Testosterone Depresses Innate and Acquired Resistance to Ticks in Natural Rodent Hosts: A Force for Aggregated Distributions of Parasites

Hughes, Victoria L.; Randolph, Sarah

doi:10.2307/3285174

Cited by 39 publications

(46 citation statements)

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“…The infestation similarity between males and females coincides with the findings of Beldomenico et al (2004), but contrasts with the results obtained by Hughes and Randolph (2001), who showed experimental evidence that testosterone depresses the innate and acquired resistance to I. ricinus in rodents. Nevertheless, Lareschi (2000) found a marked preference of I. loricatus towards male hosts.…”

Section: Discussionsupporting

confidence: 44%

The parasitism of immature stages of Ixodes loricatus (Acari: Ixodidae) on wild rodents in Argentina

Beldoménico

Lareschi²,

Nava³

et al. 2005

Exp Appl Acarol

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Ixodes loricatus has long been considered with strict-total specificity to New World Marsupials. However, frequent findings of its immature stages on rodents suggest that these vertebrates play an important role in the tick's life cycle. Aspects dealing with the ecology of Sigmodontinae rodents infestation by I. loricatus are unknown. To contribute to the knowledge of the ecology of this tick species, environmental factors, as well as host species, sex and age, were evaluated to find associations of immature I. loricatus infestation of the most abundant wild rodent species from riparian locations of Buenos Aires province (Argentina). A total of 290 hosts belonging to the subfamily Sigmodontinae were captured and examined for ticks at six locations. The data analysis showed that there was a preference of I. loricatus towards Akodon azarae, but only for those hosts captured in lands not prone to flooding. The results suggest that the host preference of I. loricatus is mainly related to factors such as habitat type and host density.

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Section: Discussionsupporting

confidence: 44%

The parasitism of immature stages of Ixodes loricatus (Acari: Ixodidae) on wild rodents in Argentina

Beldoménico

Lareschi²,

Nava³

et al. 2005

Exp Appl Acarol

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“…In our studies, rodents were not permitted to groom. Consequently, the main reason for better performance of fleas on male than on female hosts, at least at low RH, is likely due to gender differences in immunocompetence that stem from the higher level of androgens in males that compromise immune function (Folstad and Karter 1992;Hughes and Randolph 2001;Greives et al 2006, but see Vainikka et al 2004). A few experimental studies specifically aimed at testing the effect of host gender on feeding performance of fleas demonstrated that, indeed, fleas fed better on males than females (Haas 1965;Khokhlova et al 2009).…”

Section: Discussionmentioning

confidence: 95%

Effect of host gender on blood digestion in fleas: mediating role of environment

et al. 2009

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We investigated mechanisms of male-biased parasitism by studying the rate of digestion and survival time after a single blood meal in fleas Xenopsylla ramesis parasitizing males and females of the rodent Meriones crassus. Assuming that male hosts represent better patches for fleas than female hosts, we predicted that fleas (1) will digest blood of a male host faster than blood of a female host and (2) will survive longer after a single blood meal taken from a male host. To understand the possible role of environmental factors in mediation of the relationship between flea performance and host gender, we tested our predictions in male and female fleas under low (75%) and high (95%) relative humidity (RH). Host gender affected duration of digestion only at the middle and late stages of digestion and only interacting with either flea gender or RH or both. At the early stage of digestion, fleas of the same gender at the same RH digested blood at similar rates, independent of host gender. The rate of digestion did not differ between male and female fleas at 75% RH, but the duration of early stage was significantly shorter in female than in male fleas at 95% RH. At the middle stage of digestion, male fleas at both RH digested blood of male and female hosts at similar rates, but at lower RH, female fleas digested blood from male hosts at a significantly faster rate than blood from female hosts. At the late stage of digestion, both male and female fleas digested blood faster from male hosts than from female hosts at 75% RH, but the opposite was true at 95% RH. Survival time of fleas after completion of digestion was affected by RH, being longer at 95%, and flea gender, being longer in females. Fleas fed on female hosts died faster than fleas fed on male hosts, but this was found only at 95% humidity. We concluded that the relationship between flea performance and host gender was mediated by external conditions.

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“…has been previously reported (L'Hostis et al 1996;Tälleklint and Jaenson 1997;Hanincova et al 2003;Michalik et al 2003;Stanko et al 2007) and could be due to a greater home range and a better roaming within the home range for Apodemus spp. (Tälleklint and Jaenson 1997;Le Louarn and Quéré 2003), and/or a better immunity against I. ricinus for M. glareolus (Dizij and Kurtenbach 1995;Hughes and Randolph 2001). The tendency (not signiWcant) to have a higher tick burden for M. arvalis than M. glareolus is surprising compared to other studies (L'Hostis et al 1996;Sinski et al 2006;Stanko et al 2007) and to the fact that M. arvalis was not found in woody vegetation and has a smaller home range (from 25 in winter to 500 m² in summer, Le Louarn and Quéré 2003).…”

Section: Discussionmentioning

confidence: 96%

The relationships between Ixodes ricinus and small mammal species at the woodland–pasture interface

2008

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Ixodes ricinus, as vector, and small mammals, as reservoirs, are implicated in pathogen transmission between wild fauna, domestic animals and humans at the woodland-pasture interface. The ecological relationship between ticks and small mammals was monitored in 2005 on four bocage (enclosed pastureland) sites in central France, where questing ticks were collected by dragging and small mammals were trapped. Questing I. ricinus tick and small mammal locations in the environment were assessed through correspondence analysis. I. ricinus larval burden on small mammals was modeled using a negative binomial law. The correspondence analyses underlined three landscape features: grassland, hedgerow, and woodland. Seven small mammal species were trapped, while questing ticks were all I. ricinus, with the highest abundance in woodland and the lowest in pasture. The small mammals were overall more abundant in hedgerow, less present in woodland and sparse in grassland. They carried mainly I. ricinus, and secondarily I. acuminatus and I. trianguliceps. The most likely profile for a tick-infested small mammal corresponded to a male wood mouse (Apodemus sylvaticus) in woodland or hedgerow during a dry day. A. sylvaticus, which was the only species captured in grassland, but was also present in hedgerow and woodland, may be a primary means of transfer of I. ricinus larvae from woodland to pasture.

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Testosterone Depresses Innate and Acquired Resistance to Ticks in Natural Rodent Hosts: A Force for Aggregated Distributions of Parasites

Cited by 39 publications

References 0 publications

The parasitism of immature stages of Ixodes loricatus (Acari: Ixodidae) on wild rodents in Argentina

The parasitism of immature stages of Ixodes loricatus (Acari: Ixodidae) on wild rodents in Argentina

Effect of host gender on blood digestion in fleas: mediating role of environment

The relationships between Ixodes ricinus and small mammal species at the woodland–pasture interface

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