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Malaria-associated L-arginine deficiency induces mast cell-associated disruption to intestinal barrier defenses against nontyphoidal Salmonella bacteremia. Infect Immun 2013; 81:3515-26. [PMID: 23690397 DOI: 10.1128/iai.00380-13] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Coinfection with malaria and nontyphoidal Salmonella serotypes (NTS) can cause life-threatening bacteremia in humans. Coinfection with malaria is a recognized risk factor for invasive NTS, suggesting that malaria impairs intestinal barrier function. Here, we investigated mechanisms and strategies for prevention of coinfection pathology in a mouse model. Our findings reveal that malarial-parasite-infected mice, like humans, develop L-arginine deficiency, which is associated with intestinal mastocytosis, elevated levels of histamine, and enhanced intestinal permeability. Prevention or reversal of L-arginine deficiency blunts mastocytosis in ileal villi as well as bacterial translocation, measured as numbers of mesenteric lymph node CFU of noninvasive Escherichia coli Nissle and Salmonella enterica serotype Typhimurium, the latter of which is naturally invasive in mice. Dietary supplementation of malarial-parasite-infected mice with L-arginine or L-citrulline reduced levels of ileal transcripts encoding interleukin-4 (IL-4), a key mediator of intestinal mastocytosis and macromolecular permeability. Supplementation with L-citrulline also enhanced epithelial adherens and tight junctions in the ilea of coinfected mice. These data suggest that increasing L-arginine bioavailability via oral supplementation can ameliorate malaria-induced intestinal pathology, providing a basis for testing nutritional interventions to reduce malaria-associated mortality in humans.
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Christopher A, Mshana SE, Kidenya BR, Hokororo A, Morona D. Bacteremia and resistant gram-negative pathogens among under-fives in Tanzania. Ital J Pediatr 2013; 39:27. [PMID: 23657136 PMCID: PMC3665601 DOI: 10.1186/1824-7288-39-27] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 05/06/2013] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Antibiotic resistance is one of the most serious public health concerns worldwide and is increasing at an alarming rate, making daily treatment decisions more challenging. This study is aimed at identifying local bacterial isolates and their antimicrobial susceptibility patterns to avoid irrational antibiotic use, especially in settings where unguided management occurs and febrile illnesses are predominant. MATERIAL AND METHODS A hospital-based prospective cross-sectional study was conducted from September 2011 to February 2012. Febrile children were serially recruited and demographic and clinical data were collected using a standardized data collection tool. A blood culture was performed and identification of the isolates was undertaken using in-house biochemical tests. Susceptibility to common antibiotics was investigated using the disc diffusion methods. RESULTS Of the 1081 children admitted during the study period, 317 (29.3%) met the inclusion criteria and were recruited, of whom 195 (61.5%) and 122 (38.5%) were male and female respectively. The median age was 18 months with an interquartile range of 9 to 36 months. Of the 317 children, 251 (79.2%) were below or equal to 36 months of age. The prevalence of bacteremia was 6.6%. A higher prevalence of bacteraemia was observed in children below 36 months than in those ≥ 36 months (7.5% vs. 3.0%, p = 0.001). Predictors of bacteraemia were an axillary temperature of >38.5 °C (OR =7, 95% CI = 2.2 - 14.8, p-value = 0.0001), a positive malaria slide (OR =5, 95% CI = 3.0 - 21.2, p-value = 0.0001) and a high neutrophils' count (OR =21 95% CI = 5.6 - 84, p-value = 0.0001). Escherichia coli and Klebsiella pneumoniae accounted for 7 (33.3%) and 6 (28.6%) of all the isolates respectively. Others gram-negatives bacteria were Citrobacter spp 2 (9.5%), Enterobacter spp 1 (4.25%), Pseudomonas spp 2 (9.5%), Proteus spp 1 (4.25%) and Salmonella spp 1 (4.25%). These isolates were highly resistant to ampicillin (95%), co-trimoxazole (90%), tetracycline (90%), gentamicin (80%), augmentin (80%), chloramphenicol (65%), ceftriaxone (35%), cefotaxime (35%) ciprofloxacin (30%), amikacin (30%), ceftazidime (25%) and norfloxacine (10%). CONCLUSION Multi-resistant gram-negative bacteria are the commonest cause of bacteremia in under-fives attending the Bugando Medical Centre, Mwanza, Tanzania. A high body temperature, a positive malaria slide and a high absolute neutrophils' count were all independent risk factors found to predict bacteremia. A higher mortality rate was observed in children with bacteraemia. Continuous epidemiological surveillance should be conducted so that a proper and effective antibiotics management can be instituted, especially in children with a high grade fever, a positive malaria slide and a high neutrophils' count.
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Affiliation(s)
- Alexandra Christopher
- Department of Pediatric and Child Health, Weill School of Medicine, CUHAS-Bugando, Mwanza, Tanzania
| | - Stephen E Mshana
- Department of Microbiology/Immunology Weill School of Medicine, CUHAS-Bugando, BOX 1464, Mwanza, Tanzania
| | - Benson R Kidenya
- Department of Biochemistry and Molecular Biology, Weill School of Medicine, CUHAS-Bugando, Mwanza, Tanzania
| | - Aldofineh Hokororo
- Department of Pediatric and Child Health, Weill School of Medicine, CUHAS-Bugando, Mwanza, Tanzania
| | - Domenica Morona
- Department of Parasitology/Entomology Weill School of Medicine, CUHAS-Bugando, Mwanza, Tanzania
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Cunnington AJ, Bretscher MT, Nogaro SI, Riley EM, Walther M. Comparison of parasite sequestration in uncomplicated and severe childhood Plasmodium falciparum malaria. J Infect 2013; 67:220-30. [PMID: 23623771 PMCID: PMC3744804 DOI: 10.1016/j.jinf.2013.04.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 04/13/2013] [Accepted: 04/15/2013] [Indexed: 12/31/2022]
Abstract
Objectives To determine whether sequestration of parasitized red blood cells differs between children with uncomplicated and severe Plasmodium falciparum malaria. Methods We quantified circulating-, total- and sequestered-parasite biomass, using a mathematical model based on plasma concentration of P. falciparum histidine rich protein 2, in Gambian children with severe (n = 127) and uncomplicated (n = 169) malaria. Results Circulating- and total-, but not sequestered-, parasite biomass estimates were significantly greater in children with severe malaria than in those with uncomplicated malaria. Sequestered biomass estimates in children with hyperlactataemia or prostration were similar to those in uncomplicated malaria, whereas sequestered biomass was higher in patients with severe anaemia, and showed a trend to higher values in cerebral malaria and fatal cases. Blood lactate concentration correlated with circulating- and total-, but not sequestered parasite biomass. These findings were robust after controlling for age, prior antimalarial treatment and clonality of infection, and over a realistic range of variation in model parameters. Conclusion Extensive sequestration is not a uniform requirement for severe paediatric malaria. The pathophysiology of hyperlactataemia and prostration appears to be unrelated to sequestered parasite biomass. Different mechanisms may underlie different severe malaria syndromes, and different therapeutic strategies may be required to improve survival.
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Affiliation(s)
- Aubrey J Cunnington
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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van Santen S, de Mast Q, Swinkels DW, van der Ven AJAM. The iron link between malaria and invasive non-typhoid Salmonella infections. Trends Parasitol 2013; 29:220-7. [PMID: 23601932 DOI: 10.1016/j.pt.2013.03.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 03/11/2013] [Accepted: 03/12/2013] [Indexed: 02/06/2023]
Abstract
Epidemiological studies have demonstrated an association between malaria and invasive non-typhoid Salmonella (NTS) infections, especially in children. We explore the role of iron as a possible cofactor in this association. Malarial disease, among others, is associated with enhanced erythrophagocytosis and inflammation, which increases the iron content of macrophages and thereby also the survival of Salmonella spp. within macrophages. Whether iron supplementation programs augment the risk of invasive NTS infections in malaria-endemic regions is an important global health issue that still needs to be determined.
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Affiliation(s)
- Susanne van Santen
- Department of General Internal Medicine, Nijmegen Institute for International Health (456), Radboud University Medical Center, Geert Grooteplein Zuid 8, PO Box 9101, 6500 HB Nijmegen, The Netherlands
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Kendjo E, Agbenyega T, Bojang K, Newton CRJC, Bouyou-Akotet M, Pedross F, Kombila M, Helbok R, Kremsner PG. Mortality patterns and site heterogeneity of severe malaria in African children. PLoS One 2013; 8:e58686. [PMID: 23505549 PMCID: PMC3591404 DOI: 10.1371/journal.pone.0058686] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 02/05/2013] [Indexed: 11/28/2022] Open
Abstract
Background In this study we aimed to assess site heterogeneity of early, intermediate, and late mortality prediction in children with severe Plasmodium falciparum malaria in sub-Saharan Africa. Methods Medical records of 26,036 children admitted with severe Plasmodium falciparum malaria in six hospital research centers between December 2000 to May 2005 were analyzed. Demographic, clinical and laboratory data of children who died within 24 hours (early), between 24 and 47 hours (intermediate) and thereafter (48 hours or later, late mortality) were compared between groups and survivors. Results Overall mortality was 4·3% (N = 1,129). Median time to death varied across sites (P<0·001), ranging from 8h (3h–52h) in Lambaréné to 40h (10h–100h) in Kilifi. Fifty-eight percent of deaths occurred within 24 hours and intermediate and late mortality rate were 19% and 23%, respectively. Combining all sites, deep breathing, prostration and hypoglycemia were independent predictors for early, intermediate and late mortality (P<0·01). Site specific independent predictors for early death included prostration, coma and deep breathing at all sites (P<0·001). Site specific independent predictors for intermediate and late death largely varied between sites (P<0·001) and included between 1 and 7 different clinical and laboratory variables. Conclusion Site heterogeneity for mortality prediction is evident in African children with severe malaria. Prediction for early mortality has the highest consistency between sites.
