Non-severe Malaria Research Articles

Severe imported malaria in a Serbian referral center

Background/Aim. The World Health Organization estimates that 3.2 billion people are at a risk of being infected with malaria. Thus, the adequate diagnostic protocols for malaria, especially those aimed at determining disease severity, are paramount both in endemic and non-endemic setting. The aim of this study was to identify the demographic, parositological, clinical and laboratory characteristics associated with severe malaria in a non-endemic settings. Methods. We analyzed 22 patients with severe malaria and compared their clinical and laboratory findings with those of the patients with non-severe malaria in a search of predictors of disease severity. All patients were treated at the Infectious and Tropical Diseases University Hospital, Clinical Centre of Serbia in Belgrade, Serbia from 2000 to 2010. Results. The average age of patients with with severe malaria was 44.86 ? 12.33 years and men predominated (95.45%). The patients with severe malaria were infected Plasmodium falciparum (P. falciparum) significantly more frequently compared with those with non-severe disease (p =0.047). Jaundice was the most commonly observed feature of severe malaria, followed by anemia and renal failure. The multifactor analysis of variance showed that thrombocytopenia (p = 0.05) and high serum tumor necrosis factor-alpha levels (p = 0.02) were significantly associated with the disease severity. Conclusion. A high index of suspicion for malaria should be maintained when evaluating febrile patients returning from the malaria endemic regions. The elevated serum tumor necrosis factor-alpha levels and thrombocytopenia are associated with severe malaria in non-endemic settings.

432. Hold That Buzz: Timely Malaria Medication Access in New Orleans, Louisiana

BackgroundMalaria is a global health concern. Given increasing global travel and migration, hospitals may struggle to meet immediate malaria treatment needs resulting in serious and potentially fatal outcomes. New Orleans is a mid-size city with a significant immigrant population, large tourism industry, major academic centers with international faculty and many international industries with a diversity of medical systems. Assessing malaria medication accessibility across various clinical settings would address major gaps in treatment capacity and efficacy.MethodsInpatient pharmacy directors and formularies at three New Orleans-area hospitals (an academic medical center, a large safety-net hospital and a community hospital) were queried about their first-line antimalarial agents in stock within the hospital pharmacy, time needed to obtain both IV and PO first-line antimalarial agents, and barriers to expanding the formulary (including cost, number of cases, side effects, and shelf life of medications). The queries were carried out using a medications order system survey.ResultsFirst-line IV medications could not be provided in <24 hours at any of hospitals surveyed; however, all provided a form of first-line antimalarial coverage for non-severe malaria. Two of the three hospitals provided oral artemisinin-based combination therapies (ACTs) on their hospital formulary available in <24 hours and all three provided ACTs on their outpatient formularies. All hospitals surveyed could obtain intravenous ACTs from the CDC within 24–48 hours. Barriers identified for availability of oral ACTs and other antimalarials included the number of cases seen (reported by all threehospitals) and cost of medication (reported by one hospital).ConclusionOral first-line malaria treatments including ACTs could be obtained in the surveyed hospitals within 24–48 hours and all hospitals could obtain IV ACTs from the CDC within 24–48 hours. The main barrier preventing hospitals from providing ACTs and other anti-malarial medications was infrequency of malaria cases; cost was a secondary concern. This information can be used in attempts to educate hospital systems about appropriate and timely malaria treatment, inform policy and procedures, and design systems to track malaria diagnosis and treatment.Disclosures All authors: No reported disclosures.

Biochemical and clinical variations among severe Plasmodium Vivax malaria cases: A prospective study

