Immunological response of the hosts to Toxocara canis (Werner, 1782) infection I. Effect of superinfection on naturally infected puppies

Parasitology ◽  
1968 ◽  
Vol 58 (3) ◽  
pp. 547-559 ◽  
Author(s):  
S. T. Fernando
Keyword(s):  
Worm Burden ◽  
Egg Production ◽  
Technical Assistance ◽  
Acquired Resistance ◽  
Immunological Response ◽  
Toxocara Canis ◽  
Cure Reaction ◽  
Second Stage ◽  
Large Numbers ◽  
The University

Superinfection of naturally infected puppies with large numbers of Toxocara canis eggs induced a self-cure reaction. There was a sharp fall in Toxocara egg output following superinfection in most of the puppies. In most, but not all the puppies, the existing worm burden was eliminated. Eliminated worms were full of fertile eggs, but, in the puppies in which egg production fell sharply without expulsion of the worm burden, egg production by the naturally acquired worms was suppressed only transiently.Antibody production, measured by the complement-fixation test, was directly related to resistance to superinfection but not to self-cure.Acquired resistance reduced the pathogenic effects of superinfection, and prevented development of the parasite beyond the second stage.It is a pleasure to thank Professor P. Seneviratna, University of Ceylon, for his constructive criticisms of the manuscript and the facilities provided.The writer thanks Mr W. G. Senaratne for technical assistance and typing of the manuscript.This work was carried out with a special research grant from the University of Ceylon.

Distribution of the nematode Labiostrongylus longispicularis (Wood) within the stomach of the Red Kangaroo Megaleia rufa (Desmarest)

Parasitology ◽  
1965 ◽  
Vol 55 (3) ◽  
pp. 543-550 ◽  
Author(s):  
M. L. Dudzinski ◽  
R. Mykytowycz
Keyword(s):  
Technical Assistance ◽  
Female Worm ◽  
Sample Material ◽  
Quadratic Regression ◽  
Red Kangaroo ◽  
Large Numbers ◽  
Cardiac Region ◽  
The Mean ◽  
Two Stages ◽  
The University

The distribution of two stages of the nematode Labiostrongylus longispicularis (Wood) in thirty-eight stomachs of the Red Kangaroo, Megaleia rufa (Desmarest) has been analysed statistically.A quadratic regression was used where y = log of mean worm densities of stomach sections + 1 and x = numerical values of the mid-positions of the sections. The analysis revealed significant maxima in the proximity of the cardiac region. The maxima in stomachs with relatively large numbers of worms were found to be further away from the pylorus than in the stomachs with small numbers of worms. The mean maximum densities were about fifty worms per 100 g of stomach content in highly infected animals and about eight in low infections. It is suggested that freshly chewed food or saliva may be a factor regulating the distribution of worms.The parasite was absent from the stomach's pyloric region where the pH is low.Sex and size of the worm were independent of its position in the stomach.The average number of eggs per adult female in the different stomach sections roughly corresponded to the density of worms in these sections, but the sample material was inadequate to show that this relationship was statistically significant.The mean number of fertilized eggs per female worm was 3300.Thanks are due to Professor E. J. Williams of the University of Melbourne and Mr B. V. Fennessy of the Division of Wildlife Research, C.S.I.R.O., for reading and criticizing the manuscript, and to Messrs E. R. Hesterman and C. Kogon for technical assistance.

Immunological response of rabbits to Toxocara canis infection

Parasitology ◽  
1968 ◽  
Vol 58 (1) ◽  
pp. 91-103 ◽  
Author(s):  
S. T. Fernando
Keyword(s):  
Antibody Response ◽  
Large Dose ◽  
Technical Assistance ◽  
Complement Fixation ◽  
Immunological Response ◽  
Toxocara Canis ◽  
Post Mortem ◽  
Precipitin Reaction ◽  
Sublethal Doses ◽  
Constructive Criticism

Studies on immunological response of rabbits to Toxocara canis infection have been reported. It was observed that rabbits previously infected by two sublethal doses of 1200 infective ova each, with a 14-day interval between the two doses, acquired strong immunity to the effects of reinfestation induced by a large dose of infective ova, i.e. 100000. Post-mortem studies indicate that immunity is mainly directed against the migration of larvae to the lungs. The animals which resisted the effects of reinfestation showed an enhanced antibody response as shown by complement-fixation and agar-diffusion precipitin tests.The precipitin reaction in the sera of animals infected by oral and subcutaneous routes respectively was studied with three preparations of antigen, namely, saline extracts, boiled saline extracts of adult worms, and saline extracts of infective ova. It was observed that the extract of adult worms was deficient in a minimum of three antigenic components present in the extract of infective ova.It is a pleasure to thank Professor C. A. McGaughey for the facilities given for this study, Professor P. Seneviratna for his constructive criticism, and Messrs W. G. Senaratne and K. G. Karunaratne for technical assistance and the photo graphy respectively.

