Epidemiology and genetic variability of two species of 
nematodes (Heligmosomoides polygyrus and Syphacia 
stroma) of Apodemus spp.

This paper presents the first extensive data on the helminth community of the wood mouse Apodemus sylvaticus in a coastal sand dune area in Portugal. The 557 hosts analysed in this study were trapped seasonally between autumn 2002 and summer 2005 across 6 habitat types. Twelve helminth species were detected among which, Taenia parva larvae, Angiostrongylus dujardini, Heligmosomoides polygyrus, Syphacia stroma and S. frederici constitute the component species, accounting for 98.7% of all worms. H. polygyrus was the most prevalent helminth parasite. Species richness varied according to habitat and season. The highest species richness was found in sand dunes during winter whereas the lowest was detected along lake margins also during the winter. Some differences in prevalence and mean intensity values were found in relation to year (T. parva larvae and H. polygyrus), habitat (A. dujardini), season (T. parva larvae, H. polygyrus, A. dujardini and S. stroma) and host sex (T. parva larvae and S. stroma). These differences are discussed both in view of the host's biology and habitat characteristics.

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“…Differences referring to S. stroma according to host sex were also reported by Lewis (1968), Behnke et al (1999), andMüller-Graf et al (1999).…”

Section: Discussionsupporting

confidence: 69%

Ecological aspects influencing the helminth community of the wood mouse Apodemus sylvaticus in Dunas de Mira, Portugal

Eira

Torres

Vingada

et al. 2006

Acta Parasitologica

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“…Cestodes and telacids have long and indirect life cycles, with long-lived adults and a number of larval stages infecting intermediate hosts (Morand 1996). Free-living stages may either infect other hosts that ingest feces with eggs or reinfect the same host when the eggs deposited by female worms around the anus are ingested during grooming (Mü ller- Graf et al 1999). Oxyurid nematodes have direct life cycles.…”

Section: Food Availability Body Condition and Endoparasite Infectionmentioning

confidence: 99%

“…This fact could have precluded the detection of responses to these parasites due to the short duration of our experiment. The life expectancy of both adults and free-living stages is short (ϳ60 and 35 days, respectively) and eggs are not very resistant to environmental conditions (Mü ller- Graf et al 1999), so that frequent infections and reinfections are needed to maintain parasite populations. Syphacia spp.…”

Section: Food Availability Body Condition and Endoparasite Infectionmentioning

confidence: 99%

Wood Mouse Apodemus Sylvaticus Winter Food Supply: Density, Condition, Breeding, and Parasites

Dı́az

Alonso

2003

Ecology

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We determined the individual and population responses to food availability of wood mice Apodemus sylvaticus wintering in small forest woodlots by means of a food addition experiment. The allocation of the extra provided energy to the maintenance of body condition and reproduction was expected to vary between sexes due to their different energy investment in reproduction and to the different indirect costs of reproduction associated with different hormone-mediated susceptibilities to parasite infections.There were no effects of food supplementation on the density of adult males or on the overall density of mice. However, adult females were marginally more abundant and the sex ratio was more balanced in supplemented woodlots. Body condition (as estimated by body mass, body mass relative to body size, and amount of fat reserves), did not differ among treatments for either adult males or females. The prevalence and intensity of endoparasites of short life cycle (oxyurid nematodes) were lower in food-supplemented woodlots than in controls and lower in females than in males. No differences were found for endoparasites with long life cycles (telacid nematodes and cestodes). Males with intermediate parasite loads were in better body condition than either nonparasitized or highly parasitized individuals, and the body condition of each group of males was better in foodsupplemented woodlots than in controls. This nonlinear relationship between parasite loads and body condition was apparently due to indirect costs of reproduction in control woodlots, where there was a direct relationship between male reproductive effort (relative testis size) and parasite loads. This relationship was not found in supplemented woodlots.Most individuals were breeding actively at the end of winter. Males had larger testicles, and females showed an advanced breeding, and probably enhanced survival and larger litter sizes, in supplemented woodlots. Individual mice wintering in Mediterranean fragmented forests are thus food limited, and directed most of the extra provided food resources to reproduction without losing body condition or antiparasite abilities. This enhanced reproduction, rather than improved body condition, may translate into larger population densities and recruitment.

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“…polygyrus and Syphacia sp. since they have the same life cycle duration [59], while Trichuris sp. has much longer life cycle duration [60].…”

Section: Discussionmentioning

confidence: 99%

“…Male mice with B chromosomes had lower, while the female ones with B chromosomes had higher expression rates. Since H. polygyrus and S. stroma have different modes of reproduction [59], it is possible that they affect MHC II-DRB gene expression at different life stages and in interaction with different host-related variables, partially independent from the immune response. The results suggest that the presence of B chromosomes could contribute to detected sex-dependant differences in MHC II-DRB gene expression.…”

Section: Discussionmentioning

confidence: 99%

Possible Influence of B Chromosomes on Genes Included in Immune Response and Parasite Burden in Apodemus flavicollis

et al. 2014

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Genetic background underlying wild populations immune response to different parasites is still not well understood. We studied immune response to multiple infections and to competition between different parasite species at different developmental stages in population of yellow-necked mouse, Apodemus flavicollis. Quantitative real-time PCR was used to investigate associations of MHC II-DRB, IL-10 and Tgf-β genes expressions with presence of intestinal parasites at different developmental stages. Furthermore, we were interested whether the host related characteristics (sex, age, body condition, presence of B chromosomes or expression of other genes) or characteristics of present parasites (number of adult parasites of each identified species, egg count of each parasite genus, total number of nematode individuals) affect differential expression of the studied genes. A significant invert association between the expression of MHC II-DRB and Tgf-β gene was found, which together with absence of IL-10 association confirmed modified Th2 as the main type of immune response to nematode infections. Effect of recorded parasites and parasite life-cycle stage on expression levels of MHC II-DRB gene was detected only through interactions with host-related characteristics such as sex, age, and the presence of B chromosomes. The presence of B chromosomes is associated with lower expression level of Tgf-β gene. Although the influence of host genetic background on parasite infection has already been well documented, this is the first study in mammals that gave presence of B chromosomes on immune response full consideration.

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Epidemiology and genetic variability of two species of nematodes (Heligmosomoides polygyrus and Syphacia stroma) of Apodemus spp.

Cited by 16 publications

References 24 publications

Ecological aspects influencing the helminth community of the wood mouse Apodemus sylvaticus in Dunas de Mira, Portugal

Ecological aspects influencing the helminth community of the wood mouse Apodemus sylvaticus in Dunas de Mira, Portugal

Wood Mouse Apodemus Sylvaticus Winter Food Supply: Density, Condition, Breeding, and Parasites

Possible Influence of B Chromosomes on Genes Included in Immune Response and Parasite Burden in Apodemus flavicollis

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