Context: Plasmodium vivax is geographically widely distributed with up to 2.5 billion people at risk and an estimated 70-80 million cases every year. India contributes 77% of the total malaria in Southeast Asia. Retrospective analysis of burden of malaria showed that disability adjusted life years due to malaria were 1.86 million years. According to recent study, West Bengal contributes 11% of total malaria cases in country and is one of states where falciparum resistance to chloroquine has been confirmed. Aims: The aim of this study was to evaluate the biochemical and clinical profile of severe and non-severe Plasmodium vivax malaria and the complications and outcome of P. vivax malaria infections as there is very limited information on age and sex specific seasonal prevalence of malaria in different paradigms in the country. Materials and Methods: A hospital based prospective study was conducted in Medical College, Kolkata comprising of 138 patients with fever (≥37.5˚C), peripheral smear and/or rapid diagnostic tests positive for P. vivax. Previously established cases of CKD, hematological abnormalities, chronic liver diseases and neuro-psychiatric disorders were excluded from our study. Demographical, clinical and laboratory parameters including liver function test, renal function test were documented and were presented in tabular and statistical means. Results: Jaundice was present in 22% of patients and vomiting in 32% of the patients. Hepatomegaly was seen in 16 % cases and 33% cases had splenomegaly. ARDS was seen in 16% of severe malaria cases. Acute kidney injury was seen in 8% and cerebral malaria was seen in 12% of severe malaria cases. Multi organ dysfunction was seen in12 %cases. There was 1 death in the study due to multi organ dysfunction. Conclusion: Life threatening complications such as ARDS, AKI, cerebral malaria and MODS can be seen in P. vivax mono infections.

Post-malaria neurological syndrome: four cases, review of the literature and clarification of the nosological framework

BackgroundPost-malaria neurological syndrome (PMNS) is a debated entity, defined by neurological complications following a post-malaria symptom-free period and a negative blood smear. Four cases of PMNS are hereby reported and a review the literature performed to clarify the nosological framework of this syndrome.MethodsA French teaching hospital infectious diseases database was investigated for all PMNS cases occurring between 1999 and 2016 and the PubMed database for cases reported by other institutions after 1997. A case was defined by the de novo appearance of neurological signs following a post-malaria symptom-free period, a negative blood smear, and no bacterial or viral differential diagnoses.ResultsFour patients from the database and 48 from PubMed, including 4 following Plasmodium vivax infection were found matching the definition. In the institution, the estimated PMNS incidence rate was 1.7 per 1000 malaria cases overall. Of the 52 patients (mean age 33 years), 65% were men. Malaria was severe in 85% of cases, showed neurological involvement in 53%, and treated with quinine in 60%, mefloquine in 46%, artemisinin derivatives in 41%, antifolic drugs in 30%, doxycycline in 8% and other types in 8%. The mean symptom-free period was 15 days. PMNS signs were confusion (72%), fever (46%), seizures (35%), cerebellar impairment (28%), psychosis (26%), and motor disorders (13%). Cerebrospinal fluid analyses showed high protein levels in 77% (mean 1.88 g/L) and lymphocytic meningitis in 59.5% (mean 48 WBC/mm3) of cases. Electroencephalograms were pathological in 93% (14/15) of cases, and brain MRIs showed abnormalities in 43% (9/21) of cases with white matter involvement in 100%. Fourteen patients were treated with steroids. The 18 patients with follow-up data showed no sequelae. The mean time to recovery was 17.4 days.ConclusionPMNS is a rare entity englobing neurological signs after severe or non-severe malaria. It appears after a symptom-free period. PMNS occurred following treatment of malaria with a wide range of anti-malarials. The disease is self-limiting and associated with good outcome. MRI patterns underline a possible link with acute disseminated encephalomyelitis (ADEM) or auto-immune encephalitis. Plasmodium falciparum and Plasmodium vivax should be added to the list of pathogens causing ADEM.

Intravascular haemolysis in severe Plasmodium knowlesi malaria: association with endothelial activation, microvascular dysfunction, and acute kidney injury

