scholarly journals Infection Pressure is Necessary, but not Sufficient by Itself, to Explain Toxoplasma gondii Seroprevalence in Intermediate Host Species

10.1645/21-28 ◽  
2021 ◽  
Vol 107 (4) ◽  
Author(s):  
Patrick L. Taggart ◽  
Bronwyn A. Fancourt ◽  
Wayne S. J. Boardman ◽  
David E. Peacock ◽  
Charles G. B. Caraguel
Keyword(s):  
Toxoplasma Gondii ◽  
Intermediate Host ◽  
Host Species ◽  
Infection Pressure

The influence of second intermediate host species on the infectivity of metacercarial cysts of Echinoparyphium recurvatum

1999 ◽  
Vol 73 (2) ◽  
pp. 143-145 ◽  
Author(s):  
A.M. McCarthy
Keyword(s):  
Intermediate Host ◽  
Definitive Host ◽  
Host Species ◽  
Post Infection ◽  
Rana Temporaria ◽  
Biomphalaria Glabrata ◽  
Reproductive Status ◽  
Intermediate Hosts ◽  
Potential Influence ◽  
Second Intermediate Host

The potential influence of second intermediate host species on the infectivity of metacercarial cysts of Echinoparyphium recurvatum to the definitive host Anas platyrhynchos was examined experimentally. Echinoparyphium recurvatum metacercarial cysts were obtained from the following experimentally infected second intermediate hosts 14 days post expsoure to cercariae: Lymnaea peregra; Physa fontinalis; L. stagnalis;Planorbis planorbis; Biomphalaria glabrata; tadpoles of the amphibian Rana temporaria. Metacercarial cysts from each of these hosts were fed, in doses of 50 cysts per individual, to separate groups composed of between four and eight, 3-day-old A. platyrhynchos ducklings. All A. platyrhynchos were necropsied 15 days post-infection and the number, size, and reproductive status of E. recurvatum worms in the intestine was recorded. Analyses of variance on the number (transformed log (x + 1)) and size of worms revealed no significant differences in worms originating from metacercariae formed in the different second intermediate hosts (worm number P > 0.05, and worm size P > 0.05). All worms recovered were found to be gravid. It is therefore concluded that the species of second intermediate host utilized does not influence the infectivity of the metacercarial cyst of E. recurvatum, nor the subsequent establishment and reproductive status of the parasite in A. platyrhynchos.

Observations on the suitability and importance of the domestic intermediate hosts of Echinococcus granulosus in Uttah Pradesh, India

1989 ◽  
Vol 63 (1) ◽  
pp. 39-45 ◽  
Author(s):  
M. Irshadullah ◽  
W. A. Nizami ◽  
C. N. L. Macpherson
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Echinococcus Granulosus ◽  
Frequency Distribution ◽  
Host Species ◽  
Control Measures ◽  
The Other ◽  
Hydatid Cysts ◽  
Intermediate Hosts ◽  
Cyst Size

ABSTRACTThe present study investigated the suitability and importance of buffaloes, camels, sheep, goats and pigs in maintaining the life-cycle of Echinococcus granulosus in Aligarh, India. A total of 565 (36%) of 1556 buffaloes, 20 (2%) of 1208 goats, 5 (1%) of 559 pigs, 6 (6%) of 109 sheep and two of three camels were found to harbour hydatid cysts. The frequency distribution of the hydatid cysts in each intermediate host species was over-dispersed and in buffaloes cyst fertility increased with increasing cyst size. Of 2171, 95 and four buffalo, goat, and camel cysts examined 327 (15%), two (2%) and three cysts respectively were fertile. No pig or sheep cysts were found to contain protoscoleces. The unfenced buffalo abattoir and the large number of dogs allowed access to the abattoir coupled to the number of buffaloes slaughtered in comparison to the other potential hosts, indicates that the buffalo is the most significant host for maintaining the life-cycle of the parasite in this area of India. Applicable control measures for the region are suggested.

