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J. M. Pemberton - One of the best experts on this subject based on the ideXlab platform.

  • epidemiology of parasitic protozoan infections in soay sheep ovis aries l on st kilda
    Parasitology, 2007
    Co-Authors: B. H. Craig, J. G. Pilkington, L. E. B. Kruuk, J. M. Pemberton
    Abstract:

    The feral Soay sheep (Ovis aries L.) Population on Hirta, St Kilda, is Host to a diverse component parasite community, but previous parasitological studies of the Population have only focussed on the metazoan species. This paper reports the first epidemiological study of the protozoan species comprising Cryptosporidium parvum, Giardia duodenalis and 11 species of Eimeria in Soay sheep across 3 years of varying Host Population density. Prevalence and intensity of almost all species of protozoa significantly decreased with Host age, with the exception of E. granulosa, which increased in prevalence with Host age. The prevalence of C. parvum appeared to vary positively with Host Population density but that of G. duodenalis did not vary significantly with density. Most species of Eimeria showed a distinct lag in infection level following the Host Population crash of 2002, taking up to 2 years to decrease. Mixed Eimeria species intensity and diversity were highest in 2002, a year of low Host density. Parasite diversity decreased with Host age and was higher in males. There were 5 positive pair-wise associations between protozoa species in terms of prevalence. The results of this study highlight the potential for protozoal infection to shape the evolution of parasite resistance in wild Host Populations harbouring diverse parasite species.

  • Epidemiology of parasitic protozoan infections in Soay sheep (Ovis ariesL.) on St Kilda
    Parasitology, 2006
    Co-Authors: B. H. Craig, J. G. Pilkington, L. E. B. Kruuk, J. M. Pemberton
    Abstract:

    The feral Soay sheep (Ovis ariesL.) Population on Hirta, St Kilda, is Host to a diverse component parasite community, but previous parasitological studies of the Population have only focussed on the metazoan species. This paper reports the first epidemiological study of the protozoan species comprisingCryptosporidium parvum,Giardia duodenalisand 11 species ofEimeriain Soay sheep across 3 years of varying Host Population density. Prevalence and intensity of almost all species of protozoa significantly decreased with Host age, with the exception ofE. granulosa, which increased in prevalence with Host age. The prevalence ofC. parvumappeared to vary positively with Host Population density but that ofG. duodenalisdid not vary significantly with density. Most species ofEimeriashowed a distinct lag in infection level following the Host Population crash of 2002, taking up to 2 years to decrease. MixedEimeriaspecies intensity and diversity were highest in 2002, a year of low Host density. Parasite diversity decreased with Host age and was higher in males. There were 5 positive pair-wise associations between protozoa species in terms of prevalence. The results of this study highlight the potential for protozoal infection to shape the evolution of parasite resistance in wild Host Populations harbouring diverse parasite species.

B. H. Craig - One of the best experts on this subject based on the ideXlab platform.

  • epidemiology of parasitic protozoan infections in soay sheep ovis aries l on st kilda
    Parasitology, 2007
    Co-Authors: B. H. Craig, J. G. Pilkington, L. E. B. Kruuk, J. M. Pemberton
    Abstract:

    The feral Soay sheep (Ovis aries L.) Population on Hirta, St Kilda, is Host to a diverse component parasite community, but previous parasitological studies of the Population have only focussed on the metazoan species. This paper reports the first epidemiological study of the protozoan species comprising Cryptosporidium parvum, Giardia duodenalis and 11 species of Eimeria in Soay sheep across 3 years of varying Host Population density. Prevalence and intensity of almost all species of protozoa significantly decreased with Host age, with the exception of E. granulosa, which increased in prevalence with Host age. The prevalence of C. parvum appeared to vary positively with Host Population density but that of G. duodenalis did not vary significantly with density. Most species of Eimeria showed a distinct lag in infection level following the Host Population crash of 2002, taking up to 2 years to decrease. Mixed Eimeria species intensity and diversity were highest in 2002, a year of low Host density. Parasite diversity decreased with Host age and was higher in males. There were 5 positive pair-wise associations between protozoa species in terms of prevalence. The results of this study highlight the potential for protozoal infection to shape the evolution of parasite resistance in wild Host Populations harbouring diverse parasite species.