Plasmodium knowlesi occurs throughout Southeast Asia, and is the most common cause of human malaria in Malaysia. Severe disease in humans is characterised by high parasite biomass, reduced red blood cell deformability, endothelial activation and microvascular dysfunction. However, the roles of intravascular haemolysis and nitric oxide (NO)-dependent endothelial dysfunction, important features of severe falciparum malaria, have not been evaluated, nor their role in acute kidney injury (AKI). In hospitalised Malaysian adults with severe (n = 48) and non-severe (n = 154) knowlesi malaria, and in healthy controls (n = 50), we measured cell-free haemoglobin (CFHb) and assessed associations with the endothelial Weibel–Palade body (WPB) constituents, angiopoietin-2 and osteoprotegerin, endothelial and microvascular function, and other markers of disease severity. CFHb was increased in knowlesi malaria in proportion to disease severity, and to a greater extent than previously reported in severe falciparum malaria patients from the same study cohort. In knowlesi malaria, CFHb was associated with parasitaemia, and independently associated with angiopoietin-2 and osteoprotegerin. As with angiopoietin-2, osteoprotegerin was increased in proportion to disease severity, and independently associated with severity markers including creatinine, lactate, interleukin-6, endothelial cell adhesion molecules ICAM-1 and E-selectin, and impaired microvascular reactivity. Osteoprotegerin was also independently associated with NO-dependent endothelial dysfunction. AKI was found in 88% of those with severe knowlesi malaria. Angiopoietin-2 and osteoprotegerin were both independent risk factors for acute kidney injury. Our findings suggest that haemolysis-mediated endothelial activation and release of WPB constituents is likely a key contributor to end-organ dysfunction, including AKI, in severe knowlesi malaria.

Reduced red blood cell deformability in Plasmodium knowlesi malaria

AbstractThe simian parasite Plasmodium knowlesi can cause severe and fatal human malaria. However, little is known about the pathogenesis of this disease. In falciparum malaria, reduced red blood cell deformability (RBC-D) contributes to microvascular obstruction and impaired organ perfusion. In P knowlesi infection, impaired microcirculatory flow has been observed in Macaca mulatta (rhesus macaques), unnatural hosts who develop severe and fatal disease. However, RBC-D has not been measured in human infection or in the natural host M fascicularis (long-tailed macaques). Using ektacytometry, we measured RBC-D in adults with severe and non-severe knowlesi and falciparum malaria and in healthy controls. In addition, we used micropipette aspiration to determine the relative stiffness of infected RBCs (iRBCs) and uninfected RBCs (uRBCs) in P knowlesi–infected humans and M fascicularis. Ektacytometry demonstrated that RBC-D overall was reduced in human knowlesi malaria in proportion to disease severity, and in severe knowlesi malaria, it was comparable to that of severe falciparum malaria. RBC-D correlated inversely with parasitemia and lactate in knowlesi malaria and HRP2 in falciparum malaria, and it correlated with hemoglobin nadir in knowlesi malaria. Micropipette aspiration confirmed that in humans, P knowlesi infection increased stiffness of both iRBCs and uRBCs, with the latter mostly the result of echinocytosis. In contrast, in the natural host M fascicularis, echinocyte formation was not observed, and the RBC-D of uRBCs was unaffected. In unnatural primate hosts of P knowlesi, including humans, reduced deformability of iRBCs and uRBCs may represent a key pathogenic mechanism leading to microvascular accumulation, impaired organ perfusion, and anemia.

Abo Blood Variants of Selected Babcock University Students and Their Link with Malaria Parasitaemia

Five milliliters (5ml) of venous whole blood was collected from one hundred and eighty three students made up of 93(50.8%) male and 90(49.2%) female students of Babcock University, Ilishan Remo randomly selected across various Departments. Whole blood samples were dispensed into sequestrinized (EDTA anticoagulated) blood containers, properly mixed and labeled. Malaria Plasmodium falciparum parasite screening was done semi-quantitatively by Field stain A and B staining. ABO blood phenotyping was carried out with monoclonal Antisera A, B and D. A total of 169 (92.3%) and 14(7.7%) students were rhesus positive and negative respectively of which 92(54.4%) and 77(45.6%) samples were rhesus positive male and female students respectively and of which 1(7.1%) and 13(92.9%) students were rhesus negative male and female students respectively. One hundred and thirty five (73.8%), 36(19.7%) and 12(6.5%) of the sampled student population belonged to 17-20, 21-24 and 25-30yr age brackets respectively. One hundred and ten (60.1%), 38(20.8%), 29(15.9%) and 6(3.3%) students were of O, A, B and AB blood phenotypes respectively. Out of the 183 blood samples obtained from 93 (50.8%) and 90(49.2%) male and female students respectively, 126(68.9%) students were infected with P. falciparum malaria parasites. More males were infected than females and were significantly associated with malaria infection (X2 0.05, 1 =3.841, Cal. X2 =25.253, P˂0.05). Also, out of the 68.9% infected students, 47(37.3%) and 79(62.7%) had severe and non-severe forms of malaria infection respectively. Severe malaria frequency occurrences were 85.0%, 70.6%, 50.0% and 50.0% for blood types A, O, B and AB respectively while non-severe malaria frequency occurrences were 83.3%, 75.0%, 65.8% and 57.9% with respect to blood types A, AB O and B respectively. ABO blood types especially type A were significantly associated with severe form of P. falciparum malaria infection (X20.05, 3=7.815, X20.01, 3=11.350, Cal. X2 =284.601 and P˂0.05, P˂0.01). ABO blood types were also significantly associated with non-severe form of malaria especially type A (Cal. X2 =230.768 and hence, P˂0.05, P˂0.01). Implications of rising trend of rhesus negative factor in female students, population variations in association with ABO blood types and malaria parasitaemia are discussed.

