Emergency and critical care of rodents

Gastroenterology in Rodents

Gastrointestinal (GI) diseases are frequently diagnosed in rodents. Clinical signs are usually nonspecific and include anorexia, weight loss, chronic wasting, abdominal discomfort, gas accumulation in the intestine and stomach, and diarrhea. Malabsorption associated with GI dysfunction or gastroenteritis quickly leads to negative energy balance and metabolic acidosis. Therefore, all disorders of the GI tract should be treated as soon as possible. The article describes selected disorders of the GI tract in guinea pigs (Cavia porcellus), chinchillas (Chinchilla lanigera), degus (Octodon degus), and rats (Rattus norvegicus).

Electrocutions in Free-Ranging Platyrrhine Nonhuman Primates: Diagnostic Features for a Threatening Condition

Electrical accidents pose a considerable threat to wildlife in anthropized regions, particularly arboreal mammals, as evidenced by cases of electrocutions in nonhuman primates (NHPs). This study characterized the frequency, anatomic distribution, and pathological features of electrocution injuries in free-ranging NHPs based on data retrieved from necropsy archives at the Veterinary Pathology and Forensics Laboratory, University of Brasilia, Brazil. Gross and microscopic evaluations were conducted to assess the nature and extent of electrothermal injuries, including burns and tissue damage. Between 2019 and 2022, electrocution accounted for 16.5% of NHP deaths, primarily affecting black tufted marmosets. Adult NHPs, regardless of sex, were predominantly affected, mainly in the rainy season. Limbs were the most commonly affected body parts, with double, triple, or multiple injury sites being common. Gross findings mostly included severe burns (Grades III and IV), ulcerative injuries, blisters, bone exposure, singed hair, and muscle exposure. Microscopic examinations unveiled epidermal necrosis, smudging of collagen fibers, stretched epidermal nuclei, blisters (epidermal honeycomb aspect), muscle necrosis, skin metallization, and hemorrhage and congestion within internal organs. Electrocution has emerged as a substantial cause of death in free-ranging NHPs, particularly in urban and peri-urban areas. The study underscores the need for public policy adjustments to mitigate the risks of electrocution in NHPs and enhance species conservation efforts in human-dominated landscapes.

Cerebro-Cardiopulmonary Resuscitation and Postarrest Care in Exotic Animal Critical Care

Evidence-based recommendations for performing cardiopulmonary resuscitation (CPR) in domestic species provide a foundation for application to nondomestic species. The exotic and zoo practitioner must consider human safety, species anatomy, physiology, and special techniques for performing CPR. Having the hospital and team prepared and trained for a CPR response can improve outcomes. Basic life support includes various techniques for chest compressions and ventilation support. Advanced life support includes means of intravascular and intraosseous access, rescue drug administration, and consideration of the patient presenting circumstances. Team debriefs and support for mental wellness are useful to optimize performance and maintain team resiliency through CPR events.

Lower Urinary Tract Diseases in Guinea Pigs: A 14-Year Retrospective Study (2004-2018)

The clinical records of all guinea pigs diagnosed with a lower urinary tract disease in a single veterinary hospital, over a period of 14 years (2004−2018), were retrospectively searched in order to characterize this population and investigate the potential association between the epidemiological and clinical variables. A total of 117 clinical cases were identified, corresponding to 57 animals. Urolithiasis was the most common diagnosis (n = 52; 44.4%), followed by cystitis and/or a urinary tract infection (UTI). Several statistically significant associations (p < 0.05) were found between different variables, showing that female guinea pigs were more likely than the male ones to have a previous family history of urinary disease, to present dysuria and stranguria at admission, and to suffer recurrence. Moreover, males were more prone to urolithiasis and females to cystitis/UTI, and animals diagnosed with cystitis/UTI frequently had more clinical urinary signs and abdominal pain on palpation compared to those diagnosed with urolithiasis. Finally, the use of potassium citrate and the urethrotomy approach were associated with a better therapeutic response. Further studies are needed in larger populations of guinea pigs to confirm the present findings, especially as some of them were described for the first time.

