Gross and microscopic pathological changes associated with parasitic infection in European eel (Anguilla anguilla, Linnaeus 1758)

Abstract

The gross pathological and histopathological changes associated with parasitic infection in the European eel (Anguilla anguilla Linnaeus, 1758) was investigated. A total of 65 eels collected from three sampling localities in Eastern Delta, Egypt were examined over the period of January-May 2008. The fish were subjected to standard procedures for parasitological and pathological examinations. Overall, 22 (33.8%) of the 65 fish examined were found to have parasitic infections. The eels harbored a total of six parasite species; among them, the nematode Anguillicoloides crassus was the most prevalent species (10.7%), followed by the Monogenea Pseudodactylogyrus anguillae (7.7%) and Dactylogyrus species (6.1%), the ciliate Trichodinella epizootica (4.6%), the Myxozoa Myxidium giardi (3.1%), and the cestode Proteocephalus macrocephalus (1.5%). Affected fish showed varying levels of tissue damage and pathological alterations including mild to severe degenerative, necrotic, and inflammatory changes in the affected organs.

Reproductive potential of silver European eels (Anguilla anguilla) migrating from Vistonis Lake (Northern Aegean Sea, Greece)

“…Anguillicola crassus was first reported from Greece as early as 1988 (Moravec, 1992) and is now found throughout much of the eastern Mediterranean. Prevalence in the region is highly variable, ranging from 10.7% in Egypt (Abdelmonem et al, 2010), 39.7% in the Former Yugoslav Republic of Macedonia (Cakić et al, 2002), 61.7% in Greece (this study), to 78.1% in Turkey (Genç et al, 2005). The original introduction pathway to Greece appears to be through escape of its native host, the Japanese eel (A. japonica), from eel aquaculture facilities (see review by Perdikaris et al, 2010).…”

“…Eel fisheries data is limited for this region (Dekker, 2003), andavail-, 2003), and avail-2003), and available biological data (from Greece, Former Yugoslav Republic of Macedonia, Turkey, Israel and Egypt) generally relates to the glass and yellow eel life-stages (see e.g. Golani et al, 1988;Cakić et al, 2002;Genç et al, 2005;Zompola et al, 2008;Abdelmonem et al, 2010). There-2010).…”

Scanning and transmission electron microscopy of the histopathological impact of Macrogyrodactylus clarii (Monogenea: Gyrodactylidae) on the gills of catfish, Clarias gariepinus

“…For example, Perera (1992) detected large intercellular spaces between the epithelial cells of the capsule formed on the gills of Scomber australasicus Cuvier around didymozoid digenean parasites. Desquamation of gill epithelial cells of the European eel Anguilla anguilla Linnaeus infected with monogeneans was recorded by Abdelmonem et al (2010). In the infected gill regions of C. gariepinus, epithelial cells with pseudopodium-like processes were also detected.…”

Size does matter—a closer look on Anguillicola morphology

“…While A. crassus and the Japanese eel constitute a longstanding original parasite-host association (Kuwahara et al 1974), this nematode species was recorded from European eels in European open waters for the first time in the mid1980s (Neumann 1985) and has even spread to populations in North Africa ever since (Maamouri et al 1999;Loukili and Belghyti 2007;Abdelmonem et al 2010). A. novaezelandiae is endemic to the Short-finned eel (Anguilla australis Richardson, 1841) from New Zealand and Australia (Moravec 2006) and has been introduced to Europe in 1975 (Paggi et al 1982).…”