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Affiliation(s)
- Eric Kendjo
- Medical Research Unit, Albert Schweitzer Hospital, Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- Department of Parasitology, Mycology and Tropical Medicine, Faculty of Medicine, University of Health Sciences, Libreville, Gabon
- Université Pierre et Marie-Curie – CNR paludisme, Paris, France
| | - Tsiri Agbenyega
- University of Science and Technology, School of Medical Science, Kumasi, Ghana
| | - Kalifa Bojang
- Medical Research Council Laboratories, Banjul, The Gambia
| | - Charles R. J. C. Newton
- KEMRI Centre for Geographic Medicine Research (Coast), Kilifi, Kenya
- Institute of Child Health, University College London, London, United Kingdom
| | - Marielle Bouyou-Akotet
- Department of Parasitology, Mycology and Tropical Medicine, Faculty of Medicine, University of Health Sciences, Libreville, Gabon
| | - Florian Pedross
- Department of Medical Statistics, Informatics and Health Economics, Medical University Innsbruck, Innsbruck, Austria
| | - Maryvonne Kombila
- Department of Parasitology, Mycology and Tropical Medicine, Faculty of Medicine, University of Health Sciences, Libreville, Gabon
| | - Raimund Helbok
- Medical Research Unit, Albert Schweitzer Hospital, Lambaréné, Gabon
- Clinical Department of Neurology, Innsbruck Medical University, Innsbruck, Austria
- * E-mail:
| | - Peter Gottfried Kremsner
- Medical Research Unit, Albert Schweitzer Hospital, Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
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Olupot-Olupot P, Urban BC, Jemutai J, Nteziyaremye J, Fanjo HM, Karanja H, Karisa J, Ongodia P, Bwonyo P, Gitau EN, Talbert A, Akech S, Maitland K. Endotoxaemia is common in children with Plasmodium falciparum malaria. BMC Infect Dis 2013; 13:117. [PMID: 23497104 PMCID: PMC3605375 DOI: 10.1186/1471-2334-13-117] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 02/27/2013] [Indexed: 02/04/2023] Open
Abstract
Background Children presenting to hospital with recent or current Plasmodium falciparum malaria are at increased the risk of invasive bacterial disease, largely enteric gram-negative organisms (ENGO), which is associated with increased mortality and recurrent morbidity. Although incompletely understood, the most likely source of EGNO is the bowel. We hypothesised that as a result of impaired gut-barrier function endotoxin (lipopolysaccharide), present in the cell-wall of EGNO and in substantial quantities in the gut, is translocated into the bloodstream, and contributes to the pathophysiology of children with severe malaria. Methods We conducted a prospective study in 257 children presenting with malaria to two hospitals in Kenya and Uganda. We analysed the clinical presentation, endotoxin and cytokine concentration. Results Endotoxaemia (endotoxin activity ≥0.4 EAA Units) was observed in 71 (27.6%) children but its presence was independent of both disease severity and outcome. Endotoxaemia was more frequent in children with severe anaemia but not specifically associated with other complications of malaria. Endotoxaemia was associated with a depressed inflammatory and anti-inflammatory cytokine response. Plasma endotoxin levels in severe malaria negatively correlated with IL6, IL10 and TGFβ (Spearman rho: TNFα: r=−0.122, p=0.121; IL6: r=−0.330, p<0.0001; IL10: r=−0.461, p<0.0001; TGFβ: r=−0.173, p<0.027). Conclusions Endotoxaemia is common in malaria and results in temporary immune paralysis, similar to that observed in patients with sepsis and experimentally-induced endotoxaemia. Intense sequestration of P. falciparum-infected erythrocytes within the endothelial bed of the gut has been observed in pathological studies and may lead to gut-barrier dysfuction. The association of endotoxaemia with the anaemia phenotype implies that it may contribute to the dyserythropoesis accompanying malaria through inflammation. Both of these factors feasibly underpin the susceptibility to EGNO co-infection. Further research is required to investigate this initial finding, with a view to future treatment trials targeting mechanism and appropriate antimicrobial treatment.
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107
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Sumbele IUN, Samje M, Nkuo-Akenji T. A longitudinal study on anaemia in children with Plasmodium falciparum infection in the Mount Cameroon region: prevalence, risk factors and perceptions by caregivers. BMC Infect Dis 2013; 13:123. [PMID: 23497273 PMCID: PMC3600988 DOI: 10.1186/1471-2334-13-123] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Accepted: 03/01/2013] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND In heavily endemic malaria areas, it is almost inevitable that malarial infection will be associated with anaemia, although malaria may not be the prime cause of it. Anaemia is a major public health problem in Cameroon. We hypothesized that, factors other than falciparum malaria account for anaemia in the study area. METHODS A longitudinal study was conducted among 351 Plasmodium falciparum positive children to determine the prevalence, risk factors and the perception of anaemia by the caregivers in a semi-rural community. The investigative methods included the use of a structured questionnaire, clinical evaluation and laboratory investigations. RESULTS At enrolment the overall prevalence of anaemia as assessed by Hb concentration (Hb < 11 g/dl) was 80.3% (282). Following treatment the prevalence of persistent anaemia was 6% and 46.2% of the children achieved haematological recovery by day 42. Exploratory multiple linear regression analysis showed the following; parasitaemia density (P < 0.01), enlarged spleen (P < 0.05), duration of fever > 2 days (P < 0.01), high white blood cell count (P < 0.001), sex (P < 0.05), iron status indicators (ferritin and transferrin) (P < 0.001), level of education of the caregiver (P < 0.05), management of onset of malaria by caregiver (P < 0.005) and wasting (P < 0.05) to be risk factors for anaemia in children with falciparum infection. Approximately 75.5% (265) of the caregivers had some knowledge about anaemia. CONCLUSION The identified risk factors revealed the important contributors to the pathogenesis of anaemia in the Mount Cameroon region. Control efforts should therefore be directed towards proper health education emphasizing on proper health seeking behaviour and attitudes of the population.
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Affiliation(s)
- Irene Ule Ngole Sumbele
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, P. O. Box 63, Buea, Cameroon
| | - Moses Samje
- Department of Medicine, Faculty of Health Sciences, University of Bamenda, P. O. Box 39, Bambili, Cameroon
| | - Theresa Nkuo-Akenji
- Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P. O. Box 63, Buea, Cameroon
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108
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Aneni EC, Hamer DH, Gill CJ. Systematic review of current and emerging strategies for reducing morbidity from malaria in sickle cell disease. Trop Med Int Health 2013; 18:313-27. [PMID: 23320577 DOI: 10.1111/tmi.12056] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Sickle cell disease (SCD) is a chronic debilitating disorder affecting erythrocytes, which is especially prevalent throughout Sub-Saharan Africa and among individuals of African descent. Because malaria is thought to be a significant cause of morbidity and mortality in patients with SCD, malaria chemoprophylaxis is often recommended for these patients. In SCD, malaria chemoprophylaxis reduces malaria parasite count, anaemia and the need for blood transfusion, and improves clinical outcomes. However, the effectiveness of malaria chemoprophylaxis in the setting of SCD is based on a few studies conducted prior to the emergence of widespread antimalarial drug resistance. Consequently, it is uncertain what the optimal strategy for managing patients with SCD in malarious areas should be. Despite the widespread use of hydroxyurea in non-malarious regions, little is known about its effect in malaria-endemic areas or on malaria-related outcomes. On the one hand, hydroxyurea upregulates intercellular cell adhesion molecule 1 (ICAM-1), the cell surface receptor for adhesion of Plasmodium falciparum-infected erythrocytes, and theoretically, it could enhance parasite replication. On the other hand, hydroxyurea increases levels of foetal haemoglobin, which is protective against malaria. We explore what is currently known about the interactions between SCD and malaria and review the published literature on the efficacy of malaria chemoprophylaxis in SCD. We also consider alternative strategies, including hydroxyurea, in the reduction of malaria-associated morbidity and mortality in patients with SCD.
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Affiliation(s)
- Ehimen C Aneni
- Department of International Health, Boston University School of Public Health, Boston, MA 02118, USA.
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109
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Hendriksen ICE, White LJ, Veenemans J, Mtove G, Woodrow C, Amos B, Saiwaew S, Gesase S, Nadjm B, Silamut K, Joseph S, Chotivanich K, Day NPJ, von Seidlein L, Verhoef H, Reyburn H, White NJ, Dondorp AM. Defining falciparum-malaria-attributable severe febrile illness in moderate-to-high transmission settings on the basis of plasma PfHRP2 concentration. J Infect Dis 2013; 207:351-61. [PMID: 23136222 PMCID: PMC3532834 DOI: 10.1093/infdis/jis675] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 08/23/2012] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND In malaria-endemic settings, asymptomatic parasitemia complicates the diagnosis of malaria. Histidine-rich protein 2 (HRP2) is produced by Plasmodium falciparum, and its plasma concentration reflects the total body parasite burden. We aimed to define the malaria-attributable fraction of severe febrile illness, using the distributions of plasma P. falciparum HRP2 (PfHRP2) concentrations from parasitemic children with different clinical presentations. METHODS Plasma samples were collected from and peripheral blood slides prepared for 1435 children aged 6-60 months in communities and a nearby hospital in northeastern Tanzania. The study population included children with severe or uncomplicated malaria, asymptomatic carriers, and healthy control subjects who had negative results of rapid diagnostic tests. The distributions of plasma PfHRP2 concentrations among the different groups were used to model severe malaria-attributable disease. RESULTS The plasma PfHRP2 concentration showed a close correlation with the severity of infection. PfHRP2 concentrations of >1000 ng/mL denoted a malaria-attributable fraction of severe disease of 99% (95% credible interval [CI], 96%-100%), with a sensitivity of 74% (95% CI, 72%-77%), whereas a concentration of <200 ng/mL denoted severe febrile illness of an alternative diagnosis in >10% (95% CI, 3%-27%) of patients. Bacteremia was more common among patients in the lowest and highest PfHRP2 concentration quintiles. CONCLUSIONS The plasma PfHRP2 concentration defines malaria-attributable disease and distinguishes severe malaria from coincidental parasitemia in African children in a moderate-to-high transmission setting.
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Affiliation(s)
- Ilse C E Hendriksen
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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Postels DG, Chimalizeni YF, Mallewa M, Boivin MJ, Seydel KB. Pediatric cerebral malaria: a scourge of Africa. FUTURE NEUROLOGY 2013. [DOI: 10.2217/fnl.12.84] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cerebral malaria, defined as an otherwise unexplained coma in a patient with Plasmodium falciparum parasitemia, affects up to 1 million people per year, the vast majority of them being children living in sub-Saharan Africa. Despite optimal treatment, this condition kills 15% of those affected and leaves 30% of survivors with neurologic sequelae. The clinical diagnosis is hampered by its poor specificity, but the presence or absence of a malarial retinopathy in cerebral malaria has proven to be important in the differentiation of underlying coma etiology. Both antimalarials and intense supportive care are necessary for optimal treatment. As of yet, clinical trials of adjunctive therapies have not improved the high rates of mortality and morbidity. Survivors are at high risk of neurologic sequelae including epilepsy, neurodisabilities and cognitive–behavioral problems. The neuroanatomic and functional bases of these sequelae are being elucidated. Although adjunctive therapy trials continue, the best hope for African children may lie in disease prevention. Strategies include bednets, chemoprophylaxis and vaccine development.
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Affiliation(s)
| | - Yamikani F Chimalizeni
- Department of Pediatrics, University of Malawi College of Medicine, Private Bag 360, Blantyre 3, Malawi
| | - Macpherson Mallewa
- Department of Pediatrics, University of Malawi College of Medicine, Private Bag 360, Blantyre 3, Malawi
| | | | - Karl B Seydel
- Michigan State University, East Lansing, MI 48824, USA
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Olupot-Olupot P, Maitland K. Management of severe malaria: results from recent trials. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 764:241-50. [PMID: 23654072 DOI: 10.1007/978-1-4614-4726-9_20] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Globally, malaria remains a substantial public health burden with an estimated 349-552 million clinical cases of P. falciparum malaria each year--leading to 780,000 deaths directly attributable to the disease. Whilst the outcome from severe malaria in Africa children remains poor, recent developments in the management of malaria have come from two key sources--the introduction of new, safe and rapidly-effective anti-malarials and high quality evidence from two of the largest clinical trials ever conducted in African children with severe malaria. As a result, the time-honoured anti-malarial treatment for severe malaria, quinine, will now be replaced by artesunate, a water-soluble artemisinin derivative. Supportive care, specifically the management of shock, has been informed by a large late phase clinical trial which concluded that bolus resuscitation is harmful and therefore should be avoided in children with severe malaria, including the high risk group with severe metabolic acidosis and advanced shock.
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113
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Restif O, Goh YS, Palayret M, Grant AJ, McKinley TJ, Clark MR, Mastroeni P. Quantification of the effects of antibodies on the extra- and intracellular dynamics of Salmonella enterica. J R Soc Interface 2012; 10:20120866. [PMID: 23235264 PMCID: PMC3565705 DOI: 10.1098/rsif.2012.0866] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Antibodies are known to be essential in controlling Salmonella infection, but their exact role remains elusive. We recently developed an in vitro model to investigate the relative efficiency of four different human immunoglobulin G (IgG) subclasses in modulating the interaction of the bacteria with human phagocytes. Our results indicated that different IgG subclasses affect the efficacy of Salmonella uptake by human phagocytes. In this study, we aim to quantify the effects of IgG on intracellular dynamics of infection by combining distributions of bacterial numbers per phagocyte observed by fluorescence microscopy with a mathematical model that simulates the in vitro dynamics. We then use maximum likelihood to estimate the model parameters and compare them across IgG subclasses. The analysis reveals heterogeneity in the division rates of the bacteria, strongly suggesting that a subpopulation of intracellular Salmonella, while visible under the microscope, is not dividing. Clear differences in the observed distributions among the four IgG subclasses are best explained by variations in phagocytosis and intracellular dynamics. We propose and compare potential factors affecting the replication and death of bacteria within phagocytes, and we discuss these results in the light of recent findings on dormancy of Salmonella.
