How hosts control worms

Stear, M. J.; Bairden, K.; Duncan, J.L.; Holmes, Peter; McKellar, Quintin; Park, M.; Strain, S.; Murray, M.; Bishop, S.C.; Gettinby, G.

doi:10.1038/37895

Cited by 152 publications

(101 citation statements)

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“…Alexander and Stimson 1988;Poulin 1996). In our case, the pattern could also reflect a higher female fecundity in male hosts than in females (Stear et al 1997). This pattern may be due to ecological differences between sexes (Forbes 1993) or to differences in exposure to parasites because of their different feeding habits or habitat use (Wilson et al 2001).…”

Section: Discussionmentioning

confidence: 78%

Epidemiology and risk factors analysis of elaphostrongylosis in red deer (Cervus elaphus) from Spain

2005

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We studied the distribution and faecal shedding pattern of the first-stage larvae (L1) of Elaphostrongylus cervi (Nematoda: Protostrongylidae) in the red deer (Cervus elaphus) across Spain, where excretion was widespread. We evaluated the effects of individual, population and environmental factors on E. cervi L1 counts in 18 free-ranging red deer populations in South Central Spain. In this area, prevalence was 71.42+/-2.14% (n = 448) and mean intensity (n = 320) was 74.50+/-10.35. Aggregation of deer at water-holes was positively associated with E. cervi L1 prevalence, possibly due to spatial and temporal odds of infected gastropods, red deer and infective E. cervi L1 larvae being encountered. Prevalence increased with age, and there was also a trend towards males having higher intensities than females. A slightly decreasing age-intensity profile was identified for females, which may suggest a role of acquired immunity.

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Section: Discussionmentioning

confidence: 78%

Epidemiology and risk factors analysis of elaphostrongylosis in red deer (Cervus elaphus) from Spain

2005

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“…Owing to the prevalence of nematodes, we used the number of different nematode morphotype infections per individual (NNI) and the FEC value as measurements of the intensity of the parasite burden. Both measurements reflect the worm burden and fecundity, which in turn are influenced by the immune state of the host (Stear et al, 1995(Stear et al, , 1997.…”

Section: Parasite Screeningmentioning

confidence: 99%

Neutral versus adaptive genetic variation in parasite resistance: importance of major histocompatibility complex supertypes in a free-ranging primate

et al. 2007

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Current discussions in evolutionary ecology and conservation genetics focus on the relative importance of using selective neutral markers or markers of coding genes to identify adaptive and evolutionary relevant processes. Genetic diversity might be particularly important in immune genes (e.g., in genes of the major histocompatibility complex, MHC), which are influencing pathogen and parasite resistance. We investigated the effects of neutral versus adaptive genetic variation in parasite resistance in a natural population of fat-tailed dwarf lemurs (Cheirogaleus medius). No association between neutral overall individual genetic diversity and parasite load could be detected. In 149 individuals, we identified 50 MHC class II alleles of the functionally important duplicated DRB locus. The investigation of the functional importance of immune gene (MHC) diversity and parasite selection in natural populations is often problematic due to extensive polymorphism in the MHC genes and restrictions in available sample sizes. Here, for the first time we applied an approach that has been developed in human medical studies. Eleven MHC class II supertypes were identified based on shared antigen-binding similarities. The number of individual MHC supertypes had no influence on the nematode burden. However, we found evidence for a specific MHC supertype (supertype 1) that was linked to infected individuals, a higher number of different nematode infections and high intensity of infection per individual. Moreover, one rare MHC supertype (supertype 7) was revealed to be advantageous with respect to parasite burden. Thus, our results add evidence to the small body of studies that show significant associations between specific MHC constitutions and naturally occurring parasites in the complexity of natural populations.

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“…Host resistance to parasites varies and much of this variation is under genetic control (Stear et al, 1997;Woolaston and Windon, 2001;Bishop and Stear, 2003;Quinnell, 2003). In the absence of new anthelmintic compounds or commercially available vaccines, an important first phase in finding a solution to the anthelmintic resistance problem has been the development of selective breeding schemes for parasite resistance in the UK, Australia and New Zealand.…”

Section: Introductionmentioning

confidence: 99%

Quantitative trait loci associated with parasitic infection in Scottish blackface sheep

et al. 2006

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This study aimed to identify quantitative trait loci associated with endoparasitic infection in Scottish Blackface sheep. Data were collected from 789 animals over a 3-year period. All of the animals were continually exposed to a mixed nematode infection by grazing. Faecal samples were collected in August, September and October each year at ca. 16, 20 and 24 weeks of age; Nematodirus spp. eggs were counted separately from the other species of nematodes. Blood samples were collected in October from which immunoglobulin A (IgA) activity was measured and DNA was extracted for genotyping. In total, 139 Microsatellite markers were genotyped across eight chromosomal regions (chromosomes 1, 2, 3, 5, 14, 18, 20 and 21) in the sires and progeny were genotyped for the markers that were polymorphic in their sire. Evidence was found for quantitative trait loci (QTL) on chromosomes 2, 3, 14 and 20. QTL associated with specific IgA activity were identified in chromosomes 3 and 20, in regions close to IFNG (chromosome 3) and the MHC (chromosome 20). QTL associated with Nematodirus FEC were identified on chromosomes 2, 3 and 14. Lastly, QTL associated with non-Nematodirus Strongyle FEC were identified on chromosomes 3 and 20. This study has shown that some aspects of host resistance to gastrointestinal parasites are under strong genetic control, therefore these QTL could be utilised in a marker-assisted selection scheme to increase host resistance to gastrointestinal parasites.

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How hosts control worms

Cited by 152 publications

References 0 publications

Epidemiology and risk factors analysis of elaphostrongylosis in red deer (Cervus elaphus) from Spain

Epidemiology and risk factors analysis of elaphostrongylosis in red deer (Cervus elaphus) from Spain

Neutral versus adaptive genetic variation in parasite resistance: importance of major histocompatibility complex supertypes in a free-ranging primate

Quantitative trait loci associated with parasitic infection in Scottish blackface sheep

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