Subgross investigation of vessels originating from arcus aortae in guinea-pig (Cavia porcellus)

The vessels that originate from the aortic arch were studied in 16 adult guinea-pigs. Two major vessels, the left subclavian artery and the brachiocephalic trunk, were easily identified as they were branching off from the aortic arch. The brachiocephalic trunk, at first branched off to the left common carotid artery and continued as a common trunk, which was then divided into the right subclavian artery and the right common carotid artery. The left subclavian artery branched off to the following vessels: the costacervical trunk, the internal thoracic artery, a common trunk from which the dorsal scapular artery and the vertebral artery originated, and the superficial cervical artery. The right subclavian artery branched off to the bronchoesophageal artery (in five cadavers), the caudal thyroid artery (in three cadavers) and the tracheal artery (in three cadavers) in addition to the above vessels. There were two vertebral arteries branching off to the right subclavian artery in all dissected cadavers. However, only 10 cadavers had two vertebral arteries originating from the left subclavian artery. The first vertebral artery originated from the common trunk, whereas the second vertebral artery arose from the dorsal scapular artery. The second vertebral artery entered the foramen transversarium of the seventh cervical vertebrae and anastomosed with the first vertebral artery just before entering the foramen transversarium of the sixth cervical vertebrae.     

Generalized Taenia crassiceps cysticercosis in a chinchilla (Chinchilla lanigera)

Taenia crassiceps is a cestode parasite that uses carnivores as definitive hosts and rodents and rabbits as main intermediate hosts, but other animal species and humans may also get infected. One adult male chinchilla (Chinchilla lanigera) from an animal shelter in Switzerland presented widespread subcutaneous fluctuant swellings extended over the forehead, nose, face and thoracic regions with a progressive growth over 3 months. The thoracic swelling was surgically resected, and it consisted of numerous 3–4 mm small transparent vesicles, mainly confined to the subcutaneous tissue, which were morphologically identified as cysticerci of T. crassiceps. The diagnosis was confirmed by PCR and DNA sequence analysis of fragments of the mitochondrial small subunit rRNA and NADH dehydrogenase subunit 1 genes. After 1.5 months, due to enlargement of the swollen areas and deterioration of the general health condition, the chinchilla was euthanized and a necropsy was performed. Thousands of small cysticerci were observed widespread in the subcutis, involving underlying musculature of the whole body, in the thoracic cavity, larynx, pharynx and in the retropharyngeal region. Additionally, three larger metacestodes were detected in the liver and morphologically and molecularly identified as Taenia taeniaeformis strobilocerci. The present case represents an indicator of the environmental contamination with Taenia eggs, highlighting the risk of infection for susceptible animals and humans. Besides the clinical relevance for pets, T. crassiceps is a zoonotic parasite and can be also cause of severe cysticercosis in humans.     

Gross morphological features of plexus brachialis in the chinchilla (Chinchilla lanigera)

This study documents the detailed features of the morphological structure and the innervation areas of the plexus brachialis in the chinchilla (Chinchilla lanigera). The animals (5 female and 5 male) were euthanased with ketamine hydrocloride and xylazine hydrocloride combination, 60 mg/kg and 6 mg/kg, respectively. Skin, muscles and nerves were dissected under a stereo-microscope. The brachial plexus of the chinchilla is formed by rami ventrales of C5-C8, T1 and T2, and possesses a single truncus. The subscapular nerve is formed by the rami of the spinal nerves originating from C6 (one thin ramus) and C7 (one thick and 2 thin rami). These nerves innervate the subscapular and teres minor muscles. The long thoracic nerve, before joining with the brachial plexus, obtains branches from C6 and C7 in 5 cadavers (3 male, 2 female), from C7 in 4 cadavers (2 male, 2 female) and from C6-C8 in only 1 female cadaver. These nerves disperse in variable combinations to form the extrinsic and intrinstic named, nerves of the thoracic limb. An undefined nerve branch originates from the rami ventrales of C7, C8 and T1 spinal nerves enter the coracobrachial muscle.     

The right coronary artery is absent in the chinchilla (Chinchilla lanigera)

A total of 10 adult, healthy, male chinchillas (Chinchilla lanigera) were used to investigate the origin, course, and termination of the coronary arteries. Coloured latex was injected into the carotid arteries following conventional anatomical applications. In all the chinchillas examined, the left coronary artery was the single coronary artery. The right coronary artery was missing. Additionally, a small vessel originating from the cranial border of the aorta was observed in one chinchilla. The left coronary artery divided into the paraconal, interventricular and left circumflex rami. The left marginis ventricular ramus arose from the paraconal interventricular ramus in eight chinchillas, and from the left circumflex ramus in two. The ventricular and septal branches of the left coronary artery ran subepicardially at the beginning mostly parallel to the muscle fibres, also surrounded by a thin adipose tissue. It was concluded that the only left coroner artery supplied blood to the heart in the chinchilla.     

