Parasitic behavior

There are two types of input power buses. DC power buses are single-wire power connections such as found in automobiles and aircraft. The ground connection forms the other leg of the power system. The other form of input connection is the ac, or two or three-wire feed systems as found in ac power systems. The design of the EMI filter for dc systems is covered in Section 3.12 and takes the form of a simple L-C filter. All the noise is common-mode between the single power wire and the ground return. The dc filter is much more complicated, because of the parasitic behavior of the components involved. 

Though many species of viruses, bacteria, and fungi exhibit parasitic behavior and can be transmitted by par-... 

The ability of a parasite to move to different sites in its host and to maintain its position in host body fluids, where appropriate, is crucial to the parasite s survival. Understanding the mechanisms underlying its motile capabilities, particularly at the level of its neuromuscular system, is of great importance both for an understanding of basic parasite behavior and biology and for the development of anthelmintic compounds. This chapter will focus on the chemical signals affecting the neuromuscular systems of adult parasitic helminths with emphasis on putative transmitters and modulators in the trematodes, cestodes and nematodes. 

Esch, Gerald W. Parasites, People and Places Essays on Field Parasitology. New York Cambridge University Press, 2004. Anecdotal accounts of parasitology illustrate many aspects of the field and cover elements of the history of parasitology as well as medical and evolutionary investigations of parasite behavior. 

Broadly speaking, the direct behavioral effects of neurotoxic pollutants on wild animals may be on feeding, breeding, or avoidance of predation (Beitinger 1990), or any combination of these. Any of these changes may have adverse effects on populations. Additionally, in the natural world, populations may be affected indirectly because of neurotoxic and behavioral effects on other species. Thus, a population decline of one species due to a behavioral effect of a pollutant may lead to a consequent decline of its parasites or predators, even though they are not themselves directly affected by the chemical. Direct effects will now be discussed before considering indirect ones. 

Turning now to indirect effects of neurotoxic pollutants, the status of predators and parasites can be affected by reductions in numbers of the species that they feed upon. Thus, the reduction in numbers of a prey species due to a behavioral effect can, if severe enough, cause a reduction in numbers of a predator. Also, as mentioned earlier, behavioral effects upon a prey species may lead to selective bioaccumulation of persistent neurotoxic pollutants such as DDT and dieldrin by predators thus, a behavioral effect may be hazardous for predator and prey alike ... 

Parasitic hymenoptera hold promise in integrated pest management schemes, because they parasitize many economically important insect pests in a species-and stage-selective manner. The pheromones and kairomones of the parasitic hymenoptera have been studied for a long time, and there are many examples where there is evidence of chemical mediation of parasitoid behavior. This review emphasizes work done since the last major reviews [11, 12, 42] and, where it is available, on the primary bioassay-guided chemical identification of the semiochemical (Fig. 2 and Tables 3 and 4). 

Kavaliers, M., Choleris, E., Agmo, A. and Pfaff, D.W. (2004) Olfactory-mediated parasite recognition and avoidance linking genes to behavior. Horm. Behav. 46, 272-283. 

In the general spectrum of host-parasite relationships, there is considerable parasite-induced host variability resulting in perturbed host physiology, biochemistry, and developmental behavior (8, 21, 22). There is a wide range of speculation that the parasite has the capacity to modulate or regulate host systems (8, 10, 23). It is clear that the C. sonorensis polydnavirus induces developmental arrest in H. virescens larva (18, 24,... 

The combination of the wasps own toxins and those provided by the virus affect tobacco hornworms in other ways as well. One of these is to modify their behavior to the wasps benefit. Parasitized caterpillars continue to feed and behave normally until about eight hours before the larvae emerge. At that time, the caterpillars cease to eat and crawl about. They show no other deficiency and their reflexes appear normal. The details of this modification are uncertain, but it appears to favor the wasp larvae. A normal, unparasitized caterpillar readily eats wasp pupae offered to it. This implies that an active caterpillar would be a threat to larvae emerg-... 

Moore, Janice. "Parasites that Change the Behavior of Their Hosts." Scientific American 250 (May 1984) 100-108. 

Medical personnel who work in affluent areas are unlikely to see large numbers of people with vitamin deficiency diseases. However, certain groups of the population are particularly at risk, such as low-income families and chronically ill patients. The classic symptoms of any vitamin deficiency disease as observed in laboratory animals are often blurred in humans. The clinical picture is often complicated by deficiencies of other vitamins, minerals, calories, and protein and by infections and parasite infestations, which usually accompany longstanding malnutrition. Biochemical, physiological, and behavioral changes can occur in the marginal deficiency state without or before the appearance of more specific symptoms. Since the nonspecificity of these changes makes them difficult to detail, this section focuses on the symptoms associated with individual vitamin deficiency diseases. 

In Ekbom s syndrome, people are certain that they are infested with insects or worms. Swedish neurologist Karl Axel Ekbom (1907-1977) described the syndrome in 1937, and today we know that the typical patient is a woman over 40 years of age. One 68-year-old woman in the literature continually complained about something crawling up my private. She insisted that worms had invaded her rectum and spine. She searched for these for weeks and said she saw them in her feces. This behavior is typical in that most women imagine that the parasites are... 

In undisturbed ecosystems, plant and herbivorous Insect populations coexist In a steady state condition dictated by external biological and physical factors (parasites, predators, precipitation, temperature, soil quality, etc.). But this balance is also regulated by myriads of very fundamental Interactions, many or even most of which are yet unknown, between the plant allelochemi-cals and the biochemical, physiological, and behavioral functions of the Insect herbivores ( 1). 

Turlings, T. C. J. and Benrey, B. (1998). Effects of plant metabolites on the behavior and development of parasitic wasps. Ecoscience 5 321-333. 

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