DNA barcodes decode the world of soil nematodes

The research team of Professor Toshihiko Eki of the Department of Applied Chemistry and Life Science (and Research Center for Agrotechnology and Biotechnology), Toyohashi University of Technology used a next-generation sequencer ...

Preventing toxoplasmosis parasite infection

Toxoplasma gondii, the parasite responsible for toxoplasmosis, is capable of infecting almost all cell types. It is estimated that up to 30% of the world's population is chronically infected, the vast majority asymptomatically. ...

New cause found for intensification of oyster disease

A new paper in Scientific Reports led by researchers at William & Mary's Virginia Institute of Marine Science challenges increased salinity and seawater temperatures as the established explanation for a decades-long increase ...

Fungus creates a fast track for carbon

Tiny algae in Earth's oceans and lakes take in sunlight and carbon dioxide and turn them into sugars that sustain the rest of the aquatic food web, gobbling up about as much carbon as all the world's trees and plants combined.

Digital crop protection from disease and pest plants

Crop diseases threaten yields in the field. Pests and parasitic weeds cause high crop losses of up to 30 percent every year. In the FarmerSpace project, the Fraunhofer Institute for Optronics, System Technologies and Image ...

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Parasitism

Parasitism is a type of symbiotic relationship between two different organisms where one organism, the parasite, takes favor from the host, sometimes for a prolonged time. In general, parasites are much smaller than their hosts, show a high degree of specialization for their mode of life, and reproduce more quickly and in greater numbers than their hosts. Classic examples of parasitism include interactions between vertebrate hosts and diverse animals such as tapeworms, flukes, the Plasmodium species, and scabs. Parasitism is differentiated from parasitoidism, a relationship in which the host is always killed by the parasite such as moths, butterflies, ants, flies and others.

The harm and benefit in parasitic interactions concern the biological fitness of the organisms involved. Parasites reduce host fitness in many ways, ranging from general or specialized pathology (such as castration), impairment of secondary sex characteristics, to the modification of host behaviour. Parasites increase their fitness by exploiting hosts for food, habitat and dispersal.

Although the concept of parasitism applies unambiguously to many cases in nature, it is best considered part of a continuum of types of interactions between species, rather than an exclusive category. Particular interactions between species may satisfy some but not all parts of the definition. In many cases, it is difficult to demonstrate that the host is harmed. In others, there may be no apparent specialization on the part of the parasite, or the interaction between the organisms may be short-lived. In medicine, only eukaryotic organisms are considered parasites, with the exclusion of bacteria and viruses. Some branches of biology, however, regard members of these groups as parasitic.[citation needed]

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