Cleft Palate in a Chinchilla (Chinchilla lanigera)

A 5-month-old female chinchilla (Chinchilla lanigera) was evaluated for failure to thrive, difficulty drinking, and respiratory signs. Physical examination demonstrated a thin body condition score, purulent nasal and ocular discharge, and an abnormal facial appearance. Endoscope-guided oral examination and computed tomography (CT) scan demonstrated a cleft soft palate, absent nasal turbinates, and bilateral otitis media. The animal was euthanized and necropsy confirmed the diagnosis of palatoschisis (cleft palate) of the soft palate. Other relevant postmortem findings included otitis media, interna, and externa, bony bullae proliferative changes, absent nasal turbinates and rhinosinusitis. Congenital abnormalities are rarely reported in chinchillas. While cleft palates have been reported in many other domestic animals, there are no published reports of this condition in chinchillas to the best of the authors’ knowledge.     

Ultrasonographic Features of the Chinchilla (Chinchilla lanigera) Kidney

Nine healthy chinchillas (Chinchilla lanigera) were used to characterize the ultrasonographic size and anatomical structure of the kidneys. Sonographic evaluations were performed with the aid of a 12-MHz linear probe. Kidney measurements included total width and length, total organ area, cortex and medullary thickness, and width and length of the renal pelvis. Based on the results of this study, normal chinchilla kidneys are located retroperitoneally, with the right kidney in a more cranial location than the left. Statistical analysis showed that measurements were similar between contralateral kidneys and between sexes. Chinchilla kidneys have a single papilla and a wider renal pelvis compared with the renal pelvis of dogs and cats. Moreover, chinchilla kidneys have a longer medullary area. The data herein may aid diagnosis of renal disease in chinchillas, avoiding misinterpretations of ultrasonic findings involving the kidneys of this species.     

Semen-Matrix Calculi in a Juvenile Chinchilla (Chinchilla lanigera)

A 10-month-old, intact male chinchilla (Chinchilla lanigera) was diagnosed with urolithiasis, unilateral hydroureter, and hydronephrosis secondary to ureteral obstruction confirmed by radiography and ultrasonography. Nephrectomy and cystotomy were performed, and the urolith was suspected to be a semen-matrix calculus (mineralized copulatory plug) based on the discovery of sperm within the renal pelvis of the nephrectomized kidney on histopathology; this was later confirmed through a postmortem examination. Three months after initial presentation the chinchilla was diagnosed with recurrent urolithiasis, hydroureter, and hydronephrosis of the remaining kidney and ureter, and euthanized due to poor prognosis. Necropsy confirmed the presence of semen-matrix calculi in the ureter and urinary bladder. Veterinary clinicians should consider semen-matrix calculi as a differential diagnosis for radiopaque calculi within the bladder or urethra of male chinchillas. Pathogenesis may be formation of a coagulum secondary to retrograde ejaculation.     

Reference values for selected ophthalmic diagnostic tests and clinical characteristics of chinchilla eyes (Chinchilla lanigera)

Objective To establish reference values for the Schirmer tear test I (STT I), the phenol red thread tear test (PRTT), the intraocular pressure (IOP) with rebound tonometry, to determine the corneal sensitivity for healthy chinchillas, and to describe clinical aspects of normal chinchilla eyes. Animals One hundred and twenty‐two eyes of 61 healthy pet chinchillas of different age and gender were investigated. Procedures A full ophthalmic exam including slit lamp biomicroscopy, ophthalmoscopy, measurement of STT I, PRTT, determination of the corneal touch threshold (CTT), and the measurement of the IOP (TonoVet®) was performed. The normal appearance of the lid, the iris, the lens, the fundus, and the optic nerve disc was evaluated. Results The results of the STT I were very low and not reliable, and the measurement was discontinued. The median value of PRTT was 14.0 mm wetting/15 s (mean 14.6 ± 3.5 mm wetting/15 s). The median CTT was 32.5 mm (mean 31.2 ± 7.0 mm) respectively 1.2 g/mm² (mean 1.5 ± 0.9 g/mm²). The median IOP was 3.0 mmHg (mean 2.9 ± 1.8 mmHg). The predominating iris color was brown. The fundus pigmentation varied. Few lens alteration were seen in otherwise healthy chinchilla eyes. Most chinchillas had myelinated discs. Optic nerve cupping was present in 62% of the animals. Conclusion Because of the small amount of tears, the PRT test is recommended for tear measurements in chinchillas. The IOP in chinchillas seems to be quiet is low in comparison to other rodents.     

