Respiratory Distress Caused by Neoplastic Upper Respiratory Tract Obstructions in 2 Pet Rats (Rattus norvegicus domestica).

Respiratory disease is one of the primary reasons for pet owners to seek veterinary attention for their rats. While chronic respiratory disease complex is most often responsible for respiratory signs in pet rats and is well characterized, upper respiratory obstructive disease has been rarely reported in the literature. This report describes 2 pet fancy rats (Rattus norvegicus domestica) presenting with a several day history of progressive respiratory signs that were minimally responsive to supportive therapies, including antibiotics, nonsteroidal anti-inflammatories, and fluid and oxygen support. Survey radiographs were performed under sedation in both cases. In the first case, no cause for the clinical signs could be identified, in part due to suboptimal radiographic positioning, although severe aerophagia was noted. In the second case, cervical tracheal luminal narrowing and increased soft tissue opacity along the walls of the trachea were identified. Both rats declined while under sedation, resulting in cardiopulmonary arrest in the first case and humane euthanasia in the second. On necropsy, the first case had a oropharyngeal squamous cell carcinoma originating from the Zymbal's gland, which was obstructing the larynx. The second case had an intra-luminal tracheal mass obstructing the airway. This was mostly likely B-cell lymphoma or a plasma cell tumor, although definitive diagnosis was unable to be obtained. For future such cases empiric management of respiratory disease in rats with antimicrobials, anti-inflammatories, and supportive care is often appropriate based on the high prevalence of infectious agents, however, other noninfectious causes should be considered, such as neoplastic processes leading to upper airway obstructive disease and diagnostic imaging may be indicated.

Iridial melanocytoma in a ferruginous hawk (Buteo regalis): A case report and review of avian melanocytic neoplasia.

A 21-year-old, suspected female captive ferruginous hawk (Buteo regalis) was followed for 3 years due to an iridial mass of the left eye (OS) that progressively increased in size. Enucleation of OS was eventually recommended due to the iridial mass taking up approximately 75% of the anterior chamber, and the bird seemed less active. A complete physical examination, complete blood cell count, biochemistry, and survey radiographs were performed pre-surgery with no findings indicating metastasis. A subconjunctival enucleation was performed and the globe was submitted for histopathology through the Comparative Ocular Pathology Lab of Wisconsin. The histopathologic evaluation determined the mass to be consistent with an iris melanocytoma, which has not been previously reported in this species. The patient recovered well from surgery and has remained comfortable and active for 117 days post-surgery. This case report aimed to review the current available information on avian ocular neoplasms as well as describe the clinical presentation, medical management and surgical procedure, and long-term follow-up for this patient to enhance clinical understanding of the behavior of iris melanocytic tumors in avian species.

Retrospective evaluation of wobbly hedgehog syndrome in 49 African pygmy hedgehogs (Atelerix albiventris): 2000-2020.

OBJECTIVE: To retrospectively evaluate the prevalence and clinical progression of wobbly hedgehog syndrome (WHS) and concurrent incidence of neoplasia in a cohort of African pygmy hedgehogs (Atelerix albiventris). ANIMALS: 49 hedgehogs. CLINICAL PRESENTATION AND PROCEDURES: Medical records of hedgehogs from 7 institutions across the US over a 20-year period (2000 to 2020) were retrospectively reviewed. Inclusion criteria were hedgehogs of any sex or age with postmortem CNS histopathology consistent with WHS. Collected data included sex, age at onset and euthanasia, major histopathologic findings, reported neurologic clinical signs, and treatments administered. RESULTS: 24 males and 25 females were included. Fifteen of 49 (31%) individuals had subclinical WHS with no reported antemortem neurologic clinical signs. In neurologically affected (clinical) hedgehogs (n = 34), the mean ± SD age at onset was 3.3 ± 1.5 years with a median (range) time from onset to euthanasia of 51 days (1 to 319 days). In neurologically affected hedgehogs, the most commonly reported clinical signs were ataxia (n = 21) and pelvic limb paresis (16) and the most commonly administered treatment was meloxicam (13). Overall, 31 of 49 (63%) hedgehogs had a concurrent histopathologic diagnosis of neoplasia outside of the CNS. CLINICAL RELEVANCE: The prognosis for hedgehogs with WHS is poor. No treatment had a significant effect on survival time, and neoplasia was a common comorbidity in the current cohort. A small but clinically relevant subset of neurologically normal hedgehogs had a histopathologic diagnosis of WHS.

