Egg excretion in the initial phase of experimental murine schistosomiasis mansoni: stability and association with worm burden

Abstract

Stability of faecal egg excretion and correlation with results related to worm burden at the initial phase of schistosomiasis mansoni were observed in two groups of mice infected with different Schistosoma mansoni cercarial burdens, by means of analysis of quantitative parasitological studies and schistosome counts after perfusion. Thus, it may be stated that few quantitative parasitological stool examinations could be sufficient to express the infection intensity at the initial phase, on the same grounds that it was already demonstrated at the chronic phase. Furthermore, it is confirmed that the use of the number of eggs passed in the faeces as a tool to estimate the worm burden at the initial phase of schistosome infection is adequate.

Parasitological characteristics of Schistosoma mansoni infection in swiss mice with underlying malnutrition

“…The kinetics of fecal egg-output in both experimental groups were similar to other studies indicating an initial phase with low egg-shedding, another with increasing in the egg-laying and a later decreasing (Rocha et al 1995, Ribeiro-Paes & Rodrigues 1997, Thiongo et al 1997. These data suggest that the egg passage through the intestine tissue was not hampered and its maturation did not seem to be affected.…”

High fat diet has a prominent effect upon the course of chronic schistosomiasis mansoni in mice

“…In mice fed a high-fat diet, an initial low elimination was observed between 6-8 weeks, followed by significant increases at weeks 9 and 10, with week-to-week fluctuations from week 11-16, when excretion was increased. The main differences were the absence of stability and a progressive decrease, as previously reported during the chronic phase of schistosomiasis (Cheever et al 1994, Rocha et al 1995, Barth et al 1996. This study complements the existing literature (Neves et al 2007a, b) indicating that certain dietary patterns may be important for the outcome of chronic schistosomiasis.…”

“…As in other studies, mice fed a standard diet excreted few eggs by weeks 6-8 and this count then rose to a peak at week 12 and achieved stability between weeks 13-16, declining thereafter (Rocha et al 1995, El Ridi et al 2004). In mice fed a high-fat diet, an initial low elimination was observed between 6-8 weeks, followed by significant increases at weeks 9 and 10, with week-to-week fluctuations from week 11-16, when excretion was increased.…”

Características biológicas e morfológicas de cepas brasileiras de Schistosoma mansoni em Mus musculus

“…Eliminação de ovos nas fezes: entre 35 e 54 dias após a infecção, amostras de fezes de 24 horas foram recolhidas, individualmente, três vezes por semana. A análise parasitológica foi realizada pelo método de Kato-Katz 25 e uma técnica por sedimentação quantitativa 47 . Em cada exame foram analisadas duas lâminas por animal.…”