Demography, disorders and mortality of pet hamsters under primary veterinary care in the United Kingdom in 2016

BACKGROUND

Hamsters are popular pets worldwide but there is limited evidence on the overall health issues of pet hamsters. This study aimed to characterise the demography, disorder prevalence and mortality of pet hamsters in the United Kingdom.

METHOD

The VetCompass study included anonymised clinical records of 16,605 hamsters.

RESULTS

The most common hamster species were Syrian (golden) (Mesocricetus auratus) (n=12,197, 73.45%), Djungarian (winter white dwarf) (Phodopus sungorus) (2286, 13.77%) and Roborovski hamsters (Phodopus roborovskii) (1054, 6.35%). The most prevalent precise-level disorders recorded across all hamsters were a presentation categorised as 'wet tail' (n=293, 7.33%), disorder undiagnosed (292, 7.30%), bite injuries from other hamsters (235, 5.88%), overgrown nail(s) (165, 4.13%), overgrown incisor(s) (159, 3.98%) and traumatic injury (152, 3.80%). The most prevalent disorders groups across all species of hamster were traumatic injury (n=616, 15.41%), enteropathy (450, 11.26%), ophthalmological disorder (445, 11.13%), skin disorder (362, 9.05%) and mass (361, 9.03%). The median age at death across all hamsters was 1.75 years (interquartile range: 0.83 to 2.20, range: 0.01 to 3.65). The most common causes of death at a precise level were wet tail (7.88%, 95% confidence interval: 6.35 to 9.66), abdominal mass (6.40%, 95% confidence interval: 5.01 to 8.03), neoplasia (5.38%, 95% confidence interval: 4.11 to 6.90) and dyspnoea (3.99%, 95% confidence interval: 2.9 to 5.34).

CONCLUSION

This study provides veterinary professionals, educators, welfare scientists and owners with an evidence base on pet hamster health. A greater understanding of the common disorders of pet hamsters can support veterinary professionals to communicate more effectively with owners on key issues and outcomes to expect from hamster ownership.

Intratracheal Inoculation with Brucella melitensis in the Pregnant Guinea Pig Is an Improved Model for Reproductive Pathogenesis and Vaccine Studies

Reproductive failure is the hallmark of brucellosis in animals. An uncommon but important complication in pregnant women who become acutely infected with Brucella melitensis is spontaneous pregnancy loss or vertical transmission to the fetus. Unfortunately, the mechanism behind reproductive failure is still obscure, partially due to the lack of a proper study model. Recently, it was demonstrated that intratracheal (IT) inoculation of nonpregnant guinea pigs would replicate features of clinical disease in humans. To determine if IT inoculation would induce reproductive disease, guinea pigs were infected at mid-gestation and monitored daily for fever and abortions. Fever developed between day 14 to 18 postinoculation, and by 3 weeks postinoculation, 75% of pregnant guinea pigs experienced stillbirths or spontaneous abortions mimicking natural disease. Next, to investigate the guinea pig as a model for evaluating vaccine efficacy during pregnancy, nonpregnant guinea pigs were vaccinated with S19, 16MΔvjbR + Quil-A, or 100 μl PBS + Quil-A (as control). Guinea pigs were bred and vaccinated guinea pigs were challenged at mid-gestation with B. melitensis IT inoculation and monitored for fever and abortions. Vaccination with both vaccines prevented fever and protected against abortion. Together, this study indicates that pregnant guinea pigs are an appropriate animal model to study reproductive disease and offer an improved model to evaluate the ability of vaccine candidates to protect against a serious manifestation of disease.

