Host response to initial and challenge infections, following treatment, of Gyrodactylus bullatarudis and G. turnbulli (Monogenea) on the guppy (Poecilia reticulata).

The host response of Poecilia reticulata Peters against two species of Gyrodactylus (G. bullatarudis Turnbull, 1956 and G. turnbulli Harris, 1986) was investigated by comparing the dynamics of infrapopulations arising from initial infections, challenge infections begun 1 day after formalin treatment of 3-day-old initial infections and challenge control infections. The primary host response of P. reticulata to Gyrodactylus was shown to be non-(Gyrodactylus)-species-specific. Observations of differences in host-site specificities of initial and challenge infection infrapopulations indicated that the host response is largely localised to areas of heavy infection. The exact nature of the response remains unknown.