Epidemiology of struvite uroliths in ferrets: 272 cases (1981-2007)

Urine Output Monitoring and Acute Kidney Injury in Non-mammalian Exotic Animal Critical Care

Acute kidney injury (AKI) is a sudden, severe decrease in kidney function which can occur in any species. There are various causes of AKI, some of which are seen in domestic species and some that are unique to birds, reptiles, and amphibians. These species present unique challenges with AKI management, such as differences in anatomy and physiology, intravenous and urinary catheterization, repeated blood sampling, and their tendency to present in advanced states of illness. This article will discuss AKI, diagnosis, treatment, and prognosis for non-mammalian exotic species.

Urine Output Monitoring and Acute Kidney Injury in Mammalian Exotic Animal Critical Care

Acute kidney injury (AKI) is a sudden, severe decrease in kidney function which can occur in any species. There are various causes of AKI, some of which are seen in domestic species and some that are unique to exotics. Exotic animals present unique challenges with AKI management such as differences in anatomy and physiology, intravenous and urinary catheterization, repeated blood sampling, and their tendency to present in advanced states of illness. This article will discuss AKI, diagnosis, treatment, and prognosis for exotic companion mammals. The following article will discuss the same in non-mammalian patients.

Variation in mineral types of uroliths from ferrets (Mustela putorius furo) submitted for analysis in North America, Europe, or Asia over an 8-year period

OBJECTIVE

To compare mineral types of naturally occurring uroliths in ferrets (Mustela putorius furo) from North America, Europe, and Asia and to identify potential risk factors associated with cystine urolithiasis in ferrets.

SAMPLES

1,054 laboratory submission records of uroliths obtained from ferrets between January 1, 2010, and December 31, 2018.

PROCEDURES

For this cross-sectional study, the medical records databases at 4 diagnostic laboratories were searched for records of submissions of uroliths obtained from ferrets. Data collection included submission date; ferret sex, neuter status, and age; receiving laboratory and continent; and urolith mineral type. Regression analyses were performed to identify variables associated with cystine uroliths.

RESULTS

Of the 1,054 urolith submissions, 1,013 were from North America, with 92.6% (938/1,013; 95% CI, 90.8% to 94.1%) cystine uroliths, and 41 were from Europe and Asia, with only 26.8% (11/41; 95% CI, 15.7% to 41.9%) cystine uroliths. Median age was 2.0 years for ferrets with cystine urolithiasis versus 4.0 years for those with other types of uroliths. Submissions were more likely cystine uroliths for ferrets in North America versus Europe and Asia (adjusted OR [aOR], 59.5; 95% CI, 21.4 to 165.6), for ferrets that were younger (aOR, 0.67; 95% CI, 0.58 to 0.77), or for submissions in 2018 versus 2010 (aOR, 21.1; 95% CI, 5.1 to 87.9).

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that the proportion of submissions that were cystine uroliths dramatically increased in North America between 2010 and 2018. There is an urgent need to determine underlying causes and mitigate cystine urolithiasis in ferrets.

Animal models of naturally occurring stone disease

The prevalence of urolithiasis in humans is increasing worldwide; however, non-surgical treatment and prevention options remain limited despite decades of investigation. Most existing laboratory animal models for urolithiasis rely on highly artificial methods of stone induction and, as a result, might not be fully applicable to the study of natural stone initiation and growth. Animal models that naturally and spontaneously form uroliths are an underused resource in the study of human stone disease and offer many potential opportunities for improving insight into stone pathogenesis. These models include domestic dogs and cats, as well as a variety of other captive and wild species, such as otters, dolphins and ferrets, that form calcium oxalate, struvite, uric acid, cystine and other stone types. Improved collaboration between urologists, basic scientists and veterinarians is warranted to further our understanding of how stones form and to consider possible new preventive and therapeutic treatment options.

Familial disease history and fur color type are associated with urinary tract disease in farmed mink (Neovison vison)

Mink urinary tract disease (MUTD) and mink fatty liver disease (MFLD) constitute two important disease entities in the mink production associated with sudden mortality and economic loss. Genetic factors or heritability of the diseases have not previously been investigated. Since mortality associated with MUTD and MFLD mainly occurs in the young immature mink, a potential genetic predisposition would rarely be passed on by the mink itself but potentially by relatives. This study aimed to investigate familial aggregation of MUTD and MFLD based on data from four generations of mink on a research farm. The study included a total of 27,511 mink of brown and black color type with a post mortem prevalence of 0.8% for MUTD (n = 221) and 0.5% for MFLD (n = 138) within a year from birth. The prevalence in the color types brown and black were 0.6% and 1.6% for MUTD and 0.5% and 0.7% for MFLD. Family history of MUTD in breeding animals was found to be associated with a significantly higher probability of MUTD leading to mortality in offspring (p = 0.012, RR = 1.7; CI [1.1-2.4]), however this association was not significant for MFLD (p = 0.163, RR = 1.5; CI [0.9-2.7]). Mink of the color type black showed significantly higher risk of MUTD (RR = 2.6; CI [2.0-3.3]) and MFLD (R = 1.6; CI [1.1-2.2]) compared to brown mink. The results indicate that genetic factors may play a role in understanding MUTD and that selective breeding may contribute to reduce mortalities associated with this disease.

