Splenic Small Cell Lymphoma with Presumed Secondary Immune-Mediated Hemolytic Anemia in an African Penguin (Spheniscus demersus).

A 2-year-old male African penguin (Spheniscus demersus) was presented to a veterinary teaching hospital for evaluation of a previously diagnosed subclinical, marked regenerative anemia. Physical examination at the zoological institution demonstrated biliverdinuria and pale oral mucous membranes. Diagnostic tests performed on the penguin since the diagnosis and prior to presentation to the veterinary teaching hospital included serial complete blood counts, plasma biochemistry panels, radiographic imaging, blood and plasma heavy metal testing, and infectious disease testing. The abnormal diagnostic test results were consistent with marked regenerative anemia and splenomegaly. At the veterinary teaching hospital, further diagnostic testing was ordered in an attempt to determine the cause of the biliverdinuria and pale oral mucous membranes. The diagnostic tests performed included a full-body contrast computed tomographic scan, upper gastrointestinal endoscopic procedure, bone marrow aspiration and evaluation, saline agglutination testing, blood Plasmodium species polymerase chain reaction screening, a vitamin profile panel, and repeat blood heavy metal testing. The complete blood count demonstrated a marked, regenerative anemia with the presence of dysplastic erythrocytes, and splenomegaly was found on the computed tomographic images without identifying a definitive cause. Primary disease differentials for the diagnosed regenerative anemia included a myelodysplastic syndrome and primary or secondary immune-mediated hemolytic anemia. The penguin was treated with oral prednisolone as an immunomodulatory agent; however, it did not result in a positive treatment response. The patient developed hyporexia, weight loss, and lethargy 2 months post presentation to the veterinary teaching hospital. Additional therapy with cyclophosphamide was initiated, and the penguin improved clinically, but then declined. The patient was euthanized due to a poor quality of life and prognosis 4 months after initial presentation and 1.5 years after the first complete blood count revealed the penguin to be anemic. Microscopic review of submitted postmortem tissue samples demonstrated a monomorphic population of neoplastic small lymphocytes infiltrating the spleen, consistent with splenic small cell lymphoma. The neoplastic cells did not label with the T-cell marker CD3 or B-cell markers CD20, CD79a, and Pax-5.

A Comparison of Historical Control Data From Cynomolgus Macaques (Macaca Fascicularis) of Chinese, Cambodian, and Vietnamese Origin.

Cynomolgus macaques, the most commonly utilized nonhuman primate in nonclinical toxicology studies, are acquired from purpose-bred colonies across various geographic locations, including China, Cambodia, and Vietnam. Importation challenges and limited availability have restricted animals suitable for inclusion in nonclinical studies. The coronavirus disease 2019 (COVID-19) outbreak further stressed supply chains, reducing the ability to source animals from a singular location to complete a drug development program. These challenges raised concerns of increased variability in study endpoints due to heterogeneity of animals and that this could subsequently impact historical control data and toxicology study interpretation. To investigate the impact of Chinese, Vietnamese, or Cambodian geographic origin on standard nonclinical toxicology study endpoints, historical control data from studies conducted at a single facility from 2005 to 2020 were compiled and evaluated for the following: clinical observations, body weight, ophthalmoscopic examinations, and clinical and anatomic pathology data. Study populations consisted of 2- to 5-year-old cynomolgus macaques sourced from China (n = 750 males/741 females), Cambodia (n = 282 males/271 females), and Vietnam (n = 122 males/120 females). Interpretation of the various data demonstrated no notable differences in standard toxicology study endpoints or background findings among cynomolgus macaques originating from China, Cambodia, or Vietnam.

Diagnosis and clinical outcome following surgical resection of an intracranial grade III anaplastic gemistocytic astrocytoma in a cat.

CASE SUMMARY: A 10-year-old Maine Coon cat was presented for acute onset seizures and cerebrothalamic signs. An intracranial mass, suspected to be a meningioma, was diagnosed on MRI and surgically excised. Histopathology appeared consistent with an atypical meningioma. However, following rapid regrowth of the neoplasm, the patient was humanely euthanized 3 months later. On post-mortem histopathology, the neoplasm was diagnosed as a grade III anaplastic gemistocytic astrocytoma. RELEVANCE AND NOVEL INFORMATION: Gemistocytic astrocytomas are rare brain tumors in the feline patient. This case represents the first report of a feline grade III anaplastic gemistocytic astrocytoma in the cerebrum of a cat with surgical excision and recurrence. The challenging nature of ante-mortem diagnosis and the guarded prognosis, despite surgical intervention, are presented in this report.

