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Parasitemia

About: Parasitemia is a research topic. Over the lifetime, 4797 publications have been published within this topic receiving 139700 citations. The topic is also known as: Parasitemias.


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Journal ArticleDOI
04 Sep 1987-Science
TL;DR: Results indicate that TNF-alpha has an important role in the pathogenesis of cerebral malaria in this murine model and suggest that local accumulation and activation of macrophages may lead to the predominance of lesions in the central nervous system.
Abstract: Tumor necrosis factor, or cachectin (TNF-alpha), a protein with a wide range of biological activities, is produced mainly by macrophages and may be important in inflammatory processes. The role of TNF-alpha in the pathogenesis of cerebral malaria was investigated in a murine model. Most CBA mice infected with Plasmodium berghei anka die between days 6 and 14 with acute neurological manifestations unrelated to the level of parasitemia, whereas mice of some other strains have malaria of the same severity that ends in death after 3 to 4 weeks without neurological manifestations. The activity of serum TNF-alpha was considerably increased in CBA/Ca mice with cerebral malaria but not in Plasmodium berghei-infected mice that did not develop this complication. One injection of rabbit antibody to TNF-alpha on day 4 or 7 fully protected infected mice from cerebral malaria without modifying the parasitemia, whereas immunoglobulins from normal rabbit had no effect. In mice with cerebral malaria, the cerebral vessels showed focal accumulations of packed macrophages often containing infected erythrocytes; this lesion was not seen in mice treated with antibody to TNF-alpha or in untreated mice without cerebral malaria. These findings indicate that TNF-alpha has an important role in the pathogenesis of cerebral malaria in this murine model and suggest that local accumulation and activation of macrophages may lead to the predominance of lesions in the central nervous system.

763 citations

Journal ArticleDOI
TL;DR: A new technique for estimating the absolute level of parasitemias in trypanosome infections is described, achieved by matching microscopic fields of a wet blood film against charts and, where fewer organisms are present, by counting the number oftrypanosomes in 5, 10, or 20 microscope fields.

700 citations

Journal ArticleDOI
TL;DR: It is evident that the measurement of pLDH has a correlation with Parasitemia and may offer a method that can be developed into a simple test for the detection of Plasmodium parasitemia.
Abstract: This report describes an enzyme assay for the detection of Plasmodium falciparum. The assay is based on the observation that the lactate dehydrogenase (LDH) enzyme of P. falciparum has the ability to rapidly use 3-acetyl pyridine NAD (APAD) as a coenzyme in the reaction leading to the formation of pyruvate from lactate. Human red blood cell LDH carries out this reaction at a very slow rate in the presence of APAD. We measured the development of APADH and found that the formation of this product could establish the basis of an assay that detected the presence of P. falciparum from in vitro cultures at parasitemia levels of 0.02%. We also had occasion to use this assay with clinical samples. We found a correlation between levels of parasitemia and the activity of parasite LDH. Parasite LDH (pLDH) activity could be measured in blood hemolysates and in plasma and serum from patients with malaria. We used the serum assay for pLDH and followed the level of pLDH in a patient with cerebral malaria prior to antimalarial treatment and during the recovery period. From these initial studies, it is evident that the measurement of pLDH has a correlation with parasitemia and may offer a method that can be developed into a simple test for the detection of Plasmodium parasitemia.

533 citations

Journal ArticleDOI
TL;DR: It is paramount to consider malaria in every febrile patient with a history of travel in an area endemic for malaria, and exchange blood transfusion has been suggested for the treatment of patients with severe malaria and high parasitemia.
Abstract: Malaria represents a medical emergency because it may rapidly progress to complications and death without prompt and appropriate treatment. Severe malaria is almost exclusively caused by Plasmodium falciparum. The incidence of imported malaria is increasing and the case fatality rate remains high despite progress in intensive care and antimalarial treatment. Clinical deterioration usually appears 3–7 days after onset of fever. Complications involve the nervous, respiratory, renal, and/or hematopoietic systems. Metabolic acidosis and hypoglycemia are common systemic complications. Intravenous quinine and quinidine are the most widely used drugs in the initial treatment of severe falciparum malaria, whereas artemisinin derivatives are currently recommended for quinine-resistant cases. As soon as the patient is clinically stable and able to swallow, oral treatment should be given. The intravascular volume should be maintained at the lowest level sufficient for adequate systemic perfusion to prevent development of acute respiratory distress syndrome. Renal replacement therapy should be initiated early. Exchange blood transfusion has been suggested for the treatment of patients with severe malaria and high parasitemia. For early diagnosis, it is paramount to consider malaria in every febrile patient with a history of travel in an area endemic for malaria.

532 citations

Journal ArticleDOI
TL;DR: The protective effect of African IgG antibodies against Plasmodium falciparum malaria was investigated by passive transfer in Thai patients, suggesting that target antigens were equally expressed in geographically remote isolates.
Abstract: The protective effect of African IgG antibodies against Plasmodium falciparum malaria was investigated by passive transfer in Thai patients. Sera from 333 African adults were collected in the Cote d'Ivoire and subjected to extensive screening. One hundred fifty-three samples were discarded for safety reasons, and IgG was extracted from those remaining under conditions allowing their use by the intravenous (iv) route. Eight Thai patients with P. falciparum parasitemia were treated by iv inoculation of the IgG: six with a 100 mg/kg dose given over three days, one with a single 20 mg/kg dose, and one with a single 200 mg/kg dose. To ensure a safety margin of at least 48 hours, subjects were chosen among patients having a recrudescent parasitemia following quinine treatment failure at the RI level. At that stage, symptoms were mild or absent and parasitemia was low but increasing (range 4, 200-9,000/microliters). The IgG pool exerted a profound, stage-specific, but non-sterilizing effect on each of the strains tested, and proved to be safe. Asexual parasitemia decreased by a mean 728-fold (range 46-1,086), while gametocytes were unaffected. Clearance of parasites and symptoms was as fast or faster than with drugs, and was consistent in the eight patients treated, suggesting that target antigens were equally expressed in geographically remote isolates. In peripheral blood smears, no mature forms were seen at any time during the followup, which does not support the hypothesis that reversal of cytoadherence occurred. After the disappearance of the transferred antibodies, recrudescent parasites from three patients were found to be susceptible to the same extent (mean decrease of 1,310-fold) to the same IgG preparation, indicating that selection of parasites able to escape the effect of antibodies had not occurred. No adverse side-effects were detected during the followup, which lasted one year.

497 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
2023124
2022338
2021188
2020181
2019147