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Simon R Leather - One of the best experts on this subject based on the ideXlab platform.
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body condition is negatively associated with infection with Syngamus trachea in the ring necked pheasant phasianus colchicus
Veterinary Parasitology, 2016Co-Authors: Owen J Gethings, Eric R. Morgan, R B Sage, Simon R LeatherAbstract:The role that parasites play in regulating animal populations is debated, however recent research hints at their pervasiveness among free-living animal populations. Parasites exert both direct and indirect effects on host populations, and can act to regulate populations. The Ring-necked pheasant is an important game-bird species in the UK, and large numbers of birds are released annually. The impact of the ubiquitous tracheal nematode, Syngamus trachea on pheasant populations through effects on host condition was assessed on two pheasant estates in the south west of England. Pheasants infected with S. trachea demonstrated a significant reduction in host condition compared with uninfected controls, with as few as one pair of worms per bird. Although there was no difference in worm burden between sexes, analysis of regression slopes revealed there was a significant difference between sexes in the magnitude of the effect of increasing worm burden on host condition, with detectable effects observed in hosts with one and three pairs of worms for males and females respectively. The observed reductions in host condition in birds with even sub-clinical infections could be the cause of poor reproductive success and survival of pheasants post-release.
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density dependent regulation of fecundity in Syngamus trachea infrapopulations in semi naturally occurring ring necked pheasants phasianus colchicus and wild carrion crows corvus corone
Parasitology, 2016Co-Authors: O J Gethings, R B Sage, Simon R LeatherAbstract:Previous work has highlighted increased opportunities for the transmission of Syngamus trachea within pheasant release pens, due in part to high levels of environmental contamination around communal areas. Despite this, the distribution of adult worms within their definitive hosts is not significantly different from predicted distributions under Taylor's power law. Therefore, density-dependent processes are probably acting to regulate S. trachea population dynamics. Patterns of nematode fecundity were investigated in a semi-naturally occurring population of ring-necked pheasants (Phasianus colchicus) and a wild population of carrion crows (Corvus carone). Worm length was a reliable indicator of nematode fecundity, and a negative association between mean worm length and mean worm burden was identified within both the species. The stunting of worms at greater parasite densities was present in both immunologically naive and previously exposed pheasants, so is unlikely to be a function of age-dependent acquired immunity. Interestingly, the effect of parasite crowding in the crow population explained more of the variation in mean worm length, apparently driven by a greater mean worm burden when compared with pheasants. The findings of the present study suggest that fecundity is a function of parasite density, i.e. parasite-mediated competition and not host-mediated heterogeneities in immunocompetence.
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spatio temporal factors influencing the occurrence of Syngamus trachea within release pens in the south west of england
Veterinary Parasitology, 2015Co-Authors: O J Gethings, R B Sage, Simon R LeatherAbstract:Syngamus trachea is a pathogenic tracheal nematode that causes syngamiasis in wild and game birds, especially when birds are managed at high densities. Despite its pathogenic nature, very little is known about its epidemiology and relationship with ambient temperature and humidity. The spatial and temporal modelling of disease was undertaken on two pheasant estates within the South West of England from April 2014 to August 2014. Significant differences between the mean numbers of eggs per gram of soil were identified between pens at both site 1 and site 2 but did not differ significantly between sites. Egg abundance was significantly associated with soil moisture content, with greater egg survival between years in pens with higher average volumetric soil moisture content. Previous years stocking density and pen age were also associated with greater egg survival between years with more eggs being recovered in pens with greater stocking densities, and pens that had been sited longer. The greatest model to explain the variation in the numbers of eggs per gram of soil per pen was a combination of soil moisture content, stocking density and pen age. Larval recovery differed significantly between sites. Larval abundance was significantly and positively associated with temperature and relative humidity at site 1. Similarly, temperature and humidity were also positively and significantly associated with larval abundance at site 2. Rainfall did not influence larval recovery at either site 1 or site 2. The model with the greatest ability to explain larval abundance at both sites, was a combination of temperature, humidity and rainfall. Infection status (positive faecal egg counts) was significantly and positively associated with larval abundance at both sites, but rainfall was only positively associated at site 1. Temperature and humidity were positively associated with infection status at site 2, but not at site 1. The present study highlights the influence of climatic variables on both egg survival and larval abundance, and could therefore be used to develop more targeted treatment strategies around periods of higher disease risk. The frequent use of release pens is a clear factor in the epidemiology of syngamiasis, and it is recommended that pens be rested and/or rotated in order to reduce infection pressure in subsequent flocks.
Phyllis A. Clapham - One of the best experts on this subject based on the ideXlab platform.