Cystine Urolithiasis in Ferrets

Urolithiasis in captive domestic ferrets has previously been predominantly struvite uroliths, although more recent laboratory submissions show a shift to predominantly cystine uroliths. Genetic mutations for cystinuria have been identified in dogs, and it is suspected that underlying genetic mutations are partly responsible for this disease in ferrets. Currently, surgery remains the only definitive treatment of cystine urolithiasis in ferrets, since dietary dissolution protocols have not been thoroughly explored. Despite this, medical management with dietary and urinary manipulation should be considered for use in ferrets postoperatively based on principles of cystine urolithiasis management in dogs adapted for ferrets.

Urolithiasis and cystitis associated with Staphylococcus delphini group A and mortality in post-weaning mink kits (Neovison vison)

Mortality of mink kits represents a significant loss to production. However, causes of post-weaning mortality in mink kits in modern Danish mink production systems are still relatively poorly documented. We performed a cross-sectional mortality study on eight Danish mink farms including 1893 post mortem examinations of mink kits found dead or euthanized. We assessed the prevalence of cystitis and urolithiasis leading to mortality. Gross pathological findings as well as animal characteristics were recorded and associations with post mortem microbiology (using culture and MaldiTof-MS Vitek MS system) were investigated. Cystitis and/or urolithiasis were associated with death in 33 % (n = 476) and 37 % (n = 166) of the examined mink kits in 2015 and 2017. On farm level, the prevalence of cystitis and/or urolithiasis leading to mortality varied from 0.25 % to 1.27 % with a low overall mortality of 0.9-4.5 %. The bacterial agent most frequently isolated in post mortem bladder swabs from mink with a post mortem diagnosis of urolithiasis and cystitis was Staphylococcus delphini group A (51/283) with a significant (p < 0.0001, CI = [19.5;4745.7]) association to gross pathological findings in the urinary tract. Staphylococcus delphini group A was cultured from 70 % of the skin swabs obtained from apparently healthy mink euthanized at pelting (n = 222). In conclusion urinary tract disease (cystitis and urolithiasis) was the most prevalent post mortem diagnosis during the growth period and was associated with Staphylococcus delphini group A.

Diagnostic Imaging of the Renal System in Exotic Companion Mammals

Radiographs can be used to easily visualize common types of urinary calculi in all parts of the urinary tract. Positive-contrast excretory urography and cystourethrography are sensitive to diseases within the ureters and urethra, most commonly obstruction. Ultrasound is widely available and noninvasive and can be used to evaluate renal architecture, ureteral dilation, urinary bladder wall disease, and urolithiasis. Computed tomography is increasing in availability and provides a large amount of cross-sectional information quickly and noninvasively. Multiple imaging modalities can be used to estimate or quantify glomerular filtration rate.

Disease Overview of the Urinary Tract in Exotic Companion Mammals and Tips on Clinical Management

Diseases of the urinary tract are reviewed, covering infectious (bacterial, viral, parasitic), degenerative, congenital, metabolic, nutritional, neoplastic, obstructive, and toxic causes. Some clinical presentations and diagnostic procedures are described for ferrets, rabbits, guinea pigs, hamsters, mice, rats, chinchillas, hedgehogs, and sugar gliders, as well as therapies.

Disorders of the Urinary and Reproductive Systems in Ferrets

Urogenital lesions are relatively common in ferrets. Renal disease is diagnosed as in traditional small animal medicine; however, peculiarities in ferrets include physiologically low levels of creatinine. Renal cysts are very common in ferrets but are usually incidental findings. Uroliths are usually composed of struvite or cystine. Urethral obstruction in male ferrets is predominantly caused by adrenal-associated prostatic disease. Spontaneous cystitis is rare in ferrets. Primary reproductive disease is uncommon in ferrets in the United States where animals are usually neutered at 6 weeks of age. In other countries, ferrets either remain unneutered or are neutered at 5 to 6 months of age. Ferrets are seasonal breeders, and female are induced ovulators. Prolonged estrus and hyperestrogenism often causes profound bone marrow suppression.

Risk factors for calcium carbonate urolithiasis in goats

OBJECTIVE

To identify demographic or signalment factors associated with calcium carbonate urolith formation in goats.

DESIGN

Retrospective case series and case-control study.

ANIMALS

354 goats with calcium carbonate uroliths (case animals) and 16,366 goats without urinary tract disease (control animals).

PROCEDURES

Medical records of the Minnesota Urolith Center were reviewed to identify case goats for which samples were submitted between January 1, 1984, and December 31, 2012. Control goats evaluated at US veterinary teaching hospitals in the same time period were identified by searching Veterinary Medical Database records. Age, breed, sex, reproductive status, geographic location, season, and anatomic location of collected uroliths were analyzed to identify risk or protective factors associated with calcium carbonate urolithiasis.

RESULTS

Nigerian dwarf goats had higher odds of developing calcium carbonate uroliths than did Pygmy goats (reference group). Several breeds had lower odds of this finding, compared with Pygmy goats; odds were lowest for mixed, Anglo-Nubian, and Toggenburg breeds. Breeds of African origin (Pygmy, Nigerian Dwarf, and Boer) comprised 146 of 275 (53%) case goats with data available. Goats of African descent had a higher risk of developing calcium carbonate uroliths than did goats of non-African descent (reference group). Males and neutered goats had higher odds of calcium carbonate urolithiasis, compared with females and sexually intact goats, respectively. Age category, geographic location, and season were associated with detection of calcium carbonate uroliths.

CONCLUSIONS AND CLINICAL RELEVANCE

Goats with calcium carbonate uroliths were typically neutered males, > 1 year of age, and of African descent. This study identified factors associated with calcium carbonate urolithiasis in goats; however, these associations do not allow conclusions regarding cause-and-effect relationships.