Changing Trends in P. falciparum Burden, Immunity, and Disease in Pregnancy.

BACKGROUND: Prevention of reinfection and resurgence is an integral component of the goal to eradicate malaria. However, the adverse effects of malaria resurgences are not known. METHODS: We assessed the prevalence of Plasmodium falciparum infection among 1819 Mozambican women who delivered infants between 2003 and 2012. We used microscopic and histologic examination and a quantitative polymerase-chain-reaction (qPCR) assay, as well as flow-cytometric analysis of IgG antibody responses against two parasite lines. RESULTS: Positive qPCR tests for P. falciparum decreased from 33% in 2003 to 2% in 2010 and increased to 6% in 2012, with antimalarial IgG antibody responses mirroring these trends. Parasite densities in peripheral blood on qPCR assay were higher in 2010-2012 (geometric mean [±SD], 409±1569 genomes per microliter) than in 2003-2005 (44±169 genomes per microliter, P=0.02), as were parasite densities in placental blood on histologic assessment (50±39% of infected erythrocytes vs. 4±6%, P<0.001). The malaria-associated reduction in maternal hemoglobin levels was larger in 2010-2012 (10.1±1.8 g per deciliter in infected women vs. 10.9±1.7 g per deciliter in uninfected women; mean difference, -0.82 g per deciliter; 95% confidence interval [CI], -1.39 to -0.25) than in 2003-2005 (10.5±1.1 g per deciliter vs. 10.6±1.5 g per deciliter; difference, -0.12 g per deciliter; 95% CI, -0.67 to 0.43), as was the reduction in birth weight (2863±440 g in women with past or chronic infections vs. 3070±482 g in uninfected women in 2010-2012; mean difference, -164.5 g; 95% CI, -289.7 to -39.4; and 2994±487 g vs. 3117±455 g in 2003-2005; difference, -44.8 g; 95% CI, -139.1 to 49.5). CONCLUSIONS: Antimalarial antibodies were reduced and the adverse consequences of P. falciparum infections were increased in pregnant women after 5 years of a decline in the prevalence of malaria. (Funded by Malaria Eradication Scientific Alliance and others.).

Cytoadhesion to gC1qR through Plasmodium falciparum Erythrocyte Membrane Protein 1 in Severe Malaria.

Cytoadhesion of Plasmodium falciparum infected erythrocytes to gC1qR has been associated with severe malaria, but the parasite ligand involved is currently unknown. To assess if binding to gC1qR is mediated through the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family, we analyzed by static binding assays and qPCR the cytoadhesion and var gene transcriptional profile of 86 P. falciparum isolates from Mozambican children with severe and uncomplicated malaria, as well as of a P. falciparum 3D7 line selected for binding to gC1qR (Pf3D7gC1qR). Transcript levels of DC8 correlated positively with cytoadhesion to gC1qR (rho = 0.287, P = 0.007), were higher in isolates from children with severe anemia than with uncomplicated malaria, as well as in isolates from Europeans presenting a first episode of malaria (n = 21) than Mozambican adults (n = 25), and were associated with an increased IgG recognition of infected erythrocytes by flow cytometry. Pf3D7gC1qR overexpressed the DC8 type PFD0020c (5.3-fold transcript levels relative to Seryl-tRNA-synthetase gene) compared to the unselected line (0.001-fold). DBLß12 from PFD0020c bound to gC1qR in ELISA-based binding assays and polyclonal antibodies against this domain were able to inhibit binding to gC1qR of Pf3D7gC1qR and four Mozambican P. falciparum isolates by 50%. Our results show that DC8-type PfEMP1s mediate binding to gC1qR through conserved surface epitopes in DBLß12 domain which can be inhibited by strain-transcending functional antibodies. This study supports a key role for gC1qR in malaria-associated endovascular pathogenesis and suggests the feasibility of designing interventions against severe malaria targeting this specific interaction.

Hypoxaemia in Mozambican children <5 years of age admitted to hospital with clinical severe pneumonia: clinical features and performance of predictor models.