Systematization, distribution and territory of the middle cerebral artery on the brain surface in chinchilla (Chinchilla lanigera)

The aim of the present study was to analyse thirty chinchilla ( Chinchilla lanigera ) brains, injected with latex, and to systematize and describe the distribution and the vascularization territories of the middle cerebral artery. This long vessel, after it has originated from the terminal branch of the basilar artery, formed the following collateral branches: rostral, caudal and striated (perforating) central branches. After crossing the lateral rhinal sulcus, the middle cerebral artery emitted a sequence of rostral and caudal convex hemispheric cortical collateral branches on the convex surface of the cerebral hemisphere to the frontal, parietal, temporal and occipital lobes. Among the rostral convex hemispheric branches, a trunk was observed, which reached the frontal and parietal lobes and, in a few cases, the occipital lobe. The vascular territory of the chinchilla's middle cerebral artery included, in the cerebral hemisphere basis, the lateral cerebral fossa, the caudal third of the olfactory trigone, the rostral two-thirds of the piriform lobe, the lateral olfactory tract, and most of the convex surface of the cerebral hemisphere, except for a strip between the cerebral longitudinal fissure and the vallecula, which extended from the rostral to the caudal poles bordering the cerebral transverse fissure.     

Electroejaculation in the Chinchilla (Chinchilla lanigera): effects of anesthesia on seminal characteristics

Repetitive electroejaculation is probably extremely stressful in conscious animals and could adversely affect fertility. The present study was designed to (a) evaluate the effects of anesthesia (40 mg ketamine/kg body weight, i.m.) on a method of electroejaculation used previously in conscious chinchillas (Chinchilla lanigera), and (b) determine the quality of the electroejaculated semen obtained under anesthesia. In Experiment 1 (8 animals), a 4 x 4 Latin square design was used to study the effects of anesthesia and ejaculatory voltage on semen collection, ejaculate volume, sperm concentration, motility, viability, response to the hypoosmotic swelling test (HOST), and acrosomal status. In Experiment 2 (12 animals), the effects of differing voltages and the number of stimuli on ejaculation by conscious or anesthetized males was determined. In both experiments, all the conscious animals ejaculated, but only 60% ejaculated under anesthesia and they required more stimuli and higher voltages to achieve ejaculation. Ejaculate volume was significantly lower in anesthetized (<5 microl) than in conscious animals (>40 microl), but sperm concentration was unaffected. None of the indices of sperm quality were affected by anesthesia. The techniques we have developed in anesthetized domestic chinchillas should be applicable to endangered chinchillas in the wild, and though the number of sperm available is reduced, there are still sufficient for assisted reproduction.     

Ophthalmic Disorders Observed in Pet Chinchillas (Chinchilla lanigera)

This article presents a retrospective analysis of ocular disorders observed in outpatient pet chinchillas examined in a veterinary clinic between 2000 and 2010. The most common ophthalmic conditions diagnosed during this time period was alteration of the lens (15 eyes, 10 chinchillas), followed by abnormalities of the cornea (14 eyes, 13 chinchillas), and conjunctival disease (10 eyes, 9 chinchillas). The predominant lens disorder was cataracts, whereas the main alteration of the cornea was fluorescein-positive corneal substance loss. Subtle ocular changes appear to be common in the chinchilla. The data gathered within this study indicate that a thorough ophthalmic evaluation is warranted during routine physical examinations for this species.     

Lumbar osteosarcoma in a chinchilla (Chinchilla laniger)

An 11-year-old male chinchilla was presented for investigation of progressive weight loss, apathy, anorexia, changes in faecal quality and alopecia on the tip of the tail. On clinical examination, a stiffness of the back legs was noted. Abdominal palpation revealed a hard immobile, irregular structure in the region of the last lumbar vertebrae. Subsequent radiography and ultrasonography suggested the presence of neoplasia. The following day the chinchilla was showing hindlimb paralysis, and there was severe self-trauma to the distal 5 cm of the tail. In view of the rapid clinical deterioration, the chinchilla was euthanased with the owner's consent. Macroscopic examination supported the clinical suspicion of neoplasia. Histopathological examination revealed a reactive osteoblastic osteosarcoma. To the author's knowledge, this is the first report of osteosarcoma in chinchillas.