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Figure 49-45 Life cycle diagram of the microsporidia. A to G, Asexual development of sporoblasts. H, Release of spores. (Modified from Gardiner CH, Fayer R, Dubey JP: An atlas $ protozoan parasites in animal tissues, US Department of Agriculture, Agriculture Handbook No 651,1988. Illustration by Sharon Belkin.)

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Figure 49-46 Diagram illustrating the polar tubule within a microsporidian spore. (Modified from Bryan RT, Cali A, Owen KL, Spencer HC. In Sun T, editor Progress in clinical parasitology, vol n, Field and Wood Medical Publishers, distributed by WW Norton, New York, 1991. Illustration by Sharon Beiktn.)

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Figure 49-46 Diagram illustrating the polar tubule within a microsporidian spore. (Modified from Bryan RT, Cali A, Owen KL, Spencer HC. In Sun T, editor Progress in clinical parasitology, vol n, Field and Wood Medical Publishers, distributed by WW Norton, New York, 1991. Illustration by Sharon Beiktn.)

rocytic cycle. The early forms in the RBCs are called ring forms, or young trophozoites (see Figure 49-52); As the parasites continue to grow and feed, they become actively ameboid within the RBC. They feed on hemoglobin, and the residue that is left is called malarial pigment.

During the next phase of the cyde, the nuclear chromatin and cytoplasm begin to divide (schizogony), leading to the development of individual merozoitesr This infected RBC then ruptures, releasing merozoiteS that infect other RBCs and metabolic products into the bloodstream. If many of the RBCs rupture Simula taneously, a malarial paroxysm may result from the toxic materials released into the bloodstream. In the early stages of a malarial infection, the RBC rupture is not synchronized and patients may exhibit low-grade symptoms; after several days, a 48- or 72-hour period** dty is usually established.

After several erythrocytic cydes, gametocytes are formed and are infective for the mosquito vector. After Ingestion of gametocytes, the cyde continues in the mosquito, with eventual production of sporozoiteS/ which are infective for humans when the mosquito takes the next blood meal.

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Bacterial Vaginosis Facts

Bacterial Vaginosis Facts

This fact sheet is designed to provide you with information on Bacterial Vaginosis. Bacterial vaginosis is an abnormal vaginal condition that is characterized by vaginal discharge and results from an overgrowth of atypical bacteria in the vagina.

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