The dynamics of the host-parasite relationship

Parasitology ◽  
1965 ◽  
Vol 55 (3) ◽  
pp. 515-525 ◽  
Author(s):  
J. K. Dineen ◽  
A. D. Donald ◽  
B. M. Wagland ◽  
Jan Offner
Keyword(s):  
Egg Production ◽  
Technical Assistance ◽  
Parasitic Infection ◽  
Immunological Response ◽  
Major Effect ◽  
Infective Larvae ◽  
Parasite Relationship ◽  
Group 3 ◽  
Host Parasite ◽  
Group 1

Two groups of sheep born and raised worm-free were dosed with 3000 infective Haemonchus contortus larvae. Group 1 were each given a single dose of infective larvae on day 0 while the group 3 animals were dosed with 100 infective larvae per day for 30 consecutive days. The results of faecal worm-egg counts performed on alternative days, and of differential worm counts carried out on animals slaughtered at crucial times during the course of infection, showed that retardation of development at the 4th larval stage occurred in the group 3 infections and was the major effect of control of the parasitic burden. There was no evidence that egg production per female was affected.Three animals of the nineteen infected in group 1 died during the course of the experiment owing to the pathogenic effects of the worm burden. Deaths did not occur among the animals of group 3. This finding was correlated with the observation that haematocrit levels were consistently lower among the animals of group 1 than among those of group 3.The results are interpreted in terms of the theory of threshold behaviour of the immunological response to parasitic infection.We are greatly indebted to Dr D. F. Stewart for his interest and constructive criticism during the course of these studies, and to Mr E. Teleki and Misses Helen Giller and Lindy Stothart for their valuable technical assistance.

Worm burdens, acquired resistance and live weight gains in lambs during prolonged daily infections with Trichostrongylus colubriformis (Giles, 1892) Loos, 1905

Parasitology ◽  
1974 ◽  
Vol 69 (3) ◽  
pp. 315-327 ◽  
Author(s):  
S. N. Chiejina ◽  
M. M. H. Sewell
Keyword(s):  
Worm Burden ◽  
Clinical Symptoms ◽  
Acquired Resistance ◽  
Live Weight ◽  
Trichostrongylus Colubriformis ◽  
Irreversible Damage ◽  
Cure Reaction ◽  
Development Of Resistance ◽  
Weight Gains ◽  
Faecal Egg Counts

Three groups of lambs, aged 3, 5 and 6 months respectively, were infected daily with 5000 infective larvae of Trichostrongylus colubriformis for periods of 15–20 weeks. Some of the lambs also received a single challenge infection at the end of week 16. The course of the infections was monitored by means of faecal egg counts, measurement of live-weight gains and regular post mortem worm counts.There was an initial rapid increase in egg counts soon after patency, which was followed by an exponential fall in the counts in most lambs. This fall seemed to precede the expulsion of worms by a few weeks and was associated with reduced fecundity in the female worms. Furthermore, although the trend of the egg counts of some lambs suggested that a self-cure reaction had taken place, in a number of these lambs the low faecal egg counts did not reflect the size of their worm burden.Heavy worm burdens were usually associated with clinical symptoms of trichostrongylosis, including anorexia, diarrhoea and loss of weight. As the lambs developed resistance to reinfection and expelled their worm burden a rapid clinical recovery occurred, except in a few lambs which appeared to have suffered irreversible damage from the earlier heavy worm burden.The worm burden in most lambs appeared to be cumulative during the first 4–8 weeks before they developed a strong resistance to reinfection. There was considerable loss of the adult worm burden by 8–15 weeks after initial infection and some evidence of stunting in the remaining parasites.The immunological control of T. colubriformis infections in these lambs was achieved by means of the development of resistance to reinfection, inhibition of the ovulation of the female worms, stunting of adult worms and expulsion of adult worms by resistant lambs. These may be separate immune phenomena requiring different thresholds of parasitic material in individual animals, depending on their age, the rate and duration of infection and their innate ability to develop resistance to the parasite.

