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

Bacterial infections were investigated in midguts of insectary and field-collected Anopheles albimanus Weidemann from southern Mexico. Serratia marcescens, Enterobacter cloacae and Enterobacter amnigenus 2, Enterobacter sp., and Serratia sp. were isolated in field samples obtained in 1998, but only Enterobacter sp. was recovered in field samples of 1997 and no bacteria were isolated from insectary specimens. These bacteria were offered along with Plasmodium vivax infected blood to aseptic insectary An. albimanus, and the number of infected mosquitoes as well as the oocyst densities assessed after 7d. Plasmodium vivax infections in mosquitoes co-infected with En. amnigenus 2, En. cloacae, and S. marcensces were 53, 17, and 210 times, respectively, lower than in control mosquitoes, and the mean oocyst density in mosquitoes co-infected with En. cloacae was 2.5 times lower than in controls. Mortality was 13 times higher in S. marcensces-infected mosquitoes compared with controls. The overall midgut bacterial infection in mosquito field populations may influence P. vivax transmission, and could contribute to explain the annual variations in malaria incidence observed in the area.
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PMID:Bacteria in midguts of field-collected Anopheles albimanus block Plasmodium vivax sporogonic development. 1294 19

Brucellosis is a world-wide re-emerging zoonosis and the most frequent laboratory-acquired bacterial infection, causing severe disease in humans with unspecific clinical signs affecting numerous organs. Contact with infected animals, ingestion of contaminated animal products and handling of Brucella isolates in laboratories are risk factors. Various other febrile illnesses, e.g. malaria, tuberculosis, typhoid fever and tularemia may present with the same symptoms. Therefore, clinical diagnosis is difficult to establish but effective therapy requires an early diagnosis. Vaccines for humans are still not commercially available. Blood culturing of Brucella is time-consuming and not reliable. Thus diagnosis is usually based on indirect serological tests, i.e. serum agglutination test, complement fixation or the Coombs test. However, these 'conventional' serological tests lack sensitivity and specificity. Hence, a combination of various tests is mandatory for a definite diagnosis. Enzyme-linked immunosorbent assays can be used for screening and confirmation of brucellosis in one step. Molecular techniques like the polymerase chain reaction and restriction fragment length polymorphism are needed to differentiate species and strains within the genus Brucella. This review will summarize advantages and disadvantages of the techniques used in clinical laboratories for direct detection and identification of Brucella spp.
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PMID:Laboratory-based diagnosis of brucellosis--a review of the literature. Part I: Techniques for direct detection and identification of Brucella spp. 1457 5

BACKGROUND: As well as being inducible by haem, haemoxygenase -1 (HO-1) is also induced by interleukin-10 and an anti-inflammatory prostaglandin, 15d PGJ2, the carbon monoxide thus produced mediating the anti-inflammatory effects of these molecules. The cellular distribution of HO-1, by immunohistochemistry, in brain, lung and liver in fatal falciparum malaria, and in sepsis, is reported. METHODS: Wax sections were stained, at a 1:1000 dilution of primary antibody, for HO-1 in tissues collected during paediatric autopsies in Blantyre, Malawi. These comprised 37 acutely ill comatose patients, 32 of whom were diagnosed clinically as cerebral malaria and the other 5 as bacterial diseases with coma. Another 3 died unexpectedly from an alert state. Other control tissues were from Australian adults. RESULTS: Apart from its presence in splenic red pulp macrophages and microhaemorrhages, staining for HO-1 was confined to intravascular monocytes and certain tissue macrophages. Of the 32 clinically diagnosed cerebral malaria cases, 11 (category A) cases had negligible histological change in the brain and absence of or scanty intravascular sequestration of parasitized erythrocytes. Of these 11 cases, eight proved at autopsy to have other pathological changes as well, and none of these eight showed HO-1 staining within the brain apart from isolated moderate staining in one case. Two of the three without another pathological diagnosis showed moderate staining of scattered monocytes in brain vessels. Six of these 11 (category A) cases exhibited strong lung staining, and the Kupffer cells of nine of them were intensely stained. Of the seven (category B) cases with no histological changes in the brain, but appreciable sequestered parasitised erythrocytes present, one was without staining, and the other six showed strongly staining, rare or scattered monocytes in cerebral vessels. All six lung sections not obscured by neutrophils showed strong staining of monocytes and alveolar macrophages, and all six available liver sections showed moderate or strong staining of Kupffer cells. Of the 14 (category C) cases, in which brains showed micro-haemorrhages and intravascular mononuclear cell accumulations, plus sequestered parasitised erythrocytes, all exhibited strong monocyte HO-1 staining in cells forming accumulations and scattered singly within cerebral blood vessels. Eleven of the available and readable 13 lung sections showed strongly staining monocytes and alveolar macrophages, and one stained moderately. All of the 14 livers had strongly stained Kupffer cells. Of five cases of comatose culture-defined bacterial infection, three showed a scattering of stained monocytes in vessels within the brain parenchyma, three had stained cells in lung sections, and all five demonstrated moderately or strongly staining Kupffer cells. Brain sections from all three African controls, lung sections from two of them, and liver from one, showed no staining for HO-1, and other control lung and liver sections showed few, palely stained cells only. Australian-origin adult brains exhibited no staining, whether the patients had died from coronary artery disease or from non-infectious, non-cerebral conditions CONCLUSIONS: Clinically diagnosed 'cerebral malaria' in children includes some cases in whom malaria is not the only diagnosis with the hindsight afforded by autopsy. In these patients there is widespread systemic inflammation, judged by HO-1 induction, at the time of death, but minimal intracerebral inflammation. In other cases with no pathological diagnosis except malaria, there is evidence of widespread inflammatory responses both in the brain and in other major organs. The relative contributions of intracerebral and systemic host inflammatory responses in the pathogenesis of coma and death in malaria deserve further investigation.
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PMID:Induction of HO-1 in tissue macrophages and monocytes in fatal falciparum malaria and sepsis. 1462 2