Multiple Myeloma with Aberrant CD3 Expression in a Red-Lored Amazon Parrot (Amazona autumnalis).

A 20-year-old, female, red-lored Amazon parrot (Amazona autumnalis) was presented for a 2-week history of weakness. On physical examination, the bird was quiet, fluffed, weak, and had a distended coelom. Radiographic and ultrasound imaging revealed coelomic distention, increased pulmonary parenchymal opacity, renomegaly, dilated intestines, and a thickened ventricular wall. The results of a complete blood cell count indicated the patient was anemic (28%) and had intermediate to large lymphocytes with immature chromatin that were suspected to be neoplastic. Immunocytochemistry on peripheral blood determined that the suspected circulating neoplastic cells were cluster of differentiation (CD) 3+ and occasionally expressed multiple myeloma oncogene 1 (MUM1). Abnormalities from a plasma biochemistry panel were moderate hyperphosphatemia (6.8 mg/dL), marked hyperproteinemia (13.6 g/L), analbuminemia (0 g/dL), and marked hyperglobulinemia (13.6 g/dL). Agarose gel plasma protein electrophoresis documented the presence of albumin (1.2 g/dL) and monoclonal bands which, on reduced lithium dodecyl sulfate polyacrylamide gel electrophoresis, resolved as 60-kd and ∼25-kd bands consistent with immunoglobulin Y heavy and light chains. On the basis of these findings, multiple myeloma was diagnosed. Because of a poor prognosis, the bird was euthanized for postmortem examination. Bone marrow cytology from samples collected during the postmortem examination revealed 17.4% plasma cells and 24% large immature cells with occasional plasmacytoid features. Histopathologic findings included aggregates of neoplastic plasma cells in the bone marrow, spleen, kidney, liver, gastrointestinal tract, muscle, ovary, and brain. The neoplastic cells were strongly immunoreactive for MUM1 and cluster of differentiation 3 (CD3), but negative for CD79a, paired box protein 5, and CD20. This confirmed the clinical diagnosis of multiple myeloma. This report describes an avian immunoglobulin Y-secreting multiple myeloma with aberrant CD3 expression and pseudoanalbuminemia. Aberrant CD3 expression by avian multiple myeloma may explain previously published cases of birds with a monoclonal gammopathy and apparent T-cell lymphoma diagnosed by CD3 immunoreactivity.

Ophthalmic Parameters and Ophthalmoscopy of Burrowing Owls (Athene cunicularia).

Twelve adult burrowing owls (Athene cunicularia) maintained in a managed environment underwent complete bilateral ophthalmic examinations to assess ocular parameters and, if present, describe lesions (n = 24 eyes). Tear production was measured with a Schirmer tear test (STT), and intraocular pressure (IOP) was measured with rebound tonometry using established calibration settings (D = dog/cat, P = other species). Retinography was performed for all birds after application of topical rocuronium bromide, and corneal diameter was measured. Menace response was absent bilaterally in 7 of 12 (58.3%) owls; however, this did not appear to be related to the presence of fundic lesions. Ocular lesions were visualized in 6 of 12 (50%) owls. The most common ophthalmic abnormality noted was mild multifocal fundic pigment clumping, suggestive of chorioretinal scarring. Other ocular lesions included 1 retinal tear and 1 incipient cataract. Mean tear production was 6.1 ± 3.0 mm/min. Mean IOPs were 11.6 ± 1.8 mm Hg and 7.1 ± 1.3 mm Hg for the D and P settings, respectively, and these were significantly different (P < 0.001). The IOP results did not differ significantly based on patient age or between the right and left eyes, but a higher mean was obtained from males versus females using the D setting (P < 0.039; male mean 12.1 ± 1.9 mm Hg; female mean 10.9 ± 1.2 mm Hg). Measurements obtained from the STT were not affected by either age or sex. Corneal height was 11 mm and width was 12 mm, regardless of age or sex. The rebound tonometer D setting is recommended for measuring IOP values in this species. Burrowing owls had inconsistent mydriasis following topical rocuronium bromide application to the eye; however, a complete fundic examination was possible with or without complete mydriasis.

