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

When travellers return from malaria-endemic areas and present to hospital with fever, microscopy of blood smears remains the leading method to verify a suspected diagnosis of malaria. Additional laboratory abnormalities may, however, also be indicative of acute malaria infection. We monitored prospectively a group of patients with imported Plasmodium falciparum (n=28) or P. vivax/P. ovale (n=12) infection, respectively, and assessed haemoglobin, leucocytes, thrombocytes, C-reactive protein, coagulation factor II-VII-X, lactate dehydrogenase and bilirubin during 7 d of admission and weekly until d 28. For comparison, admission values of a group of febrile patients with suspected malaria, but with negative blood slides, were also assessed (n=66). The thrombocyte, leucocyte counts and coagulation factor II-VII-X were significantly lower in the malaria group compared to the non-malaria group, whereas the C-reactive protein, lactate dehydrogenase and bilirubin were significantly higher in the malaria group. The differences were particularly strong with falciparum malaria. By contrast, haemoglobin levels were not affected. In conclusion, our study emphasizes the role of a few commonly analysed laboratory parameters, in particular thrombocyte counts, in guiding the clinician managing a returning traveller with fever.
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PMID:Laboratory indicators of the diagnosis and course of imported malaria. 1836 21

A study to assess the diagnostic capabilities of three parasite lactate dehydrogenase (pan-pLDH) tests, Vistapan), Carestart and Parabank), was conducted in Uganda. An HRP2 test, Paracheck-Pf), and a Giemsa-stained blood film were performed with the pLDH tests for outpatients with suspected malaria. In total, 460 subjects were recruited: 248 with positive blood films and 212 with negative blood films. Plasmodium falciparum was present in 95% of infections. Sensitivity above 90% was shown by two pLDH tests, Carestart (95.6%) and Vistapan (91.9%), and specificity above 90% by Parabank (94.3%) and Carestart (91.5%). Sensitivity decreased with low parasitaemia (chi(2) trend, P<0.001); however, all tests achieved sensitivity >90% with parasitaemia > or =100/microl. All tests had good inter-reader reliability (kappa>0.95). Two weeks after diagnosis, 4-10% of pLDH tests were still positive compared with 69.7% of the HRP2 tests. All tests had similar ease of use. In conclusion, two pLDH tests performed well in diagnosing P. falciparum malaria, and all pLDH tests became negative after treatment more quickly than the HRP2. Therefore the rapid test of choice for use with artemisinin-combination therapies in this area would be one of these new pLDH tests.
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PMID:Assessment of three new parasite lactate dehydrogenase (pan-pLDH) tests for diagnosis of uncomplicated malaria. 1803 79

An easy and reliable diagnostic method for malaria is highly desirable. We examined the recently introduced SD Bioline Malaria Antigen test, which detects Plasmodium lactate dehydrogenase, with the additional aid of the presence or absence of thrombocytopenia to diagnose vivax malaria. We enrolled 732 patients with clinically suspected malaria in an area where vivax malaria is endemic. We performed microscopic examination of thin film, applied the SD Bioline Malaria Antigen test, and checked platelet counts. One hundred ninety-five patients were smear positive for vivax malaria. The sensitivity of the SD Bioline Malaria Antigen test was 96.4%, and its specificity was 98.9%. We found that 95.4% of malaria patients had thrombocytopenia, and the proportion with malaria increased as platelet counts decreased. A positive SD Bioline Malaria Antigen test when thrombocytopenia was present showed a 100% positive predictive value for vivax malaria. In conclusion, the SD Bioline Malaria Antigen test is a rapid and accurate diagnostic method for vivax malaria, and a platelet count can facilitate a rapid diagnosis of malaria.
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PMID:Rapid diagnosis of vivax malaria by the SD Bioline Malaria Antigen test when thrombocytopenia is present. 1816 Apr 49

Congenital malaria, defined as the presence of malaria parasites in the erythrocytes of newborns aged <7 days, was considered rare in endemic areas until recent studies started reporting high prevalence rates. Various theories have been postulated to explain this phenomenon, but they are not proven conclusively from research. Against this background, a prospective study was designed with the following objectives. To determine the prevalence of congenital malaria parasitaemia and identify possible risk factors amongst newborns delivered in O.O.U.T.H Sagamu, Ogun State. Over a 6-month period, 192 live newborns and their mothers were consecutively recruited into the study. Within 3 days of life, neonatal peripheral blood samples were collected for malaria screening by blood film microscopy and detection of plasmodium lactate dehydrogenase (pLDH) with the OptiMAL Rapid Malaria Test kit. Maternal peripheral blood samples were taken simultaneously, to check for malaria infestation by blood film microscopy, and questionnaires were administered on the mothers to identify possible factors associated with the development of neonatal parasitaemia. Neonatal clinical and laboratory data were recorded in a pro forma designed for the study. Data analysis was done with Epi-info version 6 software and level of significance set at <5%. Twenty-one of 192 newborns delivered in O.O.U.T.H within the study period were diagnosed as having congenital malaria by blood film microscopy, giving a prevalence rate of 10.9%. The main identified innate neonatal risk factor for congenital malaria parasitaemia was prematurity. First-order pregnancy, history of fever within 3 months of delivery and peripheral parasitaemia at delivery (p < 0.001) were the variables that were significantly higher in the mothers of the parasitemic newborns. We conclude that congenital malaria parasitaemia in tropical endemic areas is not rare. Pre-term neonates, infants of primigravidae, women with history of fever within 3 months of delivery and women with post-partum peripheral parasitaemia may benefit from routine screening for malaria.
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PMID:Possible risk factors for congenital malaria at a tertiary care hospital in Sagamu, Ogun State, South-West Nigeria. 1837 70

