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146:. Merozoites are non-mobile cells that are circulated through the host by the bloodstream and infect other cells in the host organism. Merozoites are released when the megaloschizont breaks apart. This can be caused by the megaloschizont simply reaching full capacity and self-lysing of the membrane or it can be caused by the membrane being attacked by the organism's immune-response cells.
119:. This sporozoite infects the host organism by entering the blood stream and eventually settling in a vital organ such as the heart, liver, lung, or spleen. Once infecting the host organism's cell, the sporozoite begins feeding and growing. While it is feeding and growing, the cell is known as a
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regions of the host, these ranged in size from 11 to 18 micrometers. The larger schizonts, ranging in size from 60 to 105 micrometers, were found in blood vessels or in contact with the muscle tissue. Dr. Huff referred to these large schizonts as megaloshizonts. It was hypothesized that in this
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phyla was found in several parakeet-like avians in areas of
Scotland. Megaloschizonts presented as gray nodules in several different areas of the infected organisms. The megaloschizonts were most numerous in the smooth muscle of the heart and gizzard, but were also found in smooth muscle of the
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phyla. The megaloschizont cells measured 50 to 100 micrometers. The merozoites inside the megaloschizonts were less than 1 micrometer in diameter. The infectious cells were found in various sections of the host organism including the liver, the spleen, the intestines, and the cloaca. Smooth
249:. This species had produced megaloschizonts in the intrahepatic bile ducts and portal veins. The presence of these megaloschizonts was hypothesized to have caused periportal hepatitis and fibrosis. The infectious disease was determined to have contributed to the death of the organisms.
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or division of the cytoplasm. There is no specific number of nuclear divisions during schizogony. The number of nuclear divisions is species specific and even within a single species the number of nuclear divisions can differ depending on the phase of the life cycle. For example,
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of parasite is known to cause many problems in closely related avian species. These problems include tissue damage, reduced fertility, and reduced growth. It was concluded that the yellow-eyed penguins were being infected by biting black flies in their nesting area.
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are antelope-like animals that are found naturally in the mountains of Europe. The animals at the zoo died over a 7-year period. After completing necropsies, it was determined that the organisms were infected with a parasitic protozoan of the genus
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are the part of the life cycle that takes place inside the infected host organism and operates as an asexually reproductive cell. Megaloschizonts appear as grey-white nodules found in the smooth muscle of major organs, such as the
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New
Zealand, 2010: The endangered yellow-eyed penguin is found in southern New Zealand. The population has been reduced by more than 60% since 1990. Researchers collected blood samples from the penguins. They found
135:(parasite that can cause malaria) undergoes four different types of schizogony producing anywhere from 8 to over 20,000 nuclei. A cell currently undergoing schizogony is known as a
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particular case, the megaloschizont (produced asexually) was responsible for producing merozoites that would develop into gametocytes, the sexually reproducing stage of the
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Atkinson, Carter T. and
Forrester, Donald J. (1987). Myopathy associated with megaolschizonts of Haemoproteus meleagridis in a wild turkey from Florida.
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The term was first used by Clay G. Huff from the
University of Chicago. In studying various infectious diseases caused by parasitic protozoans from the
115:. This is an asexual reproductive process found primarily in parasitic protists. The parasitic, infectious cell that infects a host is called a
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phylum contains several parasitic protozoans. They have a very complex life cycle that includes several stages. Megaloschizonts and the smaller
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muscle tissue surrounding the megaloschizont cells was found to be partially calcified, pale, swollen, and early signs of necrosis were noted.
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Brunnert, Steven R., Citino, Scott B., Herron, Alan T., and Altman, Norman H. (1992). Hepatic coccidiosis in chamois (Rupicapra rupicapra).
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Florida, U.S., 1987: A wild turkey that died in captivity two days after capture was found to be infected with megaloschizonts from
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Stidworthy, Mark F. and
Greenwood, Andrew G. (2006). Deaths in aviary birds associated with protozoal megaloschizonts.
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phylum, Dr. Huff noticed two types of schizonts developing in the infected hosts. He noticed smaller
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The process of schizogony is when a cell undergoes multiple nuclear divisions before undergoing
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358:(Apicomplexa: Haemoproteidae) of tortoises and turtles. (1998). The Royal Society. London.
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Hill, A.G. and Howe, L. and
Gartrell, B.D. and Alley, M.R. (2010). Prevalence of
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139:. If a cell has a very large number of nuclei, it is known as a megaloschizont.
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123:. This trophozoite is the cell that begins the process of schizogony.
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hepatic megaloschizonts in up to 95% of the sampled organisms. This
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Huff, Clay G. (1942). Schizogony and gametocyte development in
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life cycle. They are formed during a process called
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is a genus of parasitic protozoa that belong to the
142:The thousands of nuclei in a megaloschizont become
150:Megaloschizont Producing Parasitic Species/Hosts
199:infects mammals including rabbits and chamois
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203:Examples of Megaloschizont Infections
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396:Journal of Zoo and Wildlife Medicine
442:Megaloschizont in live bird liver
304:The Journal of Infectious Diseases
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424:. Volume 23. Issue 3. pp 495-499.
302:in studying parasitic diseases.
336:Impact Malaria Training website
103:Megaloshizonts are part of the
220:Scotland, 2006: A species of
191:infects various avian species
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437:Megaloschizont in bird heart
422:Journal of Wildlife Diseases
411:. Volume 159. Issue 18. UK.
233:intestine, lung, and skin.
159:infects reptiles and birds
111:, which can also be called
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398:. Volume 23. pp 276-280.
254:Haemoproteus meleagridis
240:at the Miami MetroZoo.
99:Background Information
16:Intracellular parasite
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294:and comparisons with
292:Leucocytozoon simondi
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70:History of the Term
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296:Plasmodium
271:References
144:merozoites
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117:sporozoite
109:schizogony
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223:Besnoitia
82:schizonts
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164:Nycteria
137:schizont
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247:Eimeria
242:Chamois
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86:hepatic
39:. The
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