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

A survey of the health, social and economic problems of the village of A1 Awayda, in Gezira province, Sudan, by medical students, was conducted over 2 weeks as part of their field training research and rural development curriculum. A 40% random household survey was based on a pretested structured questionnaire. The village comprises 195 households of 1201 people, with 40% under 15. As a result of the Sennar Sugar Scheme begun in 1978, 58% of the population work in the sugar factory. Rain-fed crops have failed for the last 2 years because of drought, and subsistence acreage has contracted because of sorghum planting for sugar. Sanitation consists of latrines in 15% of houses. People are at risk of contracting schistosomiasis from crossing the irrigation canal to reach the well. The diet is based on the staple starch, dura in the form of kisra. Breast feeding is continued for 1-2 years, with 47% supplementation by bottle or kisra or rice water at an average of 7 months. The major health problems are malaria, schistosomiasis, cough and diarrhea. 54% of families were immunized. 11.5% of women used modern contraceptives. Non-users cited religion as a reason for non-use. Female circumcision is common. It was recommended that latrines be dug, and that health education, immunization, prenatal care and family planning be provided.
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PMID:Community health in a rural area of Sudan. 221 96

Sequential gastrointestinal permeability in patients with Plasmodium falciparum malaria was determined by measuring the permeation of sucrose, lactulose, and mannitol to assess both gastric and small intestine permeability. Sucrose absorption (gastroduodenal permeability) was increased in patients with severe malaria (defined as either >5% parasitemia or a serum bilirubin level of >50 micromol/L) and became normal by day 2 following treatment. A similar proportion of patients with uncomplicated malaria had increased gastroduodenal permeability initially, which resolved by day 7 of treatment. During acute malarial illness, the lactulose: mannitol (L:M) ratio in urine was increased and was found to be higher in patients with severe malaria than in those with uncomplicated malaria and in controls, but this ratio reverted to normal during convalescence. At the time of admission, the L:M ratios in patients with uncomplicated malaria were increased but became normal by day 2 after treatment. Conversely, the duration of increased L:M ratios in patients with severe malaria was longer. By day 7, the L:M ratios in patients with severe malaria were higher than those in patients with uncomplicated malaria and in controls. We conclude that gastrointestinal permeability is increased during severe and uncomplicated falciparum malaria but reverts to normal during convalescence.
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PMID:Increased gastrointestinal permeability in patients with Plasmodium falciparum malaria. 911 95

643 adult male employees of the Sugar Corporation of Malawi in Nchalo, Chikwawa District, participated in a cross-sectional study during February-April 1994 to determine the relationship between fever, malaria parasitemia, and HIV infection. Participants underwent routine physical examinations and data were collected on their ages, axillary temperatures, and histories of fever or other illnesses in the 2 weeks before enrollment in the study. Blood was collected and thick blood films prepared and examined for the presence of malaria parasites. Complete information was obtained from 605 subjects, of whom 248 (41%) reported a history of fever, 139 (23%) were HIV positive, and 131 (22%) received an antimalarial drug. Only 15% of fever reporters were parasitemic. HIV infection was significantly associated with fever, but not with parasitemia. Fever reporters and non-fever reporters were of mean ages 32.8 and 33.1 years, respectively. These data suggest that there was both high HIV seroprevalence and considerable overestimation of fever as malaria in this population. This high prevalence of HIV demands the reconsideration of the common practice in Malawi of treating all fever among adults as malaria.
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PMID:Malaria and human immunodeficiency virus infection among male employees of a sugar estate in Malawi. 946 69

The malaria parasite Plasmodium falciparum faces drastic osmotic changes during kidney passages and is engaged in the massive biosynthesis of glycerolipids during its development in the blood-stage. We identified a single aquaglyceroporin (PfAQP) in the nearly finished genome of P. falciparum with highest similarity to the Escherichia coli glycerol facilitator (50.4%), but both canonical Asn-Pro-Ala (NPA) motifs in the pore region are changed to Asn-Leu-Ala (NLA) and Asn-Pro-Ser (NPS), respectively. Expression in Xenopus oocytes renders them highly permeable for both water and glycerol. Sugar alcohols up to five carbons and urea pass the pore. Mutation analyses of the NLA/NPS motifs showed their structural importance, but the symmetrical pore properties were maintained. PfAQP is expressed in blood-stage parasites throughout the development from rings via trophozoites to schizonts and is localized to the parasite but not to the erythrocyte cytoplasm or membrane. Its unique bi-functionality indicates functions in the protection from osmotic stress and efficiently provides access to the serum glycerol pool for the use in ATP generation and primarily in the phospholipid synthesis.
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PMID:A single, bi-functional aquaglyceroporin in blood-stage Plasmodium falciparum malaria parasites. 1172 4