OBJECTIVE: To determine the prevalence of hypoxaemia among under-five children admitted to hospital with clinical severe pneumonia and to assess the performance to diagnose hypoxaemia of models based on clinical signs. METHODS: We conducted a hospital-based survey in a district hospital from Southern Mozambique. RESULTS: A total of 825 children were recruited after obtaining an informed consent. The prevalence of hypoxaemia on admission was 27.9%, and 19.8% of these children died (OR compared with non-hypoxaemic children 3.22, 95% CI 1.98-5.21, P < 0.001). The model with larger area under the ROC curve (AUC-ROC) to predict hypoxaemia included cyanosis or thoracoabdominal breathing or respiratory rate ≥70 breaths per minute. None of the models performed well when tested in different case scenarios of oxygen availability through mathematical modelling, with over 50% of hypoxaemic children not receiving oxygen even in favourable case scenarios. CONCLUSIONS: Clinical signs alone or in combination are not suitable to diagnose hypoxaemia. The use of pulse oximeters should be strongly encouraged.

A phase 3 trial of RTS,S/AS01 malaria vaccine in African infants.

BACKGROUND: The candidate malaria vaccine RTS,S/AS01 reduced episodes of both clinical and severe malaria in children 5 to 17 months of age by approximately 50% in an ongoing phase 3 trial. We studied infants 6 to 12 weeks of age recruited for the same trial. METHODS: We administered RTS,S/AS01 or a comparator vaccine to 6537 infants who were 6 to 12 weeks of age at the time of the first vaccination in conjunction with Expanded Program on Immunization (EPI) vaccines in a three-dose monthly schedule. Vaccine efficacy against the first or only episode of clinical malaria during the 12 months after vaccination, a coprimary end point, was analyzed with the use of Cox regression. Vaccine efficacy against all malaria episodes, vaccine efficacy against severe malaria, safety, and immunogenicity were also assessed. RESULTS: The incidence of the first or only episode of clinical malaria in the intention-to-treat population during the 14 months after the first dose of vaccine was 0.31 per person-year in the RTS,S/AS01 group and 0.40 per person-year in the control group, for a vaccine efficacy of 30.1% (95% confidence interval [CI], 23.6 to 36.1). Vaccine efficacy in the per-protocol population was 31.3% (97.5% CI, 23.6 to 38.3). Vaccine efficacy against severe malaria was 26.0% (95% CI, -7.4 to 48.6) in the intention-to-treat population and 36.6% (95% CI, 4.6 to 57.7) in the per-protocol population. Serious adverse events occurred with a similar frequency in the two study groups. One month after administration of the third dose of RTS,S/AS01, 99.7% of children were positive for anti-circumsporozoite antibodies, with a geometric mean titer of 209 EU per milliliter (95% CI, 197 to 222). CONCLUSIONS: The RTS,S/AS01 vaccine coadministered with EPI vaccines provided modest protection against both clinical and severe malaria in young infants. (Funded by GlaxoSmithKline Biologicals and the PATH Malaria Vaccine Initiative; RTS,S ClinicalTrials.gov number, NCT00866619.).

Severe malnutrition among children under the age of 5 years admitted to a rural district hospital in southern Mozambique.

OBJECTIVE: To describe the burden, clinical characteristics and prognostic factors of severe malnutrition in children under the age of 5 years. DESIGN: Retrospective study of hospital-based data systematically collected from January 2001 to December 2010. SETTING: Rural Mozambican district hospital. SUBJECTS: All children aged <5 years admitted with severe malnutrition. RESULTS: During the 10-year long study surveillance, 274 813 children belonging to Manhiça's Demographic Surveillance System were seen at out-patient clinics, almost half of whom (47 %) presented with some indication of malnutrition and 6% (17 188/274 813) with severe malnutrition. Of these, only 15% (2522/17 188) were eventually admitted. Case fatality rate of severe malnutrition was 7% (162/2274). Bacteraemia, hypoglycaemia, oral candidiasis, prostration, oedema, pallor and acute diarrhoea were independently associated with an increased risk of in-hospital mortality, while malaria parasitaemia and breast-feeding were independently associated with a lower risk of a poor outcome. Overall minimum communitybased incidence rate was 15 cases per 1000 child-years at risk and children aged 12­23 months had the highest incidence. CONCLUSIONS: Severe malnutrition among admitted children in this Mozambican setting was common but frequently went undetected, despite being associated with a high risk of death. Measures to improve its recognition by clinicians responsible for the first evaluation of patients at the out-patient level are urgently needed so as to improve their likelihood of survival. Together with this, the rapid management of complications such as hypoglycaemia and concomitant co-infections such as bacteraemia, acute diarrhoea, oral candidiasis and HIV/AIDS may contribute to reverse the intolerable toll that malnutrition poses in the health of children in rural African settings.