Immune evasion of Plasmodium falciparum by RIFIN via inhibitory receptors.

Malaria is among the most serious infectious diseases affecting humans, accounting for approximately half a million deaths annually1. Plasmodium falciparum is the causative agent of most life-threatening malaria cases. Acquired immunity to malaria is inefficient, even after repeated exposures to P. falciparum2; immune regulatory mechanisms employed by P. falciparum remain largely unclear. Here, we show that P. falciparum uses immune inhibitory receptors for immune evasion. RIFINs, products of a polymorphic multigene family comprising approximately 150–200 genes per parasite genome3, are expressed on the surface of infected erythrocytes. We found that a subset of RIFINs binds to either leucocyte immunoglobulin-like receptor B1 (LILRB1) or leucocyte-associated immunoglobulin-like receptor 1 (LAIR1). LILRB1-binding RIFINs inhibited activation of LILRB1-expressing B cells and NK cells. Furthermore, interactions between LILRB1 and P. falciparum-infected erythrocytes isolated from malaria patients were associated with severe malaria, although an extended study with larger sample sizes is required to confirm the findings. These results suggest that P. falciparum has acquired multiple RIFINs to evade the host immune system by targeting immune inhibitory receptors.

A Proteogenomic Analysis of Haptoglobin in Malaria.

Haptoglobin (Hp), an acute phase inflammatory protein is associated with malaria pathogenesis in several proteomics and genomics studies. The Hp gene has two co-dominant alleles: Hp1 and Hp2 that produce three genotypes: Hp1/Hp1, Hp1/Hp2 and Hp2/Hp2. In this study, validation of the proteomics data with Multiple Reaction Monitoring Mass Spectroscopy (MRM-MS) is performed and the association of the Hp gene variants with severe, non-severe malaria and community (healthy) controls using genotyping PCRs and DNA sequencing is analysed. Highly significant values of Hp is observed in the MRM assay that show a correlation with severity of malaria and is clearly distinguished from another febrile disease, dengue. Moreover, the Hp2/Hp2 genotype is seen in high percentages in non-severe malaria patients (74%) and community controls (72%) whereas patients diagnosed with severe malaria show only (31%) of this genotype. Sequencing of the Hp promoter region reveals three SNPs along with 10 unique haplotypes, out of which five are associated with non-severe and three with severe malaria populations (χ2 =130; df=18; p<0.0001). This proteo-genomic study focuses on the correlation of the Hp protein and gene with malaria, thus highlighting the pivotal role of this acute phase immune gene in malaria pathogenesis.

Clinico-epidemiological features of malaria among children attending a tertiary care hospital: a two year study

