The Life Cycle of Schistosoma mansoni under Germ Free Conditions

Bezerra, Marcela; Ec, Vieira; Pleasants,; Nicoli, Jacques R.; Pm, Coelho; Ea, Bambirra

doi:10.2307/3281552

Cited by 3 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Most of the work on experimental schistosomiasis appears to be carried out on animals maintained under conventional or minimal diseased conditions, mainly as a result of practical difficulties in producing cercariae under sterile conditions. To the best of our knowledge only one group of researchers, all from the same laboratory, have conducted experimental schistosomiasis studies on germ-free animals (Bezerra et al, 1985;Vieira & Moraes-Santos, 1987). Interestingly enough these authors reported higher worm returns and milder responses to S. mansoni infection in germfree mice.…”

Section: Discussionmentioning

confidence: 99%

Intestinal parasites of conventionally maintained BALB/c mice and Mastomys coucha and the effects of a concomitant schistosome infection

et al. 1990

View full text Add to dashboard Cite

A longitudinal study was carried out to identify the spectrum of intestinal parasites present in conventionally maintained BALB/c mice and Mastomys coucha and to determine the effects of concomitant schistosome infections on their parasite status. Six parasites were observed during the course of the study, namely the nematodes Aspiculuris tetraptera and Syphacia obvelata, Entamoeba muris and the flagellates Trichomonas muris, Spironucleus muris and Chilomastix spp. Although the 2 rodents shared common facilities, the overall prevalences of S. obvelata, T. muris and S. muris were significantly higher in M. coucha than BALB/c mice. BALB/c mice with concomitant schistosome infection had increased prevalences of E. muris, T. muris and S. muris. In M. coucha, in contrast, there were no significant increases in parasite prevalences. Infection intensities of T. muris and S. muris were significantly greater in M. coucha than BALB/c mice. Concomitant schistosome infection resulted in increased intensities of T. muris infection in BALB/c mice only. The influence of immune status in determining the susceptibilities of rodents to environmentally transmitted parasites is discussed.

show abstract

Section: Discussionmentioning

confidence: 99%

Intestinal parasites of conventionally maintained BALB/c mice and Mastomys coucha and the effects of a concomitant schistosome infection

et al. 1990

View full text Add to dashboard Cite

show abstract

“…Moreover, there was greater proliferation in the granulomas around S. mansoni eggs in livers from germfree animals (13). However, granulomas from germfree and conventional animals had the same general aspect and size ( 14) and oviposition was also similar in germfree and conventional mice (13,14). TNF-α has been implicated as a required factor for optimum oviposition and granuloma formation in conventional mice (15).…”

mentioning

confidence: 99%

Parasitic infections in germfree animals

Vieira¹,

Oliveira

Nicoli

1998

Braz J Med Biol Res

View full text Add to dashboard Cite

The association of vertebrate hosts with the indigenous microbiota and its effect on the response to infections has long been a subject of scientific curiosity. From the first theory supported by Louis Pasteur that life would be impossible in the absence of associated microorganisms to the development of germfree mammals for research, a lot was learned about how the normal microbiota influences the environment in which pathogens may find themselves. In the present review, we attempt to summarize the more recent results from our group and others on the influence of the normal microbiota on the outcome of parasitic infections. Our results and those of others point to a complex relationship between the mammalian system and its indigenous microbiota, leading to greater resistance to some infections and enhanced susceptibility to others.

show abstract

“…Using gnotobiotic techniques, parasitism in mammalian and avian animals devoid of bacterial populations can be studied, although results from these experimental conditions are likely only relevant for those helminths that acquire their symbiotic bacteria from the host. Furthermore, helminths that grow normally under germfree conditions, such as Schistosoma mansoni (Bezerra et al, 1985), are known to harbour a bacterial population (Ottens & Dickerson, 1972), suggesting that these Symbiotic bacteria of helminths and environmental stress symbionts may not have a nutritional or developmental role but rather one associated with defence, other noncritical function or are using the worm as a 'reservoir' (see below). However, in contrast, others can develop normally (Reid & Bottero, 1967;Weinstein et al, 1969), or may develop in a germ-free atypical host in which, under normal circumstances, they would be unable to establish (Newton et al, 1959).…”

Section: The Relationship Between Symbiotic Bacteria and Helminthsmentioning

confidence: 99%

“…However, in contrast, others can develop normally (Reid & Bottero, 1967; Weinstein et al , 1969), or may develop in a germ-free atypical host in which, under normal circumstances, they would be unable to establish (Newton et al , 1959). Furthermore, helminths that grow normally under germ-free conditions, such as Schistosoma mansoni (Bezerra et al , 1985), are known to harbour a bacterial population (Ottens & Dickerson, 1972), suggesting that these symbionts may not have a nutritional or developmental role but rather one associated with defence, other non-critical function or are using the worm as a ‘reservoir’ (see below). Alternatively symbiotic bacteria may be facultative rather than obligatory under these conditions and the helminth's functional biology, although not performing at an optimal level, may be adequate enough to allow normal development.…”

Section: The Relationship Between Symbiotic Bacteria and Helminthsmentioning

confidence: 99%

Symbiotic bacteria of helminths: what role may they play in ecosystems under anthropogenic stress?

Morley

2016

J. Helminthol.

View full text Add to dashboard Cite

Symbiotic bacteria are a common feature of many animals, particularly invertebrates, from both aquatic and terrestrial habitats. These bacteria have increasingly been recognized as performing an important role in maintaining invertebrate health. Both ecto- and endoparasitic helminths have also been found to harbour a range of bacterial species which provide a similar function. The part symbiotic bacteria play in sustaining homeostasis of free-living invertebrates exposed to anthropogenic pressure (climate change, pollution), and the consequences to invertebrate populations when their symbionts succumb to poor environmental conditions, are increasingly important areas of research. Helminths are also susceptible to environmental stress and their symbiotic bacteria may be a key aspect of their responses to deteriorating conditions. This article summarizes the ecophysiological relationship helminths have with symbiotic bacteria and the role they play in maintaining a healthy parasite and the relevance of specific changes that occur in free-living invertebrate-bacteria interactions under anthropogenic pressure to helminths and their bacterial communities. It also discusses the importance of understanding the mechanistic sensitivity of helminth-bacteria relationships to environmental stress for comprehending the responses of parasites to challenging conditions.

show abstract

The Life Cycle of Schistosoma mansoni under Germ Free Conditions

Cited by 3 publications

References 0 publications

Intestinal parasites of conventionally maintained BALB/c mice and Mastomys coucha and the effects of a concomitant schistosome infection

Intestinal parasites of conventionally maintained BALB/c mice and Mastomys coucha and the effects of a concomitant schistosome infection

Parasitic infections in germfree animals

Symbiotic bacteria of helminths: what role may they play in ecosystems under anthropogenic stress?

Contact Info

Product

Resources

About