vaccination, and clinical data. The overall prevalence of FeLV viraemia in cats visiting a veterinary facility, of which 10.4% were shelter and rescue cats, was 2.3% (141/6005; 95% CI: 2.0%-2.8%) with the highest prevalences in Portugal, Hungary, and Italy/Malta (5.7%-8.8%). Using multivariate analysis, seven risk factors (Southern Europe, male intact, 1-6 years of age, indoor and outdoor or outdoor-only living, living in a group of ≥5 cats, illness), and three protective factors (Northern Europe, Western Europe, pedigree cats) were identified. Using classification and regression tree (CART) analysis, the origin of cats in Europe, pedigree, and access to outdoors were important predictors of FeLV status. FeLV-infected sick cats shed more viral RNA than FeLV-infected healthy cats, and they suffered more frequently from anaemia, anorexia, and gingivitis/stomatitis than uninfected sick cats. Most cats had never been FeLV-vaccinated; vaccination rates were indirectly associated with the gross domestic product (GDP) per capita. In conclusion, we identified countries where FeLV was undetectable, demonstrating that the infection can be eradicated and highlighting those regions where awareness and prevention should be increased.

Canine cutaneous and renal glomerular vasculopathy in the Republic of Ireland: a description of three cases.

BACKGROUND: Cutaneous and renal glomerular vasculopathy (CRGV) is a condition of unknown aetiology involving microvascular thrombosis. It has recently been described in over 160 dogs in the United Kingdom and usually has a grave prognosis. To date, this condition has not been described in dogs residing in the Republic of Ireland. CASE PRESENTATION: Three dogs presented to University College Dublin Veterinary Hospital (UCDVH) for investigation of rapidly progressive skin lesions. All dogs were diagnosed with CRGV on post-mortem examination. All three dogs had azotaemia on presentation or rapidly developed azotaemia, and all were euthanased because of progression of clinical signs and likelihood of CRGV. One dog was affected by seizure-like episodes and had thrombotic microangiopathy evident within the cerebrum. CONCLUSIONS: CRGV occurs in dogs residing in the Republic of Ireland and is a differential for cases presenting with skin lesions and azotaemia. The histopathological lesions of CRGV can also affect the brain leading to neurological signs such as seizures. Owners and veterinarians should be aware that this condition can occur in dogs in Ireland.

Diagnosis of spontaneous hyperadrenocorticism in dogs. Part 2: Adrenal function testing and differentiating tests.

Hyperadrenocorticism is a relatively common endocrine disorder in dogs that has been extensively described. However, its diagnosis remains challenging because there is no true reference standard test, and a myriad factors can affect the diagnostic performance of the commonly used adrenal function tests. Ultimately, the diagnosis is based on a combination of signalment, history and clinical findings, and a variety of diagnostic test results. The second part of this review aims to appraise available data on diagnostic performance of adrenal function tests in naturally occurring canine hyperadrenocorticism.

Diagnosis of spontaneous hyperadrenocorticism in dogs. Part 1: Pathophysiology, aetiology, clinical and clinicopathological features.

Hyperadrenocorticism is a relatively common endocrine disorder in dogs. It occurs as a result of a functional pituitary or adrenal tumour, although other causes have been rarely reported. Canine hyperadrenocorticism has been extensively described but diagnosing this disease remains challenging. Few studies have investigated the clinical and clinicopathological features helpful in differentiating dogs with hyperadrenocorticism from dogs in which the disease is suspected but eventually excluded. Ultimately the diagnosis is based on a combination of multiple pieces of information emanating from the signalment, history, clinical findings, and a variety of diagnostic tests. The first part of this review aims to critically appraise the available data on epidemiology, clinical and laboratory features of naturally occurring canine hyperadrenocorticism.

Evaluation of red blood cell distribution width in dogs with various illnesses.

In humans, increased red blood cell distribution width (RDW) values are associated with higher morbidity and mortality in a variety of pathological processes. The main objective of this study was to evaluate RDW in dogs with a diverse range of pathologies. Clinical data from 276 dogs were retrospectively evaluated. Significantly higher RDW values were found in dogs with primary immune-mediated hemolytic anemia (P < 0.0001), immune-mediated thrombocytopenia (P < 0.0004), hyperadrenocorticism (P < 0.0001), hypothyroidism (P = 0.0220), hepatic vascular anomaly (P < 0.0001), pneumonia (P < 0.0001), chronic kidney disease (P = 0.0005), multi-centric lymphoma (P = 0.0002), and myxomatous mitral valve degeneration (P = 0.0032). However, there was extensive overlap with the values from healthy dogs, limiting the diagnostic value of RDW in this setting. Although RDW may have a role as a potential prognostic indicator, further studies would be necessary to address this.