The influence of indoor microclimate on survival of female Anopheles gambiae sensu stricto Giles (Diptera: culicidae) mosquitoes fed on different nutrition sources was evaluated in a semifield experimental hut exposed to ambient climate in western Kenya. Cages of mosquitoes (n approximately 50 per cage) were placed in nine positions within the hut combining three different sides and three different heights. At each height and side, mosquitoes were offered either human blood (once every 2 d), glucose (6% wt:vol) or a combination of the two diets over three experiments so that each cage position received one diet source. The effect of diet on survival was significant with mean survival times of 14 d for mosquitoes fed blood alone, 29 d for sugar alone and 33 d for blood plus sugar. Sugar availability decreased the odds of mortality approximately 85% compared with the blood group. Micro heterogeneities of temperature but not relative humidity also influenced survival although to a much lesser extent. The side but not height within the hut at which mosquitoes were placed, influenced survival but could not be explained by either temperature or relative humidity differences. The potential influence of seemingly minor heterogeneities of indoor microclimate upon vector longevity and vectorial capacity may merit further investigation. Also, the availability of sugar was shown to be a potentially crucial determinant of vectorial capacity. Compared with blood alone, the availability of sugar served to increase survival potential of vectors beyond ages at which they are old enough to transmit malaria.
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PMID:Influence of sugar availability and indoor microclimate on survival of Anopheles gambiae (Diptera: Culicidae) under semifield conditions in western Kenya. 1459 79

Anopheles (Nyssorhynchus) darlingi is an important malaria vector in South and Central America; however, little is known about molecular aspects of its biology. Genomic and proteomic analyses were performed on the salivary gland products of Anopheles darlingi. A total of 593 randomly selected, salivary gland-derived cDNAs were sequenced and assembled based on their similarities into 288 clusters. The putative translated proteins were classified into three categories: (S) secretory products, (H) housekeeping products and (U) products with unknown cell location and function. Ninety-three clusters encode putative secreted proteins and several of them, such as an anophelin, a thrombin inhibitor, apyrases and several new members of the D7 protein family, were identified as molecules involved in haematophagy. Sugar-feeding related enzymes (alpha-glucosidases and alpha-amylase) also were found among the secreted salivary products. Ninety-nine clusters encode housekeeping proteins associated with energy metabolism, protein synthesis, signal transduction and other cellular functions. Ninety-seven clusters encode proteins with no similarity with known proteins. Comparison of the sequence divergence of the S and H categories of proteins of An. darlingi and An. gambiae revealed that the salivary proteins are less conserved than the housekeeping proteins, and therefore are changing at a faster evolutionary rate. Tabular and supplementary material containing the cDNA sequences and annotations are available at http://www.ncbi.nlm.nih.gov/projects/Mosquito/A_darlingi_sialome/
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PMID:The transcriptome of adult female Anopheles darlingi salivary glands. 1472 69

Infection of human erythrocytes with the malaria parasite Plasmodium falciparum induces new permeability pathways (NPPs) in the host cell membrane. Isotopic flux measurements demonstrated that the NPP are permeable to a wide variety of molecules, thus allowing uptake of nutrients and release of waste products. Recent patch-clamp recordings demonstrated the infection-induced up-regulation of an inwardly and an outwardly rectifying Cl(-) conductance. The present experiments have been performed to explore the sensitivity to cell volume and the organic osmolyte permeability of the two conductances. It is shown that the outward rectifier has a high relative lactate permeability (P(lactate)/P(Cl) = 0.4). Sucrose inhibited the outward-rectifier and abolished the infection-induced hemolysis in isosmotic sorbitol solution but had no or little effect on the inward-rectifier. Furosemide and NPPB blocked the outward-rectifying lactate current and the sorbitol hemolysis with IC(50)s in the range of 0.1 and 1 microM, respectively. In contrast, the IC(50)s of NPPB and furosemide for the inward-rectifying current were >10 microM. Osmotic cell-shrinkage inhibited the inwardly but not the outwardly rectifying conductance. In conclusion, the parasite-induced outwardly-rectifying anion conductance allows permeation of lactate and neutral carbohydrates, whereas the inward rectifier seems largely impermeable to organic solutes. All together, these data should help to resolve ongoing controversy regarding the number of unique channels that exist in P. falciparum-infected erythrocytes.
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PMID:Organic osmolyte permeabilities of the malaria-induced anion conductances in human erythrocytes. 1505 7

