, Volume 137, Issue 2, pp 286–295 | Cite as

Prevalence of coccidia parasites (Protozoa) in red squirrels ( Sciurus vulgaris): effects of host phenotype and environmental factors

  • Sandro BertolinoEmail author
  • Luc A. Wauters
  • Luc De Bruyn
  • Giorgio Canestri-Trotti
Community Ecology


We investigated the relative importance of environmental factors versus host phenotype in determining parasite prevalence in Eurasian red squirrels ( Sciurus vulgaris). One hundred and forty-three fecal samples of 116 different squirrels collected in 2000 and 2001 from five study areas in the Italian Alps, were examined for intestinal protozoans. Two species of Eimeria were present with a medium to high prevalence in both years and in all areas, while two other species were rare, occurring only in some areas and not in all years. Cryptosporidium parvum had a high prevalence in the two study areas of the Western Alps, while in the three areas of the Central Alps it was recorded only once. The prevalence of Eimeria sciurorum and C. parvum fluctuated in parallel with squirrel density, suggesting a possible correlation between the presence of these protozoans and host density. A gender effect on E. sciurorum prevalence at low density could be explained by different space use patterns and social organization of males and females. C. parvum occurred more frequently in young squirrels, suggesting an acquired immunity in adults, but age-related susceptibility was not found for eimerian species. The coccidian community was more similar within than between regions, and study area and year were key parameters in predicting coccidia infection. There was no evidence of competition between coccidian species, but one positive interaction between E. sciurorum and E. andrewsi was observed. Our results suggest that the effects of geographic region, area features, and year effects probably related to fluctuations in host population density, were more important than individual phenotypic host characteristics in structuring the coccidian assemblage and determining levels of parasite prevalence in red squirrel populations.


Alpine forests  Cryptosporidium parvum  Eimeria Parasite communities Host density 



We wish to thank Miriam Gioia, Massimiliano Zaninetti, Ambrogio Molinari, Cinzia Long, Chiara Falco, Alessandro Dellanoce, for assistance with the field work, Mariarosa Formicola and Maura Corniati for assistance in the laboratory analyses. This study was financed by a grant from the Gran Paradiso National Park, Italy (DGE 25–2000) to L. A. W., S. B. and Faunaviva, by grant no. 6997–01 from the Committee for Research and Exploration of the National Geographic Society, Washington, D.C., to L. A. W., and by a grant from MURST 60% to G. C. T.


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Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  • Sandro Bertolino
    • 1
    Email author
  • Luc A. Wauters
    • 2
  • Luc De Bruyn
    • 3
    • 4
  • Giorgio Canestri-Trotti
    • 5
  1. 1.Laboratory of Entomology and Zoology, DIVAPRAUniversity of TurinGrugliasco (TO)Italy
  2. 2.Department of Structural and Functional BiologyUniversity of InsubriaVarese (VA)Italy
  3. 3.Department of BiologyUniversity of AntwerpAntwerpBelgium
  4. 4.Institute of Nature ConservationBrusselsBelgium
  5. 5.Animal Biology DepartmentTorinoItaly

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