Several rapid diagnostic test devices (RDT) based on detection of malaria antigen in the whole blood were developed. OptiMal test the presence of parasite-specific lactate dehydrogenase (LDH) enzyme using three monoclonal antibodies was used. Two monoclonal antibodies were pan-specific and recognized all malaria species. The third one was specific only for Plasmodium falciparum. The parasite antigens were detected using an antigen-capture immunochromatographic strip format. One hundred-nine malaria positive and 730 malaria negative cases diagnosed by microscopy were included. 75/109 were P. falciparum 26 as P. vivax, 3 P. malariae and 5 mixed infection of P. falciparum & P. vivax. The RDT showed a low sensitivity (85%, 95% Confidence Interval [CI], 79-92%) with a much lower sensitivity in detecting species other than P. falciparum as well as in mixed infections. The sensitivity was 50% for less than 200 parasites/micro. The sensitivity of OptiMal for P. falciparum was 87% (95% CI, 79-94), 81% (95% CI, 66-96) for P. vivax, and failed with P. malariae. Mixed infections were misdiagnosed as Pfalciparum. The sensitivity of OptiMal was quite good in detecting both P. falciparum & P. vivax (98%; 95% CI, 97-99 & 100%; 95% CI, 100-100 respectively) and 99% (95% CI, 98-99) for all species. The positive and negative ratio for all malaria species was: (+LR = 62.3, -LR = 0.01); for P. falciparum (+LR = 38.9, -LR = 0.01) and for P. vivax (+LR = 0.8077/0, -LR = 0.2). The test value to assess drug resistance in post treatment days was discussed.
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PMID:Antigen capture immuno-chromatographic strip format in detecting parasite-specific lactate dehydrogenase to diagnose malaria in nonimmune patients. 1838 1

Plasmodium falciparum resistance to the former first-line antimalarials chloroquine and sulfadoxine/pyrimethamine has reached critically high levels in many malaria-endemic regions. This has spurred the introduction of several new artemisinin-based combination therapies (ACTs) that display excellent potency in treating drug-resistant malaria. Monitoring for the emergence of drug resistant P. falciparum is important for maximising the clinically effective lifespan of ACTs. Here, we provide a commentary on the article by Kaddouri et al., published in this issue of the International Journal of Parasitology, which documents the levels of susceptibility to ACT drugs and chloroquine in P. falciparum isolates from Mali. These authors report that some isolates approached a proposed in vitro threshold of resistance to monodesethyl-amodiaquine (the principal effective metabolite of amodiaquine, an important ACT partner drug), and establish baseline levels of susceptibility to the ACT drugs dihydroartemisinin and lumefantrine. The majority of clinical isolates manifested in vitro resistance to chloroquine. The authors also show good concordance between field-based assays employing a non-radioactive lactate dehydrogenase-based method of determining in vitro drug IC(50) values and the well-established [(3)H]hypoxanthine-based radioactive method. This work illustrates a good example of drug resistance surveillance, whose global coordination is being championed by the World Antimalarial Resistance Network. Our current opinion also more generally discusses the complexities inherent to conducting in vitro investigations with P. falciparum patient isolates and correlating these findings with treatment outcome data.
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PMID:In vitro evaluations of antimalarial drugs and their relevance to clinical outcomes. 1824 7