Confidence of veterinary surgeons in the United Kingdom in treating and diagnosing exotic pet species

BACKGROUND

With exotic pet species commonplace in the UK, owners are increasingly seeking veterinary advice regarding the health and welfare of their small mammals and reptiles. This study aimed to assess the confidence of veterinarians in the UK in treating and diagnosing rabbits, guinea pigs, small mammals and reptiles.

METHODS

A 41-question survey was promoted via social media, including on interest groups focused specifically at veterinary professionals. A total of 131 practising veterinarians in the UK completed the questionnaire.

RESULTS

Frequency of presentation of exotic pets to a practice had a significant effect (P<0.01) on the confidence of veterinarians in treating them. Veterinarians who were presented with exotics more frequently had increased self-reported knowledge of their health and disease and were more confident in treating, diagnosing and anaesthetising them. Knowledge of and confidence in diagnosing and treating exotic pets were significantly less than for dogs and cats (P<0.001). There was a significant effect of length of time qualified on confidence in treating exotic pet species (P<0.01).

CONCLUSIONS

Increased provision and engagement with continuing professional development may increase veterinary confidence in diagnosing, treating and anaesthetising exotic pet species that are less commonly encountered in practice.

Frequency of Owner-Reported Bacterial Infections in Pet Guinea Pigs

Domestic guinea pigs suffer morbidity and mortality due to a range of bacterial infections amongst other causes. Microorganisms such as Bordetella bronchiseptica and Streptococcus pneumoniae are commonly implicated in respiratory disease; however, there is a lack of research surrounding the prevalence of these bacterial infections. The aim of this study was to investigate the frequency with which owners reported bacterial infections in pet guinea pigs and to assess owner knowledge of correct husbandry practices to inform prevention of the development of bacterial infections. An online questionnaire, consisting of 30 questions was promoted to guinea pig owners. Of all respondents (n = 524), 39.39% reported that their guinea pig(s) had been clinically diagnosed with a bacterial infection, with upper respiratory tract infections the most commonly reported (46.95%), followed by urinary tract (15.49%) and then gastrointestinal infections (11.73%). Owners demonstrated knowledge of correct husbandry practices and there was no significant effect (p = 0.475) of owner knowledge on having owned a guinea pig with a bacterial infection. Bacterial infections may be more common in guinea pigs than was previously thought. Further research is required to understand why bacterial infections are common in pet guinea pigs and to help owners to prevent and recognize these infections.

Ambulatory Emergency Medicine

While practicing exotic animal medicine as an ambulatory practitioner, veterinarians need to be prepared for the inevitable emergency call. Emergencies in exotic animal medicine come in all shapes and sizes and the veterinarian must be prepared for a variety of situations. With the proper training, equipment, and managing client expectations, an ambulatory exotics animal practitioner can successfully address emergencies. This article provides a brief overview in managing emergency cases in an ambulatory exotics animal practice.

Effects of subcutaneous alfaxalone alone and in combination with dexmedetomidine and buprenorphine in guinea pigs (Cavia porcellus)

OBJECTIVE

To characterize alfaxalone administered subcutaneously (SC) in guinea pigs, both alone and in combination with dexmedetomidine and buprenorphine.

STUDY DESIGN

Prospective, blinded, crossover study.

ANIMALS

A total of 15 healthy female guinea pigs weighing 400-600 g.

METHODS

Alfaxalone (10, 20 and 40 mg kg^-1) was administered SC to three guinea pigs as a pilot dose-finding study. Alfaxalone (20 mg kg^-1; A₂₀) was selected for comparison against combination protocols of alfaxalone (15 and 20 mg kg^-1) with dexmedetomidine (0.25 mg kg^-1) and buprenorphine (0.05 mg kg^-1; A₁₅DB, A₂₀DB). Each protocol was randomly administered to 12 guinea pigs separated by ≥7 days. Time and quality of induction and recovery, heart rate, respiratory rate, peripheral hemoglobin oxygen saturation, rectal temperature, pedal withdrawal reflex and adverse effects were recorded.