Giraffe skin disease: Clinicopathologic characterization of cutaneous filariasis in the critically endangered Nubian giraffe (Giraffa camelopardalis camelopardalis).

Giraffe skin disease (GSD) is an emerging disease of free-ranging giraffe recognized in the last 25 years in several species, including the critically endangered Nubian giraffe (Giraffa camelopardalis camelopardalis) of Uganda. Identifying the cause of GSD and understanding its impact on health were deemed paramount to supporting these vulnerable populations. Sixty-four giraffes were immobilized in Murchison Falls National Park, Uganda, from 2017 to 2019, and GSD lesions were opportunistically biopsied. Fifty-five giraffes (86%) had GSD lesions on the neck, axilla, chest, and cranial trunk. Lesions were categorized into early, intermediary, and dormant stages based on gross and histological characteristics. Early lesions were smaller, crusted nodules with eosinophilic and pyogranulomatous dermatitis and furunculosis. Intermediary lesions were thick plaques of proliferative and fissured hyperkeratosis and acanthosis with dense dermal granulation tissue and severe eosinophilic and granulomatous dermatitis. Lesions appeared to resolve to dormancy, with dormant lesions consisting of hairless plaques of hyperkeratosis with dermal scarring and residual inflammation. The periphery of early and intermediary lesions included follicular granulomas containing adult filarid nematodes, with myriad encysted microfilariae in the superficial dermis. Stage L3 larvae were common in early and intermediary lesions, and dormant lesions had remnant encysted microfilariae with no adult or stage L3 larvae. Nematodes were morphologically and genetically novel with close identity to Stephanofilaria spp. and Brugia malayi, which cause infectious filariasis. Identification of potential insect vectors, long-term monitoring of GSD lesions, and evaluating response to therapy is ongoing in the efforts to help conserve the Nubian giraffe.

Pharmacokinetics of a Single Intramuscular Injection of Ceftiofur Crystalline Free Acid in Bald Eagles (Haliaeetus leucocephalus).

The objective of this study was to evaluate the pharmacokinetic properties of ceftiofur crystalline free acid (CCFA) administered intramuscularly at dosages of 10 and 20 mg/kg in bald eagles (BAEAs) (Haliaeetus leucocephalus). Ceftiofur crystalline free acid is a long-acting, injectable, third-generation cephalosporin antibiotic drug. A prospective, randomized, complete crossover design was used for this pharmacokinetic investigation. CCFA (10 or 20 mg/kg) was administered intramuscularly, and blood samples were obtained from 6 adult, nonreleasable, healthy BAEAs at predetermined sampling times. After a 4-week washout period, the protocol was repeated with each bird receiving the dose not given during the initial sample collection according to the randomized crossover design. Plasma ceftiofur free acid equivalents were quantified and data were analyzed by a noncompartmental pharmacokinetic approach. The mean observed peak plasma concentrations were 9.23 µg/mL and 15.08 µg/mL for 10 and 20 mg/kg CCFA IM administration, respectively. The mean observed time to maximum plasma concentration was 18 and 17.6 hours, and the mean terminal elimination half-life was 32.38 and 38.08 hours for intramuscular administration of 10 and 20 mg/kg CCFA, respectively, in the BAEAs. Reported minimum inhibitory concentrations of raptor bacterial isolates from a prior study was used to determine the target minimum inhibitory concentration of 1 µg/mL selected for this investigation. From the previously published information, a target plasma concentration of 4 µg/mL was determined for the CCFA in the BAEAs. From the results of this study, CCFA may be dosed every 60 and 110 hours at 10 mg/kg IM, and every 80 and 160 hours at 20 mg/kg IM in BAEAs.