Background: Malaria caused by Plasmodium species and transmitted by Female anopheles mosquito, still remains as a major public health concern around the world. India is one of the major contributors of malaria cases in South East Asia. Malaria accounts for 205,000 deaths with 55,000 deaths occurring in early childhood. In endemic areas, children under 5 years are particularly susceptible to infection, illness and death. The present study was aimed to study the clinical, epidemiological profile of malaria cases among children (&lt;12 years) attending a tertiary care hospital. We also assessed the complications associated with non-severe and severe malaria. Methods: The study was conducted at a tertiary care hospital for a period of two years and all children &lt;12 years of age diagnosed with malaria were enrolled in the study. The demographic, clinical and laboratory parameters were observed and noted. Cases were categorized into severe and non-severe malaria based on the WHO guidelines.Results: A total of 2420 cases were observed and 250 cases of malaria were diagnosed, of which 136 were p. vivax mono infections, 82 falciparum malaria and 32 had evidence of mixed infections. Males were predominant in the study (58.8%) and 1-5 years was the common age group. Fever was the most common symptom (100%) in all cases and pallor, edema was common in falciparum malaria. jaundice was observed in 62% of mixed infections and altered sensorium in 43% of mixed infections. Severe malaria was observed almost equally in vivax and falciparum cases. Hyperparasitemia, cerebral malaria was common in falciparum cases than vivax. Thrombocytopenia, hypoglycemia and impaired consciousness were more common in mixed infections than falciparum and vivax cases.Conclusions: Present study finally concludes that there is a significant change in the trends of vivax malaria in this region where both species coexist. The spectrum of complications seen in vivax and falciparum follow a similar pattern, then mentioned earlier that complications are less frequently seen in vivax than falciparum malaria. Hence more number of studies is required to generate the differing patterns associated with vivax and compare them with different studies from geographic regions.

Quantitative Proteomics Analysis of Plasmodium vivax Induced Alterations in Human Serum during the Acute and Convalescent Phases of Infection

The radial distribution of Plasmodium vivax malaria burden has evoked enormous concern among the global research community. In this study, we have investigated the serum proteome alterations in non-severe vivax malaria patients before and during patient recuperation starting from the early febrile to the defervescence and convalescent stages of the infection. We have also performed an extensive quantitative proteomics analysis to compare the serum proteome profiles of vivax malaria patients with low (LPVM) and moderately-high (MPVM) parasitemia with healthy community controls. Interestingly, some of the serum proteins such as Serum amyloid A, Apolipoprotein A1, C-reactive protein, Titin and Haptoglobin, were found to be sequentially altered with respect to increased parasite counts. Analysis of a longitudinal cohort of malaria patients indicated reversible alterations in serum levels of some proteins such as Haptoglobin, Apolipoprotein E, Apolipoprotein A1, Carbonic anhydrase 1, and Hemoglobin subunit alpha upon treatment; however, the levels of a few other proteins did not return to the baseline even during the convalescent phase of the infection. Here we present the first comprehensive serum proteomics analysis of vivax malaria patients with different levels of parasitemia and during the acute and convalescent phases of the infection.

Artemether-lumefantrine and liver enzyme abnormalities in non-severe Plasmodium falciparum malaria in returned travellers: a retrospective comparative study with quinine-doxycycline in a Portuguese centre

Background Artemisinin-based therapy is the current standard treatment for non-severe malaria due to Plasmodium falciparum. The potential for asymptomatic liver toxicity of this therapy and its implication in clinical practice is currently unknown. The aim of this study is to assess the hepatic function in patients treated with a standard three-day artemisinin-based regimen and to compare it with the quinine-doxycycline regimen.MethodsRetrospective and comparative study of returned adult travellers admitted with non-severe P. falciparum malaria. Fifty-seven patients were included: 19 treated with artemisinin-based therapy and 38 with quinine-doxycycline therapy.ResultsDuring treatment, when compared with quinine-doxycycline group, the artemisinin-lumefantrine group presented a higher proportion of significant liver enzyme abnormalities (42 vs. 5%, p < 0.01) and a higher peak value of aspartate aminotransferase (131 vs. 64 U/L, p < 0.01) and alanine aminotransferase (99 vs. 75 U/L, p = 0.05). None of the patients was symptomatic, there were no treatment interruptions and all patients achieved clinical cure.ConclusionsTreatment of uncomplicated falciparum malaria with artemisinin-based therapy might cause asymptomatic liver enzyme abnormalities in the first days of treatment. Nevertheless, these liver enzyme abnormalities seem to be harmless, asymptomatic and self-limited.

