Obligate development of Blastocrithidia papi (Trypanosomatidae) in the Malpighian tubules of Pyrrhocoris apterus (Hemiptera) and coordination of host-parasite life cycles

A unique specimen of the micromorphic fossil lingulate (organophosphatic-shelled) brachiopod Linnarssonia constans Koneva, 1983 from the late Lower Cambrian Shabakty Group of the Malyi Karatau Range in Kazakhstan, Central Asia, preserves evidence of infestation within the mantle cavity by a vermiform animal, leading to the growth of an internal tubular protuberance (Fig. 1) resulting from symbiosis some 520 million years ago. Examples of symbiotic relationships between metazoans in the early Paleozoic are sparse (Conway Morris, 1981, 1990; Conway Morris and Crompton, 1982). Descriptions of a variety of galls and tumorlike swellings in some trilobites extend records back to the Middle Cambrian (Conway Morris, 1990), but their interpretation as traces of endoparasitic activity remains somewhat speculative. Thus galllike swellings on the stems of Silurian echinoderms (Franzen, 1974), vermiform tubes on some early Ordovician dendroid graptolites (Conway Morris, 1990), and various tubes and blisters on graptoloid graptolites (see Bates and Loydell, 2000 for review) are among the hitherto earliest known convincing records of host-parasite relationships within metazoans. Our example reported here predates the oldest of these previous records by approximately 35 to 40 million years, and demonstrates that symbiosis involving complex adaptations (e.g., larval settlement on or within living tissue and exploitation of feeding systems of the host) and codependent life cycles were already established soon after the ‘explosive’ evolutionary radiation of marine metazoans in the early Cambrian. The fossil evidence of infestation on lophophorates is especially sparse, at best. The oldest hitherto undoubted records are both from brachiopods of Devonian age, in the Lower Devonian Emsian Stage of eastern Australia and in the Middle Devonian Givetian Stage of the Holy Cross Mountains in Poland, respectively.

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Coevolutionary interactions between host life histories and parasite life cycles

Parasitology ◽

10.1017/s0031182000084936 ◽

1998 ◽

Vol 116 (S1) ◽

pp. S47-S55 ◽

Cited By ~ 26

Author(s):

J. C. Koella ◽

P. Agnew ◽

Y. Michalakis

Keyword(s):

Life History ◽

Life Cycle ◽

Life Histories ◽

Life History Traits ◽

Evolutionary Ecology ◽

Life Cycles ◽

Microsporidian Parasite ◽

History Of ◽

Host Life ◽

Host Parasite

SummarySeveral recent studies have discussed the interaction of host life-history traits and parasite life cycles. It has been observed that the life-history of a host often changes after infection by a parasite. In some cases, changes of host life-history traits reduce the costs of parasitism and can be interpreted as a form of resistance against the parasite. In other cases, changes of host life-history traits increase the parasite's transmission and can be interpreted as manipulation by the parasite. Alternatively, changes of host's life-history traits can also induce responses in the parasite's life cycle traits. After a brief review of recent studies, we treat in more detail the interaction between the microsporidian parasite Edhazardia aedis and its host, the mosquito Aedes aegypti. We consider the interactions between the host's life-history and parasite's life cycle that help shape the evolutionary ecology of their relationship. In particular, these interactions determine whether the parasite is benign and transmits vertically or is virulent and transmits horizontally.Key words: host-parasite interaction, life-history, life cycle, coevolution.

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Life cycles, molecular phylogeny and historical biogeography of the ‘pygmaeus’ microphallids (Digenea: Microphallidae): widespread parasites of marine and coastal birds in the Holarctic

Parasitology ◽

10.1017/s0031182012000583 ◽

2012 ◽

Vol 139 (10) ◽

pp. 1346-1360 ◽

Cited By ~ 30

Author(s):

KIRILL V. GALAKTIONOV ◽

ISABEL BLASCO-COSTA ◽

PETER D. OLSON

Keyword(s):