Endothelial transcriptomic analysis identifies biomarkers of severe and cerebral malaria.

Malaria can quickly progress from an uncomplicated infection into a life-threatening severe disease. However, the unspecificity of early symptoms often makes it difficult to identify patients at high risk of developing severe disease. Additionally, one of the most feared malaria complications - cerebral malaria - is challenging to diagnose, often resulting in treatment delays that can lead to adverse outcomes. To identify candidate biomarkers for the prognosis and/or diagnosis of severe and cerebral malaria, we have analyzed the transcriptomic response of human brain microvascular endothelial cells to erythrocytes infected with Plasmodium falciparum. Candidates were validated in plasma samples from a cohort of pediatric patients with malaria from Mozambique, resulting in the identification of several markers with capacity to distinguish uncomplicated from severe malaria, the most potent being the metallopeptidase ADAMTS18. Two other biomarkers, Angiopoietin-like-4 and Inhibin-ßE were able to differentiate children with cerebral malaria within the severe malaria group, showing increased sensitivity after combination in a biomarker signature. The validation of the predicted candidate biomarkers in plasma of children with severe and cerebral malaria underscores the power of this transcriptomic approach and indicates that a specific endothelial response to P. falciparum-infected erythrocytes is linked to the pathophysiology of severe malaria.

Inadequate efficacy of a new formulation of fosmidomycin-clindamycin combination in Mozambican children less than three years old with uncomplicated Plasmodium falciparum malaria.

The combination of fosmidomycin and clindamycin (F/C) is effective in adults and older children for the treatment of malaria and could be an important alternative to existing artemisinin-based combinations (ACTs) if proven to work in younger children. We conducted an open-label clinical trial to assess the efficacy, safety, and tolerability of F/C for the treatment of uncomplicated P. falciparum malaria in Mozambican children <3 years of age. Aqueous solutions of the drugs were given for 3 days, and the children were followed up for 28 days. The primary outcome was the PCR-corrected adequate clinical and parasitological response at day 28. Secondary outcomes included day 7 and 28 uncorrected cure rates and fever (FCT) and parasite (PCT) clearance times. Fifty-two children were recruited, but only 37 patients were evaluable for the primary outcome. Day 7 cure rates were high (94.6%; 35/37), but the day 28 PCR-corrected cure rate was 45.9% (17/37). The FCT was short (median, 12 h), but the PCT was longer (median, 72 h) than in previous studies. Tolerability was good, and most common adverse events were related to the recurrence of malaria. The poor efficacy observed for the F/C combination may be a consequence of the new formulations used, differential bioavailability in younger children, naturally occurring variations in parasite sensitivity to the drugs, or an insufficient enhancement of their effects by naturally acquired immunity in young children. Additional studies should be conducted to respond to the many uncertainties arising from this trial, which should not discourage further evaluation of this promising combination.

Low antibodies against Plasmodium falciparum and imbalanced pro-inflammatory cytokines are associated with severe malaria in Mozambican children: a case-control study.

BACKGROUND: The factors involved in the progression from Plasmodium falciparum infection to severe malaria (SM) are still incompletely understood. Altered antibody and cellular immunity against P. falciparum might contribute to increase the risk of developing SM. METHODS: To identify immune responses associated with SM, a sex- and age-matched case-control study was carried out in 134 Mozambican children with SM (cerebral malaria, severe anaemia, acidosis and/or respiratory distress, prostration, hypoglycaemia, multiple seizures) or uncomplicated malaria (UM). IgG and IgM against P. falciparum lysate, merozoite antigens (MSP-119, AMA-1 and EBA-175), a Duffy binding like (DBL)-α rosetting domain and antigens on the surface of infected erythrocytes were measured by ELISA or flow cytometry. Plasma concentrations of IL-12p70, IL-2, IFN-γ, IL-4, IL-5, IL-10, IL-8, IL-6, IL-1ß, TNF, TNF-ß and TGF-ß1 were measured using fluorescent bead immunoassays. Data was analysed using McNemar's and Signtest. RESULTS: Compared to UM, matched children with SM had reduced levels of IgG against DBLα (P < 0.001), IgM against MSP-119 (P = 0.050) and AMA-1 (P = 0.047), TGF-ß1 (P < 0.001) and IL-12 (P = 0.039). In addition, levels of IgG against P. falciparum lysate and IL-6 concentrations were increased (P = 0.004 and P = 0.047, respectively). Anti-DBLα IgG was the only antibody response associated to reduced parasite densities in a multivariate regression model (P = 0.026). CONCLUSIONS: The lower levels of antibodies found in children with SM compared to children with UM were not attributable to lower exposure to P. falciparum in the SM group. IgM against P. falciparum and specific IgG against a rosetting PfEMP1 domain may play a role in the control of SM, whereas an imbalanced pro-inflammatory cytokine response may exacerbate the severity of infection. A high overlap in symptoms together with a limited sample size of different SM clinical groups reduced the power to identify immunological correlates for particular forms of SM.

