Host Gender in Parasitic Infections of Mammals: An Evaluation of the Female Host Supremacy Paradigm

Abstract

A review of current literature on mammalian hosts' sexual dimorphism (SD) in parasitic infections revealed that (1) it is a scarcely and superficially studied biological phenomenon of considerable significance for individual health, behavior, and lifestyles and for the evolution of species; (2) there are many notable exceptions to the rule of a favorable female bias in susceptibility to infection; (3) a complex network of molecular and cellular reactions connecting the host's immuno-neuroendocrine systems with those of the parasite is responsible for the host-parasite relationship rather than just an adaptive immune response and sex hormones; (4) a lack of gender-specific immune profiles in response to different infections; (5) the direct effects of the host hormones on parasite physiology may significantly contribute to SD in parasitism; and (6) the need to enrich the reductionist approach to complex biological issues, like SD, with more penetrating approaches to the study of cause-effect relationships, i.e., network theory. The review concludes by advising against generalization regarding SD and parasitism and by pointing to some of the most promising lines of research.

Trypanosomes, fleas and field voles: ecological dynamics of a host-vector–parasite interaction

“…The underlying mechanisms behind such discrepancies are often divided into 2 broad categories, namely ecological and physiological (Zuk and McKean, 1996 ;Morales-Montor et al 2004). The ecological mechanisms within our system are likely to be related to factors such as behavioural differences between the sexes in habitat use and hence variable exposure to parasites.…”

The effects of mite parasitism on the reproduction and survival of the Taiwan field mice (Apodemus semotus)

“…defending territories, aggression; Brown et al 1994). Nevertheless, female-biased parasitism and lack of sex-biased parasitism in small mammals have also been reported (Morales-Montor et al 2004;Christe et al 2007;Sanchez et al 2011). In species for which nutritional needs during reproduction compromise mothers' immunity (Klein and Roberts 2010) or encourage mothers to engage in behaviors with increased infection risks (e.g.…”

Calorie restriction and susceptibility to intact pathogens

“…Of course, there is variation in response to CR even among inbred mouse strains (Turturro et al 1999;Brochmann et al 2003;Rikke et al 2003Rikke et al , 2006, as well as between males and females (Wu et al 2003a;Shi et al 2007). Mouse strain and sex also influence susceptibility to pathogens (Zuk and McKean 1996;Morales-Montor et al 2004;, and these effects are pathogen-specific. Therefore, if a laboratory mouse is selected as an experimental host, mouse strain and sex must be considered from both a CR and pathogen susceptibility perspective.…”