Évaluation de l'indice de distribution des globules rouges chez des chiens avec différentes maladies. Chez les humains, une augmentation des valeurs de l'indice de distribution des globules rouges (RDW) est associée avec une plus grande morbidité et mortalité dans une variété de processus pathologiques. L'objectif principal de la présente étude était d'évaluer la RDW chez des chiens avec une variété de pathologies. Les données cliniques de 276 chiens ont été rétrospectivement évaluées. Des valeurs significativement plus élevées de RDW ont été trouvées chez des chiens avec une anémie hémolytique primaire à médiation immunitaire (P < 0,0001), une thrombocytopénie à médiation immunitaire (P < 0,0004), de l'hyperadrénocorticisme (P < 0,0001), de l'hypothyroïdisme (P < 0,0220), une anomalie vasculaire hépatique (P < 0,0001), une pneumonie (P < 0,0001), une maladie rénale chronique (P = 0,0005), un lymphome multicentrique (P = 0,0002), et une dégénérescence myxomateuse de la valvule mitrale (P = 0,0032). Toutefois, il y avait un chevauchement important avec les valeurs provenant de chiens en santé, limitant ainsi la valeur diagnostique de RDW dans ce contexte. Bien que le RDW peut avoir un rôle d'indicateur potentiel de pronostic, des études supplémentaires seraient nécessaires pour y répondre.(Traduit par Dr Serge Messier).

Non-functional thyroid cystadenoma in three boxer dogs.

BACKGROUND: Thyroid neoplasia is a common endocrine neoplasm in dogs. The boxer is one of the reported breeds predisposed to malignant thyroid neoplasia. However, the association between thyroid neoplasia, malignancy and breed should be considered with caution. CASES PRESENTATION: This article describes the presentation, clinical pathological findings, computed tomographic (CT) imaging findings and histopathological features of benign cystic thyroid tumour (cystadenoma) diagnosed in three boxers. These three dogs were presented for investigation of unilateral (n = 2) or bilateral (n = 1) cervical masses with no associated clinical signs of thyroid dysfunction. In each case, post-contrast CT scan identified a large, lateralised, non-invasive, well-defined homogeneous cystic structure with a hyperattenuating contrast-enhancing capsule of suspected thyroid origin displacing the surrounding cervical tissues. Ultrasound-guided fine needle aspiration of the cysts yielded fluid with a high thyroxine concentration in each case. Histopathology was consistent with thyroid cystadenoma in all cases. One dog was concurrently diagnosed with oral melanoma and euthanased. Two dogs underwent surgical excision with one lost to follow-up after 36 months and the other euthanased after 16 months following diagnosis of mast cell tumour. CONCLUSIONS: To the authors' knowledge, this is the first detailed report of non-functional benign thyroid cystadenoma in dogs and provides relevant information about case management for this type of tumour. The presence of a large cystic structure associated with benign non-functional thyroid neoplasia may be a condition to which boxer dogs are predisposed.

Radiotherapy and pasireotide treatment of a growth hormone producing pituitary tumor in a diabetic dog.

An 8-year-old castrated male border terrier dog was diagnosed with acromegaly resulting from a growth hormone secreting pituitary tumor. Sixteen daily fractions of radiation therapy were delivered followed, approximately 1 year later, by administration of pasireotide. The aforementioned treatment was considered effective and should be further evaluated in similar cases.

Radiothérapie et traitement au pasiréotide pour une tumeur pituitaire produisant une hormone de croissance chez un chien diabétique. Un chien Terrier-Border castré âgé de 8 ans a été diagnostiqué avec de l'acromégalie découlant d'une tumeur pituitaire secrétant une hormone de croissance. Seize fractions quotidiennes de radiothérapie ont été administrées et ont été suivies, environ un an plus tard, de l'administration du pasiréotide. Le traitement précédemment mentionné a été considéré efficace et devrait être étudié de plus près dans des cas similaires.(Traduit par Isabelle Vallières).

Evaluation of individual low-dose dexamethasone suppression test patterns in naturally occurring hyperadrenocorticism in dogs.

BACKGROUND: Dogs with hyperadrenocorticism (HAC) may be more mildly affected at the time of diagnosis today, which could influence the prevalence of associated clinical and clinicopathological abnormalities and diagnostic test performance. Different low-dose dexamethasone suppression test (LDDST) result patterns have not been evaluated individually. OBJECTIVES: To assess the current features of HAC and evaluate if the diagnostic test performance of individual LDDST result patterns differ. ANIMALS: One hundred and twenty-three dogs undergoing investigation for HAC. METHODS: Retrospective evaluation of dogs in which a LDDST was performed and HAC confirmed or excluded by alternative means. Cases with basal cortisol concentrations (t0 ) < 1 µg/dL were excluded. Each LDDST result was classified as (a) complete suppression (t3 and t8 < 1 µg/dL), (b) lack of suppression (t3 and t8 > 1 µg/dL and both > 50% t0 ), (c) partial suppression (t3 and t8 > 1 µg/dL but either < 50% t0 ), (d) escape (t8 > 1 µg/dL and t3 < 1 µg/dL) or (e) inverse (t3 > 1 µg/dL and t8 < 1 µg/dL) pattern. RESULTS: Fifty-nine (48%) dogs were diagnosed with HAC and 64 (52%) with non-adrenal illness. Hyperadrenocorticism cases had similar clinicopathological abnormalities compared to previous reports. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) (95% confidence interval [CI]) of the LDDST for diagnosing HAC were 96.6 (91.9-100)%, 67.2 (55.7-78.7)%, 73.1 (63.2-82.9)%, and 95.6 (89.5-100)%, respectively. Lack of suppression pattern had the highest PPV (93.9 [85.8-100]%) followed by the partial suppression pattern (67.9 [50.6-85.2]%) and escape or inverse pattern (36.8 [15.1-58.5]%). CONCLUSIONS AND CLINICAL IMPORTANCE: A lack of suppression LDDST pattern has the highest PPV for diagnosing HAC followed by a partial suppression pattern. By contrast, the escape or inverse pattern provided limited support of HAC.