Glucose-6-phosphate dehydrogenase deficiency, chlorproguanil-dapsone with artesunate and post-treatment haemolysis in African children treated for uncomplicated malaria.

BACKGROUND: Malaria is a leading cause of mortality, particularly in sub-Saharan African children. Prompt and efficacious treatment is important as patients may progress within a few hours to severe and possibly fatal disease. Chlorproguanil-dapsone-artesunate (CDA) was a promising artemisinin-based combination therapy (ACT), but its development was prematurely stopped because of safety concerns secondary to its associated risk of haemolytic anaemia in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals. The objective of the study was to assess whether CDA treatment and G6PD deficiency are risk factors for a post-treatment haemoglobin drop in African children<5 years of age with uncomplicated malaria. METHODS: This case-control study was performed in the context of a larger multicentre randomized clinical trial comparing safety and efficacy of four different ACT in children with uncomplicated malaria. Children, who after treatment experienced a haemoglobin drop≥2 g/dl (cases) within the first four days (days 0, 1, 2, and 3), were compared with those without an Hb drop (controls). Cases and controls were matched for study site, sex, age and baseline haemoglobin measurements. Data were analysed using a conditional logistic regression model. RESULTS: G6PD deficiency prevalence, homo- or hemizygous, was 8.5% (10/117) in cases and 6.8% (16/234) in controls (p=0.56). The risk of a Hb drop≥2 g/dl was not associated with either G6PD deficiency (adjusted odds ratio (AOR): 0.81; p=0.76) or CDA treatment (AOR: 1.28; p=0.37) alone. However, patients having both risk factors tended to have higher odds (AOR: 11.13; p=0.25) of experiencing a Hb drop≥2 g/dl within the first four days after treatment, however this finding was not statistically significant, mainly because G6PD deficient patients treated with CDA were very few. In non-G6PD deficient individuals, the proportion of cases was similar between treatment groups while in G6PD-deficient individuals, haemolytic anaemia occurred more frequently in children treated with CDA (56%) than in those treated with other ACT (29%), though the difference was not significant (p=0.49). CONCLUSION: The use of CDA for treating uncomplicated malaria may increase the risk of haemolytic anaemia in G6PD-deficient children.

The epidemiology of severe malaria at Manhiça District Hospital, Mozambique: a retrospective analysis of 20 years of malaria admissions surveillance data.