Biology and epidemiology ofToxoplasma gondiiin man and animals

2005 ◽  
Vol 6 (1) ◽  
pp. 41-61 ◽  
Author(s):  
Dolores E. Hill ◽  
Sreekumar Chirukandoth ◽  
J. P. Dubey
Keyword(s):  
Toxoplasma Gondii ◽  
Intermediate Host ◽  
Host Range ◽  
Marine Mammals ◽  
Parasitic Infections ◽  
Sea Otter ◽  
Coccidian Parasite ◽  
Wild Carnivores ◽  
Southern Sea Otter

AbstractToxoplasma gondiiis a coccidian parasite which utilizes felids as definitive hosts, and which has an unusually wide intermediate host range. The parasite was initially described by Nicolle and Manceaux in 1908 from the rodent,Ctenodactylus gundi. Infection withT. gondiiis one of the most common parasitic infections of man and other warm-blooded animals. It has been found worldwide from Alaska to Australia. Nearly one-third of humanity has been exposed to this parasite; serologic surveys indicate thatT. gondiiinfections are common in wild carnivores, including pigs, bears, felids, fox, raccoons, and skunks. Clinical and subclinical toxoplasmosis has been reported from wild cervids, ungulates, marsupials, monkeys, and marine mammals. Southern sea otter populations have been severely impacted byToxoplasmainfections.

The Genus Proteocephalus in the Netherlands

1969 ◽  
Vol 43 (1-2) ◽  
pp. 207-222 ◽  
Author(s):  
J. J. Willemse
Keyword(s):  
The Netherlands ◽  
Intermediate Host ◽  
Host Specificity ◽  
Host Species ◽  
Perca Fluviatilis ◽  
Anguilla Anguilla ◽  
Intestinal Wall ◽  
Original Host ◽  
Osmerus Eperlanus ◽  
High Degree

The present paper deals with investigations on the occurrence in Netherlands' fresh water fishes and host specificity of tapeworms belonging to the genus Proteocephalus. The species involved are:P. tetrastomus (Rudoiphi, 1810) in smelt, Osmerus eperlanus.P. longicollis (Zeder, 1800) in smelt, Osmerus eperlanus.P. cernuae (Gmelin, 1790) in pope, Acerina cernua.P. ocellatus (Rudolphi, 1802) in perch, Perca fluviatilis.P. macrocephalus (Creplin, 1825) in eel, Anguilla anguilla.Seasonal cycles were found in P. telrastomus and P. ocellalus; in the latter species this was certainly induced by low winter temperatures.Experimental infections showed that a high degree of host specificity exists in all species considered. Infections of an alien host were never successful. Two kinds of infections were carried out: (a) feeding plerocercoids (in the intermediate host), coming from a known source, to a number of fishes, belonging to several species including the original host species, and (b) transplanting worms, collected from the intestine of a fish, to the intestines of a number of other fishes, belonging to several species including the original host species.Notwithstanding the high degree of host specificity, worms may survive for one or two days, but usually in a bad condition, in the intestine of an alien host. Occasionally they survived up to 14 days: e.g. P. tetratomus in Anguilla anguilla. Consequently sometimes dissections of predator fishes or carrion eating fishes may produce dubious host records because actually Proteocephalus from their prey are recorded. We are convinced that P. tetrastomus found in Salmo trutta, Platichihys flesus and Perca fluviatilis originate from Osmerus eperlanus having been eaten by these species.Additionally cannibalism may be responsible for the fact that large specimens of some fish species, e.g. smelt, are heavily infected with Proteocephalus while they hardly eat any Cyclops, the intermediate host. This is clearly demonstrated by the transplantation experiments, transplanting worms to the proper host.From the data recorded it is apparent that representatives of the genus Proteocephalus are not harmful to commercially important fishes in the Netherlands. In these fishes natural infection with the proper species of Proteocephalus is low and successful infection with other species, showing a high incidence in less valuable fishes, is prevented by the high degree of host specificity. Additionally worms of the species studied did not injure the tissues of the intestinal wall by the action of their suckers and piercing of the intestinal wall never occurred. Even smelts infected with large numbers of worms-more than 50 in a single 20 cm. specimen-did not show any abnormalities in genital development or in the amount of fat in the body cavity.

