1. Department of Pure and Applied Zoology, University of Reading, Whiteknights, P.O. Box 228, Reading, Berks RG6 2AJ, United Kingdom; Arbovirus Unit, London School of Hygiene and Tropical Medicine, Winches Farm Laboratories, 395 Halfield Road, St
Albans, Herls AL4 0XQ, UK
2. Department of Pure and Applied Zoology, University of Reading, Whiteknights, P.O. Box 228, Reading, Berks RG6 2AJ, United Kingdom