Some observations on Babesiosoma bettencourti (Franca, 1908) n. comb. (syns. Haemogregarina bettencourti Franca, 1908; Desseria bettencourti Siddall,1995) from eels, Anguilla anguilla L., in Portugal

The stages of a babesiosome were recorded from the erythrocytes of 73 out o f 591 European eels, Anguilla anguilla L., captured in six rivers in northe rn and central Portugal during the period from January 1988 to July 1994. T he prevalence, intensity and seasonality of the infection were recorded. Pa rasites were mostly intraerythrocytic in stained blood films. Unidivided an d cruciform meronts, merozoites and gamonts were identified, and the meront stage was the most common. Mixed infections, in which the babesiosome coex isted with Trypanosoma granulosum Laveran & Mesnil, 1902, were present in 7 2 out of the 591 eels. In captive fish kept for up to 6 months, fluctuation s in the levels of infection with the babesiosome were noted. The babesioso me existed in a similar geographical location, in what was presumed to be t he same host: and in the same host cell type as a parasite described earlie r as Haemogregarina bettencourti. Furthermore, the gamonts of the babesioso me and the haemogregarine overlapped in morphometric description. Although H. bettencourti was recently assigned to the genus Desseria, a nomenclatura l correction is proposed: a new combination, Babesiosoma bettencourti (Fran ca, 1908) (syns. Haemogregarina bettencourti Franca, 1908; Desseria bettenc ourti Siddall, 1995) in the European eel, Anguilla anguilla L. The definiti ve host of B. bettencourti is unknown.