Anthropogenic land use changes often alter natural patterns of disease transmission. The goal of this study was to determine whether phosphorus input from sugarcane, Saccharum officinarum L., cultivation in northern Belize could pose a significant environmental impact on malaria transmission by changing vegetation structure and composition of wetlands and associated larval habitats. Our primary focus was on the increased dominance of cattail, Typha domingensis Pers., a favored habitat for Anopheles vestitipennis Dyar & Knab. A land cover classification based on satellite imagery was used to select 20 marshes impacted by agricultural runoff and 20 marshes surrounded by forest (nonimpacted). A 100-m transect was established into each of the 40 marshes. Water, vegetation, and larval sampling were conducted at the 0-, 10-, 25-, 50-, and 100-m locations along the transect. Analyses of larval density data indicated that Anopheles albimanus Wiedemann was negatively correlated with percentage of cover of Typha (R2 = 0.39, P < 0.001) but positively correlated with sparse Eleocharis cellulosa Torr. (rush) cover (R2 = 0.19, P < 0.05) and presence of cyanobacterial mats (CBM) (R2 = 0.33, P < 0.0001). An. vestitipennis was found to be positively correlated with percentage of cover of Typha (R2 = 0.19, P < 0.001). Canonical correspondence analysis identified CBM and light as the variables associated with the presence of An. albimanuts larvae, Typha cover with An. vestitipennis larvae, and Eleocharis and absence of light with Anopheles crucians (Wiedemann). A positive correlation also existed between marshes adjacent to agricultural activities and presence of An. vestitipennis (R2 = 0.37, P < 0.05). These results indicate that marshes in proximity to agricultural fields are conducive for Typha growth, thereby providing habitat for the more efficient malaria vector
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PMID:Distribution of Anopheles albimanus, Anopheles vestitipennis, and Anopheles crucians associated with land use in northern Belize. 1673 24

An improved knowledge of mosquito life history could strengthen malaria vector control efforts that primarily focus on killing mosquitoes indoors using insecticide treated nets and indoor residual spraying. Natural sugar sources, usually floral nectars of plants, are a primary energy resource for adult mosquitoes but their role in regulating the dynamics of mosquito populations is unclear. To determine how the sugar availability impacts Anopheles sergentii populations, mark-release-recapture studies were conducted in two oases in Israel with either absence or presence of the local primary sugar source, flowering Acacia raddiana trees. Compared with population estimates from the sugar-rich oasis, An. sergentii in the sugar-poor oasis showed smaller population size (37,494 vs. 85,595), lower survival rates (0.72 vs. 0.93), and prolonged gonotrophic cycles (3.33 vs. 2.36 days). The estimated number of females older than the extrinsic incubation period of malaria (10 days) in the sugar rich site was 4 times greater than in the sugar poor site. Sugar feeding detected in mosquito guts in the sugar-rich site was significantly higher (73%) than in the sugar-poor site (48%). In contrast, plant tissue feeding (poor quality sugar source) in the sugar-rich habitat was much less (0.3%) than in the sugar-poor site (30%). More important, the estimated vectorial capacity, a standard measure of malaria transmission potential, was more than 250-fold higher in the sugar-rich oasis than that in the sugar-poor site. Our results convincingly show that the availability of sugar sources in the local environment is a major determinant regulating the dynamics of mosquito populations and their vector potential, suggesting that control interventions targeting sugar-feeding mosquitoes pose a promising tactic for combating transmission of malaria parasites and other pathogens.
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PMID:Natural plant sugar sources of Anopheles mosquitoes strongly impact malaria transmission potential. 2128 32

Dynamics of Anopheles gambiae abundance and malaria transmission potential rely strongly on environmental conditions. Female and male An. gambiae use sugar and are affected by its absence, but how the presence or absence of nectariferous plants affects An. gambiae abundance and vectorial capacity has not been studied. We report on four replicates of a cohort study performed in mesocosms with sugar-poor and sugar-rich plants, in which we measured mosquito survival, biting rates, and fecundity. Survivorship was greater with access to sugar-rich plant species, and mortality patterns were age-dependent. Sugar-poor populations experienced Weibull mortality patterns, and of four populations in the sugar-rich environment, two female and three male subpopulations were better fitted by Gompertz functions. A tendency toward higher biting rates in sugar-poor mesocosms, particularly for young females, was found. Therefore, vectorial capacity was pulled in opposing directions by nectar availability, resulting in highly variable vectorial capacity values.
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PMID:Effects of plant-community composition on the vectorial capacity and fitness of the malaria mosquito Anopheles gambiae. 2292 93


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