Suspected macular degeneration in a captive western lowland gorilla (gorilla gorilla gorilla)

The case of a 31-year-old captive female Western lowland gorilla (Gorilla gorilla gorilla) with decreased near vision but good distance vision is presented. Examination of the fundus revealed drusen-like bodies in the macula presumably because of an age-related macular degeneration (AMD).     

Resolution of a hyperprolactinemia in a western lowland gorilla (Gorilla gorilla gorilla).

Prolactin-secreting pituitary adenomas are one of the most common causes of infertility in women. Prolactin plays an important role in lactation and is involved in producing some of the normal mammalian breeding and maternal behaviors. Elevated serum prolactin concentrations can adversely affect the reproductive cycle in females by inhibiting the normal lutenizing hormone surge that stimulates ovulation. A 17-year-old western lowland gorilla (Gorilla gorilla gorilla) presented with low fertility and hyperprolactinemia. An MRI confirmed a pituitary mass and treatment was initiated with cabergoline. Following 8 mo of treatment, mass size decreased and serum prolactin was within normal limits. The gorilla began to engage in normal breeding behavior, and within 6 mo of completing treatment, was pregnant. Hyperprolactinemia, secondary to presumed microprolactinoma, may be more common among breeding-age gorillas than is currently diagnosed and in humans is an easily diagnosed and treatable condition.     

Clostridium septicum myositis in a western lowland gorilla (Gorilla gorilla gorilla).

A 10-yr-old male gorilla (Gorilla gorilla gorilla) with a history of conspecific bite wounds was evaluated for acute onset of depression, anorexia, and right hemiparesis. The animal was immobilized for diagnostic examination and treatment for suspected toxic shock from a necrotizing, emphysematous wound infection, but was euthanized due to complications during recovery. Gross and histopathologic examination revealed acute necrotizing myositis, fasciitis, cellulitis, and emphysema in the affected wound area, with large numbers of large Gram-positive rods among necrotic muscle fibers. Severe pulmonary edema with airways containing fibrin, acute hemorrhage in multiple body sites, thrombosis in blood vessels in the skeletal muscle, liver, and lung, and lymph node hyperplasia with lymphoid necrosis and hemorrhage. Immunohistochemical fluorescent antibody staining of muscle from the wound site was positive for     

Severe idiopathic hypocalcemia in a juvenile western lowland gorilla, Gorilla gorilla gorilla

A 6-mo-old, male western lowland gorilla (Gorilla gorilla gorilla) was evaluated because of tetany of both hands. The gorilla had alternating periods of constipation, diarrhea, and bloating since birth. A diagnosis of idiopathic hypocalcemia was based on severe hypocalcemia, a normal vitamin D level, response to oral calcium and vitamin D therapy, and eventual resolution. Idiopathic hypocalcemia, an uncommon disease in neonatal humans, should be considered in young gorillas with persistent gastrointestinal problems or acute tetany.     

Acute lymphocytic leukemia in a six-month-old western lowland gorilla (Gorilla gorilla gorilla).

A 6-mo-old hand-raised male western lowland gorilla (Gorilla gorilla gorilla) was diagnosed with acute lymphocytic leukemia based on complete blood count and bone marrow cytology. Clinical signs of the disease were pyrexia, abdominal distention, splenomegaly, and lethargy. Acute lymphocytic leukemia has rarely been reported in this species, and therapy was based on human oncologic protocols. Remission induction chemotherapy resulted in complete clearing of leukemia cells from the bone marrow. Consolidation and maintenance chemotherapy followed. Therapy was facilitated by the use of an infusion port for i.v. treatments and an indwelling lumbar catheter for intrathecal therapy. Side effects associated with chemotherapy were inappetence, moderate alopecia, pancytopenia resulting in sepsis, and bleeding tendency. In spite of initial success, the leukemia reappeared 120 days into treatment. The gorilla was euthanized 7 days later when respiratory distress developed. Intensive care by the animal staff was a key factor in the treatment of this gorilla.     

Chorionic villus sampling for sex determination in a western lowland gorilla (Gorilla gorilla gorilla).

Chorionic villus sampling was undertaken on an anesthetized gorilla (Gorilla gorilla gorilla) to determine the fetal sex in the first trimester of pregnancy. The tissue samples were subject to sex determination by polymerase chain reaction, fluorescent in situ hybridization, and cell culture with cytogenetic analysis. Polymerase chain reaction testing was found to be the most accurate and rapid method of sex determination on this tissue sample.     

Chronic hypertension with subsequent congestive heart failure in a western lowland gorilla (Gorilla gorilla gorilla).

Chronic severe subclinical systemic hypertension was diagnosed in a 28-yr-old male western lowland gorilla (Gorilla gorilla gorilla). Thoracic radiography, electrocardiography, and echocardiography revealed an enlarged heart with a hypertrophied left ventricle, mitral regurgitation, and a persistent left bundle branch block. Enalapril, later combined with nifedipine, was of some value in reducing the hypertension, with partial reversal of cardiac enlargement and resolution of the bundle branch block. Two years after initiation of treatment, the gorilla developed lethargy and dyspnea. The diagnosis of heart failure was confirmed under anesthesia; the gorilla did not recover and was euthanized. Postmortem examination confirmed congestive heart failure with chronic, fibrosing cardiomyopathy similar to that in other gorillas.     

