An experimental study of the reproductive success of Echinostoma friedi (Trematoda: Echinostomatidae) in the golden hamster

Abstract

Viable eggs produced weekly per infective stage was used as a measure of the reproductive success of Echinostoma friedi during the first 12 weeks of infection in hamsters. The weekly reproductive success was not constant during the experiment in relation to the egg output and the proportion of viable eggs produced. The egg release started during week 2 post-inoculation, attaining a maximum during week 3. A decline in egg output was observed from week 9. Viable eggs were only produced from week 3 post-inoculation and a maximum was attained at week 4 of the experiment. A decline in egg viability was observed from week 9. Considering together the egg output and the egg viability, the maximum weekly reproductive success was obtained during week 4 post-inoculation. The changes in the weekly reproductive success were not reflected in variations in worm numbers and body sizes during the course of the infection. The humoral immune response of golden hamsters during the infection with E. friedi was determined. Increases of IgG levels against somatic and excretory/secretory products of E. friedi were detected coinciding with the reduction in the reproductive success.

Foodborne Intestinal Flukes in Southeast Asia

“…The elimination of E. trivolvis from mice occurs within 2-4 weeks [347], whereas worms can survive for long periods of time in golden hamsters [348]. In hamsters, E. friedi survive for at least 12 weeks, whereas the infection is expelled at 3-4 weeks in rats [349]. E. caproni worms are expelled from rats in 6-8 weeks, but they produce chronic infections in hamsters and mice [350].…”

Development of an Antibody-Based Capture Enzyme-Linked Immunosorbent Assay for Detecting Echinostoma Caproni (Trematoda) in Experimentally Infected Rats: Kinetics of Coproantigen Excretion

“…Fecal samples were examined to determine the number of eggs per gram of feces (EPG), as described in previous studies (Toledo et al, 2003). Briefly, 24-hr fecal productions were collected from each animal and weighed individually.…”

“…To obtain ES antigens of E. caproni, we followed the methodology described by Toledo et al (2003). Adult worms were collected from the intestines of rats 4 wk after experimental infection with 100 metacercariae of E. caproni.…”

“…However, this procedure is tedious, and eggs are not always present in feces because the worms may be preovigerous or mature worms may not be voiding eggs. Moreover, parasite maturation and egg production patterns may vary depending on different factors such as worm crowding or host species (Huffman and Fried, 1990;Toledo et al, 2003). Earlier studies have demonstrated that immunodiagnosis of echinostome infections is feasible by indirect enzyme-linked immunosorbent assay (ELISA) using different antigenic extracts.…”

“…However, the application of serologic diagnosis has major limitations, particularly in laboratory animals. For example, antibody titers persist after worm loss and also depend on the host species (Simonsen et al, 1991;Toledo et al, 2003). Moreover, animal handling to obtain a sufficient amount of serum samples is often difficult.…”