In March 2003 we began to investigate a syndrome of alopecia in free-ranging ring-tailed lemurs (Lemur catta) at Berenty Reserve, a 2-km2 forest fragment in southern Madagascar. Alopecia was first observed in the ring-tailed lemur population in the late 1990s in troops at the northern edge of Berenty, and by 2002 was observed in troops in the center of the reserve. While no animals exhibited alopecia in March 2003, we had the opportunity to immobilize (tiletamine-zolazepam; Telazol™, Fort Dodge) and evaluate 60 animals in an effort to determine a cause for the alopecia observed earlier in the year. We found no evidence of contagious disease upon examination of these 60 animals. However, subsequent investigation and observation revealed that alopecia was seasonal, first appearing in June and July and becoming more severe in August and September. Hair began to grow back in October and November, and by February/March alopecia was no longer apparent. The annual onset and resolution of alopecia appeared to be associated with the seasonal dependence of the lemurs on Leucaena leucocephala (leucaena) for forage. Further epidemiologic evaluation of 2003 and 2004 census data revealed strong associations between alopecia and the presence of leucaena within home ranges. Furthermore, leucaena exposure appeared to negatively impact infant recruitment. Leucaena, an introduced tree in Madagascar, is known to be toxic to mammals if ingested, particularly to non-ruminants, and has numerous effects including alopecia, growth retardation, and decreased fertility.1-3 Native to Mexico and Central America, leucaena has been promoted worldwide as an efficient source of timber as well as food for humans and livestock.3 Given its global distribution, leucaena may be negatively impacting other wildlife populations.
1. Hammond, A.C. 1995. Leucaena toxicosis and its control in ruminants. J. Anim. Sci. 73:1487–1492.
2. Owen, L.N. 1958. Hair loss and other toxic effects of Leucaena. Vet. Rec. 70(22):454–456.
3. Sethi, P., and P. Kulkarmi. 1995. Leucaena leucocephala: a nutrition profile. United Nations University Press. Food and Nutrition Bulletin. 16(3):1–26.