Severe Imported Malaria in a Serbian Referral Center

Background: World Health Organization estimates that 3.2 billion people are at risk of being infected with malaria. Thus, adequate diagnostic protocols for malaria, especially those aimed at determining disease severity, are paramount in both endemic and non-endemic settings. Methods: We analyzed 22 patients with severe malaria and compared their clinical and laboratory findings with those of patients with non-severe malaria in search of predictors of disease severity. All patients were treated at the Infectious and Tropical Diseases University Hospital, Clinical Centre of Serbia in Belgrade, Serbia from 2000 to 2010. Results: Average age was 44.86 ± 12.33 years and men predominated (95.45%) among patients with severe malaria. Patients with severe malaria were infected with P. falciparum significantly more frequently compared with those with non-severe disease (p=0.047). Jaundice was the most commonly observed feature of severe malaria, followed by anemia and renal failure. A multifactor analysis of variance showed that thrombocytopenia (p=0.05) and high serum TNF-alpha levels (p=0.02) were significantly associated with disease severity. Conclusion: A high index of suspicion for malaria should be maintained when evaluating febrile patients returning from malaria endemic regions. Elevated serum TNF-alpha levels and thrombocytopenia are associated with severe malaria in non-endemic settings.

Cord blood IgG and the risk of severe Plasmodium falciparum malaria in the first year of life

Young infants are less susceptible to severe episodes of malaria but the targets and mechanisms of protection are not clear. Cord blood antibodies may play an important role in mediating protection but many studies have examined their association with the outcome of infection or non-severe malaria. Here, we investigated whether cord blood IgG to Plasmodium falciparum merozoite antigens and antibody-mediated effector functions were associated with reduced odds of developing severe malaria at different time points during the first year of life. We conducted a case-control study of well-defined severe falciparum malaria nested within a longitudinal birth cohort of Kenyan children. We measured cord blood total IgG levels against five recombinant merozoite antigens and antibody function in the growth inhibition activity and neutrophil antibody-dependent respiratory burst assays. We also assessed the decay of maternal antibodies during the first 6months of life. The mean antibody half-life range was 2.51months (95% confidence interval (CI): 2.19–2.92) to 4.91months (95% CI: 4.47–6.07). The rate of decline of maternal antibodies was inversely proportional to the starting concentration. The functional assay of antibody-dependent respiratory burst activity predicted significantly reduced odds of developing severe malaria during the first 6months of life (Odds ratio (OR) 0.07, 95% CI: 0.007–0.74, P=0.007). Identification of the targets of antibodies mediating antibody-dependent respiratory burst activity could contribute to the development of malaria vaccines that protect against severe episodes of malaria in early infancy.

Nitric Oxide-Dependent Endothelial Dysfunction and Reduced Arginine Bioavailability in Plasmodium vivax Malaria but No Greater Increase in Intravascular Hemolysis in Severe Disease.

Pathogenesis of severe Plasmodium vivax malaria is poorly understood. Endothelial dysfunction and reduced nitric oxide (NO) bioavailability characterize severe falciparum malaria, but have not been assessed in severe vivax malaria. In patients with severe vivax malaria (n = 9), patients with nonsevere vivax malaria (n = 58), and healthy controls (n = 79), we measured NO-dependent endothelial function by using reactive hyperemia-peripheral arterial tonometry (RH-PAT) and assessed associations with arginine, asymmetric dimethylarginine (ADMA), and hemolysis. The L-arginine level and the L-arginine to ADMA ratio (a measure of L-arginine bioavailability) were reduced in patients with severe vivax malaria and those with nonsevere vivax malaria, compared with healthy controls (median L-arginine level, 65, 66, and 98 µmol/mL, respectively [P = .0001]; median L-arginine to ADMA ratio, 115, 125, and 187, respectively [P = .0001]). Endothelial function was impaired in proportion to disease severity (median RH-PAT index, 1.49, 1.73, and 1.97 in patients with severe vivax malaria, those with nonsevere vivax malaria, and healthy controls, respectively; P = .018) and was associated with the L-arginine to ADMA ratio. While the posttreatment fall in hemoglobin level was greater in severe vivax malaria as compared to nonsevere vivax malaria (2.5 vs 1 g/dL; P = .0001), markers of intravascular hemolysis were not higher in severe disease. Endothelial function is impaired in nonsevere and severe vivax malaria, is associated with reduced L-arginine bioavailability, and may contribute to microvascular pathogenesis. Severe disease appears to be more associated with extravascular hemolysis than with intravascular hemolysis.