BACKGROUND: Most malaria burden estimates rely on modelling infection prevalence to case incidence data, with insufficient attention having been paid to the changing clinical presentation of severe disease and its relationship with changing transmission intensity. We present 20 years of longitudinal surveillance data to contribute to the understanding of the relationship between malaria transmission and the burden and clinical presentation of severe malaria and to inform policy. METHODS: This retrospective analysis of clinical surveillance hospital data included all children younger than 15 years admitted with malaria to Manhiça District Hospital (MDH), Mozambique, from July 1, 1997, to June 30, 2017. Case fatality ratios (CFRs) were calculated as the number of patients who died having a specific diagnosis or syndrome divided by the total number of patients with known outcome admitted with that diagnosis or syndrome. FINDINGS: Over the study period, 32 138 children were admitted to MDH with a malaria diagnosis. Malaria accounted for a large proportion of admissions, ranging from 4083 (76·9%) of 5307 admissions in 2000-01 to 706 (27·5%) of 2568 admissions in 2010-11. Since 2000-02, the absolute and relative number of malaria admissions and deaths presented a decreasing trend. The age pattern of patients with malaria shifted to older ages with a median age of 1·7 years (IQR 0·9-3·0) in 1997-2006 and 2·6 years (IQR 1·3-4·4) in 2006-17, although most malaria deaths (60-88% in 2009-17) still occurred in children younger than 5 years. The clinical presentation of severe malaria changed, with an increase in cerebral malaria and a decrease in severe anaemia and respiratory distress, leading to similar yearly cases for the three syndromes. CFRs for severe malaria fluctuated between 1·1% (2 of 186 in 2014-15) and 7·2% (11 of 152 in 2010-11), varying by severe malaria syndrome (3·3% [70 of 2105] for severe anaemia, 5·1% [191 of 3777] for respiratory distress, and 14·8% [72 of 487] for cerebral malaria). Overall malaria CFRs (1·8% [543 of 30 163]) did not vary by age group. INTERPRETATION: Despite the unprecedented scale up of malaria control tools, malaria still represented around 30-40% of paediatric hospital admissions in 2006-17. The age shift towards older children was not accompanied by an increase in severe malaria or deaths; however, control programmes should consider adapting their high-risk target groups to include older children. Malaria remains a leading cause of disease and health-care system use and the massive unfinished malaria control agenda warrants intensified efforts. FUNDING: Spanish Agency for International Cooperation and Development.

Parity and placental infection affect antibody responses against Plasmodium falciparum during pregnancy.

Women are at higher risk of Plasmodium falciparum infection when pregnant. The decreasing risk of malaria with subsequent pregnancies is attributed to parity-dependent acquisition of antibodies against placental parasites expressing variant surface antigens, VAR2CSA, that mediate placental sequestration through adhesion to chondroitin sulfate A (CSA). However, modulation of immunity during pregnancy may also contribute to increase the risk of malaria. We compared antibody responses among 30 Mozambican primigravidae and 60 multigravidae at delivery, 40 men, and 40 children. IgG levels were measured against the surface antigens of erythrocytes infected with P. falciparum isolated from 12 pregnant women (4 placental and 8 peripheral blood isolates) and 26 nonpregnant hosts. We also measured IgG levels against merozoite recombinant antigens and total IgG. Placental P. falciparum infection was associated with increased levels of total IgG as well as IgG levels against merozoite antigens and parasite isolates from pregnant and nonpregnant hosts. We therefore stratified comparisons of antibody levels by placental infection. Compared to multigravidae, uninfected primigravidae had lower total IgG as well as lower levels of IgGs against peripheral blood isolates from both pregnant and nonpregnant hosts. These differences were not explained by use of bed nets, season at delivery, neighborhood of residence, or age. Compared to men, infected primigravidae had higher levels of IgGs against isolates from pregnant women and CSA-binding lines but not against other isolates, supporting the concept of a pregnancy-specific development of immunity to these parasite variants. Results of this study show that parity and placental infection can modulate immune responses during pregnancy against malaria parasites.

Similar efficacy and safety of artemether-lumefantrine (Coartem®) in African infants and children with uncomplicated falciparum malaria across different body weight ranges.

BACKGROUND: Artemisinin-based combination therapy, including artemether-lumefantrine (AL), is currently recommended for the treatment of uncomplicated Plasmodium falciparum malaria. The objectives of the current analysis were to compare the efficacy and safety of AL across different body weight ranges in African children, and to examine the age and body weight relationship in this population. METHODS: Efficacy, safety and pharmacokinetic data from a randomized, investigator-blinded, multicentre trial of AL for treatment of acute uncomplicated P. falciparum malaria in infants and children in Africa were analysed according to body weight group. RESULTS: The trial included 899 patients (intent-to-treat population 886). The modified intent-to-treat (ITT) population (n = 812) comprised 143 children 5 to < 10 kg, 334 children 10 to < 15 kg, 277 children 15 to < 25 kg, and 58 children 25 to < 35 kg. The 28-day PCR cure rate, the primary endpoint, was comparable across all four body weight groups (97.2%, 98.9%, 97.8% and 98.3%, respectively). There were no clinically relevant differences in safety or tolerability between body weight groups. In the three AL body weight dosing groups (5 to < 15 kg, 15 to < 25 kg and 25 to < 35 kg), 80% of patients were aged 10-50 months, 46-100 months and 90-147 months, respectively. CONCLUSION: Efficacy of AL in uncomplicated falciparum malaria is similar across body weight dosing groups as currently recommended in the label with no clinically relevant differences in safety or tolerability. AL dosing based on body weight remains advisable.