  • Epidemiology of parasitic protozoan infections in Soay sheep (Ovis ariesL.) on St Kilda
    Parasitology, 2006
    Co-Authors: B. H. Craig, J. G. Pilkington, L. E. B. Kruuk, J. M. Pemberton
    Abstract:

    The feral Soay sheep (Ovis ariesL.) Population on Hirta, St Kilda, is Host to a diverse component parasite community, but previous parasitological studies of the Population have only focussed on the metazoan species. This paper reports the first epidemiological study of the protozoan species comprisingCryptosporidium parvum,Giardia duodenalisand 11 species ofEimeriain Soay sheep across 3 years of varying Host Population density. Prevalence and intensity of almost all species of protozoa significantly decreased with Host age, with the exception ofE. granulosa, which increased in prevalence with Host age. The prevalence ofC. parvumappeared to vary positively with Host Population density but that ofG. duodenalisdid not vary significantly with density. Most species ofEimeriashowed a distinct lag in infection level following the Host Population crash of 2002, taking up to 2 years to decrease. MixedEimeriaspecies intensity and diversity were highest in 2002, a year of low Host density. Parasite diversity decreased with Host age and was higher in males. There were 5 positive pair-wise associations between protozoa species in terms of prevalence. The results of this study highlight the potential for protozoal infection to shape the evolution of parasite resistance in wild Host Populations harbouring diverse parasite species.

L. E. B. Kruuk - One of the best experts on this subject based on the ideXlab platform.

  • epidemiology of parasitic protozoan infections in soay sheep ovis aries l on st kilda
    Parasitology, 2007
    Co-Authors: B. H. Craig, J. G. Pilkington, L. E. B. Kruuk, J. M. Pemberton
    Abstract:

    The feral Soay sheep (Ovis aries L.) Population on Hirta, St Kilda, is Host to a diverse component parasite community, but previous parasitological studies of the Population have only focussed on the metazoan species. This paper reports the first epidemiological study of the protozoan species comprising Cryptosporidium parvum, Giardia duodenalis and 11 species of Eimeria in Soay sheep across 3 years of varying Host Population density. Prevalence and intensity of almost all species of protozoa significantly decreased with Host age, with the exception of E. granulosa, which increased in prevalence with Host age. The prevalence of C. parvum appeared to vary positively with Host Population density but that of G. duodenalis did not vary significantly with density. Most species of Eimeria showed a distinct lag in infection level following the Host Population crash of 2002, taking up to 2 years to decrease. Mixed Eimeria species intensity and diversity were highest in 2002, a year of low Host density. Parasite diversity decreased with Host age and was higher in males. There were 5 positive pair-wise associations between protozoa species in terms of prevalence. The results of this study highlight the potential for protozoal infection to shape the evolution of parasite resistance in wild Host Populations harbouring diverse parasite species.

  • Epidemiology of parasitic protozoan infections in Soay sheep (Ovis ariesL.) on St Kilda
    Parasitology, 2006
    Co-Authors: B. H. Craig, J. G. Pilkington, L. E. B. Kruuk, J. M. Pemberton
    Abstract:

    The feral Soay sheep (Ovis ariesL.) Population on Hirta, St Kilda, is Host to a diverse component parasite community, but previous parasitological studies of the Population have only focussed on the metazoan species. This paper reports the first epidemiological study of the protozoan species comprisingCryptosporidium parvum,Giardia duodenalisand 11 species ofEimeriain Soay sheep across 3 years of varying Host Population density. Prevalence and intensity of almost all species of protozoa significantly decreased with Host age, with the exception ofE. granulosa, which increased in prevalence with Host age. The prevalence ofC. parvumappeared to vary positively with Host Population density but that ofG. duodenalisdid not vary significantly with density. Most species ofEimeriashowed a distinct lag in infection level following the Host Population crash of 2002, taking up to 2 years to decrease. MixedEimeriaspecies intensity and diversity were highest in 2002, a year of low Host density. Parasite diversity decreased with Host age and was higher in males. There were 5 positive pair-wise associations between protozoa species in terms of prevalence. The results of this study highlight the potential for protozoal infection to shape the evolution of parasite resistance in wild Host Populations harbouring diverse parasite species.

