Transcriptome Analysis of Plasmodium falciparum Isolates From Benin Reveals Specific Gene Expression Associated With Cerebral Malaria.

Cerebral malaria (CM) is the severest form of Plasmodium falciparum infection. Children under 5 years old are those most vulnerable to CM, and they consequently have the highest risk of malaria-related death. Parasite-associated factors leading to CM are not yet fully elucidated. We therefore sought to characterize the gene expression profile associated with CM, using RNA sequencing data from 15 CM and 15 uncomplicated malaria isolates from Benin. Cerebral malaria parasites displayed reduced circulation times, possibly related to higher cytoadherence capacity. Consistent with the latter, we detected increased var genes abundance in CM isolates. Differential expression analyses showed that distinct transcriptome profiles are signatures of malaria severity. Genes involved in adhesion, excluding variant surface antigens, were dysregulated, supporting the idea of increased cytoadhesion capacity of CM parasites. Finally, we found dysregulated expression of genes in the entry into host pathway that may reflect greater erythrocyte invasion capacity of CM parasites.

PfEMP1 A-Type ICAM-1-Binding Domains Are Not Associated with Cerebral Malaria in Beninese Children.

PfEMP1 is the major antigen involved in Plasmodium falciparum-infected erythrocyte sequestration in cerebrovascular endothelium. While some PfEMP1 domains have been associated with clinical phenotypes of malaria, formal associations between the expression of a specific domain and the adhesion properties of clinical isolates are limited. In this context, 73 cerebral malaria (CM) and 98 uncomplicated malaria (UM) Beninese children were recruited. We attempted to correlate the cytoadherence phenotype of Plasmodium falciparum isolates with the clinical presentation and the expression of specific PfEMP1 domains. Cytoadherence level on Hbec-5i and CHO-ICAM-1 cell lines and var genes expression were measured. We also investigated the prevalence of the ICAM-1-binding amino acid motif and dual receptor-binding domains, described as a potential determinant of cerebral malaria pathophysiology. We finally evaluated IgG levels against PfEMP1 recombinant domains (CIDRα1.4, DBLß3, and CIDRα1.4-DBLß3). CM isolates displayed higher cytoadherence levels on both cell lines, and we found a correlation between CIDRα1.4-DBLß1/3 domain expression and CHO-ICAM-1 cytoadherence level. Endothelial protein C receptor (EPCR)-binding domains were overexpressed in CM isolates compared to UM whereas no difference was found in ICAM-1-binding DBLß1/3 domain expression. Surprisingly, both CM and UM isolates expressed ICAM-1-binding motif and dual receptor-binding domains. There was no difference in IgG response against DBLß3 between CM and UM isolates expressing ICAM-1-binding DBLß1/3 domain. It raises questions about the role of this motif in CM pathophysiology, and further studies are needed, especially on the role of DBLß1/3 without the ICAM-1-binding motif.IMPORTANCE Cerebral malaria pathophysiology remains unknown despite extensive research. PfEMP1 proteins have been identified as the main Plasmodium antigen involved in cerebrovascular endothelium sequestration, but it is unclear which var gene domain is involved in Plasmodium cytoadhesion. EPCR binding is a major determinant of cerebral malaria whereas the ICAM-1-binding role is still questioned. Our study confirmed the EPCR-binding role in CM pathophysiology with a major overexpression of EPCR-binding domains in CM isolates. In contrast, ICAM-1-binding involvement appears less obvious with A-type ICAM-1-binding and dual receptor-binding domain expression in both CM and UM isolates. We did not find any variations in ICAM-1-binding motif sequences in CM compared to UM isolates. UM and CM patients infected with isolates expressing the ICAM-1-binding motif displayed similar IgG levels against DBLß3 recombinant protein. Our study raises interrogations about the role of these domains in CM physiopathology and questions their use in vaccine strategies against cerebral malaria.

An engineered PET depolymerase to break down and recycle plastic bottles.