Inherent illnesses and attacks: an ethnographic study of interpretations of childhood Acute Respiratory Infections (ARIs) in Manhiça, southern Mozambique.

BACKGROUND: Pneumonia is a leading cause of childhood hospitalisation and child mortality in Africa. This study explores local interpretations of Acute Respiratory Infections (ARIs), focusing on caretakers of children under five in the context of hospital care seeking. METHODS: The study took place in Manhiça, southern Mozambique and used Focused Ethnographic Study tools (FES) including field exercises and interviews. RESULTS: Understandings of terms used to describe ARIs differed between caretakers and hospital staff. Children's sicknesses that hospital staff diagnosed as ARIs were interpreted by caretakers as intermittent "attacks" of xifuva, a permanent, inherent and incurable chest illness. Caretakers thought that it was possible to manage and treat the attacks, which were caused by immediate natural factors such as food or the weather, but not the underlying illness, which was seen as having more indirect and social causes. Explanations of illness could not be neatly separated into pluralistic categories, but were characterised by syncretism, with "lay" and "biomedical" terms and concepts intermingling in practical care-seeking interactions between caretakers and health staff. CONCLUSIONS: Health promotion should take into account the syncretism involved in explanations of ARIs in the context of practical care seeking for children. In doing so, it should draw upon lay interpretations and terminologies in order to stress the importance of seeking hospital care for all xifuva-type illnesses as well as seeking care for any subsequent attacks of an already diagnosed xifuva. However, this should be undertaken with awareness that the meanings of the terms used in practical care-seeking interactions may change over time. Health communication about ARIs should therefore be ongoing and evidence-based, even if ARIs appear to be well understood.

The effect of food consumption on lumefantrine bioavailability in African children receiving artemether-lumefantrine crushed or dispersible tablets (Coartem) for acute uncomplicated Plasmodium falciparum malaria.

OBJECTIVES: Artemether-lumefantrine (AL) is first-line treatment for uncomplicated malaria in many African countries. Concomitant food consumption may affect absorption of lumefantrine but data in the most important target population, i.e. children, are lacking. Therefore, we evaluated the effect of food intake on oral lumefantrine bioavailability in African children with malaria. METHODS: In a randomised, investigator-blinded, multicentre phase III efficacy trial, 899 infants and children with acute uncomplicated Plasmodium falciparum malaria received six doses of AL according to body weight over 3 days either as crushed tablets (Coartem) or as dispersible tablets. Single blood samples were obtained for lumefantrine plasma concentration determination in a subset of 621 patients, and a two-compartment pharmacokinetic model was constructed. RESULTS: The mean observed lumefantrine plasma concentration for crushed tablet and dispersible tablet, respectively, was 100% and 55% higher with a concomitant meal at the time of dose intake than when taken alone. Similarly, consumption of milk (the most common meal) increased model-estimated lumefantrine bioavailability by 57% (90% CI: 29-96%) with crushed tablets and 65% (90% CI: 28-109%) with dispersible tablets compared to no food. The 28-day PCR-corrected cure rate (primary study endpoint) in the evaluable population was 582/587 [99.1% (95% CI: 98.0-99.7%)] and was not related to food intake. CONCLUSIONS: AL was highly efficacious. Concomitant food intake increased lumefantrine absorption in children with malaria.

Functional and immunological characterization of a Duffy binding-like alpha domain from Plasmodium falciparum erythrocyte membrane protein 1 that mediates rosetting.

The Duffy binding-like (DBL) domains are common adhesion modules present in Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) variants, which are responsible for immune evasion and cytoadherence. Knowledge about how immune responses are acquired against polymorphic DBL domains of PfEMP1 can aid in the development of vaccines for malaria. A recombinant DBLalpha domain, encoded by R29 var1, which binds complement receptor 1 to mediate rosetting by the P. falciparum laboratory strain R29, was expressed in Escherichia coli, renatured by oxidative refolding to its native form, and purified to homogeneity. Antibody levels in 704 plasmas obtained from residents of areas of different levels of malaria endemicity in Orissa (India) and Manhiça (Mozambique) were assessed by enzyme-linked immunosorbent assay. The refolded DBLalpha domain was pure, homogeneous, and functional in that it bound human erythrocytes with specificity and was capable of inhibiting rosetting. The proportion of individuals who had measurable anti-DBLalpha immunoglobulin G responses was low in areas of low malaria endemicity in Orissa (6.7%) but high in areas of high endemicity in Orissa (87.5%) and Manhiça (74.5%). Seroprevalence and antibody levels against the recombinant protein increased with the age of inhabitants from areas with high transmission rates (P < 0.001). Half of the children in these areas had seroconverted by the age of 5 years. These findings suggest that in spite of the extreme polymorphism of PfEMP1 DBLalpha domains, the acquisition of specific antibodies is rapid and age related and reflects the reduced risk of malaria in areas with high transmission rates. Further studies are required to elucidate the role of these antibodies in protection from malaria.