Retinopathy of vivax malaria in adults and its relation with severity parameters

Malarial retinopathy is a set of retinal signs in severe malaria due to falciparum malaria. With increased recognition of severe manifestations of vivax malaria, a systematic study to evaluate retinal changes in vivax malaria could elaborate our knowledge about this neglected entity. This observational study included retinal examination of 104 adult patients (>14 years) with varying severity of vivax malaria admitted to a tertiary care center during peak seasons of 2012 and 2013. Thirty-eight percent of severe cases had a retinal sign as compared to 6% of non-severe cases (p < 0.01). No statistically significant effect of residence or age on the presence of retinopathy was noted. Females were found to be more prone to develop a retinal sign (p < 0.01). Presence of retinal signs was significantly associated with anemia and jaundice. No statistical association was noted for retinal signs to be present in either renal dysfunction or altered thrombocytes count. The most common signs were arteriovenous changes, present in eight cases (19%) of severe malaria and three cases (5%) of non-severe malaria. Retinal hemorrhage was present in five cases (12%) of severe malaria and no case of non-severe malaria. Both superficial and deep hemorrhages were seen including white-centered hemorrhages. Other signs included cotton wool spots, hard exudates, blurred disk margins with spontaneous venous pulsations and bilateral disk edema. A correlation between retinal signs and severity parameters was drawn from the study. This is the first systemic study to evaluate the retinal changes in vivax malaria. Larger prospective studies should be done for further knowledge regarding retinal changes in vivax malaria, especially severe disease. Apart from its clinical significance, it might lead to a better understanding of the pathogenesis of the systemic disease of vivax malaria.

Serological Conservation of Parasite-Infected Erythrocytes Predicts Plasmodium falciparum Erythrocyte Membrane Protein 1 Gene Expression but Not Severity of Childhood Malaria.

Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), expressed on P. falciparum-infected erythrocytes, is a major family of clonally variant targets of naturally acquired immunity to malaria. Previous studies have demonstrated that in areas where malaria is endemic, antibodies to infected erythrocytes from children with severe malaria tend to be more seroprevalent than antibodies to infected erythrocytes from children with nonsevere malaria. These data have led to a working hypothesis that PfEMP1 variants associated with parasite virulence are relatively conserved in structure. However, the longevity of such serologically conserved variants in the parasite population is unknown. Here, using infected erythrocytes from recently sampled clinical P. falciparum samples, we measured serological conservation using pools of antibodies in sera that had been sampled 10 to 12 years earlier. The serological conservation of infected erythrocytes strongly correlated with the expression of specific PfEMP1 subsets previously found to be associated with severe malaria. However, we found no association between serological conservation per se and disease severity within these data. This contrasts with the simple hypothesis that P. falciparum isolates with a serologically conserved group of PfEMP1 variants cause severe malaria. The data are instead consistent with periodic turnover of the immunodominant epitopes of PfEMP1 associated with severe malaria.

Cardiovascular changes in patients with non-severe Plasmodium vivax malaria

BackgroundCardiovascular system involvement in patients with Plasmodium vivax malaria has been poorly addressed. The aim of this study was to evaluate cardiac structures and function, and serum markers of cardiovascular injury in patients with the non-severe form of vivax malaria in Manaus, Amazonas State, Brazil. Methods and resultsWe prospectively evaluated 26 patients with vivax malaria in an outpatient referral hospital and compared results with a control group of 25 gender- and age-matched healthy individuals. Patients underwent clinical evaluation, laboratory tests, and transthoracic echocardiography at first evaluation (day zero, D0) and seven days (D7) after malaria diagnosis. At D0 echocardiography showed higher left ventricular (LV) systolic diameter (28.8±2.82 vs 30.9±4.03mm; p=0.037) and LV diastolic volume (82.4±12.3 vs 93.8±25.9ml; p=0.05), and lower LV ejection fraction (Teicholz method: 73.2±6.59 vs 68.4±4.87%; p=0.004) in patients compared to controls. Right ventricle (RV) fractional area change (54.7±5.11 vs 50.5±6.71%; p=0.014) was lower, and RV myocardial performance index (0.21±0.07 vs 0.33±0.19; p=0.007), and pulmonary vascular resistance (1.13±0.25 vs 1.32±0.26 Woods unit; p=0.012) were higher in patients than controls. Patients presented higher serum levels of unconjugated bilirubin (0.24±0.15 vs 1.30±0.89mg/dL; p<0.001), soluble vascular cell adhesion molecule–1 (sVCAM-1; 453±143 vs 1983±880ng/mL; p<0.001), N-terminal prohormone brain natriuretic peptide (0.59±0.86 vs 1.08±0.81pg/mL; p=0.045), and troponin T (861±338 vs 1037±264pg/mL; p=0.045), and lower levels of plasma nitrite (13.42±8.15 vs 8.98±3.97μM; p=0.016) than controls. Most alterations had reversed by D7. ConclusionPatients with non-severe Plasmodium vivax malaria present subclinical reversible cardiovascular changes.

