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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
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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

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