RESULTS

The median time to induction for A₂₀, A₁₅DB and A₂₀DB was 6.8-8.0 minutes with no significant difference between treatments. Mean duration of recumbency for A₂₀ was 73.6 ± 19.6 minutes. Recumbency duration for A₁₅DB and A₂₀DB extended to 90 minutes, at which time dexmedetomidine was antagonized using atipamezole (0.025 mg kg^-1 SC). Physiological variables were within normal limits with the exception of one animal that died 45 minutes following treatment with A₂₀DB. Pedal withdrawal reflex remained intact with all treatments. Minor side effects such as twitching or bruxism occurred sporadically with treatment A₂₀ but not with A₁₅DB and A₂₀DB.

CONCLUSIONS AND CLINICAL RELEVANCE

SC alfaxalone produced uncomplicated sedation that may be recommended for nonpainful procedures that do not require complete immobility. The addition of dexmedetomidine and buprenorphine increased the duration of sedation and immobility, but did not result in general anesthesia. This combination sedation protocol may be useful for nonpainful procedures requiring extended immobility.

Reproductive Medicine in Guinea Pigs, Chinchillas and Degus

Guinea pigs, chinchillas, and degus are hystricomorph rodents originating from South America. They are commonly presented as exotic pets in veterinary practice. Reviewing the anatomy and physiology of their reproductive tract helps to offer better client education about preventive medicine and helps to act faster in emergency situations. Choosing the right anesthetic protocol helps to prevent complications. This article should aid as a guideline on the most common reproductive problems of these 3 species and help in making decisions regarding the best treatment options.

Neurological examination in healthy chinchillas ( Chinchilla lanigera)

Chinchillas are popular as laboratory models and companion animals, and they can be affected by a variety of infectious and non-infectious neurological diseases. Little information is available on making a neurological diagnosis in this species, in part because the neurological examination has not been standardized in chinchillas and the expected physiological findings in healthy chinchillas have not been reported. In this study, a standardized neurological examination was performed on 30 clinically normal chinchillas. The perineal reflex and the menace response were absent in all chinchillas evaluated and so should not be used as functional tests. Several tests were consistently positive, such as the oculocephalic reflex, maxillary, mandibular and auricular sensations, withdrawal reflexes, thoracic limb paw replacement, and the wheelbarrow test. Other tests, such as the cutaneous trunci reflex and pelvic limb paw replacement, had variable responses. Based on these findings, it is advised that clinicians prioritize tests that can be easily performed without undue stress to the animal, and give consistent results in a healthy patient.

Common Emergencies in Small Rodents, Hedgehogs, and Sugar Gliders

Small exotic mammal pets such as rats, mice, hamsters, gerbils, degus, hedgehogs, and sugar gliders are becoming more popular. Because these animals are prone to a variety of health problems, and require specialized husbandry care to remain healthy, they may present to emergency hospitals in critical condition. This article provides a basic overview of common emergency presentations of these species.

An Investigation into the Relationship between Owner Knowledge, Diet, and Dental Disease in Guinea Pigs (Cavia porcellus)

Simple Summary

Dental disease is a serious problem in small mammals, with cases in rabbits well documented. Guinea pigs also suffer from this condition, yet the literature investigating the underlying causes in guinea pigs is limited. Owners of guinea pigs were surveyed to investigate what they fed their animals. It was discovered that there was no relationship between the overall diet of the animals and whether or not they had been diagnosed with dental disease or displayed clinical signs of the disease. However, the environment was important, with animals that had access to the outside, including the use of runs on both concrete and grass, less likely to display clinical signs of disease. Some of the clinical signs of dental disease in guinea pigs, including difficulty eating, were related to dental problems. These findings are important, as many guinea pigs may not have continuous access to the outdoors. Dental disease is a serious welfare concern, as many owners may not pick up on the clinical signs, leaving animals susceptible to pain, dysphagia, malnutrition, and secondary infection. It is important that owners are aware of key clinical signs, particularly in multi-animal households where monitoring food consumption may be challenging.

