scholarly journals Quantifying the sources of variation in eosinophilia among Scottish Blackface lambs with mixed, predominantly Teladorsagia circumcincta nematode infection

2021 ◽  
pp. 109590
Author(s):  
Caitlin J. Jenvey ◽  
Fazel Almasi ◽  
Emma U. Halliwell ◽  
Xia Li ◽  
David Piedrafita ◽  
...  
Keyword(s):  
Nematode Infection ◽  
Teladorsagia Circumcincta ◽  
Sources Of Variation

scholarly journals The dynamic influence of genetic variation on the susceptibility of sheep to gastrointestinal nematode infection

2007 ◽  
Vol 4 (16) ◽  
pp. 767-776 ◽  
Author(s):  
Michael J Stear ◽  
Lesley Fitton ◽  
Giles T Innocent ◽  
Lisa Murphy ◽  
Kerry Rennie ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Immune Responses ◽  
Gastrointestinal Nematode ◽  
Nematode Infection ◽  
Major Mechanism ◽  
Teladorsagia Circumcincta ◽  
Polymorphic Genes ◽  
Sources Of Variation ◽  
Nematode Eggs ◽  
Host Parasite

The interaction between sheep and the nematode Teladorsagia circumcincta is one of the best understood of all host–parasite interactions. Following infection, there is considerable variation among lambs in the number of nematode eggs produced, the number of early fourth-stage larvae and the number of adult worms in the mucosa. These traits have a high variance to mean ratio (i.e. they are overdispersed or aggregated among hosts), they are skewed and approximately negative binomially distributed. The sources of overdispersion are differences among lambs in the ingestion of infective larvae and the immune response. Both forces can produce aggregation but their relative importance is unknown. The key components of variation can be identified by variance analysis. The sum of the average effects of polymorphic genes is known as additive genetic variation and this increases essentially from zero at one month of age to quite high values at six months of age. The major mechanism underlying genetic variation appears to be the differences among individuals in immune responses. Two of the major sources of variation in immune responses are differences in antigen recognition and differences in the type of cytokines produced. Genes that influence both these sources of variation are associated with differences in resistance to nematode infection. Therefore, much of the heterogeneity among animals in parasite transmission appears to be due to genetic variation in immune responsiveness.

Fructosamine concentration and resistance to natural, predominantly Teladorsagia circumcincta infection

Parasitology ◽  
2001 ◽  
Vol 123 (2) ◽  
pp. 211-218 ◽  
Author(s):  
M. J. STEAR ◽  
P. D. ECKERSALL ◽  
P. A. GRAHAM ◽  
Q. A. McKELLAR ◽  
S. MITCHELL ◽  
...  
Keyword(s):  
Body Weight ◽  
Adult Female ◽  
Nematode Infection ◽  
Protein Deficiency ◽  
Subsequent Infection ◽  
Intensity Of Infection ◽  
Protein Status ◽  
Teladorsagia Circumcincta ◽  
Heritable Trait ◽  
The Mean

Fructosamine concentrations reflect protein status and because infection with Teladorsagia circumcincta can induce a relative protein deficiency, we examined the usefulness of fructosamine concentrations as markers of the intensity of infection in naturally infected lambs. Fructosamine concentration was a heritable trait and variation in fructosamine concerntrations was associated with differences in body weight, and a variety of parasitological variables; animals with increased fructosamine concentrations grew more quickly, had increased faecal egg counts in one of the three study years, had decreased pepsinogen concentrations and decreased IgA activity against 4th-stage larvae of T. circumcincta. Fructosamine concentrations were also associated with variation in the subsequent acquisition of nematodes and in the length of adult female T. circumcincta; lambs with increased fructosamine concentrations had fewer nematodes but the mean length of adult female T. circumcincta was longer. Therefore fructosamine concentrations are potentially useful indicators of the severity of nematode infection and may predict magnitude of subsequent infection.

scholarly journals Consequences of protein supplementation for anorexia, expression of immunity and plasma leptin concentrations in parasitized ewes of two breeds

2008 ◽  
Vol 101 (4) ◽  
pp. 499-509 ◽  
Author(s):  
Konstantinos Zaralis ◽  
Bert J. Tolkamp ◽  
Jos G. M. Houdijk ◽  
Alastair R. G. Wylie ◽  
Ilias Kyriazakis
Keyword(s):  
Food Intake ◽  
Dietary Protein ◽  
Protein Supplementation ◽  
Nematode Infection ◽  
Production Potential ◽  
Low Protein ◽  
Teladorsagia Circumcincta ◽  
Ad Libitum ◽  
Faecal Egg Counts ◽  
Plasma Leptin