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Affiliation(s)
- Olivier Restif
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, UK.
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Taylor WRJ, Hanson J, Turner GDH, White NJ, Dondorp AM. Respiratory manifestations of malaria. Chest 2012; 142:492-505. [PMID: 22871759 DOI: 10.1378/chest.11-2655] [Citation(s) in RCA: 168] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Respiratory distress develops in up to 25% of adults and 40% of children with severe falciparum malaria. Its diverse causes include respiratory compensation of metabolic acidosis, noncardiogenic pulmonary edema, concomitant pneumonia, and severe anemia. Patients with severe falciparum, vivax, and knowlesi malaria may develop acute lung injury (ALI) and ARDS, often several days after antimalarial drug treatment. ARDS rates, best characterized for severe Plasmodium falciparum, are 5% to 25% in adults and up to 29% in pregnant women; ARDS is rare in young children. ARDS pathophysiology centers on inflammatory-mediated increased capillary permeability or endothelial damage leading to diffuse alveolar damage that can continue after parasite clearance. The role of parasite sequestration in the pulmonary microvasculature is unclear, because sequestration occurs intensely in P falciparum, less so in P knowlesi, and has not been shown convincingly in P vivax. Because early markers of ALI/ARDS are lacking, fluid resuscitation in severe malaria should follow the old adage to "keep them dry." Bacteremia and hospital-acquired pneumonia can complicate severe malaria and may contribute to ALI/ARDS. Mechanical ventilation can save life in ALI/ARDS. Basic critical care facilities are increasingly available in tropical countries. The use of lung-protective ventilation has helped to reduce mortality from malaria-induced ALI/ARDS, but permissive hypercapnia in unconscious patients is not recommended because increased intracranial pressure and cerebral swelling may occur in cerebral malaria. The best antimalarial treatment of severe malaria is IV artesunate.
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Affiliation(s)
- Walter R J Taylor
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine, Nuffield Department of Medicine, Oxford University, The Churchill Hospital, Headington, England; Service de la Médicine Internationale et Humanitaire, Hôpitaux Universitaires de Genève, Geneva, Switzerland.
| | - Josh Hanson
- Cairns Base Hospital, Cairns, QLD, Australia
| | - Gareth D H Turner
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine, Nuffield Department of Medicine, Oxford University, The Churchill Hospital, Headington, England
| | - Nicholas J White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine, Nuffield Department of Medicine, Oxford University, The Churchill Hospital, Headington, England
| | - Arjen M Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine, Nuffield Department of Medicine, Oxford University, The Churchill Hospital, Headington, England
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Cunnington AJ, Njie M, Correa S, Takem EN, Riley EM, Walther M. Prolonged neutrophil dysfunction after Plasmodium falciparum malaria is related to hemolysis and heme oxygenase-1 induction. THE JOURNAL OF IMMUNOLOGY 2012; 189:5336-46. [PMID: 23100518 DOI: 10.4049/jimmunol.1201028] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
It is not known why people are more susceptible to bacterial infections such as nontyphoid Salmonella during and after a malaria infection, but in mice, malarial hemolysis impairs resistance to nontyphoid Salmonella by impairing the neutrophil oxidative burst. This acquired neutrophil dysfunction is a consequence of induction of the cytoprotective, heme-degrading enzyme heme oxygenase-1 (HO-1) in neutrophil progenitors in bone marrow. In this study, we assessed whether neutrophil dysfunction occurs in humans with malaria and how this relates to hemolysis. We evaluated neutrophil function in 58 Gambian children with Plasmodium falciparum malaria [55 (95%) with uncomplicated disease] and examined associations with erythrocyte count, haptoglobin, hemopexin, plasma heme, expression of receptors for heme uptake, and HO-1 induction. Malaria caused the appearance of a dominant population of neutrophils with reduced oxidative burst activity, which gradually normalized over 8 wk of follow-up. The degree of neutrophil impairment correlated significantly with markers of hemolysis and HO-1 induction. HO-1 expression was increased in blood during acute malaria, but at a cellular level HO-1 expression was modulated by changes in surface expression of the haptoglobin receptor (CD163). These findings demonstrate that neutrophil dysfunction occurs in P. falciparum malaria and support the relevance of the mechanistic studies in mice. Furthermore, they suggest the presence of a regulatory pathway to limit HO-1 induction by hemolysis in the context of infection and indicate new targets for therapeutic intervention to abrogate the susceptibility to bacterial infection in the context of hemolysis in humans.
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Affiliation(s)
- Aubrey J Cunnington
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London WC1E 7HT, United Kingdom.
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Goh YS, MacLennan CA. Invasive African nontyphoidal Salmonella requires high levels of complement for cell-free antibody-dependent killing. J Immunol Methods 2012; 387:121-9. [PMID: 23085530 DOI: 10.1016/j.jim.2012.10.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2012] [Revised: 10/09/2012] [Accepted: 10/11/2012] [Indexed: 11/18/2022]
Abstract
Nontyphoidal isolates of Salmonella (NTS), particularly Salmonella Typhimurium, are a major cause of invasive bacteremia in Africa. Despite this, no vaccine against NTS is currently available for use in humans. If a NTS vaccine is to be developed in a timely manner, there is a need to develop assays to assess its in vivo efficacy. Assessment of potential efficacy of candidate vaccines in preclinical models is important for proof-of-concept and reduces attrition of vaccines in clinical trials. Serum bactericidal assays (SBA) are often used to assess the functional activity of vaccine-induced antibody responses targeted against Gram-negative bacteria with results given as the maximum dilution of serum that can effect bacterial killing. Previously we have found evidence for a protective role for antibody-induced complement-mediated killing of NTS in African children using an undiluted whole serum SBA. However, endogenous complement in diluted human sera is limiting and insufficient to effect bactericidal activity against S. Typhimurium beyond two two-fold dilutions. In the current study, we examined the requirements for SBA against NTS using baby rabbit serum (BRS) as an exogenous source of complement. We found that the amount of complement required for antibody-mediated bactericidal activity is much higher for the invasive African S. Typhimurium isolate D23580, compared with the laboratory S. Typhimurium LT2 and Salmonella Paratyphi A CVD1901. While 20% BRS was sufficient to kill LT2 and CVD1901, 75% BRS was needed to kill D23580. Our findings demonstrate that one concentration of exogenous complement is not suitable for SBA against all Salmonella isolates. To develop SBA to assess the in vivo efficacy of Salmonella vaccines, it is necessary to optimize the assay for the Salmonella isolates against which the vaccine is targeted.
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Affiliation(s)
- Yun Shan Goh
- Novartis Vaccines Institute for Global Health, Via Fiorentina 1, 53100 Siena, Italy
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Bacterial coinfections in travelers with malaria: rationale for antibiotic therapy. J Clin Microbiol 2012; 51:15-21. [PMID: 23052321 DOI: 10.1128/jcm.02149-12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Malaria predisposes children in areas where malaria is endemic to concurrent bacteremia, often with severe outcomes. The importance of bacterial coinfections in patients diagnosed with malaria in nonendemic settings has, however, not been reported. A retrospective analysis of microbiology data was performed in 755 travelers diagnosed with malaria in Sweden. Bacterial cultures from blood and other locations were correlated to clinical outcome and antibiotic treatment. Blood cultures were drawn from 417 (55%) patients (88% of whom were >15 years old), and bacterial isolates of clinical relevance (Salmonella enterica serovar Enteritidis and Escherichia coli) were detected in 2 patients (0.3%). Cultures from other locations (mainly urine, nasopharyngeal, and fecal samples) were obtained from 44% of the patients with 4.9% positivity. Of the 38 patients given antibiotics, 47% had neither severe malaria nor positive cultures and/or radiology signs indicative of treatment. C-reactive protein levels were associated with bacterial infections but had only a fair predictive value. Bacterial coinfections are uncommon among travelers with malaria. These data suggest a weaker association between malaria and bacteremia than previously described in endemic settings and might indicate different patient populations with different pathophysiological mechanisms and microbial environments. The study supports a restrictive antibiotic policy in returning travelers with malaria.
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Kute VB, Shah PR, Munjappa BC, Gumber MR, Patel HV, Jain SH, Engineer DP, Naresh VVS, Vanikar AV, Trivedi HL. Outcome and prognostic factors of malaria-associated acute kidney injury requiring hemodialysis: A single center experience. Indian J Nephrol 2012; 22:33-8. [PMID: 22279340 PMCID: PMC3263060 DOI: 10.4103/0971-4065.83737] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Acute kidney injury (AKI) is one of the most dreaded complications of severe malaria. We carried out prospective study in 2010, to describe clinical characteristics, laboratory parameters, prognostic factors, and outcome in 59 (44 males, 15 females) smear-positive malaria patients with AKI. The severity of illness was assessed using Acute Physiology and Chronic Health Evaluation (APACHE) II, Sequential Organ Failure Assessment (SOFA) score, Multiple Organ Dysfunction Score (MODS), and Glasgow Coma Scale (GCS) scores. All patients received artesunate and hemodialysis (HD). Mean age of patients was 33.63 ± 14 years. Plasmodium falciparum malaria was seen in 76.3% (n = 45), Plasmodium vivax in 16.9% (n = 10), and mixed infection in 6.8% (n = 4) patients. Presenting clinical features were fever (100%), nausea-vomiting (85%), oliguria (61%), abdominal pain/tenderness (50.8%), and jaundice (74.5%). Mean APACHE II, SOFA, MODS, and GCS scores were 18.1 ± 3, 10.16 ± 3.09, 9.71 ± 2.69, and 14.15 ± 1.67, respectively, all were higher among patients who died than among those who survived. APACHE II ≥20, SOFA and MODS scores ≥12 were associated with higher mortality (P < 0.05). 34% patients received blood component transfusion and exchange transfusion was done in 15%. Mean number of HD sessions required was 4.59 ± 3.03. Renal biopsies were performed in five patients (three with patchy cortical necrosis and two with acute tubular necrosis). 81.3% of patients had complete renal recovery and 11.8% succumbed to malaria. Prompt diagnosis, timely HD, and supportive therapy were associated with improved survival and recovery of kidney functions in malarial with AKI. Mortality was associated with higher APACHE II, SOFA, MODS, GCS scores, requirement of inotrope, and ventilator support.
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Affiliation(s)
- V B Kute
- Department of Nephrology and Clinical Transplantation, Institute of Kidney Diseases and Research Center, Institute of Transplantation Sciences, IKDRC-ITS, Ahmedabad, India
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Severe febrile illness in adult hospital admissions in Tanzania: a prospective study in an area of high malaria transmission. Trans R Soc Trop Med Hyg 2012; 106:688-95. [PMID: 23022040 DOI: 10.1016/j.trstmh.2012.08.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 08/07/2012] [Accepted: 08/07/2012] [Indexed: 11/21/2022] Open
Abstract
Severe febrile illness is a major cause of adult hospital admission in Africa. Studies of non-malarial fever come largely from children or from high HIV prevalence settings. This prospective study of adult admissions with severe febrile illness in a malaria-endemic area with moderate/low HIV prevalence investigated admission diagnosis as well as final diagnosis based on results of investigations. Severe malaria was the admission diagnosis in 148/198 (74.7%) cases. Plasmodium falciparum was identified in 38/188 (20.2%) admissions and 26/198 (13.1%) were bacteraemic, with 13/25 (52%) prescribed empirical antibiotics. HIV was equally common among those with (16/37; 43.2%) and without P. falciparum (50/138; 36.2%) (p=0.44). In 6/22 (27.3%) deaths, blood cultures were positive for a pathogen, with Streptococcus pneumoniae, Escherichia coli and non-Typhi Salmonella predominating. Chest radiography was suspicious for bacterial/mycobacterial disease in 5/22 additional deaths. Systemic inflammatory response syndrome criteria were more sensitive but less specific than WHO severe malaria criteria for predicting mortality. Malaria is overdiagnosed in adults with severe febrile illness and was not associated with mortality in the absence of co-infection in this high-incidence setting. Adults with severe febrile illness should be tested for malaria and HIV using rapid, sensitive tests. Early antibiotic use should be promoted. Improved diagnostics for invasive bacterial disease are needed.
