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Parasites need a host body and the haematophagous insect triatomine (descriptions "assassin bug", "cone-nose bug", and "kissing bug") is the major vector in accord with a mechanism of infection. The triatomine likes the nests of vertebrate animals for shelter, where it bites and sucks blood for food.
Other intracellular parasites have developed different ways to enter a host cell that do not require a specific component or action from within the host cell. An example is intracellular parasites using a method called gliding motility. This is the use of an actin-myosin motor that is connected to the intracellular parasites' cytoskeleton.
Parasite life cycles involving only one host are called "direct"; those with a definitive host (where the parasite reproduces sexually) and at least one intermediate host are called "indirect". [12] [13] An endoparasite lives inside the host's body; an ectoparasite lives outside, on the host's surface. [14]
Inside a host cell, the parasite transforms into a replicative form called an amastigote, which undergoes several rounds of replication. [5] The replicated amastigotes transform back into trypomastigotes, which burst the host cell and are released into the bloodstream. [ 2 ]
Main article: Human parasite Endoparasites Protozoan organisms Common name of organism or disease Latin name (sorted) Body parts affected Diagnostic specimen Prevalence Source/Transmission (Reservoir/Vector) Granulomatous amoebic encephalitis and Acanthamoeba keratitis (eye infection) Acanthamoeba spp. eye, brain, skin culture worldwide contact lenses cleaned with contaminated tap water ...
Oviposition depends on finding the host and on evading host defences; the ovipositor is a tube-like organ used to inject eggs into hosts, sometimes much longer than the wasp's body. [ 30 ] [ 31 ] [ 32 ] Hosts such as ants often behave as if aware of the wasps' presence, making violent movements to prevent oviposition.
Inside the cells they undergo spontaneous transformation into oval-shaped amastigotes. [22] [23] Granulocytes selectively kill the promastigotes by oxidative mechanism, while amastigotes are resistant. [24] Then the surviving amastigotes undergo cell division using simple binary fission. Multiplication continues until the host cell can no ...
T. gondii has been shown to produce a protein called GRA28, released by the MYR1 secretory pathway, which interferes with gene expression in infected cells and results in cells that behave like dendritic cells, becoming highly mobile in the body. [41] Since the parasite can change the host's immune response, it may also have an effect, positive ...