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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In a study of the disease pattern of the elderly in Rwanda, all patients aged 60 or more, hospitalized in a one-year period at the Medical Department, University Hospital, Butare, were examined prospectively. One hundred and ninety-two patients were included; most were subsistence farmers having a mainly vegetarian diet and living in large families. Infections (37.5% of the patients) and liver cirrhosis (31.8%) were the problems most frequently encountered. Primary hepatocellular cancer was diagnosed in 5.7% of the patients and was the most frequent malignancy. The hospitalized elderly occupied 17.5% of the available beds in the Medical Department. Their disease pattern was different from that of younger patients, making heavier demands on the medical resources. Malaria and upper intestinal inflammation were less frequent in the elderly; liver cirrhosis, primary hepatocellular cancer, pneumonia, prostatic cancer, cardiovascular pathology, chronic renal pathology and chronic lung disease were more prevalent. Several age-related conditions frequently observed in industrialized countries (e.g. coronary heart disease, stroke, gallstones, renal cysts, dementia) were rare. The study thus illustrates the concept of 'secondary aging': to the primary changes induced by the aging process, additional alterations are added which depend upon the environment and the lifestyle, resulting in a varying disease pattern. Health policies thus must take into account that the demographic transition in developing countries may result in a pattern of diseases different from that seen in industrialized countries; care must be taken when transposing data obtained from elderly populations in industrialized countries.
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PMID:The disease pattern of elderly medical patients in Rwanda, central Africa. 841 4

Infections with malaria are increasing in Europe and Northern America and are also spreading in tropical endemic areas. A falciparum variety of malaria known as cerebral malaria is the most well-known neurological complication, caused by Plasmodium falciparum and characterised by a fulminant course with disturbances of consciousness and facultative seizures or focal neurological deficits. 50% of deaths caused by malaria are due to cerebral involvement. Pathologically a disseminated vasculomyelinopathic disorder is seen. Immunological changes, vascular-hypoxic disturbances and metabolic-toxic factors contribute to these pathological findings. Facts on diagnostic, differential diagnostic and therapeutic procedures are presented. Beside the severe and life-threatening cerebral malaria some unspecific cerebral symptoms are seen, such as cerebellar ataxia and chorea. Spinal disease and peripheral nerve involvement, polyradiculitis and especially psychiatric disorders have also been described. Every neurological and psychiatric disorder presented first in tropical areas or malaria-endemic regions requires malaria diagnostic tests. In our geographical region, any previous history of a journey to the tropics is an important pointer; in particular, neurological or psychiatric symptoms can be important pointers to malaria.
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PMID:[Neurologic complications of malaria infection]. 844 77

Infections with the malaria parasite Plasmodium falciparum are characterized by sequestration of erythrocytes infected by mature forms of the parasite. Sequestration seems critical for the survival of the parasite, but may lead to excessive binding in the microvasculature and death of the human host. We report here that a novel electrondense fibrillar structure, containing immunoglobulins M or M and G, is found at the surface of infected erythrocytes that adhere to host cells. In cases of cerebral malaria, fibrillar strands are also seen in the microvasculature at autopsy. Our findings may explain the adhesive mechanism by which malaria-infected erythrocytes cause the vascular obstruction seen in complicated malaria infections.
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PMID:Novel fibrillar structure confers adhesive property to malaria-infected erythrocytes. 857 66

The chimpanzee is the only animal host currently available that can support the development of the human malaria parasite Plasmodium ovale. Thirty-one infections with the Nigerian I/CDC strain were induced in splenectomized chimpanzees. Maximum parasite counts ranged from 1,240 to 127,224/microliters. Infections were transient and unpredictable. Anopheles stephensi, Anopheles gambiae, Anopheles freeborni, and Anopheles dirus mosquitoes were infected by feeding through parafilm membranes on heparinized blood containing gametocytes; each species supported development to sporozoites in the salivary glands. Mean oocyst counts per infected mosquito ranged from 1 to 85.1; 21.7% of infected lots of mosquitoes averaged > 20 oocysts per positive mosquito gut. One infection was induced via the bites of infected An. gambiae. The prepatent period was 16 days.
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PMID:The Nigerian I/CDC strain of Plasmodium ovale in chimpanzees. 863 50

