Coccidia (Apicomplexa), Genetic Diversity, and Environmental Unpredictability of Four Chromosomal Species of the Subterranean Superspecies Spalax ehrenbergi (Mole-Rat) in Israel

Authors

Lee Couch, University of New MexicoFollow
Donald W. Duszynski, University of New MexicoFollow
Eviatar Nevo, University of Haifa

Date of this Version

4-1993

Comments

Published in the Journal of Parasitology (Apri l1993) 79(2): 181-189. Copyright 1993, the American Society of Parasitologists. Used by permission.

Abstract

Forty-five mole-rats, representing 4 chromosomal species (2n = 52, 54, 58, 60) of the superspecies Spalax ehrenbergi. were collected from 12 localities in Israel in 4 distinct climatic regions. Feces were examined for coccidian oocysts and 41 (91 %) were infected; 26 (63%) had multiple infections of up to 5 coccidian species, 4 of which are described here as new species. Sporulated oocysts of Eimeria anzanensis n. sp. were ellipsoidal 18.3 x 12.5 μm (14-22 x 10-16) and had elongate-ovoidal sporocysts 7.3 x 4.9 μm (5-10 x 3-7); it occurred in 39 of 45 (87%) mole-rats, including all chromosomal species. Sporulated oocysts of Eimeria spalacensis n. sp. were ovoidal 23.4 x 18.3 μm (17-29 x 12-21) with ovoidal sporocysts 9.4 x 6.8 μm (6-12 x 4-10); it occurred in 7 of 45 (16%) mole-rats (2n = 54, 58, 60). Sporulated oocysts of Eimeria carmelensis n. sp. were subspheroidal to ellipsoidal 19.1 x 16.5 μm (14-25 x 11-20) and had sporocysts that were spheroidal to ellipsoidal 8.6 x 6.2 μm (6-13 x 4-8); it occurred in 5 of 45 (11%) mole-rats (2n = 58, 60). Sporulated oocysts of Isospora spalacensis n. sp. were ellipsoidal 14.6 x 11.0 μm (12-17 x 9-14) with ellipsoidal to ovoidal sporocysts 8.5 x 4.5 μm (7.5-11 x 4-7); it occurred in 5 of 45 (11%) mole-rats (2n = 58, 60). Twenty-five of 45 (56%) mole-rats (all 4 species) were infected with a previously described form, Eimeria elliptica Sayin, Dincer, and Meric, 1977. The genetic diversity of mole-rats in Israel is known to increase chromosomally (2n = 52 → 60) and genically (heterozygosity [H] = 0.035 → 0.069) as the environment becomes more demanding (i.e., increasingly warm, dry, and climatically unpredictable). At the same time, there is an increased diversity of coccidian parasites. This suggests correlation among host chromosomal variability, habitat, and increased prevalence of multiple infections, a pattern also seen in other fossorial rodents infected with coccidia.