Transplanted Dipetalonema viteae in the Jird: Effect of Worm Burden on Parturition Rates and Microfilaremia

1985 ◽  
Vol 71 (6) ◽  
pp. 742
Author(s):  
David Abraham
Keyword(s):  
Worm Burden ◽  
Dipetalonema Viteae

A model to account for the consequences of host nutrition on the outcome of gastrointestinal parasitism in sheep: model evaluation

Parasitology ◽  
2007 ◽  
Vol 134 (9) ◽  
pp. 1279-1289 ◽  
Author(s):  
D. VAGENAS ◽  
S. C. BISHOP ◽  
I. KYRIAZAKIS
Keyword(s):  
Mathematical Model ◽  
Worm Burden ◽  
Management Strategies ◽  
Sensitivity Analyses ◽  
Sheep Model ◽  
Host Nutrition ◽  
Gastrointestinal Parasitism ◽  
Different Characteristics ◽  
Nutritional Strategies ◽  
Different Levels

SUMMARYThis paper describes sensitivity analyses and expectations obtained from a mathematical model developed to account for the effects of host nutrition on the consequences of gastrointestinal parasitism in sheep. The scenarios explored included different levels of parasitic challenge at different planes of nutrition, for hosts differing only in their characteristics for growth. The model was able to predict the consequences of host nutrition on the outcome of parasitism, in terms of worm burden, number of eggs excreted per gram faeces and animal performance. The model outputs predict that conclusions on the ability of hosts of different characteristics for growth to cope with parasitism (i.e. resistance) depend on the plane of nutrition. Furthermore, differences in the growth rate of sheep, on their own, are not sufficient to account for differences in the observed resistance of animals. The model forms the basis for evaluating the consequences of differing management strategies and environments, such as breeding for certain traits associated with resistance and nutritional strategies, on the consequences of gastrointestinal parasitism on sheep.

Observations on the use of Trichostrongylus colubriformis (Nematoda) infections of guinea-pigs for laboratory experiments

Parasitology ◽  
1963 ◽  
Vol 53 (1-2) ◽  
pp. 189-199 ◽  
Author(s):  
R. F. Sturrock
Keyword(s):  
Multivariate Analysis ◽  
Guinea Pigs ◽  
Worm Burden ◽  
Laboratory Experiments ◽  
Statistical Treatment ◽  
Post Mortem ◽  
Infective Larvae ◽  
Final Weight ◽  
Cure Mechanism ◽  
Experimental Use

Four groups of guinea-pigs were infected with a range of doses of T. colubriformis. The infections were followed by egg counts and weight measurements, and the adult worms were recovered from the animals post mortem. A multivariate analysis, details of which are given in an appendix, showed that the sensitivity of the measures used was, in descending order, final weight, total egg count and worm burden. The course of the infection is discussed in view of the apparent self-cure mechanism. Precautions are outlined for the experimental use of this hostparasite relationship.The author is grateful to Professor B. G. Peters for his advice on this work, to Dr P. Silverman of Allen and Hanburys Limited for a supply of T. colubriformis infective larvae and to Dr R. E. Blackith for his advice on the statistical treatment of the data.

scholarly journals Field evaluation of Duddingtonia flagrans IAH 1297 for the reduction of worm burden in grazing animals: Pasture larval studies in horses, cattle and goats

2018 ◽  
Vol 258 ◽  
pp. 124-132 ◽  
Author(s):  
Kevin Healey ◽  
Chris Lawlor ◽  
Malcolm R. Knox ◽  
Michael Chambers ◽  
Jane Lamb ◽  
...  
Keyword(s):  
Worm Burden ◽  
Field Evaluation ◽  
Duddingtonia Flagrans

Immunization efficacy of ozone-exposed cercariae against subsequent Schistosoma mansoni challenge infection

