Tetrapetalonema dunni sp. n. (Nematoda: Filarioidea) from Malaysian Tree Shrews

Abstract

Tetrapetalonema dunni, a new species of filariid from Malaysian tree shrews, is described, based on specimens obtained from Tupaia glis. The parasite has been found in several Tupaia species from the Malay Peninsula and North Borneo. T. dunni is much smaller in both adult and microfilarial stages than T. marmosetae or T. tamarinae, to which it seems most closely related, and it is the only one of these 3 species found in Asian primates. Dunn (1964) reported, without describing it in detail, an unsheathed microfilaria in samples of blood taken from tree shrews (Tupaia spp.) collected on the Malay Peninsula and in North Borneo. Subsequently, each of us, while independently engaged in studying parasites of tree shrews at the Institute for Medical Research in Kuala Lumpur, Malaysia, and at the Delta Regional Primate Research Center of Tulane University in Covington, Louisiana (USA), collected the same microfilaria, together with adult worms. This report describes adult worms recovered at necropsy from the subcutaneous tissues of Tupaia glis and T. tana in Malaysia and records observations on the apparent host and geographical range of the parasite, based on data collected from 1965 to 1971. MATERIALS AND METHODS The presence of microfilariae in animals was detected by examining heart blood laked and sedimented in 2% formalin (Knott, 1939), then stained with methylene blue (1:1,000) or by examining thick blood films also prepared from heart blood and stained with Field's stain. For Received for publication 13 June 1972. * This work was supported in part by the University of California International Center for Medical Research and Training (UC ICMRT) through research grant AI 10051 to the Department of International Health, School of Medicine, University of California, San Francisco, and research grant No. FR 00164 DRFR, both from the NIH, U. S. Public Health Service. t Institute for Medical Research, Kuala Lumpur, Malaysia, and the Department of International Health, University of California, San Francisco, California. + Tulane University, Delta Regional Primate Research Center, Covington, Louisiana 70433. Requests for reprints should be sent to the Editor, G. W. Hooper Foundation, University of California, San Francisco, California 94122, USA. detailed study of the microfilaria, additional thick blood films were stained with dilute Giemsa (35 drops/100 ml buffer, pH 7.2) for 45 to 60 min. At necropsy, adult worms were either teased from the tissues with fine dissecting needles or were recovered by soaking the skin and carcass in warm, physiological saline solution. Worms were fixed in glacial acetic acid for a few minutes (Berland, 1961), transferred to 70% ethanol containing 5% glycerin, then cleared in pure glycerin fo study. En face mounts were prepared according to the method of Anderson (1958). A modification of the same technique was employed in visualizing the spicules and caudal papillae. Study of the spicule morphology was aided by the partial digestion of the male tail in a 10% solution of Cl rox (sodium hypochlorite). All measurements are in microns unless otherwise noted; ranges are followed by the means in parentheses. Drawings were made with the aid of a camera lucida or similar device.