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Bouyou-Akotet MK, Mawili-Mboumba DP, Kendjo E, Eyang Ekouma A, Abdou Raouf O, Engohang Allogho E, Kombila M. Complicated malaria and other severe febrile illness in a pediatric ward in Libreville, Gabon. BMC Infect Dis 2012; 12:216. [PMID: 22973831 PMCID: PMC3520876 DOI: 10.1186/1471-2334-12-216] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 09/05/2012] [Indexed: 11/10/2022] Open
Abstract
Background Although a substantial decline of Plasmodium falciparum infection is observed in Africa following implementation of new control strategies, malaria is still considered as the major cause of febrile illness in hospitalized African children. The present study was designed to assess the management of febrile illness and to determine the proportion of children with febrile illness hospitalized for primary diagnosis of malaria who had confirmed complicated malaria after implementation of new malaria control strategies in Libreville, Gabon. Methods Demographic, clinical and biological data from hospitalized children with fever or a history of fever, with a primary diagnosis of clinical malaria, aged less than 18 years old, who benefited from hematological measurements and microscopic malaria diagnosis, were recorded and analyzed during a prospective and observational study conducted in 2008 in the Centre Hospitalier de Libreville. Results A total of 418 febrile children were admitted at hospital as malaria cases. Majority of them (79.4%) were aged below five years. After medical examination, 168 were diagnosed and treated as clinical malaria and, among them, only 56.7% (n = 95) had Plasmodium falciparum positive blood smears. Age above five years, pallor, Blantyre Coma Score ≤2 and thrombocytopenia were predictive of malaria infection. Respiratory tract infections were the first leading cause of hospitalization (41.1%), followed by malaria (22.7%); co-morbidities were frequent (22%). Less than 5% of suspected bacterial infections were confirmed by culture. Global case fatality rate was 2.1% and 1% for malaria. Almost half (46%) of the children who received antimalarial therapy had negative blood smears. Likewise, antibiotics were frequently prescribed without bacteriological confirmation. Conclusions The use of clinical symptoms for the management of children febrile illness is frequent in Gabon. Information, training of health workers and strengthening of diagnosis tools are necessary to improve febrile children care.
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Dasari P, Bhakdi S. Pathogenesis of malaria revisited. Med Microbiol Immunol 2012; 201:599-604. [PMID: 22955244 DOI: 10.1007/s00430-012-0265-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 08/24/2012] [Indexed: 11/28/2022]
Abstract
Plasmodium falciparum malaria claims 1 million lives around the globe every year. Parasitemia can reach remarkably high levels. The developing parasite digests hemoglobin and converts the waste product to hemozoin alias malaria pigment. These processes occur in a vesicular compartment named the digestive vacuole (DV). Each parasitized cell releases one DV upon rupture. Myriads of DVs thus gain entry into the blood, but whether they trigger pathobiological events has never been investigated. We recently discovered that the DV membrane simultaneously activates the two major enzyme cascades in blood, complement and coagulation. Activation of both is known to occur in patients with severe malaria, so discovery of the common trigger has large consequences. The DV membrane but not the merozoite has the capacity to spontaneously activate the alternative complement and intrinsic clotting pathway. Ejection of merozoites and the DV into the bloodstream, therefore, results in selective opsonization and phagocytosis of the DV, leaving merozoites free to invade new cells. The DV membrane furthermore has the capacity to assemble prothrombinase, the key convertase of the intrinsic clotting pathway. The dual capacity of the DV to activate both complement and coagulation can be suppressed by low-molecular-weight dextran sulfate. This agent protects experimental animals from the detrimental consequences, resulting from intravenous application of purified DVs. Phagocytosis of DVs not only deploys PMN away from merozoites, but also drives the cells into a state of functional exhaustion. This may be one reason for the enhanced susceptibility of patients with severe malaria toward systemic bacterial infections. Together, these findings indicate that the DV may represent a hitherto unrecognized, important determinant of parasite pathogenicity.
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Affiliation(s)
- Prasad Dasari
- Institute of Medical Microbiology and Hygiene, University Medical Center, Johannes Gutenberg University Mainz, Hochhaus Augustusplatz, 55101 Mainz, Germany
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Prashanth GP, Maralihalli MB, Bagalkot PS, Joshi SN. Intravenous artesunate for transfusion-transmitted plasmodium vivax malaria in a preterm neonate. Pediatrics 2012; 130:e706-9. [PMID: 22891231 DOI: 10.1542/peds.2011-2023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Transfusion-transmitted malaria (TTM) in neonates is rare. TTM can occur in both endemic and nonendemic areas because the current tests used to screen the donor blood for malaria are unreliable when there is low parasitemia. Malaria must be considered as an important differential diagnosis for neonatal sepsis after exchange transfusion. Management strategy in TTM in the neonatal period is not standardized; exchange transfusion is often considered. We used intravenous artesunate in a case of severe malaria caused by Plasmodium vivax in a 30-week preterm neonate after packed red blood cell transfusion on day 19 of life. This is the first clinical report of parenteral artesunate successfully used in the neonatal period. We emphasize the need for further investigation of the safety and efficacy of intravenous artesunate in the treatment of severe neonatal malaria.
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Affiliation(s)
- Gowda Parameshwar Prashanth
- Department of Pediatrics, KLE University's Jawaharlal Nehru Medical College, Nehru Nagar, Belgaum 590010, Karnataka, India.
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Deaths due to Plasmodium knowlesi malaria in Sabah, Malaysia: association with reporting as Plasmodium malariae and delayed parenteral artesunate. Malar J 2012; 11:284. [PMID: 22905799 PMCID: PMC3472242 DOI: 10.1186/1475-2875-11-284] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 07/13/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The simian parasite Plasmodium knowlesi is recognized as a common cause of severe and fatal human malaria in Sabah, Malaysia, but is morphologically indistinguishable from and still commonly reported as Plasmodium malariae, despite the paucity of this species in Sabah. Since December 2008 Sabah Department of Health has recommended intravenous artesunate and referral to a general hospital for all severe malaria cases of any species. This paper reviews all malaria deaths in Sabah subsequent to the introduction of these measures. Reporting of malaria deaths in Malaysia is mandatory. METHODS Details of reported malaria deaths during 2010-2011 were reviewed to determine the proportion of each Plasmodium species. Demographics, clinical presentations and management of severe malaria caused by each species were compared. RESULTS Fourteen malaria deaths were reported, comprising seven Plasmodium falciparum, six P. knowlesi and one Plasmodium vivax (all PCR-confirmed). Of the six P. knowlesi deaths, five were attributable to knowlesi malaria and one was attributable to P. knowlesi-associated enterobacter sepsis. Patients with directly attributable P. knowlesi deaths (N = 5) were older than those with P. falciparum (median age 51 [IQR 50-65] vs 22 [IQR 9-55] years, p = 0.06). Complications in fatal P. knowlesi included respiratory distress (N = 5, 100%), hypotension (N = 4, 80%), and renal failure (N = 4, 80%). All patients with P. knowlesi were reported as P. malariae by microscopy. Only two of five patients with severe knowlesi malaria on presentation received immediate parenteral anti-malarial treatment. The patient with P. vivax-associated severe illness did not receive parenteral treatment. In contrast six of seven patients with severe falciparum malaria received immediate parenteral treatment. CONCLUSION Plasmodium knowlesi was responsible, either directly or through gram-negative bacteraemia, for almost half of malaria deaths in Sabah. Patients with severe non-falciparum malaria were less likely to receive immediate parenteral therapy. This highlights the need in Sabah for microscopically diagnosed P. malariae to be reported as P. knowlesi to improve recognition and management of this potentially fatal species. Clinicians need to be better informed of the potential for severe and fatal malaria from non-falciparum species, and the need to treat all severe malaria with immediate intravenous artesunate.
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Abstract
BACKGROUND Invasive, extraintestinal salmonellosis carries a significant burden of childhood morbidity especially among infants and young children in developing countries. OBJECTIVES To determine the clinical manifestations, outcomes, laboratory findings and antimicrobial susceptibility patterns in patients with invasive salmonellosis. METHODS A retrospective chart review was conducted among children 0-18 years of age diagnosed with invasive salmonellosis receiving care at Queen Sirikit National Institute of Child Health, Bangkok, Thailand, from 2001 to 2010. RESULTS We analyzed the records of 229 patients with culture-proven invasive salmonellosis. Sixty-three percent of cases had no documented underlying disease. Fever, diarrhea and respiratory symptoms were reported in 92%, 40% and 29% of cases, respectively. The spectrum of disease included isolated bacteremia (90%), clinical pneumonia (24.8%), bacteremia with meningitis (7.8%), septic arthritis (1.3%) and empyema thoracis (0.4%). Forty-seven of 57 cases presenting with clinical pneumonia had abnormal infiltrations on chest radiograph (20.5% of all cases). Despite the invasive nature of the illness, 53.1% of patients had a normal white blood cell count. Antimicrobial resistance was found among ampicillin (68.3%), chloramphenical (15.2%), trimethoprim-sulfamethoxazole (33.9%), ceftriaxone (17.4%) and ciprofloxacin (3%). The case fatality rate was 4.8%, 91% of whom had an underlying disease. Multivariate analysis indicated that age, underlying liver disease and presence of pneumonia were significant predictors of fatality. CONCLUSIONS Fever, diarrhea and respiratory symptoms were among the most common presenting symptoms of invasive nontyphoidal salmonellosis. Older age, hepatobiliary disease and presence of pneumonia were associated with increased risk of fatality. Resistance to third-generation cephalosporins poses a major concern for its use as empiric antimicrobial therapy for this condition.
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Hendriksen ICE, Ferro J, Montoya P, Chhaganlal KD, Seni A, Gomes E, Silamut K, Lee SJ, Lucas M, Chotivanich K, Fanello CI, Day NPJ, White NJ, von Seidlein L, Dondorp AM. Diagnosis, clinical presentation, and in-hospital mortality of severe malaria in HIV-coinfected children and adults in Mozambique. Clin Infect Dis 2012; 55:1144-53. [PMID: 22752514 PMCID: PMC3447636 DOI: 10.1093/cid/cis590] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background. Severe falciparum malaria with human immunodeficiency virus (HIV) coinfection is common in settings with a high prevalence of both diseases, but there is little information on whether HIV affects the clinical presentation and outcome of severe malaria. Methods. HIV status was assessed prospectively in hospitalized parasitemic adults and children with severe malaria in Beira, Mozambique, as part of a clinical trial comparing parenteral artesunate versus quinine (ISRCTN50258054). Clinical signs, comorbidity, complications, and disease outcome were compared according to HIV status. Results. HIV-1 seroprevalence was 11% (74/655) in children under 15 years and 72% (49/68) in adults with severe malaria. Children with HIV coinfection presented with more severe acidosis, anemia, and respiratory distress, and higher peripheral blood parasitemia and plasma Plasmodium falciparum histidine-rich protein-2 (PfHRP2). During hospitalization, deterioration in coma score, convulsions, respiratory distress, and pneumonia were more common in HIV-coinfected children, and mortality was 26% (19/74) versus 9% (53/581) in uninfected children (P < .001). In an age- and antimalarial treatment–adjusted logistic regression model, significant, independent predictors for death were renal impairment, acidosis, parasitemia, and plasma PfHRP2 concentration. Conclusions. Severe malaria in HIV-coinfected patients presents with higher parasite burden, more complications, and comorbidity, and carries a higher case fatality rate. Early identification of HIV coinfection is important for the clinical management of severe malaria.
