On the life cycle of Aggregata eberthi and observations on Aggregata octopiana (Apicomplexa, Aggregatidae) from Galicia (NE Atlantic)

Stages of merogony of a coccidian parasite were commonly observed during histological examination of the digestive tract of 7 crustacean species from Galician coastal waters. Study of the fine structure of these merogonial stages by transmission electron microscopy revealed the presence of a typical apicomplexan apical complex. Newly hatched Sepia officinalis obtained from egg masses, cultured in 3 separate tanks, were fed with three parasitised prawn species in infection experiments. Cuttlefish fed with Palaemon elegans and P. adpersus developed sexual stages and sporocysts diagnostic of Aggregata eberthi, identifying these prawns as new intermediate hosts of this parasite. No infection was found in Sepia fed with P. serratus, suggesting that this prawn could be an intermediate host of another species of Aggregata. By experimental infections of cultured cuttlefish, achieved here for the first time, the complete life cycle of A. eberthi in Spanish NE Atlantic waters was established.