Since the first description of infection-associated hemophagocytosis (IAHS), the list of precipitating infectious agents causing hemophagocytic syndrome has grown. A lymphohistiocytic proliferation with hemophagocytosis may develop as a result of macrophage activation, viral or bacterial infection, parasitic infestations, or malignancy. The authors report on a 3-year-old boy with Langerhans cell histiocytosis (LCH), who developed IAHS during malaria infection. Hemophagocytic syndromes may complicate the course of LCH and cause diagnostics problems. Malaria is one of many infections that can precipitate secondary hemophagocytic lymphohistiocytosis.
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PMID:Secondary hemophagocytic lymphohistiocytosis induced by malaria infection in a child with Langerhans cell histiocytosis. 1520 66

Different studies have illustrated the activation of the innate immune system during infection with protozoan parasites. Experiments performed in vivo also support the notion that innate immunity has a crucial role in resistance as well as pathogenesis observed during protozoan infections such as malaria, leishmaniasis, toxoplasmosis, and trypanosomiasis. While major advances have been made in the assignment of bacterial molecules as Toll-like receptors (TLRs) agonists as well as defining the role of the Toll/interleukin-1 receptor (TIR) signaling pathway in host resistance to bacterial infection, this research area is now emerging in the field of protozoan parasites. In this review, we discuss the recent studies describing parasite molecules as TLR agonists and those studies indicating the essential role of the TIR-domain bearing molecule named myeloid differentiation factor 88 in host resistance to infection with protozoan parasites. Together, these studies support the hypothesis that the TIR signaling pathway is involved in the initial recognition of protozoan parasites by the immune system of the vertebrate host, early resistance to infection, development of acquired immunity, as well as pathology observed during acute infection with this class of pathogens.
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PMID:Role of the Toll/interleukin-1 receptor signaling pathway in host resistance and pathogenesis during infection with protozoan parasites. 1536 Dec 29

In the tropics, febrile illnesses are often presumed to be due to malaria, because of its endemicity, and treatment can lead to delay in diagnosis or failure to detect severe infections such as bacteraemia. This study sought to determine the prevalence of bacteraemia and malaria parasitaemia in febrile post-neonatal infants (age 1-12 months) at the University College Hospital, Ibadan, Nigeria, and the bacterial aetiological agents of bacteraemia in the infants. Therefore, 102 infants aged 1-12 months who presented with fever with a negative history of antimicrobial use in the week prior to presentation were evaluated and had blood cultures done for the detection of aerobic organisms by standard methods and blood films for malaria parasites. Bacteraemia was found in 38.2% of the infants, malaria parasitaemia was found in 46.1%. The most common organisms isolated were Escherichia coli (35.9%), Staphylococcus aureus (33.3%) and Klebsiella spp. (10.3%). Febrile children should be investigated for the presence of bacterial infection even if the blood film for malaria parasites is positive. Where laboratory facilities are not available, consideration should be given to the use of both anti-malarial therapy and empiric antibiotic therapy in the management of febrile infants, depending on the clinician's judgement.
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PMID:Concurrent bacteraemia and malaria in febrile Nigerian infants. 1571 44

The prevalence of malaria parasitemia, bacteremia, certain hematological parameters, leucocyte migration index and nitroblue tetrazolium dye reduction were determined in 147 Nigerian children (4.24+/-2.88 years of age). Sixty (40.8%), 28(19.1%) and 26(17.7%) had malaria parasitemia only, bacteremia only and both malaria parasitemia and bacteremia, respectively. Four genera of bacteria, i.e E. coli, Proteus, Staphylococcus and Salmonella, were detected in subjects with both malaria parasitemia and bacteremia. The 4 bacterial genera and Klebsiella were detected in subjects with bacterial infection only. P. falciparum (68%), P. malariae (25%) and P. ovale (7%) were the species of malaria parasites identified in our subjects. Bacteremia was most prevalent in subjects with hemoglobin AA (HbAA) (60.7%) followed by HbAC (21.45%). Packed cell volume (PCV) and Hb concentration were similar in all groups but mean counts of red blood cells (RBC) and white blood cells (WBC) were statistically significantly lower in subjects with malaria parasites only compared to the controls. Leucocyte migration was significantly reduced in children with bacteremia only or both malaria parasitemia and bacteremia compared to controls, while the nitroblue tetrazolium assay was significantly reduced in children with bacteremia only. It may be concluded that malaria parasitemia significantly affects both leucocyte migration and nitroblue tetrazolium assay.
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PMID:Leucocyte migration and nitroblue tetrazolium assay in Nigerian children with bacteremia and malaria parasitemia. 1578 34