Antiviral treatment using the adenosine nucleoside analogue GS-441524 in cats with clinically diagnosed neurological feline infectious peritonitis.

Feline infectious peritonitis (FIP) is caused by a mutant biotype of the feline enteric coronavirus. The resulting FIP virus (FIPV) commonly causes central nervous system (CNS) and ocular pathology in cases of noneffusive disease. Over 95% of cats with FIP will succumb to disease in days to months after diagnosis despite a variety of historically used treatments. Recently developed antiviral drugs have shown promise in treatment of nonneurological FIP, but data from neurological FIP cases are limited. Four cases of naturally occurring FIP with CNS involvement were treated with the antiviral nucleoside analogue GS-441524 (5-10 mg/kg) for at least 12 weeks. Cats were monitored serially with physical, neurologic, and ophthalmic examinations. One cat had serial magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) analysis (including feline coronavirus [FCoV]) titers and FCoV reverse transcriptase [RT]-PCR) and serial ocular imaging using Fourier-domain optical coherence tomography (FD-OCT) and in vivo confocal microscopy (IVCM). All cats had a positive response to treatment. Three cats are alive off treatment (528, 516, and 354 days after treatment initiation) with normal physical and neurologic examinations. One cat was euthanized 216 days after treatment initiation following relapses after primary and secondary treatment. In 1 case, resolution of disease was defined based on normalization of MRI and CSF findings and resolution of cranial and caudal segment disease with ocular imaging. Treatment with GS-441524 shows clinical efficacy and may result in clearance and long-term resolution of neurological FIP. Dosages required for CNS disease may be higher than those used for nonneurological FIP.

Efficacy and safety of the nucleoside analog GS-441524 for treatment of cats with naturally occurring feline infectious peritonitis.

OBJECTIVES: The aim of this study was to determine the safety and efficacy of the nucleoside analog GS-441524 for cats suffering from various forms of naturally acquired feline infectious peritonitis (FIP). METHODS: Cats ranged from 3.4-73 months of age (mean 13.6 months); 26 had effusive or dry-to-effusive FIP and five had non-effusive disease. Cats with severe neurological and ocular FIP were not recruited. The group was started on GS-441524 at a dosage of 2.0 mg/kg SC q24h for at least 12 weeks and increased when indicated to 4.0 mg/kg SC q24h. RESULTS: Four of the 31 cats that presented with severe disease died or were euthanized within 2-5 days and a fifth cat after 26 days. The 26 remaining cats completed the planned 12 weeks or more of treatment. Eighteen of these 26 cats remain healthy at the time of publication (OnlineFirst, February 2019) after one round of treatment, while eight others suffered disease relapses within 3-84 days. Six of the relapses were non-neurological and two neurological. Three of the eight relapsing cats were treated again at the same dosage, while five cats had the dosage increased from 2.0 to 4.0 mg/kg q24h. The five cats treated a second time at the higher dosage, including one with neurological disease, responded well and also remain healthy at the time of publication. However, one of the three cats re-treated at the original lower dosage relapsed with neurological disease and was euthanized, while the two remaining cats responded favorably but relapsed a second time. These two cats were successfully treated a third time at the higher dosage, producing 25 long-time survivors. One of the 25 successfully treated cats was subsequently euthanized due to presumably unrelated heart disease, while 24 remain healthy. CONCLUSIONS AND RELEVANCE: GS-441524 was shown to be a safe and effective treatment for FIP. The optimum dosage was found to be 4.0 mg/kg SC q24h for at least 12 weeks.

OUTBREAK AND TREATMENT OF CARP EDEMA VIRUS IN KOI ( CYPRINUS CARPIO) FROM NORTHERN CALIFORNIA.

