Nico J. Schoemaker

The role of luteinizing hormone in the pathogenesis of hyperadrenocorticism in neutered ferrets

Four studies were performed to test the hypothesis that gonadotrophic hormones, and particularly luteinizing hormone (LH) play a role in the pathogenesis of ferrets: (I) adrenal glands of ferrets with hyperadrenocorticism were studied immunohistochemically to detect LH-receptors (LH-R); (II) gonadotrophin-releasing hormone (GnRH) stimulation tests were performed in 10 neutered ferrets, with measurement of androstenedione, 17alpha-hydroxyprogesterone and cortisol as endpoints; (III) GnRH stimulation tests were performed in 15 ferrets of which 8 had hyperadrenocorticism, via puncture of the vena cava under anesthesia; and (IV) urinary corticoid/creatinine (C/C) ratios were measured at 2-week intervals for 1 year in the same ferrets as used in study II. Clear cells in hyperplastic or neoplastic adrenal glands of hyperadrenocorticoid ferrets stained positive with the LH-R antibody. Plasma androstenedione and 17alpha-hydroxyprogesterone concentrations increased after stimulation with GnRH in 7 out of 8 hyperadrenocorticoid ferrets but in only 1 out of 7 healthy ferrets. Hyperadrenocorticoid ferrets had elevated urinary C/C ratios during the breeding season. The observations support the hypothesis that gonadotrophic hormones play a role in the pathogenesis of hyperadrenocorticism in ferrets. This condition may be defined as a disease resulting from the expression of LH-R on sex steroid-producing adrenocortical cells.

Use of a gonadotropin releasing hormone agonist implant as an alternative for surgical castration in male ferrets (Mustela putorius furo)

Surgical castration in ferrets has been implicated as an etiological factor in the development of hyperadrenocorticism in this species due to a castration-related increase in plasma gonadotropins. In search for a suitable alternative, the effect of treatment with the depot GnRH-agonist implant, deslorelin, on plasma testosterone concentrations and concurrent testes size, spermatogenesis, and the typical musky odor of intact male ferrets was investigated. Twenty-one male ferrets, equally divided into three groups, were either surgically castrated, received a slow release deslorelin implant or received a placebo implant. Plasma FSH and testosterone concentrations, testis size and spermatogenesis were all suppressed after the use of the deslorelin implant. The musky odor in the ferrets which had received a deslorelin implant was less compared to the ferrets which were either surgically castrated or had received a placebo implant. These results indicate that the deslorelin implant effectively prevents reproduction and the musky odor of intact male ferrets and is therefore considered a suitable alternative for surgical castration in these animals.

Ferret oncology: diseases, diagnostics, and therapeutics

Neoplastic disease is common in ferrets. Approximately half of all tumors diagnosed in ferrets are located in the endocrine or hemolymphatic system. Many factors may influence the choice of treatment. Medical management of adrenal tumors has a greater disease-free period compared to adrenalectomy. In ferrets with an insulinoma, no difference is seen in the mean survival time of medically and surgically treated patients. Aside from medical and surgical treatment modalities, chemotherapy and radiation therapy have also been described in ferrets in other types of tumors. The outcome of these treatment modalities is not always favorable.

Severe leukopenia and liver necrosis in young African grey parrots (Psittacus erithacus erithacus) infected with psittacine circovirus.

This paper describes the signs, clinical pathology, and postmortem findings in 14 young African grey parrots (Psittacus erithacus erithacus) that were naturally infected with psittacine beak and feather disease (PBFD) virus (psittacine circovirus). All but two of the parrots had severe leukopenia at clinical presentation. Two other parrots also had severe anemia. All birds died within 3 wk after presentation. Postmortem examination documented liver necrosis in 11 of 14 birds and secondary bacterial or fungal infections in 9 of 14 birds. Tests for Chlamydia psittaci, polyomavirus, and Salmonella sp. were negative. PBFD viral infection could be demonstrated in all birds by polymerase chain reaction. Supporting evidence of PBFD viral infection was gathered by histologic examination of the bursa of Fabricius, electron microscopy, and DNA in situ hybridization. Electron microscopic examination of both the bursa of Fabricius and liver revealed virus particles resembling circovirus. DNA in situ hybridization of six liver tissue samples confirmed the presence of PBFD virus and excluded the presence of avian polyomavirus. Our findings suggest that a specific presentation of peracute PBFD viral infection, characterized by severe leukopenia, anemia, or pancytopenia and liver necrosis in the absence of feather and beak abnormalities, may occur in young African grey parrots.