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On the larval migration of Syngamus trachea and its causal relationship to pneumonia in young birds.
Journal of Helminthology, 2020Co-Authors: Phyllis A. ClaphamAbstract:Larvae of Syngamus trachea pass from the intestine to the lungs of the definitive host via the blood stream. They have been recovered from blood taken from the auricles of the heart and from the posterior vena cava.The condition of the lungs heavily infected with larvae is described.A condition of ‘Syngamus pneumonia’ occurs in the wild state among poults of partridges and pheasants.
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On the helminths of corvid birds in the British Isles.
Journal of Helminthology, 2020Co-Authors: Phyllis A. ClaphamAbstract:In 1925 Chapin reviewed the genera Syngamus and Cyathostoma and in the review described a new species of Syngamus which he had obtained from the American Crow, Corvus brachyrhynchos: this, he called Syngamus gracilis. It had been found in a bird from the Zoological Gardens at Philadelphia. He was of the opinion that this species had probably been recovered before from the American Crow but that its specificity had not been recognised. He assumes, in fact, that some if not all of the records of the occurrence of S. trachea in this species of host, and by inference probably in other Corvidae also, are incorrect and that S. gracilis is the species found. He bases this assumption on the physiological reactions of the parasite. It is a well known fact that S. trachea does not establish itself well in chickens and can in fact only reach maturity in young or very sick birds. The turkey is generally assumed to be the natural host of this helminth and Chapin is of the opinion that if S. trachea cannot establish itself satisfactorily in the chicken, then it is highly improbable that it can do so in the crow. For the chicken and the turkey are closely related phylogenetically, both being gallinaceous birds while the crow belongs to the Corvidae, which has no near kinship with the Galliformes.
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Some observations on the response of chickens to infestation with Heterakis gallinae.
Journal of Helminthology, 2020Co-Authors: Phyllis A. ClaphamAbstract:Experimental evidence of immunity to helminth parasites is on the whole very scanty. Several workers have drawn attention to the fact that immunity can be acquired as a result of age alone. Ransom (1921) using Syngamus trachealis in chickens, Herrick (1925) with Ascaridia lineata also in chickens, Sandground (1928) with Strongyloides and Nanophyes in dogs and cats, are three examples.
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Three new intermediary Vectors for Syngamus trachea.
Journal of Helminthology, 2020Co-Authors: Phyllis A. ClaphamAbstract:Our knowledge of the range of intermediate hosts of which Syngamus trachea can take advantage is increasing. Recent observations have shown that the centipede, Scolopendra sp., the leatherjacket, Tipula sp., and the spring tail, Sminthurus viridis may all act as vectors. In each case the larvae had migrated from the gut into the surrounding tissues where they had settled down. All these Arthropods have been found naturally infected on a plot of land known to be carrying a heavy burden of gapes.
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Are there Host Strains within the Species of Syngamus trachea?
Journal of Helminthology, 2020Co-Authors: Phyllis A. ClaphamAbstract:In 1928 Taylor put forward the theory that “…Syngamus trachea is a species within which there may be found a number of strains showing a peculiar physiological adaptation to the host in which they occur.” He had not had much success in a number of experiments in which he had tried to infect chickens with S. trachea from starlings. The first experimental feedings resulted in only light infections though control experiments with the chicken “strain” resulted in much heavier ones. After the first passage through the chicken however, the gapeworms had become more adapted to the new host, and could produce much more serious infections in the next generation.
R B Sage - One of the best experts on this subject based on the ideXlab platform.
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body condition is negatively associated with infection with Syngamus trachea in the ring necked pheasant phasianus colchicus
Veterinary Parasitology, 2016Co-Authors: Owen J Gethings, Eric R. Morgan, R B Sage, Simon R LeatherAbstract:The role that parasites play in regulating animal populations is debated, however recent research hints at their pervasiveness among free-living animal populations. Parasites exert both direct and indirect effects on host populations, and can act to regulate populations. The Ring-necked pheasant is an important game-bird species in the UK, and large numbers of birds are released annually. The impact of the ubiquitous tracheal nematode, Syngamus trachea on pheasant populations through effects on host condition was assessed on two pheasant estates in the south west of England. Pheasants infected with S. trachea demonstrated a significant reduction in host condition compared with uninfected controls, with as few as one pair of worms per bird. Although there was no difference in worm burden between sexes, analysis of regression slopes revealed there was a significant difference between sexes in the magnitude of the effect of increasing worm burden on host condition, with detectable effects observed in hosts with one and three pairs of worms for males and females respectively. The observed reductions in host condition in birds with even sub-clinical infections could be the cause of poor reproductive success and survival of pheasants post-release.