Abstract

Recent studies have highlighted a high prevalence of dental disease in domestic guinea pigs, yet the aetiology of this multi-factorial disease is still unclear. Factors that have been associated with dental disease include feeding a diet that is high in energy but low in fibre, feeding an insufficiently abrasive diet, a lack of dietary calcium, and genetics. As many of these factors relate to the husbandry requirements of guinea pigs, owner awareness of dietary requirements is of the utmost importance. An online questionnaire was created based on previous research into the husbandry and feeding of rabbits. Guinea pig owners were asked to answer questions on the clinical history of their animals and their diet and management. In total, 150 surveys were completed for 344 guinea pigs, where owners of multiple animals could complete the survey for individuals. According to the owners, 6.7% of guinea pigs had been clinically diagnosed with dental disease, but 16.6% had signs consistent with dental disease. The specific clinical signs of having difficulty eating (Exp(B) = 33.927, Nagelkerke R² = 0.301, p < 0.05) and producing fewer or smaller faecal droppings (Exp(B) = 13.733, Nagelkerke R² = 0.149, p < 0.05) were predictive for the presence of dental disease. Having access to an outside environment, including the use of runs on both concrete and grass, was significantly related to not displaying clinical signs of dental disease (Exp(B) = 1.894, Nagelkerke R² = 0.021, p < 0.05). There was no significant relationship between owner knowledge, guinea pig diet, and dental disease in the study population. This study highlights the importance of access to the outdoors for the health and welfare of guinea pigs in addition to the need for owners to be alert to key clinical signs. A relationship between diet and dental disease was not identified in this study; however, the underlying aetiological causes of this condition require further investigation.

A randomized controlled trial of factors influencing fire occurrence during laser surgery of cadaveric rodents under simulated mask anesthesia

OBJECTIVE

To determine whether face mask fit during anesthesia affects the occurrence of fire episodes during laser surgery in nonintubated cadaveric rodents under volatile anesthesia.

DESIGN

Adaptive single-center randomized controlled trial with an interim analysis.

SAMPLE

100 dead rats intended for animal consumption.

PROCEDURES

Rat carcasses were randomly allocated to undergo simulated anesthetic procedures with 2 face masks: open mask versus tight-fitting mask. Under volatile anesthesia, 4 cutaneous surgeries were performed (skin biopsies at 3 different sites and resection of a pinna) by means of a diode laser on each carcass. A single interim analysis of 50 rats was planned a priori to drop an arm of the study in the case of a highly significant difference in the incidence of fire events. Surgeries would have continued with the other face mask until completion of the study. Univariate and multivariate analyses were performed.

RESULTS

Overall, 25 surgeries were performed with open face masks and 75 with tight-fitting masks. During 400 surgical procedures on 100 rat carcasses, 11 (11%; 95% confidence interval, 5.62% to 18.83%) fire events occurred. Ten fire events occurred with the open masks, and 1 fire event occurred with the tight-fitting masks (relative risk, 30.0; 95% confidence interval, 4.0 to 222.8). All of the fire events occurred on different carcasses when cheek skin biopsy was performed. Procedure time, body weight, and surgeon did not significantly concur in the prediction of fire events.

CONCLUSIONS AND CLINICAL RELEVANCE

Modification of open masks by the addition of a latex diaphragm significantly reduced the occurrence of fire ignition during laser surgery. Results suggested that open masks should not be used for laser surgery of nonintubated rodents during volatile anesthesia. Additionally, results indicated that surgical lasers should be avoided for facial surgery of nonintubated anesthetized rodents, even if tight-fitting masks are used.