Functional CD1d and/or NKT cell invariant chain transcript in horse, pig, African elephant and guinea pig, but not in ruminants

CD1d-restricted invariant natural killer T cells (NKT cells) have been well characterized in humans and mice, but it is unknown whether they are present in other species. Here we describe the invariant TCR α chain and the full length CD1d transcript of pig and horse. Molecular modeling predicts that porcine (po) invariant TCR α chain/poCD1d/α-GalCer and equine (eq) invariant TCR α chain/eqCD1d/α-GalCer form complexes that are highly homologous to the human complex. Since a prerequisite for the presence of NKT cells is the expression of CD1d protein, we performed searches for CD1D genes and CD1d transcripts in multiple species. Previously, cattle and guinea pig have been suggested to lack CD1D genes. The CD1D genes of European taurine cattle (Bos taurus) are known to be pseudogenes because of disrupting mutations in the start codon and in the donor splice site of the first intron. Here we show that the same mutations are found in six other ruminants: African buffalo, sheep, bushbuck, bongo, N’Dama cattle, and roe deer. In contrast, intact CD1d transcripts were found in guinea pig, African elephant, horse, rabbit, and pig. Despite the discovery of a highly homologous NKT/CD1d system in pig and horse, our data suggest that functional CD1D and CD1d-restricted NKT cells are not universally present in mammals.

Ultrasonographic Visualization of the Adrenal Glands of Healthy Ferrets and Ferrets With Hyperadrenocorticism

A protocol was developed to compare the ultrasonographic characteristics of the adrenal glands of 21 healthy ferrets and 37 ferrets with hyperadrenocorticism. By using specific landmarks, the adrenal glands were imaged in 97% of the cases. The adrenal glands of ferrets with hyperadrenocorticism had a significantly increased thickness, with changes in shape, structure, and echogenicity compared to the adrenal glands of healthy ferrets. Based on the findings of the study, adrenal glands may be classified as abnormal when they have a rounded appearance, increased size of the cranial/caudal pole (thickness >3.9 mm), a heterogeneous structure, increased echogenicity, and/or signs of mineralization.

Myofasciitis in the domestic ferret

Since late 2003, an inflammatory disease of muscle and fascia has been diagnosed in several ferrets at Northwest ZooPath, and this report describes the condition in 17 ferrets. It is a disease of young ferrets, characterized by rapid onset of clinical signs, high fever, neutrophilic leukocytosis, treatment failure, and death (or euthanasia). Gross lesions include atrophy of skeletal muscle; red and white mottling and dilatation of the esophagus; and splenomegaly. Histologically, moderate to severe suppurative to pyogranulomatous inflammation is in the skeletal muscle and the fascia at multiple sites, including esophagus, heart, limbs, body wall, head, and lumbar regions. Myeloid hyperplasia of spleen and/or bone marrow also is a prominent feature. Ultrastructural lesions include mitochondrial swelling, intracellular edema, disruption of myofibrils and Z bands. Bacterial and viral cultures, electron microscopy, immunohistochemistry, and polymerase chain reaction were negative for a variety of infectious agents. The clinical presentation and distribution of lesions suggests that polymyositis in domestic ferrets is likely a distinct entity. The etiopathogenesis if this condition is not known.

Hypercalcemia in Two Amazon Parrots with Malignant Lymphoma

SUMMARY. Malignant lymphoma is a common malignancy in birds. Paraneoplastic syndromes, which are commonly observed in domestic animals, have not been reported in association with lymphoma in birds. Hypercalcemia and hyperglobulinemia were found on plasma chemistry in two Amazon parrots, which were presented with aspecific symptoms. In both cases radiography and ultrasound demonstrated signs of hepatomegaly, which proved to be due to malignant lymphoma on postmortem examination. The hypercalcemia was found to be most consistent with a paraneoplastic effect of the malignant lymphoma in these birds. The exact origin of the hyperglobulinemia remains unclear.

Pain Management in Ferrets

The growing popularity of ferrets as pets has created the demand for advanced veterinary care for these patients. Pain is associated with a broad range of conditions, including acute or chronic inflammatory disease, neoplasia, and trauma, as well as iatrogenic causes, such as surgery and diagnostic procedures. Effective pain management requires knowledge and skills to assess pain, good understanding of the pathophysiology of pain, and general knowledge of pharmacologic and pharmacodynamic principles. Unfortunately, scientific studies on efficacy, pharmacokinetics, pharmacodynamics, and safety of analgesic drugs in the ferret are limited. However, basic rules on the treatment of pain and mechanisms of action, safety, and efficacy of analgesic drugs in other species can be adapted and applied to pain management in ferrets. This article aims to make an inventory of what is known on the recognition of pain in ferrets, what analgesic drugs are currently used in ferrets, and how they can be adopted in a patient-orientated pain management plan to provide effective pain relief while reducing and monitoring for unwanted side effects.

Polyuria and polydipsia due to vitamin and mineral oversupplementation of the diet of a salmon crested cockatoo (Cacatua moluccensis) and a blue and gold macaw (Ara ararauna).

This paper describes a salmon-crested cockatoo (Cacatua moluccensis) and a blue and gold macaw (Ara ararauna) of one owner, both presented with polyuria/polydipsia and weight loss. A tentative diagnosis of hypervitaminosis D(3) was based on the condition of hypercalcaemia, radiological findings and dietary history. On postmortem examination of the cockatoo, metastatic calcifications in the kidneys, lungs and proventriculus were seen. The diet was found to be oversupplemented with vitamin and mineral mixtures. The dietary concentrations of vitamins D(3) and A were over 20-fold higher than the recommended levels. The diet also contained more calcium than is recommended. Although macaws are considered to be more susceptible to hypervitaminosis D(3) than other psittacines, the cockatoo had more severe signs and died.