J. G. Pilkington - One of the best experts on this subject based on the ideXlab platform.

  • epidemiology of parasitic protozoan infections in soay sheep ovis aries l on st kilda
    Parasitology, 2007
    Co-Authors: B. H. Craig, J. G. Pilkington, L. E. B. Kruuk, J. M. Pemberton
    Abstract:

    The feral Soay sheep (Ovis aries L.) Population on Hirta, St Kilda, is Host to a diverse component parasite community, but previous parasitological studies of the Population have only focussed on the metazoan species. This paper reports the first epidemiological study of the protozoan species comprising Cryptosporidium parvum, Giardia duodenalis and 11 species of Eimeria in Soay sheep across 3 years of varying Host Population density. Prevalence and intensity of almost all species of protozoa significantly decreased with Host age, with the exception of E. granulosa, which increased in prevalence with Host age. The prevalence of C. parvum appeared to vary positively with Host Population density but that of G. duodenalis did not vary significantly with density. Most species of Eimeria showed a distinct lag in infection level following the Host Population crash of 2002, taking up to 2 years to decrease. Mixed Eimeria species intensity and diversity were highest in 2002, a year of low Host density. Parasite diversity decreased with Host age and was higher in males. There were 5 positive pair-wise associations between protozoa species in terms of prevalence. The results of this study highlight the potential for protozoal infection to shape the evolution of parasite resistance in wild Host Populations harbouring diverse parasite species.

  • Epidemiology of parasitic protozoan infections in Soay sheep (Ovis ariesL.) on St Kilda
    Parasitology, 2006
    Co-Authors: B. H. Craig, J. G. Pilkington, L. E. B. Kruuk, J. M. Pemberton
    Abstract:

    The feral Soay sheep (Ovis ariesL.) Population on Hirta, St Kilda, is Host to a diverse component parasite community, but previous parasitological studies of the Population have only focussed on the metazoan species. This paper reports the first epidemiological study of the protozoan species comprisingCryptosporidium parvum,Giardia duodenalisand 11 species ofEimeriain Soay sheep across 3 years of varying Host Population density. Prevalence and intensity of almost all species of protozoa significantly decreased with Host age, with the exception ofE. granulosa, which increased in prevalence with Host age. The prevalence ofC. parvumappeared to vary positively with Host Population density but that ofG. duodenalisdid not vary significantly with density. Most species ofEimeriashowed a distinct lag in infection level following the Host Population crash of 2002, taking up to 2 years to decrease. MixedEimeriaspecies intensity and diversity were highest in 2002, a year of low Host density. Parasite diversity decreased with Host age and was higher in males. There were 5 positive pair-wise associations between protozoa species in terms of prevalence. The results of this study highlight the potential for protozoal infection to shape the evolution of parasite resistance in wild Host Populations harbouring diverse parasite species.

F M D Gulland - One of the best experts on this subject based on the ideXlab platform.

  • epidemiology of nematode infections of soay sheep ovis aries l on st kilda
    Parasitology, 1992
    Co-Authors: F M D Gulland
    Abstract:

    : The epidemiology of nematode infections of Soay sheep on the island of St Kilda over a period of 2 years (August 1988-August 1990) spanning a Host Population crash is described. Infective larvae (L3) levels on pasture were high (2422 +/- 365 L3/kg D.M. grass in midsummer 1988) when Host Population density was high, decreasing after the sheep Population declined by 70% in early 1989 (601 +/- 14 L3/kg D.M. in midsummer 1989). The availability of infective larvae to sheep increased during the winter of 1988-1989, probably as a result of concentration of existing larvae on grass as vegetation was destroyed by bad weather and overgrazing. Increased availability of pre-parasitic stages was accompanied by a marked increased in faecal egg counts from sheep of all ages and both sexes. Prevalence and intensity of infection (faecal egg counts) were higher in males than females throughout the 2-year study (chi 2 = 208.3, P < 0.005 and F1, 2000 = 304, P < 0.001 respectively), except during the lambing periods, and decreased with age in both sexes. Changes in prevalence and intensity of strongyle infections were associated with changes in Host Population density. Prevalence and intensity of Dictyocaulus filaria larvae in faeces increased during the Host Population crash. Infection intensity decreased with age (F1, 203 = 44.02, P < 0.001) and was higher in males than females (F1, 203 = 13.45, P < 0.001).