Present estimates suggest that of the 359 million tons of plastics produced annually worldwide1, 150-200 million tons accumulate in landfill or in the natural environment2. Poly(ethylene terephthalate) (PET) is the most abundant polyester plastic, with almost 70 million tons manufactured annually worldwide for use in textiles and packaging3. The main recycling process for PET, via thermomechanical means, results in a loss of mechanical properties4. Consequently, de novo synthesis is preferred and PET waste continues to accumulate. With a high ratio of aromatic terephthalate units-which reduce chain mobility-PET is a polyester that is extremely difficult to hydrolyse5. Several PET hydrolase enzymes have been reported, but show limited productivity6,7. Here we describe an improved PET hydrolase that ultimately achieves, over 10 hours, a minimum of 90 per cent PET depolymerization into monomers, with a productivity of 16.7 grams of terephthalate per litre per hour (200 grams per kilogram of PET suspension, with an enzyme concentration of 3 milligrams per gram of PET). This highly efficient, optimized enzyme outperforms all PET hydrolases reported so far, including an enzyme8,9 from the bacterium Ideonella sakaiensis strain 201-F6 (even assisted by a secondary enzyme10) and related improved variants11-14 that have attracted recent interest. We also show that biologically recycled PET exhibiting the same properties as petrochemical PET can be produced from enzymatically depolymerized PET waste, before being processed into bottles, thereby contributing towards the concept of a circular PET economy.

Changes in malaria epidemiology in France and worldwide, 2000-2015.

In 2015, 212 million new cases of malaria were reported, causing 429,000 deaths. The World Health Organization (WHO) estimated a 41% decrease in the number of new cases worldwide between 2000 and 2015. The number of deaths from malaria fell by 62% worldwide and by 71% in Africa. In mainland France, malaria is mainly imported by travelers or migrants from endemic areas, in particular sub-Saharan Africa (95%). In France, the number of imported malaria cases, mainly due to Plasmodium falciparum (85%), was estimated at about 82,000 for the period 2000-2015. Over the same period, 6,468 cases of malaria were reported in the French armed forces, of which 2,430 cases (37.6%) were considered as imported because occurring outside of endemic areas. The number of malaria cases also fell between 2000 and 2015 in Mayotte and French Guiana, a malaria transmission zone. Mayotte has entered the elimination of malaria with less than 15 cases per year. In French Guiana, between 300 and 500 cases have been reported annually in recent years. The decline in morbidity and mortality is usually attributed to vector control measures and improved access to effective treatments. However, the Anopheles mosquitoes that transmit the disease have developed resistance against most insecticides. Similarly, malaria parasites have developed resistance against most of the antimalarial drugs used as prevention or treatment, even the latest marketed combinations such as artemisinin-based combination therapies.

[Determination of prevalence and etiology of anemia during pregnancy in southern Benin, in conjunction with revision of national management policy]. / Prévalence et etiologies de l'anémie chez la femme enceinte au sud Bénin au moment du changement de politique nationale de prise en charge.

BACKGROUND: Anemia during pregnancy is a serious public health problem. Control requires identification of the underlying etiology. The objective of this study carried out in conjunction with revision of the national policy for the protection of pregnant women in Benin was to determine the prevalence and etiology of anemia. METHODS: From October 2006 to April 2007, 300 pregnant women were examined at two maternities in Ouidah, Benin. Sociodemographic and environmental characteristics, dietary data, behavioral practices, and history of malaria infection during pregnancy were collected. Blood and stool samples were tested for the presence of malaria parasites and intestinal worms respectively. Hemoglobin and ferritinemia levels were also determined. RESULTS: The prevalence of anemia (Hb < 11 g/dL) was 65.7% while that of malaria and intestinal worms was 4.3% and 8% respectively. Iron deficiency was not found. A borderline significant correlation was found between helminthiasis and anemia. No correlation was found between anemia and malaria. These findings indicate that kits progressively introduced by the health system during the study period provided relatively effective care. CONCLUSION: This study demonstrates a high prevalence of moderate anemia during pregnancy and suggests that it is mainly due to intestinal helminthiasis. These findings underline the importance of preventive antihelminthic treatment during pregnancy.