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Affiliation(s)
- Ilse C E Hendriksen
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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Feasey NA, Dougan G, Kingsley RA, Heyderman RS, Gordon MA. Invasive non-typhoidal salmonella disease: an emerging and neglected tropical disease in Africa. Lancet 2012; 379:2489-2499. [PMID: 22587967 PMCID: PMC3402672 DOI: 10.1016/s0140-6736(11)61752-2] [Citation(s) in RCA: 645] [Impact Index Per Article: 53.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Invasive strains of non-typhoidal salmonellae have emerged as a prominent cause of bloodstream infection in African adults and children, with an associated case fatality of 20-25%. The clinical presentation of invasive non-typhoidal salmonella disease in Africa is diverse: fever, hepatosplenomegaly, and respiratory symptoms are common, and features of enterocolitis are often absent. The most important risk factors are HIV infection in adults, and malaria, HIV, and malnutrition in children. A distinct genotype of Salmonella enterica var Typhimurium, ST313, has emerged as a new pathogenic clade in sub-Saharan Africa, and might have adapted to cause invasive disease in human beings. Multidrug-resistant ST313 has caused epidemics in several African countries, and has driven the use of expensive antimicrobial drugs in the poorest health services in the world. Studies of systemic cellular and humoral immune responses in adults infected with HIV have revealed key host immune defects contributing to invasive non-typhoidal salmonella disease. This emerging pathogen might therefore have adapted to occupy an ecological and immunological niche provided by HIV, malaria, and malnutrition in Africa. A good understanding of the epidemiology of this neglected disease will open new avenues for development and implementation of vaccine and public health strategies to prevent infections and interrupt transmission.
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Affiliation(s)
- Nicholas A Feasey
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Gastroenterology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | | | | | - Robert S Heyderman
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Liverpool School of Tropical Medicine, Liverpool, UK
| | - Melita A Gordon
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi; Department of Gastroenterology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
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Leoratti FMDS, Trevelin SC, Cunha FQ, Rocha BC, Costa PAC, Gravina HD, Tada MS, Pereira DB, Golenbock DT, do Valle Antonelli LR, Gazzinelli RT. Neutrophil paralysis in Plasmodium vivax malaria. PLoS Negl Trop Dis 2012; 6:e1710. [PMID: 22745844 PMCID: PMC3383745 DOI: 10.1371/journal.pntd.0001710] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 05/13/2012] [Indexed: 12/03/2022] Open
Abstract
Background The activation of innate immune responses by Plasmodium vivax results in activation of effector cells and an excessive production of pro-inflammatory cytokines that may culminate in deleterious effects. Here, we examined the activation and function of neutrophils during acute episodes of malaria. Materials and Methods Blood samples were collected from P. vivax-infected patients at admission (day 0) and 30–45 days after treatment with chloroquine and primaquine. Expression of activation markers and cytokine levels produced by highly purified monocytes and neutrophils were measured by the Cytometric Bead Assay. Phagocytic activity, superoxide production, chemotaxis and the presence of G protein-coupled receptor (GRK2) were also evaluated in neutrophils from malaria patients. Principal Findings Both monocytes and neutrophils from P. vivax-infected patients were highly activated. While monocytes were found to be the main source of cytokines in response to TLR ligands, neutrophils showed enhanced phagocytic activity and superoxide production. Interestingly, neutrophils from the malaria patients expressed high levels of GRK2, low levels of CXCR2, and displayed impaired chemotaxis towards IL-8 (CXCL8). Conclusion Activated neutrophils from malaria patients are a poor source of pro-inflammatory cytokines and display reduced chemotactic activity, suggesting a possible mechanism for an enhanced susceptibility to secondary bacterial infection during malaria. Plasmodium vivax is responsible for approximately 60–80% of the malaria cases in the world, and contributes to significant social and economic instability in the developing countries of Latin America and Asia. The pathogenesis of P. vivax malaria is a consequence of host derived inflammatory mediators. Hence, a better understanding of the mechanisms involved in induction of systemic inflammation during P. vivax malaria is critical for the clinical management and prevention of severe disease. The innate immune receptors recognize Plasmodium sp. and initiate a broad spectrum of host defense mechanisms that mediate resistance to infection. However, the innate immune response is the classic “two-edged sword”, and clinical malaria is associated with high levels of circulating pro-inflammatory cytokines. Our findings show that both monocytes and neutrophils are highly activated during malaria. Monocytes produced high levels of IL-1β, IL-6 and TNF-α during acute malaria. On the other hand, neutrophils were a poor source of cytokines, but displayed an enhanced phagocytic activity and superoxide production. Unexpectedly, we noticed an impaired chemotaxis of neutrophils towards an IL-8 (CXCL8) gradient. We proposed that neutrophil paralysis is in part responsible for the enhanced susceptibility to bacterial infection observed in malaria patients.
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Affiliation(s)
| | - Silvia Cellone Trevelin
- Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Fernando Queiroz Cunha
- Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Bruno Coelho Rocha
- Laboratório de Imunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Pedro Augusto Carvalho Costa
- Laboratório de Imunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | - Humberto Doriguêtto Gravina
- Laboratório de Imunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Mauro Shugiro Tada
- Centro de Pesquisas em Medicina Tropical de Rondônia, Porto Velho, Rondônia, Brazil
| | | | - Douglas Taylor Golenbock
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Lis Ribeiro do Valle Antonelli
- Laboratório de Imunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
| | - Ricardo T. Gazzinelli
- Laboratório de Imunopatologia, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Belo Horizonte, Minas Gerais, Brazil
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail:
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González R, Ataíde R, Naniche D, Menéndez C, Mayor A. HIV and malaria interactions: where do we stand? Expert Rev Anti Infect Ther 2012; 10:153-65. [PMID: 22339190 DOI: 10.1586/eri.11.167] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Reversing the spread of HIV infection and the incidence of malaria constitute two of the Millenium Development Goals. However, despite recent achievements, both diseases still entail global heath problems. Furthermore, their overlapping geographical distribution raises concerns and challenges for potential immunological, clinical and therapeutic interactions. It has been reported that HIV infection increases malaria susceptibility and reduces the efficacy of antimalarial drugs. On the other hand, the effect of malaria on HIV-infected individuals has also been explored, with the parasitic infection increasing the risk of HIV disease progression and mother-to-child transmission of HIV. The spread of malaria and parasite resistance to antimalarials could also be accelerated by HIV-associated immunosuppresion. Current knowledge of the epidemiological, clinical, immunological and therapeutic interactions of the two diseases is reviewed in this article. We focus on the latest available data, pointing out key future research areas and challenges of the field.
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Affiliation(s)
- Raquel González
- Barcelona Centre for International Heath Research (CRESIB), Hospital Clínic/IDIBAPS, Universitat de Barcelona, Spain
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129
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Edwards MD, Morris GAJ, Burr SE, Walther M. Evaluating the frequency of bacterial co-infections in children recruited into a malaria pathogenesis study in The Gambia, West Africa using molecular methods. Mol Cell Probes 2012; 26:151-8. [PMID: 22548974 DOI: 10.1016/j.mcp.2012.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 04/12/2012] [Accepted: 04/12/2012] [Indexed: 10/28/2022]
Abstract
Systemic bacteraemia has been reported in children with severe Plasmodium falciparum malaria in Sub Saharan Africa, making the identification or exclusion of concurrent infections a prerequisite for adequate treatment and studies of the immune responses to particular infections. Given the overlap in clinical signs in humans between malaria and, for example, pneumonia, the true cause of severe illness is sometimes difficult to establish. Traditional microbiological culture methods employed to detect systemic bacteraemia are often time consuming and have modest sensitivity. Therefore, molecular methods have become increasingly used in the diagnosis of septicaemia. Here, we evaluated the usefulness of both broad-range 16S rRNA PCR, in conjunction with DNA sequencing and species-specific PCR targeting of Streptococcus pneumoniae and non-typhoidal Salmonella, to screen for bacterial co-infections in blood samples from children enrolled in a malaria pathogenesis study. PCR revealed no test-positive results for these pathogens and DNA sequencing of 16S rRNA amplicons identified the presence of bacterial genomic DNA (most probably from environmental bacterial sources) in a large proportion of samples. We demonstrate that the issue of potential mixed bacteraemic infection and/or background bacterial genomic DNA, which may relate to co-migration of PCR amplicons on agarose gels, can be overcome by using denaturing gradient gel electrophoresis (DGGE). PCR for Plasmodium spp. was also performed on genomic DNA from bloods from Gambian children with pneumonia, in order to estimate the prevalence of Plasmodium/pneumonia co-infections in the study population. While 12.2% of samples were test-positive, parasite density was very low and did not vary significantly between cases and controls.
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Affiliation(s)
- Mathew D Edwards
- Medical Research Council Unit, The Gambia, Fajara, PO Box 273, Banjul, Gambia
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130
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Glennie SJ, Nyirenda M, Williams NA, Heyderman RS. Do multiple concurrent infections in African children cause irreversible immunological damage? Immunology 2012; 135:125-32. [PMID: 22044389 DOI: 10.1111/j.1365-2567.2011.03523.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Much of the developing world, particularly sub-Saharan Africa, has high levels of morbidity and mortality associated with infectious diseases. The greatest risk of invasive disease is in the young, the malnourished and HIV-infected individuals. In many regions in Africa these vulnerable groups and the wider general population are under constant immune pressure from a range of environmental factors, under-nutrition and multiple concurrent infections from birth through to adulthood. Intermittent microbial exposure during childhood is required for the generation of naturally acquired immunity capable of protection against a range of infectious diseases in adult life. However, in the context of a resource-poor setting, the heavy burden of malarial, diarrhoeal and respiratory infections in childhood may subvert or suppress immune responses rather than protect, resulting in sub-optimal immunity. This review will explore how poor maternal health, HIV exposure, socio-economic and seasonal factors conspire to weaken childhood immune defences to disease and discuss the hypothesis that recurrent infections may drive immune dysregulation, leading to relative immune senescence and premature immunological aging.
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Affiliation(s)
- Sarah J Glennie
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.
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131
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Makoka MH, Miller WC, Hoffman IF, Cholera R, Gilligan PH, Kamwendo D, Malunga G, Joaki G, Martinson F, Hosseinipour MC. Bacterial infections in Lilongwe, Malawi: aetiology and antibiotic resistance. BMC Infect Dis 2012; 12:67. [PMID: 22436174 PMCID: PMC3342226 DOI: 10.1186/1471-2334-12-67] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 03/21/2012] [Indexed: 11/28/2022] Open
Abstract
Background Life-threatening infections present major challenges for health systems in Malawi and the developing world because routine microbiologic culture and sensitivity testing are not performed due to lack of capacity. Use of empirical antimicrobial therapy without regular microbiologic surveillance is unable to provide adequate treatment in the face of emerging antimicrobial resistance. This study was conducted to determine antimicrobial susceptibility patterns in order to inform treatment choices and generate hospital-wide baseline data. Methods Culture and susceptibility testing was performed on various specimens from patients presenting with possible infectious diseases at Kamuzu Central Hospital, Lilongwe, Malawi. Results Between July 2006 and December 2007 3104 specimens from 2458 patients were evaluated, with 60.1% from the adult medical service. Common presentations were sepsis, meningitis, pneumonia and abscess. An etiologic agent was detected in 13% of patients. The most common organisms detected from blood cultures were Staphylococcus aureus, Escherichia coli, Salmonella species and Streptococcus pneumoniae, whereas Streptococcus pneumoniae and Cryptococcus neoformans were most frequently detected from cerebrospinal fluid. Haemophilus influenzae was rarely isolated. Resistance to commonly used antibiotics was observed in up to 80% of the isolates while antibiotics that were not commonly in use maintained susceptibility. Conclusions There is widespread resistance to almost all of the antibiotics that are empirically used in Malawi. Antibiotics that have not been widely introduced in Malawi show better laboratory performance. Choices for empirical therapy in Malawi should be revised accordingly. A microbiologic surveillance system should be established and prudent use of antimicrobials promoted to improve patient care.
