Parasite regulation by host hormones: an old mechanism of host exploitation?

Escobedo, Galileo; Roberts, Craig W.; Carrero, Julio César; Morales‐Montor, Jorge

doi:10.1016/j.pt.2005.09.013

Cited by 127 publications

(137 citation statements)

References 51 publications

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“…Whether observed changes occurred as a coordinated host response to the effects of parasitism (e.g. tolerance) or as a result of parasite exploitation of the host [52,53] remains to be determined. Parasite infections appear to have induced stress in naturally infected red-capped mangabeys.…”

Section: Discussionmentioning

confidence: 99%

Changes in physiological stress and behaviour in semi-free-ranging red-capped mangabeys ( Cercocebus torquatus ) following antiparasitic treatment

2016

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Parasites are ubiquitous in wildlife populations, but physiological and behavioural responses of hosts to infection are difficult to measure. We experimentally treated semi-free-ranging red-capped mangabeys (Cercocebus torquatus) in Nigeria with antiparasitic drugs and examined subsequent changes in glucocorticoid production and individual behaviour. Because both parasites and stress impact energy balance and health, we measured (i) behavioural time re-allocation via activity budgets, (ii) social relationships (e.g. social connectivity and dominance hierarchy stability) and (iii) body condition. We collected triplicate faecal samples (n ¼ 441) from 49 individuals prior to and following treatment. Cortisol levels fluctuated in parallel with parasite abundance. Elevations in cortisol, but not parasitism, were related to reduced body condition. Behaviour also shifted according to infection status, with uninfected individuals spending more time foraging and less time resting and vigilant compared with when they were infected. Time spent feeding, travelling or socializing did not differ between pre-and posttreatment time periods. Group cohesion, but not dominance stability, changed following treatment, suggesting parasite-induced social avoidance. Together, these findings show a coordinated response to infection that promotes host tolerance through stress and energy conservation, reduces transmission risk and increases protection when infected hosts are vulnerable.

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Section: Discussionmentioning

confidence: 99%

Changes in physiological stress and behaviour in semi-free-ranging red-capped mangabeys ( Cercocebus torquatus ) following antiparasitic treatment

2016

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“…In the case of schistosomes, hormonal signals from the host seem to have a major influence on larval homing, survival, growth and sexual maturation (Mendonça et al, 2000;Escobedo et al, 2005). In the case of schistosomes, some hormonal signals from the host seem to have a major influence on larval homing, survival, growth, and sexual maturation.…”

Section: Introductionmentioning

confidence: 99%

Schistosoma haematobium: Identification of new estrogenic molecules with estradiol antagonistic activity and ability to inactivate estrogen receptor in mammalian cells

Botelho

Soares

Vale

et al. 2010

Experimental Parasitology

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a b s t r a c tWe have previously identified the expression of an estradiol (E2)-related molecule by Schistosoma haematobium total antigen (Sh). We now show that this molecule has an antagonistic effect of estradiol in vitro. Our results are consistent with the existence of an estrogenic molecule that antagonizes the activity of estradiol. We found evidence for this molecule as we identified and characterized by mass spectrometry new estrogenic molecules previously unknown, present in schistosome worm extracts and sera of Schistosoma-infected individuals. We also show that Sh is able to interact in vitro with estrogen receptor (ER), explaining how host endocrine system can favor the establishment of schistosomes. These findings highlight the exploitation of the host endocrine system by schistosomes and represent an additional regulatory component of schistosome development that defines a novel paradigm enabling host-parasite interactions. The identification of these molecules opens new ways for the development of alternative drugs to treat schistosomiasis.

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“…If host CR allows for enhanced production or function of these parasite-derived factors, parasites may be able to survive better in CR hosts. It is also well known that host hormones influence parasite establishment and reproduction (Escobedo 2005). If CR-induced changes in host hormone production alter parasite establishment or survival, they also could affect host susceptibility.…”

Section: Benefits Of Using Intact Pathogensmentioning

confidence: 99%

Calorie restriction and susceptibility to intact pathogens

Kristan

2008

AGE

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Long-term calorie restriction (CR) causes numerous physiological changes that ultimately increase mean and maximum lifespan of most species examined to date. One physiological change that occurs with CR is enhanced immune function, as tested using antigens and mitogens to stimulate an immune response. Fewer studies have used intact pathogen exposure to test whether the enhanced capacity of the immune response during CR actually decreases susceptibility of hosts to their pathogens. So far, studies using intact bacteria, virus, and helminth worm exposure indicate that, despite similar or enhanced immune system function, CR hosts are more susceptible to infection by intact pathogens than their fully fed counterparts. Long-term CR studies that examine susceptibility to a variety of parasite taxa will help determine if direct CR or CR mimetics will be beneficial to people living in pathogen-rich environments.

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Parasite regulation by host hormones: an old mechanism of host exploitation?

Cited by 127 publications

References 51 publications

Changes in physiological stress and behaviour in semi-free-ranging red-capped mangabeys ( Cercocebus torquatus ) following antiparasitic treatment

Changes in physiological stress and behaviour in semi-free-ranging red-capped mangabeys ( Cercocebus torquatus ) following antiparasitic treatment

Schistosoma haematobium: Identification of new estrogenic molecules with estradiol antagonistic activity and ability to inactivate estrogen receptor in mammalian cells

Calorie restriction and susceptibility to intact pathogens

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