Current applications of oogram methodology in experimental schistosomiasis; fecundity of femaleSchistosoma mansoniand egg release in the intestine of AKR/J mice following immunomodulatory treatment with pentoxifylline

Abstract

<jats:title>Abstract</jats:title><jats:p>Oogram methodology permitted a direct assessment of the fecundity of<jats:italic>Schistosoma mansoni</jats:italic>and the passage of parasite eggs from mesenteric vessels into the intestinal lumen in AKR/J mice that had been infected via the intraperitoneal route with 60 cercariae of the trematode and later subjected to short-term subcutaneous treatments with pentoxifylline (PTX). The administration of PTX did not change oviposition kinetics, the individual fecundity of female parasites (as determined by the study of the ratio of second-stage<jats:italic>S. mansoni</jats:italic>eggs per g intestine/number of female parasites recovered from the portal system), nor the number of mature and dead eggs retained in the host tissue, though the drug has known immunomodulatory effects, as shown previously in experimental schistosomiasis. A better appraisal was also carried out, including the study of statistical parameters, concerning the utilization of the ratios of each stage of immature eggs (first to fourth) per g intestine/number of female worms from the portal system. The second-stage eggs had the lowest variability, confirming that the utilization of this stage as an indicator of the individual fecundity of parasite females is indeed viable. In the light of our findings, current uses of oogram methodology are discussed. Moreover, additional consideration is given to data obtained in the present study concerning intraperitoneal infection with<jats:italic>S. mansoni</jats:italic>cercariae in both untreated and treated mice of the AKR/J strain, such as the recovery of mature worms, eggs and free granulomas from the peritoneal cavity of these rodents.</jats:p>

Protective immune responses against Schistosoma mansoni infection by immunization with functionally active gut-derived cysteine peptidases alone and in combination with glyceraldehyde 3-phosphate dehydrogenase

“…mansoni cysteine peptidase was associated with low but significant ( P < 0.05) decreases in parasite eggs within the intestine and liver in comparison to the infected controls, and a very significant effect ( P < 0.005) on the maturation and viability of eggs in these tissues observed. This is relevant as dead ova are likely unable to elicit inflammatory responses in the host or participate in transmission of the infection [24]. The data may indicate that cysteine peptidase-induced immune responses that may not only act directly on the female worm reproductive system via reducing fecundity but also interfere somehow in the development of the embryo within the egg.…”

“…After washing in 0.9% saline solution and slight drying on absorbent paper, each intestinal fragment was placed between 2 slides and analyzed by light microscopy to classify the eggs. For each fragment, up to 400 eggs were counted and classified according to their developmental stage as immature, with miracidium occupying less than two-thirds of the shell, mature containing an already developed miracidium, and non-viable, dead, clearly calcified, opaque [24]. …”

Effect of Crocus sativus aqueous extract (saffron) on Schistosoma mansoni worms in experimentally infected mice

“…The worms were classified according to sex and counted. The oogram count was performed by microscopic examination and classified according to different developmental stages of eggs (Mati and Melo, 2013). The number of S. mansoni ova/g tissue (liver or intestine) was demonstrated according to (Herbert et al, 2010).…”

Evaluation of a method for induction of praziquantel resistance inSchistosoma mansoni

“…Immature eggs require about 6 d for the miracidium to develop (Pellegrino et al, 1962). Studying the oogram pattern permits a direct assessment of the production and development of S. mansoni eggs, and their passage from mesenteric vessels into the intestinal lumen in mice (Mati & Melo, 2013). A drug that shows a chemotherapeutic effect causes a progressive change in the percentages of different developmental stages with a decrease in immature stages and an increase in the percentages of mature and/or dead eggs (Delgado et al, 1992).…”