Clinical management of a western lowland gorilla (Gorilla gorilla gorilla) with a cardiac resynchronization therapy device

A 24-yr-old, male western lowland gorilla (Gorilla gorilla gorilla) was diagnosed with congestive heart failure using transesophageal and transthoracic echocardiology. New York Heart Association (NYHA) Class III was assigned to the severity of the condition. Over 16 mo, this progressed to NYHA Class IV despite increasing medical therapy. Repeated evaluations suggested that implantation of a cardiac resynchronization therapy device with a defibrillator (CRT-D) could benefit this animal based on clinical signs and underlying evidence of dyssynchrony and suspected fibrotic myocardial disease. Surgical implantation of leads into the right atrium, right ventricle, and left ventricle was accomplished. The CRT-D device was placed under the thoracic pectoral muscles during an initial surgical procedure. Improvement in the gorilla's clinical condition after implantation of the CRT-D device was immediate and dramatic. Subsequent scanning of the device was accomplished through operant conditioning. The data from these device interrogations included stored and real-time cardiac data, which were used to minimize recognized environmental stressors and change device settings. Over 4 yr, case management was critical to successful device use in treatment of the clinical disease. This involved medications, training for device interrogation, exercise to increase activity and improve body condition, and phlebotomy attempts. Dietary management was necessary to manipulate caloric and sodium intake and encourage medication compliance. Cardiac resynchronization therapy device implantation, although requiring specialized equipment and surgical skill, appears to be a viable option for treatment of fibrosing cardiomyopathy with systolic dysfunction in gorillas refractory to medical management. In addition to treatment, this device provides cardiovascular data at rest that could allow for early diagnosis and treatment of gorillas with this and other cardiac conditions in the future. This describes the comprehensive medical, husbandry, and training techniques necessary to successfully manage this intense clinical case in conjunction with intracardiac device therapy.     

Management of reactive arthritis in a juvenile gorilla (Gorilla gorilla gorilla) with long-term sulfasalazine therapy.

A juvenile western lowland gorilla (Gorilla gorilla gorilla) experienced recurrent fever, lethargy, diarrhea, and/or arthritis starting at age 6 mo. During an episode at age 15 mo, Shigella sp. was isolated from diarrheic feces. At age 41 mo, reactive arthritis was diagnosed. In addition, the gorilla's growth was retarded. All arthritic attacks were managed symptomatically prior to age 4 yr, at which time a severe episode precipitated the implementation of therapy with sulfasalazine, an arthritis suppressive medication. Examination 27 mo later revealed cessation of progressive joint pathology although the animal exhibited decreased range of motion in most joints. The gorilla has been on sulfasalazine therapy for 4 yr without lameness. Growth has resumed, and there has been no radiographic evidence of progressive joint degeneration. Immunogenetic analysis of whole blood obtained at age 68 mo identified the gorilla major histocompatibility class I allele, Gogo-B*0101, which has limited nucleotide sequence similarity to HLA-B27, an allele associated with postinfection reactive arthritis in humans. Sulfasalazine therapy effectively managed reactive arthritis in this gorilla and should be considered for similarly frequently affected animals. Juvenile gorillas, in populations with a history of clinical shigellosis and/or postdiarrhea arthritis, may benefit from prophylactic sulfasalazine therapy after episodes of bacterial enterocolitis. Sulfasalazine therapy should be considered in all gorillas, juvenile and adult, experiencing confirmed Shigella sp.-associated enterocolitis.     

Diagnosis of hypothyroidism in a western lowland gorilla (Gorilla gorilla gorilla) using human thyroid-stimulating hormone assay.

Primary hypothyroidism was diagnosed in a 26-yr-old female western lowland gorilla (Gorilla gorilla gorilla) on the basis of serum levels of thyroxine (T4), free T4, and thyroid-stimulating hormone (TSH) measured by human immunoassays. Compared with clinically normal gorillas, the TSH level (107 mlIU/L) was markedly elevated, and T4 (<14.0 nmol/L) and free T4 (5.0 pmol/L) levels were decreased. Thyroid hypofunction could explain the weight gain, unsettled appetite, anxious behavior, lethargy, and poor intraspecies interactions shown by this gorilla. The antibodies in the commercial immunoassay used in this study apparently cross-reacted with gorilla TSH. Supplementation with levothyroxine sodium was initiated and was followed by a marked decrease in circulating TSH and a noticeable improvement in the animal's physiologic status and activity level.     

Dose related mucosal hyperplasia induced by Oesophagostomum dentatum infection in pigs.

The present work was undertaken to examine the effects of 3 different population densities of Oesophagostomum dentatum upon the development of worm induced mucosal changes in the colon following single infections. Groups of pigs were infected with single doses of 2000 (low dose), 20,000 (medium dose) or 200,000 (high dose) infective larvae, respectively. A total of 18 infected pigs (6 from each group) were examined for histopathological changes together with 3 helminth-free control pigs. There was a dose related difference in the intensity of colonic lesions; and using morphometry it was observed that the mucosal crypts of pigs in the high dose group were significantly longer than those in the 2 other groups. These differences disappeared by day 25 after infection despite the presence of larvae in the mucosa of the high dose group. This phenomenon may be related to inflammatory reactions in the colon, possibly in connection with the initiation of an immunological response in sites distant from the parasite larvae.