Cathy V. Williams

Five of a cohort of 13 aye-ayes (Daubentonia madagascariensis) at the Duke Lemur Center (DLC) exhibited acute, nonspecific signs of lethargy and ataxia within 24 h of ingesting a meal containing avocado fruit (Persea americana) that included the skin and pit. Deaths rapidly ensued in four of the five animals within 13 h of initial symptoms. All animals that died had pericardial effusion on postmortem examination and microscopic findings of acute myocardial degeneration. After ruling out other causes, all evidence points to avocado toxicity as the cause of death. Following an analysis of the DLC deaths in 2016, all deaths in aye-ayes from 1985 to 2022 occurring at the DLC or on loan to other institutions were reviewed. An additional six cases of acute death and pericardial effusion associated with cardiomyopathy and acute myocardial degeneration were identified for a total of 10 of 27 deaths (37%) over 37 yr. This analysis led the authors to conclude that aye-ayes may be acutely sensitive to toxins present in avocado and that mortality due to avocado toxicosis in this species is more common than previously recognized. Prior stress on animals in advance of avocado consumption may have contributed to the acute myocardial degeneration and death following avocado fruit ingestion, as noted in this report. Avocado toxicosis has been reported in various avian and mammalian species, but adverse effects have not been previously noted in other lemur or primate species. This case series is of particular interest because all affected animals had regularly been fed avocado previously and some zoologic institutions routinely use avocado in diets for primates.

A new species of the genus Lemuralges Fain, 1963 (Acariformes: Psoroptidae: Makialginae) is described from the Malagasy lemur Propithecus diadema (Bennett) (Primates: Indriidae) based on all postembryonic instars. This new species differs from the only known species in this genus, Lemuralges intermedius Fain, 1963, by the following features: both sexes of L. propithecus sp. n. show a pair of medioventral projections of the subcapitulum (vs without projections in L. intermedius) and the propodonotal shield is slightly ornamented (vs unornamented); in males the hysteronotal shield is completely covered by longitudinal striae (vs median part without striae), setae c2 are 120-140 µm long (vs 200-210 µm long), and femur III has a short transverse furrow dorsally (vs a longitudinal furrow); in females, setae h2 are, at least, 2 times shorter than h3 (vs slightly longer, or subequal to, h3), tibia IV has a ventro-apical projection (vs without projection). Larvae and protonymphs of the new species show some unique developmental delays. Female and male tritonymphs differ by their external morphology.

Lemurs kept in captivity have been reported to be highly prone to accumulate excessive amounts of iron in tissues (hemosiderosis). Diagnosis of the condition is most commonly made during a postmortem examination because an antemortem diagnosis requires a liver biopsy, a procedure that may not be well tolerated by all animals. The lack of a noninvasive method to evaluate iron status in captive lemurs limits investigators' ability to effectively screen animals for the presence of hemosiderosis, and to detect the condition early when treatment protocols are most effective. This study was conducted in an effort to provide data regarding iron analyte values in healthy captive lemurs of multiple species. The relationship of various iron‐related metabolites was evaluated in 177 clinically normal lemurs of nine different species. Serum iron (sI), total iron binding capacity (TIBC), and ferritin concentration were measured directly and the percent transferrin saturation (TS) was calculated. Significant differences in various iron metabolites were observed among several species, suggesting that normal reference values for iron metabolites in lemurs may need to be developed on a species by species basis. Am. J. Primatol. 68:1–13, 2006.

A naturally occurring infection of Ehrlichia chaffeensis in lemurs is described. DNA of Ehrlichia chaffeensis was identified by polymerase chain reaction in peripheral blood from six of eight clinically ill lemurs. Organisms were cultured from the blood of one lemur exhibiting clinical and hematologic abnormalities similar to those of humans infected with E. chaffeensis.