Life Cycles ◽

The Arctic ◽

Host Switching ◽

Glacial Cycles ◽

Related Group ◽

Coastal Birds ◽

Host Life ◽

Host Parasite ◽

Its1 And Its2 Rdna ◽

Its1 And Its2

SUMMARYThe ‘pygmaeus’ microphallids (MPG) are a closely related group of 6 digenean (Platyhelminthes: Trematoda) Microphallus species that share a derived 2-host life cycle in which metacercariae develop inside daughter sporocysts in the intermediate host (intertidal and subtidal gastropods, mostly of the genus Littorina) and are infective to marine birds (ducks, gulls and waders). Here we investigate MPG transmission patterns in coastal ecosystems and their diversification with respect to historical events, host switching and host-parasite co-evolution. Species phylogenies and phylogeographical reconstructions are estimated on the basis of 28S, ITS1 and ITS2 rDNA data and we use a combination of analyses to test the robustness and stability of the results, and the likelihood of alternative biogeographical scenarios. Results demonstrate that speciation within the MPG was not associated with co-speciation with either the first intermediate or final hosts, but rather by host-switching events coincident with glacial cycles in the Northern Hemisphere during the late Pliocene/Pleistocene. These resulted in the expansion of Pacific biota into the Arctic-North Atlantic and periodic isolation of Atlantic and Pacific populations. Thus we hypothesize that contemporary species of MPG and their host associations resulted from fragmentation of populations in regional refugia during stadials, and their subsequent range expansion from refugial centres during interstadials.

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Immune Evasion Strategies of Schistosomes

Frontiers in Immunology ◽

10.3389/fimmu.2020.624178 ◽

2021 ◽

Vol 11 ◽

Author(s):

Jacob R. Hambrook ◽

Patrick C. Hanington

Keyword(s):

Immune Evasion ◽

Immune Cell ◽

Molecular Mimicry ◽

Life Cycles ◽

Host Responses ◽

Immune Recognition ◽

Factors Affecting ◽

Cell Functions ◽

Treatment Plans ◽

Host Parasite

Human schistosomes combat the unique immune systems of two vastly different hosts during their indirect life cycles. In gastropod molluscs, they face a potent innate immune response composed of variable immune recognition molecules and highly phagocytic hemocytes. In humans, a wide variety of innate and adaptive immune processes exist in proximity to these parasites throughout their lifespan. To survive and thrive as the second most common parasitic disease in humans, schistosomes have evolved many techniques to avoid and combat these targeted host responses. Among these techniques are molecular mimicry of host antigens, the utilization of an immune resistant outer tegument, the secretion of several potent proteases, and targeted release of specific immunomodulatory factors affecting immune cell functions. This review seeks to describe these key immune evasion mechanisms, among others, which schistosomes use to survive in both of their hosts. After diving into foundational observational studies of the processes mediating the establishment of schistosome infections, more recent transcriptomic and proteomic studies revealing crucial components of the host/parasite molecular interface are discussed. In order to combat this debilitating and lethal disease, a comprehensive understanding of schistosome immune evasion strategies is necessary for the development of novel therapeutics and treatment plans, necessitating the discussion of the numerous ways in which these parasitic flatworms overcome the immune responses of both hosts.

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Culture of Protozoan Parasites

Clinical Microbiology Reviews ◽

10.1128/cmr.15.3.327-328.2002 ◽

2002 ◽

Vol 15 (3) ◽

pp. 327-328 ◽

Cited By ~ 25

Author(s):

Govinda S. Visvesvara ◽

Lynne S. Garcia

Keyword(s):

Strain Differences ◽

Life Cycle Stage ◽

Life Cycles ◽

In Vitro Cultivation ◽

Protozoan Parasites ◽

Complex Life Cycles ◽

Host Parasite Interactions ◽

Host Parasite

SUMMARY The in vitro culture of protozoan parasites involves highly complex procedures, which are subject to many variables. These parasites have very complex life cycles and, depending on the life cycle stage, may require different culture parameters. However, in vitro cultivation is important for many reasons, some of which include: diagnosis, antigen and antibody production, assessment of parasite immune modulating capabilities, drug screening, improvements in chemotherapy, differentiation of clinical isolates, determination of strain differences, vaccine production, development of attenuated strains, and the continued supply of viable organisms for studying host-parasite interactions.