Comparison of intraosseous and peripheral venous fluid dynamics in the desert tortoise (Gopherus agassizii)

The efficacy of intraosseous catheterization has not been described previously in the desert tortoise (Gopherus agassizii). The goal of this study was to describe and compare the efficacy of four intraosseous catheter sites (humerus, femur, plastocarapacial junction [bridge], and gular region of the plastron) to jugular catheterization. Five adult tortoises were catheterized in each of the sites at least once. The distribution of a bolus injection of radiopharmaceutical (technetium-99m-diethylenetriaminepentaacidic acid [99mTc -DTPA]) was monitored via gamma camera over 2-min periods at five time intervals over 24 min. Compared to jugular catheterization, the humerus and femur sites provided the next best vascular access, with 84.4 and 61.8% of activity reaching the systemic circulation by 7 min, respectively. The bridge and gular catheter sites were less effective with only 41.9 and 40.8% systemic activity, respectively. Intraosseous catheters were no more technically difficult to place than jugular catheters and were less commonly dislodged, making them a viable option for vascular access in tortoises.

Respiratory system anatomy, physiology, and disease: Guinea pigs and chinchillas

Respiratory diseases are common in guinea pigs and chinchillas. There are multifactorial causes of respiratory involvement in these species of rodents, from infectious (bacterial, viral, and fungal) to neoplastic causes. Toxicoses and diseases affecting other systems may also induce respiratory signs. Knowledge of biology, including husbandry, nutritional requirements, and behavior, are important clues for the clinician to determine the role these issues may play in the development, progression, and prognosis of respiratory clinical cases in rodents. Current approaches in the diagnosis and therapy for respiratory disease in small mammals warrant more research concerning response-to-treatment reports.

Advanced diagnostic approaches and current management of internal disorders of select species (rodents, sugar gliders, hedgehogs)

African pygmy and European hedgehogs, sugar gliders, and rodents such as rats, mice, gerbils, hamsters, guinea pigs, and chinchillas are becoming increasingly popular as pets in the United States, and more practitioners are being asked to examine, diagnose, and treat these animals for a bevy of disorders and diseases. Many procedures and techniques used in traditional small and large animal medicine are used for these species, with minor adaptations or considerations. This article examines available diagnostic tools and treatment methodologies for use in hedgehogs, sugar gliders, and selected rodents.

Endoscopic intubation of exotic companion mammals

Rabbits, guinea pigs, chinchillas and many other small exotic mammals are not intubated routinely, because intubation requires specialized equipment and is difficult to perfect. Using a face mask for these species solely on the basis that they are unable to regurgitate ignores the numerous other benefits of airway control. This article summarizes the many advantages of endotracheal intubation and the various methods of intubation that have been reported. It introduces endoscopic intubation as a method that overcomes many of the difficulties associated with other methods and describes the equipment needed, how to intubate with an endoscope, how to confirm proper endotracheal tube placement, and possible complications. Over-the-endoscope intubation is discussed in detail, as it appears to provide the most versatile and reliable method of intubating exotic companion mammals.

Gastric Dilatation-Volvulus in a Guinea Pig (Cavia porcellus)

A 3-year-old, intact female guinea pig (Cavia porcellus) was presented for anorexia and abdominal distention of 24 hours’ duration. Radiographs revealed a severely distended stomach, suggestive of severe gastric dilatation or gastric dilatation-volvulus (GDV). Exploratory surgery was recommended, but the owners elected euthanasia. On necropsy, the guinea pig was found to have GDV. No underlying conditions were identified that could have predisposed this guinea pig to the development of GDV.

Emergency care and managing toxicoses in the exotic animal patient

The poisoned exotic veterinary patient remains a significant challenge to the clinician. A patient presenting with the history of exposure to a toxin or poison should be considered to have a potentially life-threatening problem. This article details the ABCs of emergency medicine including fluid therapy and discusses the principles of neurologic management. The last part of the article provides the clinician with guidelines for decontamination and critical care management of some of the more common toxicoses in exotic animals.