The effect of Toxoplasma gondii and other parasites on activity levels in wild and hybrid Rattus norvegicus

Parasitology ◽  
1994 ◽  
Vol 109 (5) ◽  
pp. 583-589 ◽  
Author(s):  
J. P. Webster
Keyword(s):  
Life Cycle ◽  
Toxoplasma Gondii ◽  
Intermediate Host ◽  
Definitive Host ◽  
Rattus Norvegicus ◽  
Parasite Load ◽  
Life Cycles ◽  
Parasitic Infections ◽  
Activity Levels ◽  
In The Wild

Using both correlational and experimental evidence, the relationship between parasite load and host activity was assessed in brown rats, Rattus norvegicus. Two hypotheses were tested – (1) that parasites with indirect life-cycles, involving transmission between a prey and its predator, will alter the activity of the intermediate host so as to increase its susceptibility to predation by the definitive host and (2) that activity levels in parasitized rats would be increased rather than decreased. Four groups of rats (n = 140) were examined. One group (n = 50) were wild brown rats trapped from 3 UK farmsteads, with naturally occurring parasites. The others were purpose-bred wild/laboratory hybrid rats with experimentally induced parasitic infections of either (n = 15) adult-acquired or (n = 15) congenitally-acquired Toxoplasma gondii (an indirect life-cycle parasite), or (n = 15) Syphacia muris (a direct life-cycle parasite). Uninfected hybrid rats (n = 45), matched for sex, age and weight, served as controls. Rats were housed individually in outdoor cages, and their activities were recorded on video-tapes for 6 non-consecutive 10 h nights. Exercise wheels were also available for the hybrid rats. Out of 6 parasite species detected in the wild rats, T. gondii was the only one which required predation by a definitive host to complete its life-cycle, and was also the only parasite to be associated with higher activity levels in infected than uninfected rats. Hybrid rats infected with T. gondii were also more active than those uninfected, whereas there were no differences in activity levels between S. muris infected and uninfected rats. This study shows that the indirect life-cycle parasite T. gondii can influence the activity of its intermediate host the rat. I suggest that this may facilitate its transmission to the cat definitive host.

scholarly journals An experimental field approach to parasitism and immune defence in voles

Parasitology ◽  
2004 ◽  
Vol 129 (1) ◽  
pp. 93-99 ◽  
Author(s):  
G. A. SCHWARZENBACH ◽  
D. HEGGLIN ◽  
C. STIEGER ◽  
P. DEPLAZES ◽  
P. I. WARD
Keyword(s):  
Immune System ◽  
Intermediate Host ◽  
Host Species ◽  
Immune Defence ◽  
Infection Rates ◽  
Intermediate Hosts ◽  
Red Foxes ◽  
Field Approach ◽  
Faecal Samples ◽  
In The Wild

The fox tapewormEchinococcus multilocularisis typically perpetuated in a cycle with red foxes as definitive hosts and various rodent species as intermediate hosts. In this study, foxes were baited with a highly efficient drug against cestodes (praziquantel) in 5 blocks of 1 km2. Voles,Arvicola terrestris, the most abundant intermediate host species, were trapped in the 5 baited blocks and in 5 non-baited control blocks. Baiting the foxes reduced the prevalence ofE. multilocularisin fox faecal samples in the baited blocks, but voles trapped in the two blocks did not differ in their infection rates. However, voles from the baited blocks had significantly smaller spleen masses and were more likely to be infested with mites than those from the control blocks, possibly reflecting different immunological activities. Our study suggests that the environmental contamination withE. multiloculariseggs, and perhaps those of other tapeworms, influences the immune system of the intermediate host speciesA. terrestrisin the wild.

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