Resistance of mice to Toxocara canis: effect of prechallenge infections and injections of worm extracts

1970 ◽  
Vol 48 (5) ◽  
pp. 1063-1066 ◽  
Author(s):  
N. N. Izzat ◽  
L. J. Olson
Keyword(s):  
Ascaris Lumbricoides ◽  
Worm Burden ◽  
Acquired Resistance ◽  
Paratenic Host ◽  
Toxocara Canis ◽  
Challenge Infection

Test mice have been infected one or more times and challenged with Toxocara canis larvae in an attempt to demonstrate acquired resistance to this nematode in a paratenic host. The worm burden of these mice at necropsy was not significantly less than that for controls.Mice given prechallenge injections of somatic fractions of T. canis eggs and adult worms, together with adjuvant, were found to harbor significantly fewer larvae after a challenge infection than did controls. The worm burden of mice similarly injected with fractions of adult Ascaris lumbricoides had worm burdens after challenge which were about equal to that of controls.

Hatching of second-stage larvae of Toxocara canis: a rapid method for processing large numbers of worms

1991 ◽  
Vol 65 (4) ◽  
pp. 311-312 ◽  
Author(s):  
N. S Crowcroft ◽  
S. H Gillespie
Keyword(s):  
Rapid Method ◽  
Toxocara Canis ◽  
High Yield ◽  
Second Stage ◽  
Large Numbers

ABSTRACTA method for hatching second-stage larvae of Toxocara canis is described. Whole adult worms are processed by centrifugation in the presence of hypochlorite which allows the grinding step to be eliminated. The technique is more rapid and a high yield is obtained.

scholarly journals Optimizing COVID-19 testing capabilities and clinical management using pathology informatics

JAMIA Open ◽  
2020 ◽  
Author(s):  
Srikar Chamala ◽  
Sherri Flax ◽  
Petr Starostik ◽  
Kartikeya Cherabuddi ◽  
Nicole M Iovine ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Clinical Management ◽  
World Health ◽  
University Of Florida ◽  
Pathology Informatics ◽  
Large Numbers ◽  
The World ◽  
Health Organization ◽  
The University ◽  
Reporting Data

Abstract Coronavirus disease 2019, first reported in China in late 2019, has quickly spread across the world. The outbreak was declared a pandemic by the World Health Organization on March 11, 2020. Here, we describe our initial efforts at the University of Florida Health for processing of large numbers of tests, streamlining data collection, and reporting data for optimizing testing capabilities and superior clinical management. Specifically, we discuss clinical and pathology informatics workflows and informatics instruments which we designed to meet the unique challenges of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing. We hope these results benefit institutions preparing to implement SARS-CoV-2 testing.

scholarly journals Mobility Inhibition and Nematocidal Activity of Asarone and Related Phenylpropanoids on Second-Stage Larvae of Toxocara canis.

1995 ◽  
Vol 18 (4) ◽  
pp. 605-609 ◽  
Author(s):  
Naoki SUGIMOTO ◽  
Yoshihisa GOTO ◽  
Nobuaki AKAO ◽  
Fumiyuki KIUCHI ◽  
Kaoru KONDO ◽  
...  
Keyword(s):  
Toxocara Canis ◽  
Second Stage ◽  
Nematocidal Activity

Teaching Enterprise — Can it Be Done in Large Groups?

2003 ◽  
Vol 17 (1) ◽  
pp. 37-44
Author(s):  
Raymond D. Donnelly
Keyword(s):  
Market Research ◽  
Business Plan ◽  
Management Programme ◽  
First Year ◽  
Large Numbers ◽  
Commercial Sources ◽  
To Come ◽  
The University ◽  
Large Groups

This paper reports on work carried out in the School of Management at Heriot-Watt University in Edinburgh. Following a wide-ranging review of the first-year management programme, a module on enterprise was introduced. As part of that module students had to compete in a game, the object of which was to come up with a business idea, conduct market research and present a business plan and proposal to a panel of judges. The number of students was 225 in year one but reached around 500 within five years. The module has generated many good ideas and has attracted sponsorship from commercial sources. As yet the university has been unable to take the ideas further. It is possible that enterprise can be learned by people in large numbers, but perhaps universities are not the places in which to attempt such work.

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.

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