Abstract
Medical records of 15 black howler monkeys (Alouatta caraya) were reviewed. Six of the 15 (40%) records included a diagnosis of renal disease. The six animals were wild caught and included three males and three females. The hematologic and serum values, gross and histopathologic abnormalities, as well as subjective clinical findings were compared and documented. Further comparisons included age of onset of disease, duration of disease and age at death. Average age of onset of azotemia was 14.8±2.9 yr while the average age at subjective notation of clinical signs was 17±4.7 yr. For most of the cases (66.6%), the mean age of onset of azotemia (14.8±2.9 yr of age) was often much earlier that the onset of notation of clinical disease (17.7±4.7 yr of age). Average duration of disease was found to be 2.83±1.6 yr with an average age at euthanasia of 18±4.7 yr. Chronic tubulointerstitial nephritis with secondary glomerular sclerosis was the common histopathologic lesion in all the cases. Further investigations into specific etiologies of chronic tubulointerstitial disease in this species are warranted.
Conclusions
1. A high prevalence (40%) of irreversible, chronic renal disease exists in the black howler monkeys in this study. The etiology of the disease is unknown at this time.
2. Onset of azotemia appears in middle-age to older animals (14.8±2.9 yr).
3. This disease appears to be chronic in nature with duration of disease in 50% of the cases averaging 3–4 yr.
4. In azotemic patients, helpful diagnostic aids to determine extent of renal disease include urinalysis, UP:UC, urine protein electrophoresis, survey and contrast radiology, and ultrasonography. Antemortem investigation into etiologies of renal disease, nephron component involvement, and degree of tissue damage may warrant renal biopsy.
5. Supportive care with oral fluid supplementation, dietary protein restriction, and phosphate binding therapy may have contributed to the slow progression of disease.
6. The decline in quality of life warranting euthanasia corresponded to dramatic progression of azotemia (BUN = 124±58.9 mg/dl, creatinine = 7.8±1.4 mg/dl).
7. Chronic tubulointerstitial nephritis with secondary glomerular sclerosis was the common histopathologic lesion in all the cases.