Acquired resistance of the eel, Anguilla anguilla L., to challenge infections with gill monogeneans

Abstract. The European eel, Anguilla anguilla L., is able to respond to infections with ectoparasitic gill monogeneans of the genus Pseudodactylogyrus Gussev, 1965. A primary infection offers the host a relative resistance to challenge infections. The relative protection was detected at both 14 and 33 days after mebendazole termination of the primary infection by a significantly greater parasite reduction in previously infected eels compared to non‐primed eels. No complete immunity was obtained.