Carp edema virus (CEV) is the causative agent of carp edema virus disease (CEVD), also referred to as koi sleepy disease, which is an emerging disease of global concern that may cause high rates of morbidity and mortality in common carp and ornamental koi ( Cyprinus carpio). This article reports the third confirmed outbreak of CEVD in California. In June 2015, three koi presented with clinical signs of cutaneous lesions, severe lethargy, and signs of hypoxia. All fish tested positive for CEV by polymerase chain reaction (PCR). Euthanasia and complete necropsy were performed on two fish. The most significant necropsy findings included necrotizing branchitis with marked interstitial edema, multifocal cutaneous ulcerations, and severe cutaneous edema. Treatment of the pond with 0.3-0.5% salt was recommended to the owner. Approximately 7 wk later, a recheck visit was made to the pond. No mortalities had been noted since the initiation of the salt treatment. Physical examination revealed a vast improvement but not complete elimination of the clinical signs of hypoxia and intermittent lethargy in the affected fish. Gill biopsy samples from the two most affected fish were tested and remained PCR positive for CEV. Subsequent recheck visits over 11 mo postdiagnosis and initiation of treatment showed continued improvement in most fish. Gill samples from all fish in the pond ( n = 9) were repeatedly tested by quantitative PCR for CEV, and all samples were negative. This case series further confirms the global spread of CEV and the need for practitioners to be vigilant for outbreaks of this disease. If CEVD is suspected, treatment with 0.3-0.5% salt can be recommended to potentially mitigate the effects of this disease. However, fish may remain potential carriers of this pathogen, and strict biosecurity measures should continue to be enforced for any pond that has had a confirmed CEV outbreak.

Multiple, Independent T Cell Lymphomas Arising in an Experimentally FIV-Infected Cat during the Terminal Stage of Infection.

Our laboratory has serially reported on the virologic and immunopathologic features of a cohort of experimental feline immunodeficiency virus (FIV)-infected cats for more than eight years. At 8.09 years post infection (PI), one of these animals entered the terminal stage of infection, characterized by undulating hyperthermia, progressive anorexia, weight loss, and pancytopenia; the animal was not responsive to therapeutic interventions, necessitating euthanasia six weeks later (8.20 years PI). Subsequent analyses indicated that neoplastic lymphocytes infiltrated multiple cervical lymph nodes and a band-like region of the mucosal lamina propria within a segment of the intestine. Immunohistochemistry and T cell clonality testing determined that the nodal and intestinal lesions were independently arising from CD3 T cell lymphomas. In-situ RNA hybridization studies indicated that diffuse neoplastic lymphocytes from the cervical lymph node contained abundant viral nucleic acid, while viral nucleic acid was not detectable in lymphocytes from the intestinal lymphoma lesion. The proviral long terminal repeat (LTR) was amplified and sequenced from multiple anatomic sites, and a common clone containing a single nucleotide polymorphism was determined to be defective in response to phorbol myristate acetate (PMA)-mediated promoter activation in a reporter gene assay. This assay revealed a previously unidentified PMA response element within the FIV U3 region 3' to the TATA box. The possible implications of these results on FIV-lymphoma pathogenesis are discussed.

Treatment of chronically FIV-infected cats with suberoylanilide hydroxamic acid.

Feline immunodeficiency virus (FIV) is a naturally-occurring, large animal model of lentiviral-induced immunodeficiency syndrome, and has been used as a model of HIV pathogenesis and therapeutic interventions. HIV reservoirs in the form of latent virus remain the primary roadblock to viral eradication and cure, and FIV has been previously established an animal model of lentiviral latency. The goal of this study was to determine whether administration of the histone deacetylase inhibitor (HDACi) suberoylanilide hydroxamic acid (SAHA) to aviremic, chronically FIV-infected cats would induce latent viral reactivation in vivo. A proof-of-concept experiment in a Transwell co-culture system demonstrated the ability of SAHA to reactivate latent virus which was replication competent and able to infect naïve cells. Oral SAHA (250mg/m(2)) was administered with food to four asymptomatic, experimentally FIV-infected cats and one uninfected control cat, and a limited pharmacokinetic and pharmacodynamic analysis was performed. A statistically significant increase in cell-associated FIV RNA was detected in the cat with the greatest serum SAHA exposure, and cell-free viral RNA was detected at one time point in the three cats that achieved the highest levels of SAHA in serum. Interestingly, there was a significant decrease in viral DNA burden at 2h post drug administration in the same three cats. Though the sample size is small and the drug response was modest, this study provides evidence that in vivo treatment of FIV-infected cats with the HDACi SAHA can induce viral transcriptional reactivation, which may be dependent upon the concentration of SAHA achieved in blood. Importantly, alternative putative antilatency therapy drugs, and multimodal drug combinations, could be studied in this in vivo system. The FIV/cat model provides a unique opportunity to test novel therapeutic interventions aimed at eradicating latent virus in vivo.