Animal Models for <i>Echinostoma malayanum</i> Infection: Worm Recovery and Some Pathology

Abstract

Echinostomes are intestinal trematodes that infect a wide range of vertebrate hosts, including humans, in their adult stage and also parasitize numerous invertebrate and cold-blooded vertebrate hosts in their larval stages. The purpose of this study was to compare Echinostoma malayanum parasite growth, including worm recovery, body size of adult worms, eggs per worm, eggs per gram of feces, and pathological changes in the small intestine of experimental animals. In this study, 6-8-week-old male hamsters, rats, mice, and gerbils were infected with echinostome metacercariae and then sacrificed at day 60 post-infection. The small intestine and feces of each infected animal were collected and then processed for analysis. The results showed that worm recovery, eggs per worm, and eggs per gram of feces from all infected hamsters were higher compared with infected rats and mice. However, in infected gerbils, no parasites were observed in the small intestine, and there were no parasite eggs in the feces. The volume of eggs per gram of feces and eggs per worm were related to parasite size. The results of histopathological changes in the small intestine of infected groups showed abnormal villi and goblet cells, as evidenced by short villi and an increase in the number and size of goblet cells compared with the normal control group.

Research Note: Genetic analysis, pathology, and vectors of echinostomiasis, a zoonotic helminth infection in chickens in Bangladesh

“…Additionally, the cuticle of the worms is spiny ( Soulsby, 1982 ), which give continuous mechanical insults. Adult parasites can survive for years and feed on soft mucosal tissues, leading to the development of inflammations, which in turns elicit thickening of mucosal layer of the intestine, proliferation of goblet cells and excessive mucus production ( Songsri et al., 2016 ). The flukes eat off the mucosal tissues, therefore, petechial hemorrhages are not unexpected.…”

Immune pathogenesis in pigeons during experimental Prohemistomum vivax infection

“…Intestinal tissue lesions included shortening and thickening or atrophy of villi, villous fusion, inflammatory cell infiltration in mucosal lamina propria, and focal epithelial ulcerations. Similar pathological changes were seen in the upper intestine of P. vivax -infected pigeons and mice ( 7 , 17 ), Heterophyes heterophyes -infected mice ( 43 ), Echinostoma malayanum -infected hamsters, rats, mice, and gerbils ( 44 ), Metagonimus yokogawai -infected cats, N. seoulense -infected rats and mice, Pygidiopsis summa -infected rats and mice, and Gymnophalloides seoi -infected mice, reviewed by Chai ( 2 ). The observed pathological alterations might be attributed to the parasite's direct effect and the host's response.…”

A relatively high zoonotic trematode prevalence in Orientogalba ollula and the developmental characteristics of isolated trematodes by experimental infection in the animal model

“…The developmental cycle of echinostomes in their definitive hosts is short and uncomplicated [31]. Therefore, the animal model for echinostomes will help elucidate the interaction between the trematode and its host [32,33]. Thus, our research results can also be used to reference other small intestinal flukes that induce an immune response in the definitive host.…”

“…For the experimental animals, mammals are not susceptible to echinostomes infection, so ducklings were used as the definitive host in this study. Although other animal models have been reported for some echinostomes, the different Echinostomatidae has certain differences in their biology and life cycle [32]. Future animal studies on various aspects of echinostome infection are still needed.…”