Community-acquired bacteremia among children admitted to a rural hospital in Mozambique.

BACKGROUND: Although community-acquired bacteremia is an important cause of childhood mortality in Africa, recognition of disease burden and potential impact of bacterial vaccines is limited. METHODS: Blood cultures for bacterial pathogens were conducted systematically among children <15 years of age admitted to Manhiça District Hospital, from 2001 to 2006. RESULTS: Blood-stream infections were identified in 8% (1550/19,896) of pediatric hospital admissions. Nontyphoidal Salmonella (NTS) and Pneumococcus were the most prevalent pathogens isolated (26% and 25% of 1550 cases, respectively). Until 28 days of life, Staphylococcus aureus (39%) and group B Streptococcus (20%) predominated. Incidence of community-acquired bacteremia per 100,000 child-years was 1730/10 in children <1 year old, 782/10 in 1-4 year oldd, and 49/10 in children 5 years and older. Case-fatality of bacteremia was 12%. Community-acquired bacteremia associated mortality accounted for 21% (162/788) of hospital deaths. Resistance to antibiotics commonly used in Mozambique was high among invasive isolates of Haemophilus influenzae, Escherichia coli, and NTS. CONCLUSIONS: Community-acquired bacteremia is an important cause of pediatric hospital admission and death in rural African hospitals. The high burden of disease, mortality, and pattern of antibiotic resistance associated with bacteremia underscore the need for prevention in Sub-Saharan Africa.

Severe malaria and concomitant bacteraemia in children admitted to a rural Mozambican hospital.

OBJECTIVES: To describe the prevalence, aetiology and prognostic implications of coexisting invasive bacterial disease in children admitted with severe malaria in a rural Mozambican Hospital. METHODS: Retrospective study of data systematically collected from June 2003 to May 2007 in a rural Mozambican hospital, from all children younger than 5 years admitted with severe malaria. RESULTS: Seven thousand and forty-three children were admitted with a diagnosis of malaria. 25.2% fulfilled the criteria for severe malaria. 5.4% of the children with severe malaria and valid blood culture results had a concomitant bacteraemia. Case fatality rates of severe malaria cases rose steeply when bacteraemia was also present (from 4.0% to 22.0%, P < 0.0001), and bacteraemia was an independent risk factor for death among severe malaria patients (adjusted OR 6.2, 95% CI 2.8-13.7, P = 0.0001). Streptococcus pneumoniae, Gram-negative bacteria, Staphilococcus aureus and non-typhoid Salmonella (NTS) were the most frequently isolated microorganisms among severe malaria cases. Their frequency and associated case fatality rates (CFR) varied according to age and to syndromic presentation. Streptococcus pneumoniae had a relatively low CFR, but was consistently associated with severe malaria syndromes, or anaemia severity groups. No clear-cut relationship between malarial anaemia and NTS bacteraemia was found. CONCLUSIONS: The coexistence of malaria and invasive bacterial infections is a frequent and life-threatening condition in many endemic African settings. In Mozambique, S. pneumoniae is the leading pathogen in this interaction, possibly as a consequence of the high HIV prevalence in the area. Measures directed at reducing the burden of both those infections are urgently needed to reduce child mortality in Africa.

Invasive non-typhoidal Salmonella in Mozambican children.

