Prosimian Taxon Advisory Group (TAG) veterinary advisors are Randy Junge, St. Louis Zoo (TAG advisor); Cathy Williams, Duke Lemur Center (Eulemurs, nocturnal lemurs, and sifaka); Roberta Wallace, Milwaukee County Zoo (ring-tailed lemurs); Meg Sutherland-Smith, San Diego Zoo (lorises); and Ilse Stalis, Dan Diego Zoo (pathology). The postmortem protocol has been updated and is available on the AAZV website.
Hemosiderosis and Iron Overload
Recent projects have contributed to clarifying iron storage disease in prosimian species. Historically and anecdotally this syndrome is thought to be important for lemurs in captivity. It has been suggested that high dietary levels of iron combined with low levels of iron binding compounds in captive diets result in excess iron absorption and storage in tissues. A recent survey documented hemosiderosis (iron pigment in tissues) in 32% of lemur postmortem reports; however, hemochromatosis (actual pathology associated with iron deposition) was rare. In a subsequent study that measured iron accumulation in liver tissue of lemur species, ruffed lemurs (Varecia rubra) had highest levels, ring-tailed lemurs (Lemur catta) lowest levels, and black lemurs (Eulemur macaco) intermediate levels. This suggests that there may be species differences in the propensity to develop hemosiderosis. Iron metabolites in serum, specifically ferritin and the calculated transferrin saturation value, may have some value in evaluating iron status in lemurs antemortem; however, correlation of these tests with hepatic iron content showed marked variability within and between taxa. Individual variation between samples was also marked. Thus, the reliability of using these tests to evaluate iron status in individual animals remains uncertain. The development of species-specific reference ranges and performing repeat sampling for individuals may improve the diagnostic value of these tests.
Anesthetic Complications in Giant Mouse Lemurs (Mirza)
Very little information is available regarding appropriate anesthetic drugs and doses for lemurs; however, common anesthetics used in other primate species works well in most lemur species. A major exception is the use of isoflurane anesthesia in giant mouse lemurs (Mirza coquereli). There are several anecdotal reports of respiratory arrest resulting in death in this species when individuals were mask induced with isoflurane. The mechanism is not known, and data is not currently available on the safety of other inhalant anesthetics such as sevoflurane. Until further information is available, inhalant anesthetics should only be used in Mirza sp. with extreme caution.
In attempts to better understand the incidence of diabetes in lemurs in North American zoos, a preliminary survey is being developed for distribution to veterinarians working with lemurs in zoo settings. The goal is to collect preliminary information concerning numbers, species, diagnostic approaches, and treatment used for lemurs suspected of having diabetes.
1. Glenn, K. M., J. L. Campbell, D. Rotstein, et al. 2006. Retrospective evaluation of the incidence and severity of hemosiderosis in a large captive lemur population. Am. J. Primatol. 68:369–381.
2. Williams, C. V., J. L. Campbell, and K. M. Glenn. 2006. Comparison of serum iron, total iron binding capacity, ferritin, and percent transferring saturation in nine species of apparently health captive lemurs. Am. J. Primatol. 68:477–489.
3. Williams, C. V., R. E. Junge, and I. H. Stalis. 2008. Evaluation of iron status in lemurs by analysis of serum iron and ferritin concentrations, total iron-binding capacity, and transferrin saturation. J. Am. Vet. Med. Assoc. 232:578–585.