REFERENCES
- Capron, A., Yarzabal, L., Vernes, A. & Fruit, J. (1970). Pathologie Biologique, 18, 357–365.
- Chordi, A. & Kagan, I. (1965). Journal of Parasitology, 51, 63–71.
- Mcmanus, D. P. & Smyth, J. D. (1979). Transactions of the Royal Society of Tropical Medicine and Hygiene, 73, 259–265.
- Oriol, R., Williams, J. F., Perez-Esandi, M. V. & Oriol, C. (1971). American Journal of Tropical Medicine and Hygiene, 20, 569–574.
- Oriol, C. & Oriol, R. (1975). American Journal of Tropical Medicine and Hygiene, 24, 96–100.
- Varela-Dìaz, V. M., Coltorti, E. A., Ricardes, M. I. & Guisantes, G. A. (1974). American Journal of Tropical Medicine and Hygiene, 23, 1092–1096.
- Please address all correspondence to: Dr. M. Pezzella, via Silvio Pellico 42, 00195 Rome, Italy.