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Stage-dependent behavioural changes but early castration induced by the acanthocephalan parasite Polymorphus minutus in its Gammarus pulex intermediate host

Parasitology ◽

10.1017/s0031182017001457 ◽

2017 ◽

Vol 145 (3) ◽

pp. 260-268 ◽

Cited By ~ 6

Author(s):

YANN BAILLY ◽

FRANK CÉZILLY ◽

THIERRY RIGAUD

Keyword(s):

Significant Variation ◽

Developmental Stages ◽

Life Cycles ◽

Gammarus Pulex ◽

Complex Life Cycles ◽

Behavioural Changes ◽

Single Mechanism ◽

Behavioural Alteration ◽

Host Parasite ◽

Acanthocephalan Parasite

SUMMARYMultidimensionality in parasite-induced phenotypic alterations (PIPA) has been observed in a large number of host–parasite associations, particularly in parasites with complex life cycles. However, it is still unclear whether such a syndrome is due to the successive activation of independent PIPAs, or results from the synchronous disruption of a single mechanism. The aim of the present study was to investigate the onset and progression of two PIPAs (a behavioural alteration: reversion of geotaxis, and castration) occurring in the crustacean amphipod Gammarus pulex infected with the acanthocephalan Polymorphus minutus, at different parasite developmental stages. Modifications of geotaxis in hosts differed according to the parasite developmental stage. Whereas the cystacanth stage induced a negative geotaxis (exposing the gammarid to predation by birds, the definitive hosts), the acanthella stage, not yet infective for the definitive host, induced a stronger positive geotaxis (presumably protecting gammarids from bird predation). In contrast, castration was almost total at the acanthella stage, with no significant variation in the intensity according to parasite maturation. Finally, no significant correlation was found between the intensity of behavioural changes and the intensity of castration. We discuss our results in relation with current views on the evolution of multidimensionality in PIPA.

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Morphology and histology of the alimentary canal, salivary glands and Malpighian tubules in Pyrrhocoris apterus (Linnaeus, 1758) (Hemiptera: Pyrrhocoridae): a scanning electron and light microscopies study

International Journal of Tropical Insect Science ◽

10.1007/s42690-021-00530-7 ◽

2021 ◽

Author(s):

Nurcan Özyurt Koçakoğlu

Keyword(s):

Salivary Glands ◽

Alimentary Canal ◽

Malpighian Tubules ◽

Pyrrhocoris Apterus ◽

Scanning Electron

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Elevational Patterns of Blowfly Parasitism in Two Hole Nesting Avian Species

Diversity ◽

10.3390/d13110591 ◽

2021 ◽

Vol 13 (11) ◽

pp. 591

Author(s):

Gregorio Moreno-Rueda

Keyword(s):

Sierra Nevada ◽

Negative Impact ◽

Parus Major ◽

Climatic Conditions ◽

Life Cycles ◽

Parasite Abundance ◽

Coal Tit ◽

Elevational Variation ◽

Host Parasite ◽

High Elevations

Climate change is predicted to cause shifts in parasite distributions, leading to encounters with new hosts. Mountains offer a natural experimental background to study how parasite distributions vary across climatic gradients. Parasite abundance is generally assumed to decrease with ascending elevation, as colder climates may preclude several parasites to complete their life cycles. The present study analyses the elevational variation in the prevalence and intensity of the blowfly Protocalliphora azurea found in the nests of two hosts—the coal tit (Periparus ater) and great tit (Parus major)—in Sierra Nevada (SE Spain). Protocalliphora azurea adults are free-living flies, while their larvae are nest-dwelling parasites that feed on nestling blood. In contrast to initial predictions, P. azurea larvae were less prevalent at lower elevations. In Mediterranean environments, the colder and damper climate of medium and high elevations might favour this parasite. Alternatively, greater anthropogenic perturbation in lowland environments may have a negative impact on the parasite. The findings also show that the two host species had similar parasite loads. As coal tits are half the size of great tits, this suggests that the coal tits were more severely parasitised. In conclusion, the generalised assumption that parasite abundance decreases with elevation does not hold true for the present case and elevational parasite patterns probably depend on specific host–parasite systems and climatic conditions in the mountains.

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