Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-16T11:18:37.761Z Has data issue: false hasContentIssue false
  • English
  • Français

Hepatozoon griseisciuri in grey squirrels (Sciurus carolinensis): changes of blood leucocyte numbers resulting from infection

Published online by Cambridge University Press:  09 October 2003

B. M. WATKINS  and
F. NOWELL
B. M. WATKINS
Affiliation:
Division of Zoology, School of Animal and Microbial Sciences, The University of Reading, Whiteknights, PO Box 228, Reading RG6 6AJ, UK
F. NOWELL
Affiliation:
Division of Zoology, School of Animal and Microbial Sciences, The University of Reading, Whiteknights, PO Box 228, Reading RG6 6AJ, UK
Get access Rights & Permissions [Opens in a new window]

Abstract

Numbers of leucocytes in squirrels with gametocytes of Hepatozoon in their blood (infected) were compared with animals without gametocytes (uninfected). Typical values for leucocytes/mm3 blood in uninfected squirrels were: leucocytes 5·7×103, granulocytes 3·4×103, lymphocytes 2·0×103 and monocytes 0·3×103 cells. Infection caused an increase in monocytes, lymphocytes and granulocytes, and there was a significant positive association between parasitaemia level and numbers of both total leucocytes and monocytes. Infected animals had more uninfected monocytes/mm3 blood than did uninfected animals. The proportions of monocytes were more variable over time in infected animals, but no shift between infected and uninfected status was detected. Transfer of serum from infected squirrels to mice resulted in elevated counts of total blood leucocytes, monocytes and granulocytes, but not of lymphocytes, as compared with controls. Serum from squirrels with high parasitaemias had a more marked effect than serum from squirrels with low parasitaemias. Results indicate an infection-related monocytosis, possibly controlled by cytokines, that increases the number of cells available for invasion by gametocytes, thus enhancing the chances of parasite transmission.

Keywords

Sciurus carolinensisHepatozoonleucocytesmonocytesmonocytosiscytokines
Type
Research Article
Information
Parasitology , Volume 127 , Issue 2 , August 2003 , pp. 115 - 120
Copyright
2003 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

BANETH, G., SHKAP, V., SAMISH, M., PIPANO, E. & SAVITSKY, I. (1998). Antibody response to Hepatozoon canis in experimentally infected dogs. Veterinary Parasitology 74, 299–305.CrossRefGoogle Scholar
BRITT, D. & MOLYNEAUX, D. H. (1979). Parasites of grey squirrels in Cheshire, England. Journal of Parasitology 65, 408.CrossRefGoogle Scholar
CALLARD, R. E. & GEARING, A. J. H. (1994). The Cytokine Factsbook. Academic Press/Harcourt Brace, London.
CAMPBELL, J. D. M. & SPOONER, R. L. (1999). Macrophages behaving badly: infected cells and subversion of immune responses to Theileria annulata. Parasitology Today 15, 10–16.CrossRefGoogle Scholar
COX, F. E. G. (2001). Concomitant infections, parasites and immune responses. Parasitology 122, S23–S38.CrossRefGoogle Scholar
DACIE, J. V. & LEWIS, S. M. (1984). Practical Haematology, 6th Edn. Churchill Livingstone, Edinburgh.
DAVIDSON, W. R. & CALPIN, J. P. (1976). Hepatozoon griseisciuri infection in gray squirrels of the southeastern United States. Journal of Wildlife Diseases 12, 72–76.CrossRefGoogle Scholar
DESSER, S. S. (1990). Tissue cysts of Hepatozoon griseisciuri Clark 1958 in the grey squirrel Sciurus carolinensis: the significance of these cysts in species of Hepatozoon. Journal of Parasitology 76, 257–259.CrossRefGoogle Scholar
GONDIM, L. F. P., KOHAYAGAWA, A., ALENCAR, N. X., BIONDO, A. W., TAKAHIRA, R. K. & FRANCO, S. R. V. (1998). Canine Hepatozoonosis in Brazil: description of eight naturally occurring cases. Veterinary Parasitology 74, 319–323.CrossRefGoogle Scholar
HENDRICKS, L. D. (1972). Schizogonic development of Hepatozoon griseisciuri of the Eastern grey squirrel. Ph.D. thesis, University of Maryland, USA.
HENDRICKS, L. D. (1975). Schizogonic development of Hepatozoon griseisciuri Clark 1958 (Sporozoa: Haemogregarinidae), of the grey squirrel (Sciurus carolinensis Gmelin 1788). Journal of Parasitology 61, 458–461.CrossRefGoogle Scholar
KAYE, P. (1999). Parasite derived immunoregulatory molecules. Parasite Immunology 21, 595–596.CrossRefGoogle Scholar
MOORE, K. J. & MATLASHEWSKI, G. (1994). Intracellular infection by Leishmania donovani inhibits macrophage apoptosis. Journal of Immunology 152, 2930–2937.Google Scholar
MORRISON, W. I., MacHUGH, N. D. & LALOR, P. A. (1996). Pathogenicity of Theileria parva is influenced by the host cell type infected by the parasite. Infection and Immunity 64, 557–562.Google Scholar
TERRITO, M. & CLINE, M. J. (1976). Macrophages and their disorders in Man. In Immunobiology of the Macrophage (ed. Nelson, D. S.), pp. 593–618. Academic Press, New York.CrossRef
VOLKMAN, A. & COLLINS, E. M. (1974). The cytokinetics of monocytosis in acute salmonella infection in rats. Journal of Experimental Medicine 139, 264–277.CrossRefGoogle Scholar
WATKINS, B. M. & NOWELL, F. (1991). Hepatozoon in grey squirrels (Sciurus carolinensis) trapped near Reading, Berkshire. Journal of Zoology 224, 101–112.CrossRefGoogle Scholar