Immunogenicity testing of Plasmodium falciparum antigens being considered as malaria vaccine candidates was undertaken in rabbits. The antigens compared were recombinant baculovirus MSP-1(19) and five Pichia pastoris candidates, including two versions of MSP-1(19), AMA-1 (domains I and II), AMA-1+MSP-1(19), and fused AMA-1/MSP-1(19)). Animals were immunized with equimolar amounts of each antigen, formulated in Montanide ISA720. The specificities and titers of antibodies were compared using immunofluorescence assays and enzyme-linked immunosorbent assay (ELISA). The antiparasite activity of immunoglobulin G (IgG) in in vitro cultures was determined by growth inhibition assay, flow cytometry, lactate dehydrogenase assay, and microscopy. Baculovirus MSP-1(19) immunizations produced the highest parasite-specific antibody titers in immunofluorescence assays. In ELISAs, baculovirus-produced MSP-1(19) induced more antibodies than any other single MSP-1(19) immunogen and three times more MSP-1(19) specific antibodies than the AMA-1/MSP-1(19) fusion. Antibodies induced by baculovirus MSP-1(19) gave the highest levels of growth inhibition in HB3 and 3D7 parasite cultures, followed by AMA-1+MSP-1(19) and the AMA-1/MSP-1(19) fusion. With the FCR3 isolate (homologous to the AMA-1 construct), antibodies to the three AMA-1-containing candidates gave the highest levels of growth inhibition at high IgG concentrations, but antibodies to baculovirus MSP-1(19) inhibited as well or better at lower IgG concentrations. The two P. pastoris-produced MSP-1(19)-induced IgGs conferred the lowest growth inhibition. Comparative analysis of immunogenicity of vaccine antigens can be used to prioritize candidates before moving to expensive GMP production and clinical testing. The assays used have given discriminating readouts but it is not known whether any of them accurately reflect clinical protection.
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PMID:Comparative testing of six antigen-based malaria vaccine candidates directed toward merozoite-stage Plasmodium falciparum. 1855 Jul 31

No studies have been performed on the mitochondria of malaria vector mosquitoes. This information would be valuable in understanding mosquito aging and detoxification of insecticides, two parameters that have a significant impact on malaria parasite transmission in endemic regions. In the present study, we report the analyses of respiration and oxidative phosphorylation in mitochondria of cultured cells [ASE (Anopheles stephensi Mos. 43) cell line] from A. stephensi, a major vector of malaria in India, South-East Asia and parts of the Middle East. ASE cell mitochondria share many features in common with mammalian muscle mitochondria, despite the fact that these cells are of larval origin. However, two major differences with mammalian mitochondria were apparent. One, the glycerol-phosphate shuttle plays as major a role in NADH oxidation in ASE cell mitochondria as it does in insect muscle mitochondria. In contrast, mammalian white muscle mitochondria depend primarily on lactate dehydrogenase, whereas red muscle mitochondria depend on the malate-oxaloacetate shuttle. Two, ASE mitochondria were able to oxidize proline at a rate comparable with that of alpha-glycerophosphate. However, the proline pathway appeared to differ from the currently accepted pathway, in that oxoglutarate could be catabolized completely by the tricarboxylic acid cycle or via transamination, depending on the ATP need.
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PMID:Metabolic pathways in Anopheles stephensi mitochondria. 1858 3

This study compared conventional PCR with microscopy and 2 rapid detection methods, the pLDH which detected lactic dehydrogenase enzyme produced by actively metabolizing organisms and the malaria antibody tests. The sensitivity of PCR was 1 parasite/microl, i.e.: 50 times more sensitive than microscopy. When PCR was compared with microscopy, the sensitivity and specificity were 90% & 100% respectively. The sensitivity recorded was pLDH test in comparison to PCR (95%). The malaria antibody test recorded the least sensitivity (68%) PCR proved as the gold standard for evaluation of applied tests and the newly introduced ones. In absence of an expert microscopist, the pLDH test could substitute for microscopy. The test proved valuable to assess clinical cure, and predict drug resistance. Its advantage over microscopy was the ability to diagnose infection with low parasitemic patients. Antibody rapid tests might be not valuable in acute cases, but still accepted as a tool in epidemiological studies and in screening patients in blood banks in malaria endemic areas.
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PMID:Comparison of two commercial assays and microscopy with PCR for diagnosis of malaria. 1885 8

Fevers of unknown origin (FUOs) are defined as prolonged fevers of 101 degrees F or greater lasting 3 or more weeks that remain undiagnosed after comprehensive inpatient/outpatient laboratory testing. Tick-borne infections are uncommon causes of FUOs. Any infectious disease accompanied by prolonged fevers can present as an FUO if the diagnosis is not suspected or if specific laboratory testing is not done to confirm the diagnosis. Babesiosis is transmitted by the Ixodes scapularis ticks endemic to areas in the northeastern United States. We present the case of a 73-year-old, non-human immunodeficiency virus, male from Long Island who presented with FUO for 6 weeks. As with malaria, there are usually few or no localizing signs in babesiosis. During the patient's hospitalization, babesiosis was suspected on the basis of nonspecific laboratory findings, that is, relative lymphopenia, thrombocytopenia, thrombocytopenia, and an elevated lactate dehydrogenase. When babesiosis was considered in the differential diagnosis, stained blood smears demonstrated the red blood cell inclusions of babesiosis. In the hospital, the patient developed noncardiac pulmonary edema, which rapidly resolved which has been described as a rare complication of babesiosis. He also had an elevated immunoglobulin-M Lyme titer indicating coinfection with Lyme disease. Although his hemolytic anemia persisted for weeks, he only had 3% parasitemia and intact splenic function. We believe this to be the first case of babesiosis presenting as an FUO in a normal host.
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PMID:Fever of unknown origin (FUO) due to babesiosis in a immunocompetent host. 1899 33


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