OBJECTIVE: To describe the epidemiology and clinical presentation of invasive non-typhoidal Salmonella (NTS) in Mozambique. METHODOLOGY: We analysed the epidemiology, clinical presentation and serotype distribution of invasive NTS among Mozambican children admitted to the Manhiça District Hospital between May 2001 and April 2006. RESULTS: A total of 401 NTS cases were analysed; the median age was 16 months [interquartile range (IQR): 10-24]. Fever, cough and increased respiratory rate were the most common symptoms reported, while diarrhoea was present in only 29%. In the univariate analysis, invasive NTS was associated with age, fever, diarrhoea, increased respiratory rate, splenomegaly, hepatomegaly, severe malnutrition, and severe anaemia. Young age, severe malnutrition, diarrhoea and pneumonia were independent risk factors of death. S. typhimurium (66%), and S. enteritidis (25%) were the most frequent serotypes, with incidence rates of 240.4 and 108.6 per 100,000 child years among infants for S. typhimurium and S. enteritidis, respectively; and no significant differences were found regarding their clinical presentation. Resistance to ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole was high for both S. typhimurium and S. enteritidis. CONCLUSIONS: Clinical presentation of invasive NTS was non-specific and similar to that of other infections, with some factors being associated with NTS. Antibiotic resistance was very common to currently recommended and available antibiotics for suspected sepsis.

A 10 year study of the cause of death in children under 15 years in Manhiça, Mozambique.

BACKGROUND: Approximately 46 million of the estimated 60 million deaths that occur in the world each year take place in developing countries. Further, this mortality is highest in Sub-Saharan Africa, although causes of mortality in this region are not well documented. The objective of this study is to describe the most frequent causes of mortality in children under 15 years of age in the demographic surveillance area of the Manhiça Health Research Centre, between 1997 and 2006, using the verbal autopsy tool. METHODS: Verbal autopsy interviews for causes of death in children began in 1997. Each questionnaire was reviewed independently by three physicians with experience in tropical paediatrics, who assigned the cause of death according to the International Classification of Diseases (ICD-10). Each medical doctor attributed a minimum of one and a maximum of 2 causes. A final diagnosis is reached when at least two physicians agreed on the cause of death. RESULTS: From January 1997 to December 2006, 568,499 person-year at risk (pyrs) and 10,037 deaths were recorded in the Manhiça DSS. 3,730 deaths with 246,658 pyrs were recorded for children under 15 years of age. Verbal autopsy interviews were conducted on 3,002 (80.4%) of these deaths. 73.6% of deaths were attributed to communicable diseases, non-communicable diseases accounted for 9.5% of the defined causes of death, and injuries for 3.9% of causes of deaths. Malaria was the single largest cause, accounting for 21.8% of cases. Pneumonia with 9.8% was the second leading cause of death, followed by HIV/AIDS (8.3%) and diarrhoeal diseases with 8%. CONCLUSION: The results of this study stand out the big challenges that lie ahead in the fight against infectious diseases in the study area. The pattern of childhood mortality in Manhiça area is typical of developing countries where malaria, pneumonia and HIV/AIDS are important causes of death.

Severe pneumonia in Mozambican young children: clinical and radiological characteristics and risk factors.

BACKGROUND: Pneumonia is a leading cause of hospitalization and death among children in Africa. We describe the clinical presentation of severe pneumonia among hospitalized children in a malaria endemic area with a high prevalence of HIV infection. METHODS: As part of a 2-year prospective study of radiologically confirmed pneumonia, chest radiographs, malaria parasite counts and bacterial blood cultures were systematically performed for children 0-23 months admitted with severe pneumonia. Radiographs were interpreted according to WHO guidelines. HIV tests were performed during a 12-month period. RESULTS: Severe pneumonia accounted for 16% of 4838 hospital admissions among children 0-23 months; 43% of episodes had endpoint consolidation, 15% were associated with bacteremia and 11% were fatal. Fever, cough >3 days, crepitations, hypoxemia and absence of malaria parasitemia were associated with radiologically confirmed pneumonia. Nineteen per cent of children with severe pneumonia and 27% with radiologically confirmed pneumonia had clinical malaria. HIV-prevalence was 26% among children hospitalized with severe pneumonia and HIV-testing results. HIV infection, anaemia, malnutrition, hypoxemia and bacteremia were associated with fatal episodes of severe pneumonia. CONCLUSION: Treatment of admitted children with severe pneumonia is complicated in settings with prevalent HIV and malaria. Children with severe pneumonia and clinical malaria require antibiotic and antimalarial treatment. In addition to vertical programs, integrated approaches may greatly contribute to reduction of pneumonia-related mortality.