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density dependent regulation of fecundity in Syngamus trachea infrapopulations in semi naturally occurring ring necked pheasants phasianus colchicus and wild carrion crows corvus corone
Parasitology, 2016Co-Authors: O J Gethings, R B Sage, Simon R LeatherAbstract:Previous work has highlighted increased opportunities for the transmission of Syngamus trachea within pheasant release pens, due in part to high levels of environmental contamination around communal areas. Despite this, the distribution of adult worms within their definitive hosts is not significantly different from predicted distributions under Taylor's power law. Therefore, density-dependent processes are probably acting to regulate S. trachea population dynamics. Patterns of nematode fecundity were investigated in a semi-naturally occurring population of ring-necked pheasants (Phasianus colchicus) and a wild population of carrion crows (Corvus carone). Worm length was a reliable indicator of nematode fecundity, and a negative association between mean worm length and mean worm burden was identified within both the species. The stunting of worms at greater parasite densities was present in both immunologically naive and previously exposed pheasants, so is unlikely to be a function of age-dependent acquired immunity. Interestingly, the effect of parasite crowding in the crow population explained more of the variation in mean worm length, apparently driven by a greater mean worm burden when compared with pheasants. The findings of the present study suggest that fecundity is a function of parasite density, i.e. parasite-mediated competition and not host-mediated heterogeneities in immunocompetence.
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spatio temporal factors influencing the occurrence of Syngamus trachea within release pens in the south west of england
Veterinary Parasitology, 2015Co-Authors: O J Gethings, R B Sage, Simon R LeatherAbstract:Syngamus trachea is a pathogenic tracheal nematode that causes syngamiasis in wild and game birds, especially when birds are managed at high densities. Despite its pathogenic nature, very little is known about its epidemiology and relationship with ambient temperature and humidity. The spatial and temporal modelling of disease was undertaken on two pheasant estates within the South West of England from April 2014 to August 2014. Significant differences between the mean numbers of eggs per gram of soil were identified between pens at both site 1 and site 2 but did not differ significantly between sites. Egg abundance was significantly associated with soil moisture content, with greater egg survival between years in pens with higher average volumetric soil moisture content. Previous years stocking density and pen age were also associated with greater egg survival between years with more eggs being recovered in pens with greater stocking densities, and pens that had been sited longer. The greatest model to explain the variation in the numbers of eggs per gram of soil per pen was a combination of soil moisture content, stocking density and pen age. Larval recovery differed significantly between sites. Larval abundance was significantly and positively associated with temperature and relative humidity at site 1. Similarly, temperature and humidity were also positively and significantly associated with larval abundance at site 2. Rainfall did not influence larval recovery at either site 1 or site 2. The model with the greatest ability to explain larval abundance at both sites, was a combination of temperature, humidity and rainfall. Infection status (positive faecal egg counts) was significantly and positively associated with larval abundance at both sites, but rainfall was only positively associated at site 1. Temperature and humidity were positively associated with infection status at site 2, but not at site 1. The present study highlights the influence of climatic variables on both egg survival and larval abundance, and could therefore be used to develop more targeted treatment strategies around periods of higher disease risk. The frequent use of release pens is a clear factor in the epidemiology of syngamiasis, and it is recommended that pens be rested and/or rotated in order to reduce infection pressure in subsequent flocks.
O J Gethings - One of the best experts on this subject based on the ideXlab platform.
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density dependent regulation of fecundity in Syngamus trachea infrapopulations in semi naturally occurring ring necked pheasants phasianus colchicus and wild carrion crows corvus corone
Parasitology, 2016Co-Authors: O J Gethings, R B Sage, Simon R LeatherAbstract:Previous work has highlighted increased opportunities for the transmission of Syngamus trachea within pheasant release pens, due in part to high levels of environmental contamination around communal areas. Despite this, the distribution of adult worms within their definitive hosts is not significantly different from predicted distributions under Taylor's power law. Therefore, density-dependent processes are probably acting to regulate S. trachea population dynamics. Patterns of nematode fecundity were investigated in a semi-naturally occurring population of ring-necked pheasants (Phasianus colchicus) and a wild population of carrion crows (Corvus carone). Worm length was a reliable indicator of nematode fecundity, and a negative association between mean worm length and mean worm burden was identified within both the species. The stunting of worms at greater parasite densities was present in both immunologically naive and previously exposed pheasants, so is unlikely to be a function of age-dependent acquired immunity. Interestingly, the effect of parasite crowding in the crow population explained more of the variation in mean worm length, apparently driven by a greater mean worm burden when compared with pheasants. The findings of the present study suggest that fecundity is a function of parasite density, i.e. parasite-mediated competition and not host-mediated heterogeneities in immunocompetence.