Plasma and joint tissue pharmacokinetics of two doses of oral cannabidiol oil in guinea pigs (Cavia porcellus).

Cannabidiol (CBD) has gained widespread popularity as a treatment for osteoarthritis (OA) in pets; however, there is minimal scientific evidence regarding safe and effective dosing. This study determined plasma and tissue pharmacokinetics after oral CBD oil suspension administration in Hartley guinea pigs (Cavia porcellus), which spontaneously develop OA at 3 months of age. Ten, 5-month-old, male guinea pigs were randomly assigned to receive 25 (n = 5) or 50 mg/kg (n = 5) CBD oil once orally. Blood samples were collected at 0, 0.25, 0.5, 1, 2, 4, 8, 12, and 24 h timepoints. Open-field enclosure monitoring revealed no adverse effects. After euthanasia, stifle cartilage and infrapatellar fat pads were collected to quantitate CBD. CBD concentrations were determined using a validated liquid chromatography-mass spectrometry method, and pharmacokinetic parameters were calculated using noncompartmental analysis. The area under the plasma concentration-versus-time curve was 379.5 and 873.7 h*ng/mL, maximum plasma concentration was 42 and 96.8 ng/mL, time to maximum plasma concentration was 1.6 and 4.8 h, and terminal phase half-life was 8.1 and 10.8 h for the 25 and 50 mg/kg doses, respectively. CBD was detected in joint tissues of all animals. Further studies, including work in female guinea pigs, are needed to determine the efficacy of CBD for OA.

Unfolding the diagnosis of subspectacular fluid opacity in a corn snake (Pantherophis guttatus).

OBJECTIVE: To present the results of clinical, surgical, and histopathologic procedures and how these were compared with the initial presumptive clinical diagnosis in a corn snake (Pantherophis guttatus) presenting with subspectacular fluid opacity; and to improve upon currently established surgical enucleation techniques in the snake. ANIMAL STUDIED: An 8-month-old corn snake was presented for enlarged globe OD. PROCEDURES: The following diagnostics were performed: systemic and ophthalmic examinations, complete blood count, cytology and culture of subspectacular fluid, and histopathology of enucleated globe and spectacle. Enucleation was performed in a routine fashion with the addition of a porcine small intestinal submucosa bioscaffold graft (SISplus™; Avalon Medical, Stillwater, MN), sutured over the orbit. RESULTS: Systemic examination revealed signs of maxillary stomatitis. Ophthalmic examination revealed semitransparent fluid in the subspectacular space. Complete blood count was unremarkable. Cytology of fluid obtained via subspectacular centesis was acellular, and culture grew Clostridium perfringens, which was consistent with the clinical suspicion of right maxillary stomatitis. Histopathology of the enucleated globe revealed spectaculitis, characterized by regional heterophilic inflammation, and no evidence of lymph dissection in the (peri)ocular tissues. The final diagnosis was a subspectacular abscess. Follow-up revealed that the SIS graft provided excellent healing and cosmesis of the surgical site. CONCLUSIONS: While there are reports of lymphatic fluid dissection between skin layers during ecdysis, which can result in an opaque spectacle, the fluid opacity in this case was attributed to a subspectacular abscess secondary to an ascending oral infection. Addition of biological wound dressing may contribute to positive post-enucleation outcome in the snake.

Ultrasonographic features of mesenteric cysticercosis in a domestic rabbit (Oryctolagus cuniculus).