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132
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Hochman S, Kim K. The Impact of HIV Coinfection on Cerebral Malaria Pathogenesis. JOURNAL OF NEUROPARASITOLOGY 2012; 3:235547. [PMID: 22545215 PMCID: PMC3336366 DOI: 10.4303/jnp/235547] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
HIV infection is widespread throughout the world and is especially prevalent in sub-Saharan Africa and Asia. Similarly, Plasmodium falciparum, the most common cause of severe malaria, affects large areas of sub-Saharan Africa, the Indian subcontinent, and Southeast Asia. Although initial studies suggested that HIV and malaria had independent impact upon patient outcomes, recent studies have indicated a more significant interaction. Clinical studies have shown that people infected with HIV have more frequent and severe episodes of malaria, and parameters of HIV disease progression worsen in individuals during acute malaria episodes. However, the effect of HIV on development of cerebral malaria, a manifestation of P. falciparum infection that is frequently fatal, has not been characterized. We review clinical and basic science studies pertaining to HIV and malaria coinfection and cerebral malaria in particular in order to highlight the likely role HIV plays in exacerbating cerebral malaria pathogenesis.
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Affiliation(s)
- Sarah Hochman
- Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA
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133
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Challenges in the Management of HIV-Infected Malnourished Children in Sub-Saharan Africa. AIDS Res Treat 2012; 2012:790786. [PMID: 22606378 PMCID: PMC3353143 DOI: 10.1155/2012/790786] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 11/16/2011] [Accepted: 11/17/2011] [Indexed: 12/20/2022] Open
Abstract
Infection with HIV, and oftentimes coinfection with TB, complicates the care of severely malnourished children in sub-Saharan Africa. These superimposed infections challenge clinicians faced with a population of malnourished children for whose care evidence-based guidelines have not kept up. Even as the care of HIV-uninfected malnourished children has improved dramatically with the advent of community-based care and even as there are hopeful signs that the HIV epidemic may be stabilizing or ameliorating, significant gaps remain in the care of malnourished children with HIV. Here we summarize what is currently known, what remains unknown, and what remains challenging about how to treat severely malnourished children with HIV and TB.
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134
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Tabu C, Breiman RF, Ochieng B, Aura B, Cosmas L, Audi A, Olack B, Bigogo G, Ongus JR, Fields P, Mintz E, Burton D, Oundo J, Feikin DR. Differing burden and epidemiology of non-Typhi Salmonella bacteremia in rural and urban Kenya, 2006-2009. PLoS One 2012; 7:e31237. [PMID: 22363591 PMCID: PMC3283637 DOI: 10.1371/journal.pone.0031237] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Accepted: 01/05/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The epidemiology of non-Typhi Salmonella (NTS) bacteremia in Africa will likely evolve as potential co-factors, such as HIV, malaria, and urbanization, also change. METHODS As part of population-based surveillance among 55,000 persons in malaria-endemic, rural and malaria-nonendemic, urban Kenya from 2006-2009, blood cultures were obtained from patients presenting to referral clinics with fever ≥38.0°C or severe acute respiratory infection. Incidence rates were adjusted based on persons with compatible illnesses, but whose blood was not cultured. RESULTS NTS accounted for 60/155 (39%) of blood culture isolates in the rural and 7/230 (3%) in the urban sites. The adjusted incidence in the rural site was 568/100,000 person-years, and the urban site was 51/100,000 person-years. In both sites, the incidence was highest in children <5 years old. The NTS-to-typhoid bacteremia ratio in the rural site was 4.6 and in the urban site was 0.05. S. Typhimurium represented >85% of blood NTS isolates in both sites, but only 21% (urban) and 64% (rural) of stool NTS isolates. Overall, 76% of S. Typhimurium blood isolates were multi-drug resistant, most of which had an identical profile in Pulse Field Gel Electrophoresis. In the rural site, the incidence of NTS bacteremia increased during the study period, concomitant with rising malaria prevalence (monthly correlation of malaria positive blood smears and NTS bacteremia cases, Spearman's correlation, p = 0.018 for children, p = 0.16 adults). In the rural site, 80% of adults with NTS bacteremia were HIV-infected. Six of 7 deaths within 90 days of NTS bacteremia had HIV/AIDS as the primary cause of death assigned on verbal autopsy. CONCLUSIONS NTS caused the majority of bacteremias in rural Kenya, but typhoid predominated in urban Kenya, which most likely reflects differences in malaria endemicity. Control measures for malaria, as well as HIV, will likely decrease the burden of NTS bacteremia in Africa.
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Affiliation(s)
- Collins Tabu
- Field Epidemiology and Laboratory Training Program, Nairobi, Kenya
- Ministry of Public Health and Sanitation, Nairobi, Kenya
| | - Robert F. Breiman
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Nairobi, Kenya
- International Emerging Infections Program, Global Disease Detection, Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Benjamin Ochieng
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Barrack Aura
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Leonard Cosmas
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Allan Audi
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Beatrice Olack
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Godfrey Bigogo
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Juliette R. Ongus
- Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya
| | - Patricia Fields
- Division of Foodborne, Waterborne, and Environmental Diseases, Centers For Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Eric Mintz
- Division of Foodborne, Waterborne, and Environmental Diseases, Centers For Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Deron Burton
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Nairobi, Kenya
- International Emerging Infections Program, Global Disease Detection, Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Joe Oundo
- Field Epidemiology and Laboratory Training Program, Nairobi, Kenya
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Nairobi, Kenya
| | - Daniel R. Feikin
- Kenya Medical Research Institute/Centers for Disease Control and Prevention, Nairobi, Kenya
- International Emerging Infections Program, Global Disease Detection, Centers for Disease Control and Prevention, Nairobi, Kenya
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Cunnington AJ, de Souza JB, Walther M, Riley EM. Malaria impairs resistance to Salmonella through heme- and heme oxygenase-dependent dysfunctional granulocyte mobilization. Nat Med 2011; 18:120-7. [PMID: 22179318 PMCID: PMC3272454 DOI: 10.1038/nm.2601] [Citation(s) in RCA: 183] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 11/08/2011] [Indexed: 12/04/2022]
Abstract
In sub-Saharan Africa, invasive non-Typhoid Salmonella (NTS) is a common and often fatal complication of Plasmodium falciparum infection. Induction of heme oxygenase-1 (HO-1) mediates tolerance to the cytotoxic effects of heme during malarial hemolysis but might impair resistance to NTS by limiting production of bactericidal reactive oxygen species. We show that co-infection of mice with Plasmodium yoelii 17XNL (Py17XNL) and S. typhimurium causes acute, fatal bacteremia with increased bacterial load; features reproduced by phenylhydrazine hemolysis or hemin administration. S. typhimurium localized predominantly in granulocytes. Py17XNL, phenylhydrazine and hemin caused premature mobilization of granulocytes from bone marrow with a quantitative defect in the oxidative burst. Inhibition of HO by tin protoporphyrin abrogated the impairment of resistance to S. typhimurium by hemolysis. Thus a mechanism of tolerance to one infection, malaria, impairs resistance to another, NTS. Furthermore, HO inhibitors may be useful adjunctive therapy for NTS infection in the context of hemolysis.
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Affiliation(s)
- Aubrey J Cunnington
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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137
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Digestive vacuoles of Plasmodium falciparum are selectively phagocytosed by and impair killing function of polymorphonuclear leukocytes. Blood 2011; 118:4946-56. [DOI: 10.1182/blood-2011-05-353920] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
AbstractSequestration of parasitized erythrocytes and dysregulation of the coagulation and complement system are hallmarks of severe Plasmodium falciparum malaria. A link between these events emerged through the discovery that the parasite digestive vacuole (DV), which is released together with infective merozoites into the bloodstream, dually activates the intrinsic clotting and alternative complement pathway. Complement attack occurs exclusively on the membrane of the DVs, and the question followed whether DVs might be marked for uptake by polymorphonuclear granulocytes (PMNs). We report that DVs are indeed rapidly phagocytosed by PMNs after schizont rupture in active human serum. Uptake of malaria pigment requires an intact DV membrane and does not occur when the pigment is extracted from the organelle. Merozoites are not opsonized and escape phagocytosis in nonimmune serum. Antimalarial Abs mediate some uptake of the parasites, but to an extent that is not sufficient to markedly reduce reinvasion rates. Phagocytosis of DVs induces a vigorous respiratory burst that drives the cells into a state of functional exhaustion, blunting the production of reactive oxygen species (ROS) and microbicidal activity upon challenge with bacterial pathogens. Systemic overloading of PMNs with DVs may contribute to the enhanced susceptibility of patients with severe malaria toward invasive bacterial infections.
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138
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Mtove G, Amos B, Nadjm B, Hendriksen ICE, Dondorp AM, Mwambuli A, Kim DR, Ochiai RL, Clemens JD, von Seidlein L, Reyburn H, Deen J. Decreasing incidence of severe malaria and community-acquired bacteraemia among hospitalized children in Muheza, north-eastern Tanzania, 2006-2010. Malar J 2011; 10:320. [PMID: 22029477 PMCID: PMC3219788 DOI: 10.1186/1475-2875-10-320] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 10/27/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The annual incidence and temporal trend of severe malaria and community-acquired bacteraemia during a four-year period in Muheza, Tanzania was assessed. METHODS Data on severely ill febrile children aged 2 months to 14 years from three prospective studies conducted at Muheza District Hospital from 2006 to 2010 was pooled and analysed. On admission, each enrolled child had a thin and thick blood film and at least one rapid diagnostic test for falciparum malaria, as well as a blood culture. The annual incidence of bacteraemia and severe malaria among children coming from Muheza was calculated and their temporal trend was assessed. RESULTS Overall, 1, 898 severe falciparum malaria and 684 bacteraemia cases were included. Of these, 1, 356 (71%) and 482 (71%), respectively, were from the referral population of Muheza. The incidence of falciparum malaria and all-cause bacteraemia in Muheza decreased five-fold and three-fold, respectively, from the first to the fourth year of surveillance (p < 0.0001). During this period, the median ages of children from Muheza admitted with severe malaria increased from 1.7 to 2.5 years (p < 0.0001). The reduction in all-cause bacteraemia was mainly driven by the 11-fold decline in the incidence of non-typhoidal salmonellosis. The annual incidences of Haemophilus influenzae and pneumococcal invasive bacterial infections decreased as well but were much fewer in number. CONCLUSIONS These results add to the growing evidence of the decline in malaria associated with a decrease in non-typhoidal salmonellosis and possibly other bacteraemias. Malarial prevention and control strategies may provide a greater benefit than the mere reduction of malaria alone.