Infection of human erythrocytes with the malaria parasite, Plasmodium falciparum, results in the exposure of amino acid residues 542-555 of the anion-exchange protein, band 3, in a conformation that enables the cell to adhere to C32 amelanotic melanoma cells. Attempts to isolate this adhesive form from infected cells by immunoaffinity were unsuccessful, and so other approaches were utilized. Chinese hamster ovary (CHO) cells transfected with cDNA encoding the first 578 amino acid residues of human band 3 protein transiently expressed the protein efficiently. A murine monoclonal antibody (MAb) that specifically recognizes the adhesin exposed on the surface of erythrocytes bearing mature stages of P. falciparum immunostained some transfected cells, confirming that the first 578 amino residues are sufficient for the adhesive conformation. As a more efficient alternative to transgenic expression of the adhesin, microspheres with covalently bound peptides fashioned on band 3 sequences previously found to be adherent (residues 546-553 and 820-829 and called pfalhesin) were produced. The pfalhesin-coated microspheres specifically bound to C32 amelanotic melanoma cells, whereas microspheres coupled with a scrambled version of residues 546-553 had little binding capacity for melanoma cells. These results demonstrate that the previously identified band 3-related peptides that inhibit cytoadherence interact directly with target cells and suggest that microspheres with covalently coupled peptides might constitute novel 'artificial' P. falciparum-infected erythrocytes for use in in vitro and in vivo studies.
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PMID:Plasmodium falciparum: the adherence of erythrocytes infected with human malaria can be mimicked using pfalhesin-coated microspheres. 864 Mar 78

A study was conducted in the city of Lubumbashi, Zaire: (1) to survey parasitic infections and clinical conditions in the local children and their mothers; (2) to identify combinations of parasites and clinical conditions that commonly occurred together in individuals; and (3) to determine whether single- and/or multiple-species infections were risk determinants of the observed clinical conditions. Overall, 1100 children and mothers from three subdivisions, two of low socio-economic status (LSES) and one of relatively high socio-economic status (HSES), provided stool and blood samples and were clinically examined. Plasmodium prevalence was higher in the two LSES subdivisions than in the HSES subdivision. Prevalence and intensity of Ascaris lumbricoides infection were low in the HSES subdivision and one of the two LSES subdivisions. In contrast, prevalence and intensity of Trichuris trichiura and of hookworms were similar in all subdivisions. Plasmodium and A. lumbricoides were the most frequently found single-species infections. The combination of A. lumbricoides and Plasmodium was the most frequent double-species infection and that of A. lumbricoides, Plasmodium and T. trichiura was the most frequent triple-species infection. Significant positive associations between parasite species were detected in the HSES subdivision, and in one of the two LSES subdivisions. Because the relationships were not consistently detected, it is hypothesized that the associations are determined by environmental conditions rather than synergy between the parasites in the host. The most commonly observed clinical conditions were abdominal pain, diarrhoea, fever, and low packed-cell volume (PCV). The occurrence of each was significantly lower in the HSES subdivision than in at least one of the two LSES subdivisions. Abdominal pain and low PCV were most common in individuals presenting with only a single clinical condition, and the combination of this symptom and sign was the most commonly observed pair of conditions. Abdominal pain, low PCV and diarrhoea was the most common combination in individuals with three clinical conditions. Logistic regression revealed that hookworm infection, T. trichiura infection, young age and residence in an LSES subdivision were determinants of diarrhoea. Trichuris trichiura infection, young age and living in an LSES subdivision were risk factors for abdominal pain. Plasmodium infection and young age were risk factors for fever. LSES was the only predictor of low PCV. Infection with A. lumbricoides did not enter any of the models. No significant interactions were detected among parasites, indicating that there was no synergism or antagonism among parasites in the induced disease.
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PMID:Multiple infection with Plasmodium and helminths in communities of low and relatively high socio-economic status. 875 42

Infections of human erythrocytes with the mature asexual blood stages of Plasmodium falciparum result in antigenic changes in the host cell membrane that, by virtue of their position, length of exposure, and close association with functional changes critical to pathogenesis, are a potential important target for host effector mechanisms. These parasite-induced antigens expressed on the surface of infected erythrocytes have been shown to exhibit considerable polymorphism. An antibody-mediated agglutination assay using malaria serum samples from different regions of Venezuela has been developed to examine the extent of antigenic diversity of infected red blood cells (IRBC) taken from subjects with naturally acquired P. falciparum infections. An important humoral immune recognition of surface molecules from red blood cells infected with a wide variety of clinical isolates of P. falciparum was observed even when sera from individuals experiencing a single episode of malaria were used. A process of in vivo antigenic variation of surface molecules is postulated, since agglutination of IRBC was observed with acute heterologous but not autologous sera. When sera obtained from Amerindians inhabiting the Venezuelan Amazon were assayed, a strong immune response to different parasite isolates, including those of another geographic region, was observed, suggesting the recognition of highly conserved immunogenic parasitic epitopes in people exposed to multiple malaria infections.
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PMID:Plasmodium falciparum: surface modifications of infected erythrocytes from clinical isolates. Evidence of antigenic diversity using Venezuelan human malarial sera. 883 28