A 5-year-old, 0.92-kg (2-lb), spayed female Dwarf Hotot rabbit was evaluated for a 1-day duration of lethargy and anorexia. Survey radiographs revealed evidence of gastrointestinal stasis. Abdominal ultrasonography characterized multiple small, round, anechoic structures embedded in the mesentery. These structures were thin walled with hyperechoic strands/septations. Most of the structures contained a well-defined, eccentric, hyperechoic nodule adherent to the intraluminal wall. Mesenteric cysticercosis was confirmed via exploratory laparotomy and histopathology. To the authors' knowledge, this is the first description of the ultrasonographic features of mesenteric cysticercosis in a domestic rabbit.

Partial gastrectomy for resection of a gastric leiomyoma in a guinea pig (Cavia porcellus).

CASE DESCRIPTION A 4-year-old sexually intact male pet guinea pig (Cavia porcellus) was evaluated for a routine wellness examination. CLINICAL FINDINGS During physical examination, a small mass was palpated in the cranial aspect of the abdomen. Abdominal radiographic and ultrasonographic findings were suggestive of a gastric mass. Cytologic evaluation of a fine-needle aspirate of the mass was indicative of spindle cell proliferation most consistent with a sarcoma. TREATMENT AND OUTCOME The patient was anesthetized, and an exploratory laparotomy and partial gastrectomy were performed to resect the gastric mass. Histologic and immunohistochemical examinations of the mass revealed that it was a gastric leiomyoma. The patient recovered from surgery without complications. No evidence of mass recurrence was observed during an abdominal ultrasonographic examination performed approximately 19 months after surgery. CLINICAL RELEVANCE To our knowledge, this was the first report of the clinical diagnosis and successful surgical treatment of a gastric neoplasm in a guinea pig. Gastric leiomyomas are not uncommon in guinea pigs, and although benign, they can cause clinical signs if they become large enough to impair gastric function. Gastrointestinal surgery should be considered as a treatment option for guinea pigs with similar gastric neoplasms.

Pharmacokinetics of a single intramuscular injection of ceftiofur crystalline-free acid in red-tailed hawks (Buteo jamaicensis).

OBJECTIVE: To determine the pharmacokinetics and adverse effects at the injection site of ceftiofur crystalline-free acid (CCFA) following IM administration of 1 dose to red-tailed hawks (Buteo jamaicensis). ANIMALS: 7 adult nonreleasable healthy red-tailed hawks. PROCEDURES: In a randomized crossover study, CCFA (10 or 20 mg/kg) was administered IM to each hawk and blood samples were obtained. After a 2-month washout period, administration was repeated with the opposite dose. Muscle biopsy specimens were collected from the injection site 10 days after each sample collection period. Pharmacokinetic data were calculated. Minimum inhibitory concentrations of ceftiofur for various bacterial isolates were assessed. RESULTS: Mean peak plasma concentrations of ceftiofur-free acid equivalent were 6.8 and 15.1 µg/mL for the 10 and 20 mg/kg doses, respectively. Mean times to maximum plasma concentration were 6.4 and 6.7 hours, and mean terminal half-lives were 29 and 50 hours, respectively. Little to no muscle inflammation was identified. On the basis of a target MIC of 1 µg/mL and target plasma ceftiofur concentration of 4 µg/mL, dose administration frequencies for infections with gram-negative and gram-positive organisms were estimated as every 36 and 45 hours for the 10 mg/kg dose and every 96 and 120 hours for the 20 mg/kg dose, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Study results suggested that CCFA could be administered IM to red-tailed hawks at 10 or 20 mg/kg to treat infections with ceftiofur-susceptible bacteria. Administration resulted in little to no inflammation at the injection site. Additional studies are needed to evaluate effects of repeated CCFA administration.

Mange Caused by a Novel Micnemidocoptes Mite in a Golden Eagle ( Aquila chrysaetos ).