Reduced Hsp70 and Glutamine in Pediatric Severe Malaria Anemia: Role of Hemozoin in Suppressing Hsp70 and NF-κB activation.

Severe malarial anemia [SMA, hemoglobin (Hb) <5.0 g/dL] is a leading cause of global morbidity and mortality among children residing in Plasmodium falciparum transmission regions. Exploration of molecular pathways through global gene expression profiling revealed that SMA was characterized by decreased HSPA1A, a heat shock protein (Hsp) 70 coding gene. Hsp70 is a ubiquitous chaperone that regulates Nuclear Factor-kappa B (NF-κB) signaling and production of pro-inflammatory cytokines known to be important in malaria pathogenesis (e.g., IL-1β, IL-6 and TNF-α). Since the role of host Hsp70 in malaria pathogenesis is unexplored, we investigated Hsp70 and molecular pathways in children with SMA. Validation experiments revealed that leukocytic HSP70 transcripts were reduced in SMA relative to non-severe malaria, and that intraleukocytic hemozoin (PfHz) was associated with lower HSP70. HSP70 was correlated with reticulocyte production and Hb. Since glutamine (Gln) up-regulates Hsp70, modulates NF-κB activation, and attenuates over-expression of pro-inflammatory cytokines, circulating Gln was measured in children with malaria. Reduced Gln was associated with increased risk of developing SMA. Treatment of cultured peripheral blood mononuclear cells (PBMCs) with PfHz caused a time-dependent decrease in Hsp70 transcripts/protein, and NF-κB activation. Gln treatment of PBMCs overcame PfHz-induced suppression of HSP70 transcripts/protein, reduced NF-κB activation, and suppressed over-expression of IL-1β, IL-6 and TNF-α. Findings here demonstrate that SMA is characterized by reduced intraleukocytic HSP70 and circulating Gln, and that PfHz-induced suppression of HSP70 can be reversed by Gln. Thus, Gln supplementation may offer important immunotherapeutic options for futures studies in children with SMA.

Retinal Changes in Uncomplicated and Severe Plasmodium knowlesi Malaria.

Plasmodium knowlesi causes severe malaria, but its pathogenesis is poorly understood. Retinal changes provide insights into falciparum malaria pathogenesis but have not been studied in knowlesi malaria. An observational study was conducted in Malaysian adults hospitalized with severe (n = 20) and nonsevere (n = 24) knowlesi malaria using indirect ophthalmoscopy (n = 44) and fundus photography (n = 29). The patients' median age was 44 years (range, 18-74 years). No coma or deaths occurred. Photography detected retinal changes in 11 of 12 patients (92%) with severe and 14 of 17 (82%) with nonsevere knowlesi malaria. Nonspecific retinal whitening occurred in 3 (35%) and 5 (29%) patients with severe and nonsevere disease, respectively; hemorrhages in 2 (17%) and 3 (18%); loss of retinal pigment epithelium in 1 (8%) and 4 (24%); and drusen in 9 (71%) and 12 (75%). All changes were mild, with no significant differences between severe and nonsevere disease. Patients with retinal hemorrhages had lower platelet counts than those without (median, 22 vs 43 × 10(9)/L; P= .04). The paucity of specific retinal findings associated with disease severity in knowlesi malaria contrasts with the retinopathy of severe adult falciparum malaria with and without coma, suggesting that falciparum-like microvascular sequestration in the brain is not a major component in severe knowlesi malaria pathogenesis.