History, signs and symptoms, chemoprophylaxis and management of 150 malaria patients hospitalized at the University Hospital and St. Clara Hospital (Claraspital) of Basel, Switzerland, were analyzed from 1970 to 1992. Mainly due to increasing travel in endemic areas, an increase from 3.2 cases per year for the years 1970 to 1981 to 9.5 cases per year for the years 1982 to 1992 occurred. In the latest period, more patients had to be admitted to the intensive care unit (14.0% from 1970 to 1986, 28.1% from 1987 to 1992). Infections with plasmodium falciparum were more frequent in later years, the incidence of plasmodium vivax and non-typifiable plasmodia decreased. Compliance for chemoprophylaxis was insufficient, with only 21.8% of all patients taking a correct prophylaxis in the latest period. Malaria is a significant health problem in industrialized countries like Switzerland with increasing incidence and worsening course due to the development of drug resistance.
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PMID:[Epidemiology and clinical aspects of malaria in the canton hospital and in St. Clara Hospital, Basel 1970-1992]. 884 66

Anemia is estimated to affect one-half of school-age children in developing countries. The school years are an opportune time to intervene, and interventions must be based on sound epidemiologic understanding of the problem in this age group. We report on the distribution of iron deficiency and anemia across age, sex, anthropometric indexes, and parasitic infections in a representative sample of 3595 schoolchildren from Pemba Island, Zanzibar. Iron status was assessed by hemoglobin, erythrocyte protoporphyrin (EP), and serum ferritin concentrations from a venous blood sample. Overall, 62.3% of children were anemic (hemoglobin < 110 g/L), and 82.7% of anemia was associated with iron deficiency. The overall prevalence of iron-deficient erythropoiesis (EP > 90 mumol/mol heme) was 48.5%, and the prevalence of exhausted iron stores (serum ferritin < 12 micrograms/L) was 41.3%. In bivariate analyses, iron status was slightly better in girls than in boys, and was better in children aged 7-11 y than in those older or younger. Hemoglobin but not EP or serum ferritin concentrations were lower in stunted children. Infection with malaria, Trichuris trichiura, Ascaris lumbricoides, and hookworms were all associated with worse iron status; the association with hookworms was strongest by far. In multivariate analyses, hookworm infection intensity was the strongest explanatory variable for hemoglobin, EP, and serum ferritin. Sex, malarial parasitemia, A. lumbricoides infection, and stunting were also retained in the multivariate model for hemoglobin. Twenty-five percent of all anemia, 35% of iron deficiency anemia, and 73% of severe anemia were attributable to hookworm infection; < 10% of anemia was attributable to A. lumbricoides, malaria infection, or stunting. We conclude that anthelminthic therapy is an essential component of anemia control in schoolchildren in whom hookworms are endemic, and should be complemented with school-based iron supplementation.
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PMID:Epidemiology of iron deficiency anemia in Zanzibari schoolchildren: the importance of hookworms. 898 28

Infection of human erythrocytes with the malaria parasite Plasmodium falciparum induces many morphological and biochemical changes in the host cell. Host serine/threonine protein kinases could be involved in some of these processes. The aim of this study was to determine the effect of infection on red blood cell protein kinase C (PKC) and establish the importance of this enzyme in parasite growth and sexual stage differentiation. Phorbol myristate acetate (PMA)-induced translocation of erythrocyte PKC activity is impaired in erythrocytes enriched for mature asexual stage infected cells. Western blotting shows that this is due to a relative reduction in membrane PKC protein levels rather than inhibition of enzyme activity and analysis of PKC activity isolated from whole cell lysates by DE52 chromatography suggests that total activatable PKC levels are lower in infected erythrocytes. A reduction in PMA-induced activation is also observed in PKC assays performed in situ. Downregulation of erythrocyte PKC by overnight incubation with PMA before infection causes a significant decrease in the rate of the asexual growth, suggesting that the enzyme, although lost later in infection, may be important in the earlier development of the parasite. By contrast, the lack of PKC had no effect on the production of sexual stage parasites.
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PMID:Modulation of protein kinase C activity in Plasmodium falciparum-infected erythrocytes. 905 62


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