A second-year, female golden eagle ( Aquila chrysaetos ) was live trapped in northern California because of severe feather loss and crusting of the skin on the head and legs. On physical examination, the bird was lethargic, dehydrated, and thin, with severe feather loss and diffuse hyperemia and crusting on the head, ventral wings, ventrum, dorsum, and pelvic limbs. Mites morphologically similar to Micnemidocoptes derooi were identified with scanning electron microscopy. The eagle was treated with ivermectin (0.4 mg/kg) once weekly for 7 weeks, as well as pyrethrin, meloxicam, ceftiofur crystalline free acid, and voriconazole. Although the eagle's condition improved, and live mites or eggs were not evident on skin scrapings at the time of completion of ivermectin treatment, evidence of dead mites and mite feces were present after the last dose of ivermectin. Two additional doses of ivermectin and 2 doses of topical selamectin (23 mg/kg) were administered 2 and 4 weeks apart, respectively. No mite eggs, feces, or adults were evident after treatment was completed. A second golden eagle found in the same region was also affected with this mite but died soon after presentation. This is the first report, to our knowledge, of successful treatment, as well as treatment with selamectin, of mites consistent with Micnemidocoptes species in any raptorial species.

Multifocal respiratory and vertebral mycobacteriosis in a red-tailed hawk (Buteo jamaicensis).

An adult, female, free-ranging red-tailed hawk (Buteo jamaicensis) was presented to a rehabilitation facility for an inability to stand. On examination, it displayed bilateral exaggeration of the pelvic limb reflexes with extensor muscle rigidity, intact superficial pain response, and positive withdrawal reflexes. A complete blood count identified moderate leukocytosis characterized by moderate heterophilia. No abnormalities were appreciable on radiographic evaluation. After initial improvement, it regressed and was euthanized 27 days after presentation. Necropsy and histologic investigation identified reduction in the diameter of the vertebral canal and spinal cord at cervical segments 8-9 with coalescing granulomas and intralesional acid-fast bacilli within the intertrabecular space, left side of the clavicular air sac, and cranial left lung. Bacterial culture and genetic sequencing from respiratory lesions identified Mycobacterium avium avium. Real time-polymerase chain reaction of paraffin-fixed spinal tissue tested positive for M. avium complex. Mycobacteriosis should be considered when peripheral neurologic deficits are present in raptors.

Mycotic Keratitis in a Khaki Campbell Duck ( Anas platyrhynchos domesticus).

A 1.5-year-old, intact female khaki Campbell duck (Anas platyrhynchos domesticus) was evaluated for lethargy and a swollen left eye (OS). Mucoid discharge, chemosis, and conjunctival hyperemia with trace aqueous flare, indicating anterior uveitis, in the anterior chamber were evident on ophthalmic examination. There was no fluorescein stain uptake by the cornea. Initial topical antibiotic therapy and systemic anti-inflammatory treatments were unsuccessful, and the lesion progressed to a diffuse, yellow-white plaque, which covered 90%-95% of the cornea 4 days later. There was moderate blepharospasm, mild blepharedema, and epiphora OS. The mobility of the nictitating membrane was impaired because of the presence of the plaque over the cornea. Cytologic examination of a corneal scraping revealed fungal hyphae, and aerobic culture confirmed Aspergillus species. Treatment with topical voriconazole (1 drop OS q4h-q6h) was initiated and was switched to oral voriconazole (20 mg/kg PO q12h) 6 days after initiating treatment. The ocular disease improved during the antifungal treatment period. Eighty-four days after initial presentation (9 days after discontinuation of treatment), there was no clinical evidence of mycotic keratitis on ophthalmic examination.

Two cases of vaginal bleeding in pet rats.

Two unrelated rats were presented to the Western College of Veterinary Medicine emergency service for vaginal bleeding. Each was taken to surgery due to marked blood loss and suspicion of uterine pathology. Despite similar clinical presentation, gross and histopathologic examination revealed 2 different underlying disease processes, uterine dilatation with mild endometritis and vaginal polyp.