The periparturient relaxation of immunity (PPRI) against parasites in ewes has a nutritional basis. We investigated whether ewes experience a reduction in food intake (anorexia) during PPRI and if the magnitude of anorexia is affected by host production potential and dietary protein supplementation. We also investigated whether nematode infection is linked to plasma leptin concentrations in periparturient ewes. The experiment was a 2 × 2 × 2 factorial design. Two breeds of twin-bearing/lactating ewes (Greyface cross, G (n 32) and Scottish Blackface, B (n 32)) were used. Half of the ewes were trickle infected with 30 000 larvae of the abomasal parasite Teladorsagia circumcincta per week and the other half were not. During the experiment, all ewes had ad libitum access to a low-protein diet that provided less protein than the recommended allowance. In addition, half of the ewes received a protein supplement that resulted in protein intakes that exceeded recommendations. Nematode infection resulted in a breakdown of immunity to parasites and a reduction in food intake in both breeds. The breeds differed in the extent of PPRI (G ewes having higher faecal egg counts than B ewes), but not in the magnitude of anorexia. Protein supplementation resulted in a reduction in faecal egg counts, but had no effect on the magnitude of anorexia. Plasma leptin concentrations changed significantly over time, but were not affected by protein supplementation or infection. It is concluded that infection with T. circumcincta in periparturient ewes results in anorexia that is not alleviated by protein supplementation and seems unrelated to plasma leptin concentrations.

Role of stat6 in hypercontractility of murine small intestinal smooth muscle induced by nematode infection

2001 ◽  
Vol 120 (5) ◽  
pp. A534-A534
Author(s):  
A ZHAO ◽  
D MULLOY ◽  
J URBANJR ◽  
W GAUSE ◽  
T SHEADONOHUE
Keyword(s):  
Smooth Muscle ◽  
Nematode Infection ◽  
Intestinal Smooth Muscle ◽  
Small Intestinal

Gnathostomiasis: a rare nematode infection

2007 ◽  
Vol 15 (1) ◽  
Author(s):  
MM Rahman ◽  
MR Moula
Keyword(s):  
Nematode Infection

Genetic Sources of Variation in the Gestation Length of the Horse

1951 ◽  
Vol 10 (4) ◽  
pp. 797-806 ◽  
Author(s):  
W. C. Rollins ◽  
C. E. Howell
Keyword(s):  
Gestation Length ◽  
Sources Of Variation

It Takes Two to Make an Interview Go Right: Round-Robin Designs to Demonstrate Interviewer and Witness Variance

2018 ◽  
Author(s):  
Charlotte A. Hudson ◽  
Liam Satchell ◽  
Nicole M Adams-Quackenbush
Keyword(s):  
Grain Size ◽  
Individual Differences ◽  
Individual Difference ◽  
Round Robin ◽  
Investigative Interviews ◽  
Sources Of Variation ◽  
Interview Performance ◽  
Report Accuracy ◽  
Statistical Demonstration

Purpose: Investigative interviews are complex, dyadic, activities typically studied by focusing on developing techniques to improve witness performance. However, in field settings, interviewers are known to vary in their presentation of good interviewing practice. Thus, it is important to conduct research reflective of complex idiosyncrasies in witnesses, interviewers and unique pairings of both. This study explores such sources of variation in an by making use of a 'round-robin' design. Such methodology allows the statistical demonstration of individual difference and unique partner-generated variance in interview performance. Methods: In our study, a total of 45 witnesses were questioned about five real crime videos. After witnessing each event, witnesses were interviewed by a different interviewer (or a computer self-administered interview). In total, nine 'rounds' of interviews occurred, with five new witnesses being interviewed in the same five interview settings (resulting in 225 interviews). After each interview both interviewers and witnesses were asked to complete subjective interview experience ratings. The quality (grain size) and quantity of information in the statements was coded to index witness report accuracy. Results: Principally, the results demonstrate the degree to which witnesses and interviewers affect statement quality, and highlight the influence of unique interviewer-witness pairs. (Participant personality and interviewer behaviour were also analysed, but with limited effects). Conclusion: This study presents the useful round-robin methodology for studying interviewer-witness behaviour. Whilst the current personality and behavioural measures do not account for these individual differences, we advocate this methodology be adopted more widely to better understand interview performance.

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