Transmission of malaria is dependent on the successful completion of the Plasmodium lifecycle in the Anopheles vector. Major obstacles are encountered in the midgut tissue, where most parasites are killed by the mosquito's immune system. In the present study, DNA microarray analyses have been used to compare Anopheles gambiae responses to invasion of the midgut epithelium by the ookinete stage of the human pathogen Plasmodium falciparum and the rodent experimental model pathogen P. berghei. Invasion by P. berghei had a more profound impact on the mosquito transcriptome, including a variety of functional gene classes, while P. falciparum elicited a broader immune response at the gene transcript level. Ingestion of human malaria-infected blood lacking invasive ookinetes also induced a variety of immune genes, including several anti-Plasmodium factors. Twelve selected genes were assessed for effect on infection with both parasite species and bacteria using RNAi gene silencing assays, and seven of these genes were found to influence mosquito resistance to both parasite species. An MD2-like receptor, AgMDL1, and an immunolectin, FBN39, showed specificity in regulating only resistance to P. falciparum, while the antimicrobial peptide gambicin and a novel putative short secreted peptide, IRSP5, were more specific for defense against the rodent parasite P. berghei. While all the genes that affected Plasmodium development also influenced mosquito resistance to bacterial infection, four of the antimicrobial genes had no effect on Plasmodium development. Our study shows that the impact of P. falciparum and P. berghei infection on A. gambiae biology at the gene transcript level is quite diverse, and the defense against the two Plasmodium species is mediated by antimicrobial factors with both universal and Plasmodium-species specific activities. Furthermore, our data indicate that the mosquito is capable of sensing infected blood constituents in the absence of invading ookinetes, thereby inducing anti-Plasmodium immune responses.
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PMID:Anopheles gambiae immune responses to human and rodent Plasmodium parasite species. 1678 37

The conventional 8-day Integrated Management of Neonatal and Childhood Illness (IMNCI) training package poses several operational constraints, particularly due to its long duration. A 5-day training package was developed and administered in an interrupted mode of 3 days and 2 days duration with a break of 4 days in-between, in a district of Haryana state in northern India. Improvement in the knowledge and skills of 50 primary health care workers following the interrupted 5-day training was compared with that of 35 primary health care workers after the conventional 8-day IMNCI training package. The average score increased significantly (P < 0.05) from 46.3 to 74.6 in 8-day training and from 40.0 to 73.2 in 5-day training. Knowledge score improved for all health conditions, like anaemia, diarrhoea, immunization, malnutrition, malaria, meningitis and possible severe bacterial infection, and for breastfeeding in 8-day as well as in 5-day training. Average skills score for respiratory problems increased from 38 to 57 in 8-day training and from 41 to 91 in 5-day training. Corresponding increases in skill scores for diarrhoea assessment were from 28 to 67 and 48 to 75, and for breastfeeding assessment from 33 to 84 and 42 to 86 in 8-day and 5-day training, respectively. Average counselling skill score also rose from 42 to 89 in 8-day and from 37 to 70 in 5-day training. A direct cost saving of US$813 for a batch of 25 trainees and an indirect cost saving of 3 days per trainee and resource person makes the interrupted 5-day IMNCI training more cost-effective.
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PMID:The effect of interrupted 5-day training on Integrated Management of Neonatal and Childhood Illness on the knowledge and skills of primary health care workers. 1918 73

Infection may cause stillbirth by several mechanisms, including direct infection, placental damage, and severe maternal illness. Various organisms have been associated with stillbirth, including many bacteria, viruses, and protozoa. In developed countries, between 10% and 25% of stillbirths may be caused by an infection, whereas in developing countries, which have much higher stillbirth rates, the contribution of infection is much greater. In developed countries, ascending bacterial infection, both before and after membrane rupture, with organisms such as Escherichia coli, group B streptococci, and Ureaplasma urealyticum is usually the most common infectious cause of stillbirth. However, in areas where syphilis is prevalent, up to half of all stillbirths may be caused by this infection alone. Malaria may be an important cause of stillbirth in women infected for the first time in pregnancy. The two most important viral causes of stillbirth are parvovirus and Coxsackie virus, although a number of other viral infections appear to be causal. Toxoplasma gondii, Listeria monocytogenes, and the organisms that cause leptospirosis, Q fever, and Lyme disease have all been implicated as etiologic for stillbirth. In certain developing countries, the stillbirth rate is high and the infection-related component so great that achieving a substantial reduction in stillbirth should be possible by reducing maternal infections. However, because infection-related stillbirth is uncommon in developed countries, and because those that do occur are caused by a wide variety of organisms, reducing this etiologic component of stillbirth much further will be difficult.
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PMID:Infection and stillbirth. 1928 57


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