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Affiliation(s)
- George Mtove
- National Institute for Medical Research - Amani Centre, Tanga, Tanzania
- Joint Malaria Programme, Moshi, Tanzania
| | - Ben Amos
- Joint Malaria Programme, Moshi, Tanzania
- Teule Hospital, Muheza, Tanga, Tanzania
| | - Behzad Nadjm
- Joint Malaria Programme, Moshi, Tanzania
- London School of Hygiene and Tropical Medicine, London, UK
| | - Ilse CE Hendriksen
- Joint Malaria Programme, Moshi, Tanzania
- Mahidol-Oxford Research Unit, Bangkok, Thailand
| | | | | | - Deok Ryun Kim
- International Vaccine Institute, SNU Research Park, San 4-8, Nakseongdae-dong, Gwanak-gu, Seoul, Korea
| | - R Leon Ochiai
- International Vaccine Institute, SNU Research Park, San 4-8, Nakseongdae-dong, Gwanak-gu, Seoul, Korea
| | - John D Clemens
- International Vaccine Institute, SNU Research Park, San 4-8, Nakseongdae-dong, Gwanak-gu, Seoul, Korea
| | - Lorenz von Seidlein
- Joint Malaria Programme, Moshi, Tanzania
- Menzies School of Health Research, Casuarina, NT, Australia
| | - Hugh Reyburn
- Joint Malaria Programme, Moshi, Tanzania
- London School of Hygiene and Tropical Medicine, London, UK
| | - Jacqueline Deen
- Joint Malaria Programme, Moshi, Tanzania
- International Vaccine Institute, SNU Research Park, San 4-8, Nakseongdae-dong, Gwanak-gu, Seoul, Korea
- Menzies School of Health Research, Casuarina, NT, Australia
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Scott JAG, Berkley JA, Mwangi I, Ochola L, Uyoga S, Macharia A, Ndila C, Lowe BS, Mwarumba S, Bauni E, Marsh K, Williams TN. Relation between falciparum malaria and bacteraemia in Kenyan children: a population-based, case-control study and a longitudinal study. Lancet 2011; 378:1316-23. [PMID: 21903251 PMCID: PMC3192903 DOI: 10.1016/s0140-6736(11)60888-x] [Citation(s) in RCA: 231] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Many investigators have suggested that malaria infection predisposes individuals to bacteraemia. We tested this hypothesis with mendelian randomisation studies of children with the malaria-protective phenotype of sickle-cell trait (HbAS). METHODS This study was done in a defined area around Kilifi District Hospital, Kilifi, Kenya. We did a matched case-control study to identify risk factors for invasive bacterial disease, in which cases were children aged 3 months to 13 years who were admitted to hospital with bacteraemia between Sept 16, 1999, and July 31, 2002. We aimed to match two controls, by age, sex, location, and time of recruitment, for every case. We then did a longitudinal case-control study to assess the relation between HbAS and invasive bacterial disease as malaria incidence decreased. Cases were children aged 0-13 years who were admitted to hospital with bacteraemia between Jan 1, 1999, and Dec 31, 2007. Controls were born in the study area between Jan 1, 2006, and June 23, 2009. Finally, we modelled the annual incidence of bacteraemia against the community prevalence of malaria during 9 years with Poisson regression. RESULTS In the matched case-control study, we recruited 292 cases-we recruited two controls for 236, and one for the remaining 56. Sickle-cell disease, HIV, leucocyte haemozoin pigment, and undernutrition were positively associated with bacteraemia and HbAS was strongly negatively associated with bacteraemia (odds ratio 0·36; 95% CI 0·20-0·65). In the longitudinal case-control study, we assessed data from 1454 cases and 10,749 controls. During the study period, the incidence of admission to hospital with malaria per 1000 child-years decreased from 28·5 to 3·45, with a reduction in protection afforded by HbAS against bacteraemia occurring in parallel (p=0·0008). The incidence of hospital admissions for bacteraemia per 1000 child-years also decreased from 2·59 to 1·45. The bacteraemia incidence rate ratio associated with malaria parasitaemia was 6·69 (95% CI 1·31-34·3) and, at a community parasite prevalence of 29% in 1999, 62% (8·2-91) of bacteraemia cases were attributable to malaria. INTERPRETATION Malaria infection strongly predisposes individuals to bacteraemia and can account for more than half of all cases of bacteraemia in malaria-endemic areas. Interventions to control malaria will have a major additional benefit by reducing the burden of invasive bacterial disease. FUNDING Wellcome Trust.
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Affiliation(s)
- J Anthony G Scott
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
- INDEPTH Network, Accra, Ghana
- Correspondence to: Dr Anthony Scott, KEMRI-Wellcome Trust Programme, Centre for Geographic Medicine Research-Coast, P O Box 230, Kilifi, Kenya
| | - James A Berkley
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Isaiah Mwangi
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Lucy Ochola
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Sophie Uyoga
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Alexander Macharia
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Carolyne Ndila
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Brett S Lowe
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Salim Mwarumba
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Evasius Bauni
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Kevin Marsh
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Thomas N Williams
- Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
- INDEPTH Network, Accra, Ghana
- Department of Paediatrics, University of Oxford, Oxford, UK
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140
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Abstract
PURPOSE OF REVIEW This review highlights and discusses important publications over the past 12 months providing new insights on invasive nontyphoidal Salmonella (iNTS) disease. RECENT FINDINGS There have been informative new estimates of the burden of iNTS in Asia and in high-resource, low-incidence settings. Important information has emerged in the last year about the relationships between HIV, malaria, iNTS and typhoid fever in adults and children in Africa. HIV causes susceptibility to iNTS disease, but has been shown to be protective against typhoid fever. Clinical guidelines for presumptive diagnosis frequently fail to identify iNTS disease in Africa, and there remains a need for improved diagnostic tools. Experimental studies in humans have helped us to understand the intracellular pathogenesis of iNTS and to direct the search for appropriate protein vaccine targets. SUMMARY The most important remaining gap in our knowledge is probably an understanding of how NTS is transmitted, and the nature of the relationship between diarrhoeal disease, carriage and invasive disease in Africa, so that diagnostic and prevention tools can be appropriately directed.
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Affiliation(s)
- Melita A Gordon
- Department of Gastroenterology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK.
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141
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Glennie SJ, Sepako E, Mzinza D, Harawa V, Miles DJC, Jambo KC, Gordon SB, Williams NA, Heyderman RS. Impaired CD4 T cell memory response to Streptococcus pneumoniae precedes CD4 T cell depletion in HIV-infected Malawian adults. PLoS One 2011; 6:e25610. [PMID: 21980502 PMCID: PMC3181344 DOI: 10.1371/journal.pone.0025610] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 09/07/2011] [Indexed: 12/04/2022] Open
Abstract
OBJECTIVE Invasive pneumococcal disease (IPD) is a leading cause of morbidity and mortality in HIV-infected African adults. CD4 T cell depletion may partially explain this high disease burden but those with relatively preserved T cell numbers are still at increased risk of IPD. This study evaluated the extent of pneumococcal-specific T cell memory dysfunction in asymptomatic HIV infection early on in the evolution of the disease. METHODS Peripheral blood mononuclear cells were isolated from asymptomatic HIV-infected and HIV-uninfected Malawian adults and stained to characterize the underlying degree of CD4 T cell immune activation, senescence and regulation. Pneumococcal-specific T cell proliferation, IFN-γ, IL-17 production and CD154 expression was assessed using flow cytometry and ELISpot. RESULTS We find that in asymptomatic HIV-infected Malawian adults, there is considerable immune disruption with an increase in activated and senescent CD4+CD38+PD-1+ and CD4+CD25(high)Foxp3+ Treg cells. In the context of high pneumococcal exposure and therefore immune stimulation, show a failure in pneumococcal-specific memory T cell proliferation, skewing of T cell cytokine production with preservation of interleukin-17 but decreased interferon-gamma responses, and failure of activated T cells to express the co-stimulatory molecule CD154. CONCLUSION Asymptomatic HIV-infected Malawian adults show early signs of pneumococcal- specific immune dysregulation with a shift in the balance of CD4 memory, T helper 17 cells and Treg. Together these data offer a mechanistic understanding of how antigen-specific T cell dysfunction occurs prior to T cell depletion and may explain the early susceptibility to IPD in those with relatively preserved CD4 T cell numbers.
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Affiliation(s)
- Sarah J Glennie
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi.
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Flateau C, Le Loup G, Pialoux G. Consequences of HIV infection on malaria and therapeutic implications: a systematic review. THE LANCET. INFECTIOUS DISEASES 2011; 11:541-56. [PMID: 21700241 DOI: 10.1016/s1473-3099(11)70031-7] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Despite recent changes in the epidemiology of HIV infection and malaria and major improvements in their control, these diseases remain two of the most important infectious diseases and global health priorities. As they have overlapping distribution in tropical areas, particularly sub-Saharan Africa, any of their clinical, diagnostic, and therapeutic interactions might have important effects on patient care and public health policy. The biological basis of these interactions is well established. HIV infection induces cellular depletion and early abnormalities of CD4+ T cells, decreases CD8+ T-cell counts and function (cellular immunity), causes deterioration of specific antigen responses (humoral immunity), and leads to alteration of innate immunity through impairment of cytolytic activity and cytokine production by natural killer cells. Therefore, HIV infection affects the immune response to malaria, particularly premunition in adolescents and adults, and pregnancy-specific immunity, leading to different patterns of disease in HIV-infected patients compared with HIV-uninfected patients. In this systematic review, we collate data on the effects of HIV on malaria and discuss their therapeutic consequences. HIV infection is associated with increased prevalence and severity of clinical malaria and impaired response to antimalarial treatment, depending on age, immunodepression, and previous immunity to malaria. HIV also affects pregnancy-specific immunity to malaria and response to intermittent preventive treatment. Co-trimoxazole (trimethoprim-sulfamethoxazole) prophylaxis and antiretroviral treatment reduce occurrence of clinical malaria; however, these therapies interact with antimalarial drugs, and new therapeutic guidelines are needed for concomitant use.
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Affiliation(s)
- Clara Flateau
- Service des Maladies Infectieuses et Tropicales, Hôpital Tenon, AP-HP, University Pierre et Marie Curie, Paris, France
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143
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Hickey PW, Cape KE, Masuoka P, Campos JM, Pastor W, Wong EC, Singh N. A local, regional, and national assessment of pediatric malaria in the United States. J Travel Med 2011; 18:153-60. [PMID: 21539653 DOI: 10.1111/j.1708-8305.2011.00514.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Imported malaria remains a public health concern in the United States, but the health impact on children and the financial costs to society have not been well defined. METHODS Inpatient and outpatient malaria cases diagnosed at Children's National Medical Center (CNMC) in Washington, DC over an 8-year period are retrospectively reviewed. Cases are mapped against Census Bureau population data. These observations are compared with the national burden of pediatric malaria, including both disease severity and cost, by reviewing inpatient malaria cases in the Pediatric Health Information System (PHIS), January 2003 to June 2008. RESULTS At CNMC, malaria most commonly affects children who traveled to West Africa to visit friends and relatives. Poor adherence to prophylaxis and self-treatment with antimalarial medications were commonly identified. Mapping demonstrates case clustering in communities with large sub-Saharan African populations. The cumulative incidence (CI) of malaria at CNMC of 9.0 per 10,000 admissions is 7.6 times the national average. The CI of malaria at PHIS hospitals is 1.2 per 10,000 admissions with an average cost of $17,519. CONCLUSIONS Malaria is a preventable disease for which the risk to life and costs of treatment are significant. Patterns of risk can be used by health planners to target prevention strategies at the community level. In regions with a high density of immigrants, particularly from sub-Saharan Africa, physicians must be aware of the risk, understand recommended prophylaxis and treatment regimens, and advocate for their appropriate use in the community.
