Life cycle of a new echinostome from Egypt, Echinostoma liei sp.nov. (Trematoda: Echinostomatidae)

Abstract

A 37-spined Egyptian echinostome, Echinostoma liei sp.nov., is described in adult and larval stages. The parasite develops readily in the laboratory in chicks and ducklings, hamsters and rats. Its natural final host in or near irrigation ditches of the Nile delta involves the roof rat, Egyptian giant shrew and aquatic bird hosts. Developmental forms are described from infection of the NIH strain of Biomphalaria glabrata in the laboratory. B. alexandrina, is infected in the normal habitat in Egypt and contains both developmental stages in the heart or aorta and the hepatopancreas, and metacercariae encyst in the pericardium and kidney. E. liei sp.nov. is one of six very similar species characterized by 37 collar spines with a pattern of (3 + 2) corner spines in each lappet, six laterals on each side, and 15 dorsals in alternating rows; two pairs of dorsoventral and one small pair of ventro-lateral finfolds on the cercarial tail; and rodlike cystogenous material filling the cercarial encystation glands. In addition to distinctive intermediate-host specificity, differentiating characteristics of E. liei cercariae include presence of six sets of three flame cells each per side (total 36), seven oesophageal cells, eight penetration gland outlets on the dorsal lip of the oral sucker, and an absence of paraoesophageal gland cells as determined by intravital dyes. Significance of these and other cercarial traits is emphasized to aid in defining highly similar, but none the less distinct, sibling species.

Cost of resistance, expressed as a delayed maturity, detected in the host–parasite system Biomphalaria glabrata/Echinostoma caproni

“…Biomphalaria glabrata is a hermaphroditic snail able to self-fertilize. The strain of E. caproni (Jeyarasasingam et al, 1972) has been maintained for several years in our laboratory. Echinostoma caproni is a hermaphroditic parasite with an indirect life cycle involving three hosts.…”

Effects of benzimidazole anthelmintics as microtubule-active drugs on the synthesis and transport of surface glycoconjugates in Hymenolepis microstoma , Echinostoma caproni , and Schistosoma mansoni

“…Mice were infected with 6 cysticercoids/mouse, and drug treatments were commenced at about 3 weeks postinfection (p.i.). Echinostoma caproni, an isolate from Egypt that was obtained from the Danish Bilharziasis Laboratory (Charlottenlund, Denmark), was reared in BALB/c mice and Biomphalaria glabrata snails (Jeyarasasingam et al 1972;Christensen et al 1988;Fried and Human 1996). Mice were infected with 25 metacercariae, and drug treatments were commenced at days 18±24 p.i.…”

Scanning electron microscopy ofEchinostoma trivolvisandE. caproni(Trematoda) adults from experimental infections in the Golden Hamster

“…, when discussing 37-collar-spined echinostomes, suggested that Echinostoma caproni Richard, 1964 is the correct name for an Egyptian species described by Jeyarasasingam et al (1972) as E. liei and Echinostoma trivolvis (Cort, 1914) Kanev, 1985 the correct name for a North American form described by Beaver (1937) from north central USA as E. revolutum. Our study uses the Egyptian and North American species and refers to them as E. caproni and E. trivolvis, respectively.…”