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spatio temporal factors influencing the occurrence of Syngamus trachea within release pens in the south west of england
Veterinary Parasitology, 2015Co-Authors: O J Gethings, R B Sage, Simon R LeatherAbstract:Syngamus trachea is a pathogenic tracheal nematode that causes syngamiasis in wild and game birds, especially when birds are managed at high densities. Despite its pathogenic nature, very little is known about its epidemiology and relationship with ambient temperature and humidity. The spatial and temporal modelling of disease was undertaken on two pheasant estates within the South West of England from April 2014 to August 2014. Significant differences between the mean numbers of eggs per gram of soil were identified between pens at both site 1 and site 2 but did not differ significantly between sites. Egg abundance was significantly associated with soil moisture content, with greater egg survival between years in pens with higher average volumetric soil moisture content. Previous years stocking density and pen age were also associated with greater egg survival between years with more eggs being recovered in pens with greater stocking densities, and pens that had been sited longer. The greatest model to explain the variation in the numbers of eggs per gram of soil per pen was a combination of soil moisture content, stocking density and pen age. Larval recovery differed significantly between sites. Larval abundance was significantly and positively associated with temperature and relative humidity at site 1. Similarly, temperature and humidity were also positively and significantly associated with larval abundance at site 2. Rainfall did not influence larval recovery at either site 1 or site 2. The model with the greatest ability to explain larval abundance at both sites, was a combination of temperature, humidity and rainfall. Infection status (positive faecal egg counts) was significantly and positively associated with larval abundance at both sites, but rainfall was only positively associated at site 1. Temperature and humidity were positively associated with infection status at site 2, but not at site 1. The present study highlights the influence of climatic variables on both egg survival and larval abundance, and could therefore be used to develop more targeted treatment strategies around periods of higher disease risk. The frequent use of release pens is a clear factor in the epidemiology of syngamiasis, and it is recommended that pens be rested and/or rotated in order to reduce infection pressure in subsequent flocks.
J. Monrad - One of the best experts on this subject based on the ideXlab platform.
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Prevalence and distribution of gastrointestinal helminths and their effects on weight gain in free-range chickens in Central Zambia
Tropical Animal Health and Production, 2007Co-Authors: I. K. Phiri, A. M. Phiri, M. Ziela, A. Chota, M. Masuku, J. MonradAbstract:Examination of helminths from gastrointestinal tracts of 125 free-range chickens in Zambia revealed a 95.2% prevalence rate. The species and their prevalences were: Allodapa suctoria (85.6%), Tetrameres americana (80.8%), Ascaridia galli (28.8%), Gonglonema ingluvicola (50.4%), Raillietina spp. (81.6%) and Heterakis gallinarum (32.8%). No trematodes or Syngamus trachea were found. Mixed infections accounted for 88.2% as compared to 7.2% of single infections. Effects of helminthoses on weight gain were investigated in 100 growing chickens randomly assigned to treatment (levamisole) and untreated control groups. There was a significant mean (±SEM) weight gain (grams) of 812.8 ± 51.4 in the treatment group and 623 ± 57.4 in the control group (p < 0.01). The mean (±SEM) worm burdens from the control group and the treatment group were 96.3 ± 5.61 and 22.05 ± 2.61, respectively. These results confirm the higher risk of helminth infections in free-range systems and may explain the deleterious effects in chickens.
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Prevalence and distribution of gastrointestinal helminths and their effects on weight gain in free-range chickens in Central Zambia
Tropical Animal Health and Production, 2007Co-Authors: I. K. Phiri, A. M. Phiri, M. Ziela, A. Chota, M. Masuku, J. MonradAbstract:Examination of helminths from gastrointestinal tracts of 125 free-range chickens in Zambia revealed a 95.2% prevalence rate. The species and their prevalences were: Allodapa suctoria (85.6%), Tetrameres americana (80.8%), Ascaridia galli (28.8%), Gonglonema ingluvicola (50.4%), Raillietina spp. (81.6%) and Heterakis gallinarum (32.8%). No trematodes or Syngamus trachea were found. Mixed infections accounted for 88.2% as compared to 7.2% of single infections. Effects of helminthoses on weight gain were investigated in 100 growing chickens randomly assigned to treatment (levamisole) and untreated control groups. There was a significant mean (±SEM) weight gain (grams) of 812.8 ± 51.4 in the treatment group and 623 ± 57.4 in the control group ( p
