Leucocytozoon grusi sp. n. (Sporozoa: Leucocytozoidae) from a Sandhill Crane, Grus canadensis (L.)

Abstract

Leucocytozoon grusi sp. n. from a sandhill crane, Grus canadensis (L.), is described, and the species compared with similar forms in the literature. Potentially useful new characters for the separation of species of the Leucocytozoidae are suggested; these include the area of the parasite, area of host cell nucleus and ratios comparing the area of the normal erythrocyte with the area of the parasite and the area of the host cell-parasite complex. There are few reports of hematozoa from the avian order Gruiformes and only one recorded case of Leucocytozoon infection. Rodhain et al. (1913) noted this parasite in Balaeniceps rex from the Congo and provided a brief description of it, although not designating a specific name. Recently, a series of blood films from sandhill cranes were referred to us for analysis of the hematozoon infections. Several films contained gametocytes of a species of Leucocytozoon whose morphological parameters bore little relationship to other described species of the genus. The species was therefore considered to be new and designated as Leucocytozoon grusi. Concurrent infections of an unknown hemoproteid were also noted in these films. Gametocytes of the Leucocytozoidae are generally difficult to identify, apart from their hosts, on purely morphological grounds. Furthermore, as Fallis and Bennett (1966) and Khan and Fallis (1970) have demonstrated, species of Leucocytozoon from one avian order or family are not normally infective, even under experimental conditions, to members of another order. Some 77 species of Leucocytozoon have been described (Berson, 1960), usually on the basis of the "one host-one parasite" philosophy prevalent in the late 19th and early 20th centuries (Bennett and Laird, 1973). The measurements included in these species descriptions (if measurements were included at all) were the mean and the range-data which are statistically limited and present little information about the normal parasite populaReceived for publication 26 April 1973. * Department of Biology and WHO International Reference Center for Avian Malaria Parasites, Memorial University of Newfoundland, St. John's, Newfoundland, Canada. tion. These facts pose obvious taxonomic problems towards the solution of which certain parameters, previously employed only for the Haemoproteidae by Bennett and Campbell (1972), could be significant. Such parameters include the area of the parasite, the area of the distorted host cell nucleus, and the length and breadth of the distorted host cell nucleus. Certain ratios have also been calculated and these ratios (herein termed indices) are the host nucleus index, the parasite index, and the host-parasite index. These parameters and indices have been obtained for L. grusi and are presented as part of the species descrip-