Prevalence and risk factors for hyperthyroidism in Irish cats from the greater Dublin area.

BACKGROUND: Hyperthyroidism is common in older cats. Prevalence varies geographically, but is anecdotally considered low in Ireland. The aim of this study was to document prevalence of hyperthyroidism in older cats in the greater Dublin area of Ireland and to assess environmental and clinical associations for development and identification of the disease. METHODS: Primary-care veterinary practices were requested to select cats aged 10 years or older where blood sampling was being performed for health screening or clinical investigations. Surplus serum/plasma samples were submitted to University College Dublin Diagnostic Endocrine Laboratory for total thyroxine (T4) measurement. Cats were classified as hyperthyroid, equivocal or euthyroid based on a total T4 concentration (reference interval, 15-60 nmol/L), of >60 nmol/L, 30-60 nmol/L or <30 nmol/L, respectively. Simultaneous free T4 or repeat (after 4-6 weeks) total T4 measurement was recommended in all equivocal cases. Animals receiving treatment for hyperthyroidism were excluded. A questionnaire completed by the client and veterinarian detailing historical and physical information was also required. Associations between categorical variables were analysed by Chi-square or Fisher's exact test and odds ratio (OR) calculated. A P value of <0.05 was considered statistically significant. RESULTS: Samples were submitted from 507 cats including 107 (21.1%) hyperthyroid, 54 (10.6%) equivocal and 346 (68.2%) euthyroid. The presence of goitre (P < 0.0001), tachypnoea (P = 0.0378), tachycardia (P = 0.002), polyphagia (P = 0.0003) and weight loss (P < 0.0001) were significantly associated with hyperthyroidism. Cats with goitre were more likely to be diagnosed as hyperthyroid [OR 2.85, (95% CI 1.75-4.62] compared to those without. However, goitre was only palpated in 40 of 102 (39.2%) hyperthyroid cats. Increasing age was the only significant (P < 0.002) risk factor for development of hyperthyroidism. A relationship between hyperthyroidism and sex, breed, lifestyle, parasite control, vaccination status or feeding habits was not identified. CONCLUSIONS: Hyperthyroidism is not uncommon in Irish cats. Age was the only significant risk factor for its development. The high proportion of hyperthyroid cats without palpable goitre (> 60%) may reflect failure to detect goitre and account for the perceived low prevalence of this condition in Ireland.

Prevalence of and risk factors for feline hyperthyroidism in South Africa.

Objectives Hyperthyroidism is a disorder of older cats that may have a geographical variation in prevalence. Prevalence studies have not yet been performed in South Africa, a geographical area where hyperthyroidism in cats has recently been observed and where, reportedly, the incidence appears to be increasing. The purpose of this study was to determine the prevalence of feline hyperthyroidism in South Africa and to identify any potential risk factors. Further information on the worldwide prevalence and possible causative factors would increase our understanding of the aetiology of this disease and help identify any preventive measures. Methods Serum total thyroxine (tT4) and canine thyroid-stimulating hormone (cTSH) were measured in 302 cats aged 9 years and older that were presented at various veterinary clinics throughout South Africa. In cats with equivocal tT4 and undetectable cTSH values, serum free thyroxine (fT4) was also measured. At the time of blood sampling a questionnaire was completed regarding vaccination history, internal and external parasite control, diet and environment. Results Prevalence of hyperthyroidism (tT4 >50 nmol/l or tT4 between 30 and 50 nmol/l with TSH <0.03 ng/ml and fT4 >50 pmol/l) was 7% (95% confidence interval 4.4-10.4), with no significant difference between healthy (5%) and sick (8%) cats. Cats ⩾12 years of age (odds ratio [OR] 4.3, P = 0.02) and cats eating canned food (OR 2.1, P = 0.1) were more likely to be diagnosed with hyperthyroidism. No significant relationship between vaccinations, parasite control or indoor environment and hyperthyroidism was observed. Hyperthyroid cats were more likely to present with weight loss (OR 3.2, P = 0.01) and with a heart rate ⩾200 beats per min (OR 5, P = 0.01) than cats without the disease. Conclusions and relevance Hyperthyroidism does not appear to be uncommon in the South African cat population. Risk factors for hyperthyroidism, specifically older age and eating canned food, were present in this as in other reported populations.