Host–Parasite Relationships and Life Histories of Trypanosomes in Australia

2017 ◽  
pp. 47-109 ◽  
Author(s):  
C. Cooper ◽  
P.L. Clode ◽  
C. Peacock ◽  
R.C.A. Thompson
Keyword(s):  
2021 ◽  
Vol 66 (1) ◽  
pp. 257-276 ◽  
Author(s):  
Danny Haelewaters ◽  
Meredith Blackwell ◽  
Donald H. Pfister

Arthropod–fungus interactions involving the Laboulbeniomycetes have been pondered for several hundred years. Early studies of Laboulbeniomycetes faced several uncertainties. Were they parasitic worms, red algal relatives, or fungi? If they were fungi, to which group did they belong? What was the nature of their interactions with their arthropod hosts? The historical misperceptions resulted from the extraordinary morphological features of these oddly constructed ectoparasitic fungi. More recently, molecular phylogenetic studies, in combination with a better understanding of life histories, have clearly placed these fungi among filamentous Ascomycota (subphylum Pezizomycotina). Species discovery and research on the classification of the group continue today as arthropods, and especially insects, are routinely collected and examined for the presence of Laboulbeniomycetes. Newly armed with molecular methods, mycologists are poisedto use Laboulbeniomycetes–insect associations as models for the study of a variety of basic evolutionary and ecological questions involving host–parasite relationships, modes of nutrient intake, population biology, host specificity, biological control, and invasion biology. Collaboration between mycologists and entomologists is essential to successfully advance knowledge of Laboulbeniomycetes and their intimate association with their hosts.


Parasitology ◽  
1998 ◽  
Vol 116 (S1) ◽  
pp. S47-S55 ◽  
Author(s):  
J. C. Koella ◽  
P. Agnew ◽  
Y. Michalakis

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.


Parasitology ◽  
2018 ◽  
Vol 145 (11) ◽  
pp. 1469-1474 ◽  
Author(s):  
Christian Selbach ◽  
Robert Poulin

AbstractThe transmission from one host to another constitutes a challenging obstacle for parasites and is a key determinant of their fitness. Due to their complex life histories involving several different hosts, the free-living dispersal stages (cercariae) of digenean trematodes show a huge diversity in morphology and behaviour. On a finer scale, we still have an extremely limited understanding of the inter- and intraspecific variation in transmission strategies of many trematode species. Here, we present a novel method to study the movement patterns of cercariae of four New Zealand trematode species (Coitocaecum parvum, Maritrema poulini, Apatemon sp. and Aporocotylid sp. I.) via automated video tracking. This approach allows to quantify parameters otherwise not measurable and clearly illustrates the individual strategies of parasites to search for their respective target hosts. Cercariae that seek out an evasive fish target hosts showed higher swimming speeds (acceleration and velocity) and travelled further distances, compared with species searching for high-density crustacean hosts. Automated video tracking provides a powerful tool for such detailed analyses of parasites’ host-searching strategies and can enhance our understanding of complex host–parasite interactions, ranging from parasite community structure to the transmission of potential disease agents.


Author(s):  
Paul Schmid-Hempel

Parasites are ubiquitous and shape almost every aspect of their hosts, including physiology, behaviour, life histories, the structure of the microbiota, and entire communities. Hence, parasitism is one of the most potent forces in nature and, without parasites, the world would look very different. The book gives an overview over the parasite groups and the diversity of defences that hosts have evolved, such as immune systems. Principles of evolutionary biology and ecology analyse major elements of host–parasite interactions, including virulence, infection processes, tolerance, resistance, specificity, memory, polymorphisms, within-host dynamics, diseases spaces, and many other aspects. Genetics is always one of the key elements in these topics. Modelling, furthermore, can predict best strategies for host and parasites. Similarly, the spread of an infectious disease in epidemiology combines with molecular data and genomics. Furthermore, parasites have evolved ways to overcome defences and to manipulate their hosts. Hosts and parasites, therefore, continuously co-evolve, with changes sometimes occurring very rapidly, and sometimes requiring geological times. Many infectious diseases of humans have emerged from a zoonotic origin, in processes governed by the basic principles discussed in the different sections. Hence, this book integrates different fields to study the diversity of host–parasite processes and phenomena. It summarizes the essential topics for the study of evolutionary parasitology and will be useful for a broad audience.