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Affiliation(s)
- Patrick W Hickey
- Department of Preventive Medicine & Biometrics, Uniformed Services University, Bethesda, MD, USA
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144
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In vivo and in vitro antimalarial properties of azithromycin-chloroquine combinations that include the resistance reversal agent amlodipine. Antimicrob Agents Chemother 2011; 55:3115-24. [PMID: 21464242 DOI: 10.1128/aac.01566-10] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Evidence of emerging Plasmodium falciparum resistance to artemisinin-based combination therapies, documented in western Cambodia, underscores the continuing need to identify new antimalarial combinations. Given recent reports of the resurgence of chloroquine-sensitive P. falciparum parasites in Malawi, after the enforced and prolonged withdrawal of this drug, and indications of a possible synergistic interaction with the macrolide azithromycin, we sought to further characterize chloroquine-azithromycin combinations for their in vitro and in vivo antimalarial properties. In vitro 96-h susceptibility testing of chloroquine-azithromycin combinations showed mostly additive interactions against freshly cultured P. falciparum field isolates obtained from Mali. Some evidence of synergy, however, was apparent at the fractional 90% inhibitory concentration level. Additional in vitro testing highlighted the resistance reversal properties of amlodipine for both chloroquine and quinine. In vivo experiments, using the Peters 4-day suppressive test in a P. yoelii mouse model, revealed up to 99.9% suppression of parasitemia following treatment with chloroquine-azithromycin plus the R enantiomer of amlodipine. This enantiomer was chosen because it does not manifest the cardiac toxicities observed with the racemic mixture. Pharmacokinetic/pharmacodynamic analyses in this rodent model and subsequent extrapolation to a 65-kg adult led to the estimation that 1.8 g daily of R-amlodipine would be required to achieve similar efficacy in humans, for whom this is likely an unsafe dose. While these data discount amlodipine as an additional partner for chloroquine-based combination therapy, our studies continue to support azithromycin as a safe and effective addition to antimalarial combination therapies.
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145
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White VA. Malaria in Malawi: inside a research autopsy study of pediatric cerebral malaria. Arch Pathol Lab Med 2011; 135:220-6. [PMID: 21284442 DOI: 10.5858/135.2.220] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
CONTEXT Malaria is still a major cause of death in sub-Saharan Africa. OBJECTIVES To describe my participation as a pathologist in a research autopsy study in Malawi and to examine retinal pathologic findings in cerebral malaria and correlate them with those in the brain. To describe the challenges of conducting a research study in sub-Saharan Africa and the personal and scientific benefits resulting from this. DESIGN Children with coma are admitted to the pediatric research ward, classified according to the clinical definition of severe malaria or another cause of coma, evaluated, and treated systematically. The eyes are examined by indirect ophthalmoscopy after dilatation. If a child dies and permission is given, a standardized autopsy is carried out. The patients' condition is then reclassified pathologically. RESULTS Ninety autopsies have been completed, with the cause of death confirmed as cerebral malaria in 64 cases (71.1%). These patients showed heavy parasite sequestration and often extravascular pathologic findings in the brain, retina, gastrointestinal tract, and subcutaneous fat. Clinical and pathologic findings in the retina correlated with those in the brain, and ophthalmoscopy has become a useful tool in the diagnosis and prognosis of children with cerebral malaria. Twenty-eight percent of patients clinically classified as having cerebral malaria showed another cause of death and no malarial pathologic process or retinopathy. CONCLUSIONS The human, financial, and transportation resources and organization required for this autopsy project are substantial. The scientific benefits are now becoming evident after sufficient autopsies have been completed for detailed comparisons. Personal benefits include the opportunity to work and travel in an African setting and to develop collaborations world-wide.
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Affiliation(s)
- Valerie A White
- Department of Pathology, Vancouver General Hospital, British Columbia, Canada.
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146
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Goh YS, Grant AJ, Restif O, McKinley TJ, Armour KL, Clark MR, Mastroeni P. Human IgG isotypes and activating Fcγ receptors in the interaction of Salmonella enterica serovar Typhimurium with phagocytic cells. Immunology 2011; 133:74-83. [PMID: 21323662 DOI: 10.1111/j.1365-2567.2011.03411.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Several classes and multiple subclasses of immunoglobulins are produced towards protein and polysaccharide antigens in response to Salmonella infection and play a key role in protection against systemic disease. The targeting of Salmonella to Fc receptors (FcR) on phagocytes is a key step in the antibody-mediated antibacterial functions of host cells. We wished to compare the relative efficiency of different human IgG subclasses, which targeted the Salmonella enterica OmpA surface protein in modulating the interaction of bacteria with human phagocytes. To this end, we developed a novel system by tagging OmpA with a foreign CD52 mimotope (TSSPSAD) and opsonizing the bacteria with a panel of humanized CD52 antibodies that share the same antigen-binding V-region, but have constant regions of different subclasses. Our data revealed that opsonization with all the IgG subclasses increases Salmonella uptake by human phagocytes. IgG3 resulted in the highest level of bacterial uptake and the highest average bacterial load per infected cell, which was closely followed by IgG1, then IgG4 and lastly IgG2. Phagocytosis mediated by IgG1, IgG3 and IgG4 had a higher dependency on FcγRI than FcγRIIA, whereas IgG2-mediated phagocytosis required FcγRIIA more than FcγRI. The results show that IgG binding to OmpA increases the uptake of Salmonella by human phagocytic cells and that the efficiency of this process depends both on the subclass of the IgG and the type of FcR that is available for antibody binding.
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Affiliation(s)
- Yun S Goh
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
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147
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Were T, Davenport GC, Hittner JB, Ouma C, Vulule JM, Ong'echa JM, Perkins DJ. Bacteremia in Kenyan children presenting with malaria. J Clin Microbiol 2011; 49:671-6. [PMID: 21106789 PMCID: PMC3043473 DOI: 10.1128/jcm.01864-10] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 11/15/2010] [Indexed: 11/20/2022] Open
Abstract
Since the etiologies and clinical outcomes of bacteremia in children with Plasmodium falciparum infections, particularly in areas of holoendemic malaria transmission, are largely unexplored, blood cultures and comprehensive clinical, laboratory, hematological, and nutritional parameters for malaria-infected children (aged 1 to 36 months, n = 585 patients) were investigated at a rural hospital in western Kenya. After the exclusion of contaminant microorganisms, the prevalence of bacteremia was 11.7% in the cohort (n = 506), with nontyphoidal Salmonella spp. being the most common isolates (42.4%). Bacteremia was found to occur in a significantly higher proportion of females than males and was associated with elevated blood glucose concentrations and lowered malaria parasite and hemoglobin (Hb) levels compared to those in abacteremic participants. In addition, the incidences of respiratory distress and severe malarial anemia (SMA; Hb level of <6.0 g/dl) were nonsignificantly greater in children with bacteremia. Mortality was 8.5-fold higher in children with bacteremia. Multivariate logistic regression analyses revealed that bacteremia was significantly associated with reduced incidences of high-density parasitemia (HDP; ≥ 10,000/μl) and increased incidences of malnutrition (i.e., underweight; weight-for-age Z score of <-2 using the NCHS system). Since previous studies showed that bacteremia caused by Gram-negative organisms is associated with enhanced anemia and mortality, multivariate logistic regression was also performed separately for randomly age- and gender-matched children with bacteremia caused by Gram-negative organisms (n = 37) and for children found to be abacteremic (n = 74). These results revealed that the presence of bacteremia caused by Gram-negative organisms was significantly associated with reduced HDP, enhanced susceptibility to respiratory distress, SMA (Hb level of <6.0 g/dl), and being underweight (Z score, <-2). Data presented here from a region of holoendemic P. falciparum transmission demonstrate that although bacteremia is associated with reduced malaria parasitemia, a number of unfavorable clinical outcomes, including malnutrition, respiratory distress, anemia, and mortality, are elevated in children with bacteremia, particularly in cases of Gram-negative origin.
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Affiliation(s)
- T. Were
- University of New Mexico/Kenya Medical Research Institute, Laboratories of Parasitic and Viral Diseases, Centre for Global Health Research, Kisumu, Kenya
- Department of Pathology, School of Health Sciences, Kenyatta University, Nairobi, Kenya
| | - G. C. Davenport
- University of New Mexico/Kenya Medical Research Institute, Laboratories of Parasitic and Viral Diseases, Centre for Global Health Research, Kisumu, Kenya
- Center for Global Health, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico
- Center for Infectious Diseases and Immunity, University of New Mexico Health Sciences, Albuquerque, New Mexico
| | - J. B. Hittner
- University of New Mexico/Kenya Medical Research Institute, Laboratories of Parasitic and Viral Diseases, Centre for Global Health Research, Kisumu, Kenya
- Department of Psychology, College of Charleston, Charleston, South Carolina
| | - C. Ouma
- University of New Mexico/Kenya Medical Research Institute, Laboratories of Parasitic and Viral Diseases, Centre for Global Health Research, Kisumu, Kenya
- Department of Biomedical Sciences and Technology, Maseno University, Kisumu, Kenya
| | - J. M. Vulule
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - J. M. Ong'echa
- University of New Mexico/Kenya Medical Research Institute, Laboratories of Parasitic and Viral Diseases, Centre for Global Health Research, Kisumu, Kenya
- Center for Global Health, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - D. J. Perkins
- University of New Mexico/Kenya Medical Research Institute, Laboratories of Parasitic and Viral Diseases, Centre for Global Health Research, Kisumu, Kenya
- Center for Global Health, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, New Mexico
- Center for Infectious Diseases and Immunity, University of New Mexico Health Sciences, Albuquerque, New Mexico
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148
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Färnert A, Gwer S, Berkley JA. Clinical considerations for antibiotic choices in the treatment of severe malaria. Trends Parasitol 2010; 26:465-6. [DOI: 10.1016/j.pt.2010.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 05/31/2010] [Accepted: 06/01/2010] [Indexed: 10/19/2022]
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149
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Glennie SJ, Williams NA, Heyderman RS. Mucosal immunity in resource-limited setting: is the battle ground different? Trends Microbiol 2010; 18:487-93. [PMID: 20832319 DOI: 10.1016/j.tim.2010.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 07/29/2010] [Accepted: 08/06/2010] [Indexed: 01/28/2023]
Abstract
In many developing countries, populations are under considerable pressure from high bacterial exposure on mucosal surfaces. Immune dysregulation in this setting is multifactorial and is driven by a range of environmental factors, undernutrition and coinfections such as measles, malaria and HIV. Disruption or subversion of respiratory-tract and intestinal epithelial barriers leads to increased invasion by mucosal pathogens and a high frequency of life-threatening bacterial disease. It is our opinion that a process of epithelial barrier dysfunction and immune dysregulation at these mucosal surfaces leads to the much higher rates of pneumonia, meningitis and severe sepsis seen in resource-limited countries.
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Affiliation(s)
- Sarah J Glennie
- Malawi-Liverpool Wellcome Trust Clinical Research Programme, Blantyre, Malawi.
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150
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Sullivan D. Uncertainty in mapping malaria epidemiology: implications for control. Epidemiol Rev 2010; 32:175-87. [PMID: 20581219 DOI: 10.1093/epirev/mxq013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Malaria is a location-specific, dynamic infectious disease transmitted by mosquitoes to humans and is influenced by environmental, vector, parasite, and host factors. The principal purposes of malarial epidemiology are 1) to describe the malarial distribution in space and time along with the physical, biologic, and social etiologic factors and 2) to guide control objectives for either modeling impact or measuring progress of control tactics. Mapping malaria and many of its causative factors has been achieved on many different levels from global distribution to biologic quantitative trait localization in humans, parasites, and mosquitoes. Despite these important achievements, a large degree of uncertainty still exists on the annual burden of malarial cases. Accurate, sensitive detection and treatment of asymptomatic reservoirs important to infectious transmission are additional components necessary for future control measures. Presently spurred by the leadership and funding of Bill and Melinda Gates, the malarial community is developing and implementing plans for elimination of malaria. The challenge for malariologists is to digitally integrate and map epidemiologic factors and intervention measures in space and time to target effective, sustainable control alongside research efforts.
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Affiliation(s)
- David Sullivan
- The Malaria Research Institute, W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, MD 21205, USA.
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