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.

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.

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.

scholarly journals Avaliação da contaminação experimental de areias de praias por enteroparasitas: pesquisa de ovos de Helmintos

1991 ◽  
Vol 7 (1) ◽  
pp. 90-99 ◽  
Author(s):  
Joaquim Pereira da Silva ◽  
Mauro Célio de A. Marzochi ◽  
Elisabeth Cardoso Leal dos Santos
Keyword(s):  
Ascaris Lumbricoides ◽  
Toxocara Canis ◽  
Trichuris Trichiura

Procurou-se avaliar métodos e soluções tradicionalmente utilizados na evidenciação de ovos de helmintos parásitos, de fezes ou do solo, em amostras de areia de praia experimentalmente contaminadas com ovos de Ascaris lumbricoides, Trichuris trichiura, Toxocara canis e Ancylostoma sp. Das soluções classicamente utilizadas, a de Dicromato de Sódio (d= 1,350) foi a que apresentou melhores resultados (índice de recuperação = 50%) para ovos de Ascaris, em 24 horas de observação. As duas soluções propostas: Carbonato de Sódio (d= 1,040) e Detergente aniônico sintético - Sulfonato de Sódio (d= 1,040), apresentaram índices de recuperação surpreendentes, superiores a 80% para os ovos de Ascaris, em 24 horas de observação. Conclui-se que o detergente de uso doméstico, pelo seu baixo custo e facilidade de aquisição, pode ser usado na avaliação de rotina da contaminação de areias de praias pelos ovos de enteroparasitos, importantes indicadores de contaminação fecal, necessários a um adequado monitoramento sanitário do meio.

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.

The dynamics of the host-parasite relationship

Parasitology ◽  
1969 ◽  
Vol 59 (3) ◽  
pp. 497-503 ◽  
Author(s):  
A. D. Donald ◽  
J. K. Dineen ◽  
D. B. Adams
Keyword(s):  
Single Dose ◽  
Worm Burden ◽  
Residual Effect ◽  
Challenge Infection ◽  
Single Infection ◽  
Development Of Resistance ◽  
Host Parasite Relationship ◽  
Parasite Relationship ◽  
Resistance To Infection ◽  
Host Parasite

An experiment has been conducted to examine the effects of discontinuous infection with H. contortus in sheep on the development of resistance to infection. When sheep were given four doses of 3000 larvae at fortnightly intervals and these sensitizing infections were removed on day 56, there was no evidence of resistance at that time nor of any residual effect of the sensitizing infections on the response to challenge at day 140. When, however, the sensitizing infections were permitted to persist until day 132, there was strong resistance to the establishment of a challenge infection whether or not the sensitizing worm burden was removed prior to challenge, and, in the case of superimposed challenge, resistance was coupled with rejection of most of the sensitizing population. When a single infection with 3000 larvae was followed 22 days later with a further single dose of 3000 larvae, there was no evidence of resistance whether or not the first infection was removed with anthelmintic. If the interval between two doses of 3000 larvae was extended to 76 days there was resistance to the establishment of the second dose if this was superimposed on the first, but not if the first infection was removed 8 days prior to the second dose.It is suggested that the manifestations of resistance appear in a sequence of (i) resistance only to a superimposed infection, followed by (ii) resistance to a challenge infection in the presence or absence of a previously existing worm burden, coupled in the former case with rejection of much of the existing population. This sequence could be related crudely to a product of larval dose and time. Although larval dose and time were to some extent confounded in the design of the experiment strong resistance was associated with prolonged uninterrupted infection.

The evaluation of potential global morbidity attributable to intestinal nematode infections

Parasitology ◽  
1994 ◽  
Vol 109 (3) ◽  
pp. 373-387 ◽  
Author(s):  
M. S. Chan ◽  
G. F. Medley ◽  
D. Jamison ◽  
D. A. P. Bundy
Keyword(s):  
Spatial Heterogeneity ◽  
Ascaris Lumbricoides ◽  
Worm Burden ◽  
Disease Burden ◽  
Trichuris Trichiura ◽  
Intensity Of Infection ◽  
Intestinal Nematode ◽  
Prevalence Estimates ◽  
Global Disease Burden

SummaryThis paper presents a method of estimating the potential global morbidity due to human intestinal nematode infections (Ascaris lumbricoides, Trichuris trichiura and hookworms), based on the observed prevalence of infection. The method relies on the observed relationships between prevalence and intensity of infection, and between worm burden and potential morbidity. This approach is shown to be sensitive to the precision of the original prevalence estimates and, in particular, to the degree of spatial heterogeneity in levels of infection. The estimates presented here indicate that several tens of millions of children are likely to suffer developmental consequences from infection, and suggest that the global disease burden of geohelminthiasis may be significantly greater than was supposed.

Acquired resistance to experimental Heterakis gallinarum infections in pheasants: Relative immunity conferred by exposure to heterakids of different ages

1974 ◽  
Vol 48 (3) ◽  
pp. 155-159
Author(s):  
Anne M. Chute ◽  
Everett E. Lund
Keyword(s):  
Acquired Resistance ◽  
Challenge Infection ◽  
Challenge Dose ◽  
Heterakis Gallinarum ◽  
Subsequent Challenge ◽  
Different Ages

AbstractRing-necked pheasants were exposed to artificially limited 10-day infections with heterakids either from 0-10 or 10–20 days old. The number and length of worms developing from a subsequent challenge dose were compared with those in nonimmunized control birds and with those in birds that had been exposed to a continuous immunizing infection for a total of 49 days: 28 days before challenge and 21 days during the challenge infection.

Homologous and heterologous resistance in Echinostoma revolutum infections in mice

Parasitology ◽  
1980 ◽  
Vol 80 (3) ◽  
pp. 479-486 ◽  
Author(s):  
S. B. Sirag ◽  
N. Ø. Christensen ◽  
F. Frandsen ◽  
J. Monrad ◽  
P. Nansen
Keyword(s):  
Primary Infection ◽  
Worm Burden ◽  
Challenge Infection ◽  
Control Group ◽  
Echinostoma Revolutum ◽  
Heterologous Challenge ◽  
Challenge Control ◽  
Complete Resistance ◽  
Group A ◽  
High Level

SummaryHomologous and heterologous resistance in Echinostoma revolutum infections was studied in mice. A high level of homologous resistance was demonstrated in mice harbouring a 13-day-old primary E. revolutum infection with 9–10 and 11–15 worms, corresponding to a 70·0 and 66·7% reduction in the size of the established worm burden as compared with that of the challenge control group. A 14- and 20-day-old primary infection with 3–4 worms induced a level of resistance of 61·7 and 81·8% respectively, while higher worm levels of 9–10 and 11–15 induced almost complete resistance corresponding to a 95·1–100% reduction in the size of the established worm burden. Complete resistance was also demonstrated in mice challenged 8 days after elimination of a 20-day-old primary infection with 11–15 worms by anthelmintic treatment. A primary 43-day-old Schistosoma mansoni infection induced a 73·1% reduction in the size of the established E. revolutum challenge infection while infections of an age of 79 and 99 days conferred complete resistance to heterologous challenge with E. revolutum. Primary pre-patent S. mansoni infections and a patent S. bovis infection of an age of 56 days did not induce any resistance to challenge with E. revolutum. A primary 14- and 21-day-old infection of E. revolutum did not stimulate any significant level of resistance to heterologous challenge with S. mansoni.

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