2019 ◽  
Vol 24 (6) ◽  
pp. 692-700
Author(s):  
Gabriel Mouahid ◽  
Rodrigue Mintsa Nguema ◽  
Khalid M. Al Mashikhi ◽  
Salem A. Al Yafae ◽  
Mohamed A. Idris ◽  
...  

2011 ◽  
Vol 279 (1733) ◽  
pp. 1544-1550 ◽  
Author(s):  
Janet Koprivnikar ◽  
Chris H. Gibson ◽  
Julia C. Redfern

Behavioural consistency or predictability through time and/or different contexts (‘syndromes’ or ‘personality types’) is likely to have substantial influence on animal life histories and fitness. Consequently, there is much interest in the forces driving and maintaining various syndromes. Individual host behaviours have been associated with susceptibility to parasitism, yet the role of pre-existing personality types in acquiring infections has not been investigated experimentally. Using a larval amphibian–trematode parasite model system, we report that tadpoles generally showed consistency in their activity level in response to both novel food and parasite exposure. Not only were individual activity level and exploration in the novel food context correlated with each other and with anti-parasite behaviour, all three were significant predictors of host parasite load. This is the first empirical demonstration that host behaviours in other contexts are related to behaviours mitigating infection risk and, ultimately, host parasite load. We suggest that this system illustrates how reliably high levels of activity and exploratory behaviour in different contexts might maximize both energy acquisition and resistance to trematode parasites. Such benefits could drive selection for the behavioural syndrome seen here owing to the life histories and ecological circumstances typical of wood frog ( Lithobates sylvaticus ) larvae.


2020 ◽  
pp. 233-256
Author(s):  
Tal Ben-Horin ◽  
Gorka Bidegain ◽  
Giulio de Leo ◽  
Maya L. Groner ◽  
Eileen Hofmann ◽  
...  

The unique characteristics of marine ecosystems have pushed investigators to refine well-tested and widely applied epidemiological modeling methods to understand marine disease dynamics. This chapter begins by reviewing models used to quantify within-host parasite dynamics in open marine ecosystems where infection is near universal. These models are powerful tools for quantifying how diseases respond to changing environmental conditions and, when reliable environmental data are available, can forecast marine disease risks into the future. This chapter then describes epidemiological models that consider transmission processes and parasite life histories unique to marine systems, and then incorporates disease processes in fisheries assessment models. Finally, because disease dynamics vary across local host populations, this chapter concludes by overviewing ocean circulation models and their use in understanding parasite dispersal and spread in marine ecosystems.


The comparative method as recently developed can be used to identify statistically independent instances of life-history evolution. When life-history traits show evidence for correlated evolutionary change with each other or with ecological differences, it is often possible to single out the trade-offs and selective forces responsible for the evolution of life-history diversity. Suites of life-history characters often evolve in concert, and recent optimality models incorporating few variables show promise for interpreting that evolution in terms of few selective forces. Because hosts provide well-defined environments for their parasites, when host-parasite phylogenies are congruent it is possible to test ideas about the evolution of particular life-history and size-related traits.


Author(s):  
James A. Swenberg ◽  
Adalbert Koestner ◽  
R.P. Tewari

Previous investigations of pathogenetic mechanisms in mycotic encephalitis have been restricted to light microscopic and mycologic approaches. In this study, electron microscopy was utilized to determine the mode of vascular penetration and the cellular and subcellular host-parasite interrelationships in brains of mice infected with Oidiodendron kalrai. This newly isolated fungus was selected because of its ability to consistently produce encephalitis with gross and microscopic lesions similar to those observed in naturally occuring mycoses.


Author(s):  
D. Johnson ◽  
P. Moriearty

Since several species of Schistosoma, or blood fluke, parasitize man, these trematodes have been subjected to extensive study. Light microscopy and conventional electron microscopy have yielded much information about the morphology of the various stages; however, scanning electron microscopy has been little utilized for this purpose. As the figures demonstrate, scanning microscopy is particularly helpful in studying at high resolution characteristics of surface structure, which are important in determining host-parasite relationships.


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