2011 ◽  
Vol 61 (3) ◽  
pp. 289-301
Author(s):  
Azza H. Mohamed
Keyword(s):  
Schistosoma Mansoni ◽  
Worm Burden ◽  
Structural Changes ◽  
Relative Weight ◽  
Challenge Infection ◽  
Total Leukocyte Count ◽  
Post Challenge ◽  
Igg Antibody ◽  
Sem Images ◽  
Infected Control

AbstractCD1 mice were immunized subcutaneously with 20 ozone-exposed (70μg/ml, 1 minute exposure) Schistosoma mansoni cercariae weekly/three weeks. The efficacy of immunization was assessed 10 weeks post challenge infection by the determination of the worm burden, ova count, oogram, granuloma diameter, IgG reactions against soluble egg antigen (SEA) and tegument structural changes of recovered worms that are immunized. A reduced worm length and a reduction in worm burden were observed in the immunized group as compared to the infected not immunized group. Moreover, no ova were found in liver and intestine from the immunized mice as compared with infected control mice. Also, immunization with ozonated cercariae showed a decrement in the mean relative weight of liver and spleen. Total leukocyte count was increased in the immunized animal as compared to the infected control. The level of total IgG antibody against SEA decreased in immunized mice as compared with the infected control mice. Scanning electron microscope (SEM) images of worms recovered 10 weeks post challenge from the immunized group revealed extensive tegumental destruction. This study underlines the significant role of ozone attenuated cercariae vaccine against S. mansoni infection, which generated specific immunity with a significant level of protection.

The regulation ofOstertagia ostertagipopulations in calves: density-dependent control of fecundity

Parasitology ◽  
1987 ◽  
Vol 95 (2) ◽  
pp. 373-388 ◽  
Author(s):  
G. Smith ◽  
B. T. Grenfell ◽  
R. M. Anderson
Keyword(s):  
Worm Burden ◽  
Egg Production ◽  
Inverse Function ◽  
Single Infection ◽  
Intensity Of Infection ◽  
Density Dependent ◽  
Helminth Infections ◽  
Model Predictions ◽  
Initial Peak ◽  
Infection Experiments

SUMMARYThe decline in faecal egg counts, characteristic of calves which have been experimentally infected withOstertagia ostertagi, is analysed using a mathematical model in which parasite fecundity is assumed to be an inverse function of both the duration and intensity of infection. The model incorporates a description of the frequency distribution of mature parasites between hosts (which is less over-dispersed than is usual for many other helminth infections). The model provides a good overall description of the decline in faecal egg production observed during trickle and single infection experiments. The main discrepancy between a comparison of the model predictions and the results of the most detailed available series of trickle infection experiments occurs at the initial peak of egg production. The magnitude of this difference appears to be related to the worm burden at the peak of egg production. The possible mechanisms underlying density-dependent regulation of the fecundity ofO. ostertagiaare discussed.

scholarly journals Aspiculuris tetraptera in wild Mus musculus. Age resistance and acquired immunity.

1976 ◽  
Vol 50 (3) ◽  
pp. 197-202 ◽  
Author(s):  
M. Behnke Jerzy
Keyword(s):  
Mus Musculus ◽  
Worm Burden ◽  
Acquired Resistance ◽  
Age Groups ◽  
Acquired Immunity ◽  
House Mice ◽  
Wild House Mice ◽  
The Mean ◽  
Aspiculuris Tetraptera

AbstractWild house mice, naturally infected with Aspiculuris tetraptera were segregated according to their weight into six age groups. The prevalence of infection and the mean worm burden of these mice were studied in the different age groups. The overall prevalence of infection was high (57% or more) in all the groups except the youngest. Mice acquired larvae soon after weaning; the highest larval burdens were reached in juvenile mice and the highest mature worm burdens, a group later, in mature mice. Older mice had fewer larvae and fewer mature worms. The mature worm burdens decreased but relatively slower than the larval burdens. It is suggested that either innate or acquired resistance could account for these observations.

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