Folia Parasitologica 55[1] 53-59 (2008) | DOI: 10.14411/fp.2008.007

Crustacean-acanthocephalan interaction and host cell-mediated immunity: parasite encapsulation and melanization

Bahram Sayyaf Dezfuli¹, Edi Simoni¹, Laura Duclos², Emanuele Rossetti¹

¹ Department of Biology and Evolution, University of Ferrara, St. Borsari, 46, 44100 Ferrara, Italy

² Nature's Variety, P.O. Box 29345, Lincoln, NE 68529, USA

Host-parasite interactions of Pomphorhynchus laevis (Müller, 1776) in naturally infected amphipod, Echinogammarus stammeri (Karaman), from the Brenta River (northern Italy) are described. A fully developed acanthocephalan larva occupies a large portion of an amphipod's haemocoelic space; thus, the parasite frequently induces displacement of host digestive tract and other internal organs. However, no apparent damage to the host's internal structures was observed. Within the haemocoel of E. stammeri, each larva of P. laevis is surrounded with a membranous layer, formed by microvilli, which maintains intimate contact with the amphipod's internal organs and haemocytes. Three types of circulatory haemocytes were identified based upon their distinct appearance: hyaline cell, semi-granular cell and granular cell. Echinogammarus stammeri haemocytes surrounded acanthocephalan larvae and in some instances a partially and/or totally melanized P. laevis larva was noticed. Interestingly, no melanized larvae were found in E. stammeri parasitized with other acanthocephalans namely Echinorhynchus truttae (Schrank, 1788), Polymorphus minutus (Goeze, 1782) and Acanthocephalus clavula (Dujardin, 1845).

Keywords: Pomphorhynchus laevis, Echinogammarus stammeri, host immunity, parasite melanization

Received: October 24, 2007; Accepted: December 27, 2007; Published: March 1, 2008  Show citation