Some Parasites of the Howler Monkey of Northern Argentina

Abstract

A large series of wild howler monkeys (Alouatta caraya) of northern Argentina was found to be infested by a louse, Pediculus mjobergi; a pinworm, Trypanoxyuris (Trypanoxyuris) minutus; and a tapeworm, Bertiella mucronata. There was a sex-related difference in louse infestations before and after sexual maturity. This phenomenon may reflect a difference in hormonal status of male and female howler monkeys that is present before sexual maturity and to which the lice are sensitive. Five of the six tapeworm infections were in older animals, one in a late juvenile, and none in the younger. This correlation with time is expected from what is known of the life cycle of the parasite and is here demonstrated within a wild-caught population sample. During August 1964, postmortem findings were recorded on more than 300 wild-caught howler monkeys, Alouatta caraya (Humboldt, 1812), in Bella Vista, Provincia de Corrientes, Argentina, South America. During autopsy, three parasite species were observed: a louse, Pediculus mjobergi; a pinworm, Trypanoxyuris minutus; and a tapeworm, Bertiella mucronata (Table I). Representative samples of lice were sent to Dr. William L. Jellison, USPHS-RML, for specific determination. His identification of these specimens as Pediculus mjobergi Ferris (1916) has been confirmed by C. F. W. Muesebeck, U. S. National Museum, in whose collection material has also been deposited. Nematodes were sent to Dr. William Inglis, British Museum (Natural History), London, England, who identified them as Trypanoxyuris (Trypanoxyuris) minutus (Schneider, 1866) Inglis and Diaz-Ungria, 1959. The tapeworms were identified by the author as Bertiella mucronata (Meyner, 1895), the New World variation of B. studeri (Blanchard, 1891), see Baer, 1927. Additional unstained material has been given to Dr. Paul C. Received for publication 21 June 1965. * Publication No. 91 from the Oregon Regional Primate Research Center, supported in part by grant FR-00163 of the NIH. Beaver, Tulane University, Department of Tropical Medicine and Public Health, for further research in the clarification of the studerimucronata problem.