[Multiple imputation of missing at random data: General points and presentation of a Monte-Carlo method]. / L'imputation multiple des données manquantes aléatoirement : concepts généraux et présentation d'une méthode Monte-Carlo.

BACKGROUND: Statistical analysis of a data set with missing data is a frequent problem to deal with in epidemiology. Methods are available to manage incomplete observations, avoiding biased estimates and improving their precision, compared to more traditional methods, such as the analysis of the sub-sample of complete observations. METHODS: One of these approaches is multiple imputation, which consists in imputing successively several values for each missing data item. Several completed data sets having the same distribution characteristics as the observed data (variability and correlations) are thus generated. Standard analyses are done separately on each completed dataset then combined to obtain a global result. In this paper, we discuss the various assumptions made on the origin of missing data (at random or not), and we present in a pragmatic way the process of multiple imputation. A recent method, Multiple Imputation by Chained Equations (MICE), based on a Monte-Carlo Markov Chain algorithm under missing at random data (MAR) hypothesis, is described. An illustrative example of the MICE method is detailed for the analysis of the relation between a dichotomous variable and two covariates presenting MAR data with no particular structure, through multivariate logistic regression. RESULTS: Compared with the original dataset without missing data, the results show a substantial improvement of the regression coefficient estimates with the MICE method, relatively to those obtained on the dataset with complete observations. CONCLUSION: This method does not require any direct assumption on joint distribution of the variables and it is presently implemented in standard statistical software (Splus, Stata). It can be used for multiple imputation of missing data of several variables with no particular structure.

Placental malaria, maternal HIV infection and infant morbidity.

Co-infection with malaria and HIV in pregnant women is particularly common in sub-Saharan Africa and has serious consequences for both mother and newborn child. Numerous studies have been published on the effects in pregnancy of HIV on malaria infection and on the effects of malaria on HIV infection. The increased prevalence and intensity of parasitaemia (placental and peripheral infection and parasite density) in HIV-infected women is well established. Similarly, malaria infection seems to be associated with higher viral loads. However, there is still uncertainty as to the influence of malaria on the clinical course of HIV infection, mother-to-child transmission of HIV, and the consequences of co-infection on post-neonatal infant morbidity and mortality. These questions require further investigation. In terms of prevention, intermittent preventive treatment with two doses of sulfadoxine-pyrimethamine (SP) has been found less effective in preventing malaria in HIV-infected than uninfected women, and a higher dosage (such as monthly SP) has been recommended. Regarding malaria, there is also a lack of clear recommendations for women taking daily cotrimoxazole prophylaxis, and anti-malarial-anti-retroviral interactions are not well understood. Multi-centre clinical trials should be undertaken to investigate effective, coherent and well-tolerated strategies to prevent malaria in HIV-infected women. Safe alternatives to SP should be identified and evaluated rapidly. Finally, a central pharmaco-vigilance network should be instituted to report adverse effects.

Risk factors and consequences of congenital Chagas disease in Yacuiba, south Bolivia.

OBJECTIVE: To determine the risk factors of congenital Chagas disease and the consequences of the disease in newborns. METHODS: Study of 2712 pregnant women and 2742 newborns in Yacuiba, south Bolivia. Chagas infection was determined serologically in mothers and parasitologically in newborns. Consequences of congenital Chagas disease were assessed clinically. RESULTS: The prevalence of Chagas disease in pregnant women was 42.2%. Congenital transmission was estimated at 6% of infected mothers leading to an incidence rate of 2.6% among newborns. Main risk factors of congenital transmission were mothers' seropositivity and maternal Trypanosoma cruzi parasitaemia. Parity was higher in infected than in non-infected mothers, but it was not associated with the risk of congenital transmission. The rate of congenital infection was significantly higher in newborns from multiple pregnancies than in singletons. However, we did not observe statistically significant consequences of Chagas disease in newborns from single pregnancies or among twins. CONCLUSIONS: The main risk factors for congenital transmission were infection and parasitaemia of mothers. Consequences of the disease seemed mild in newborns from single pregnancies and perhaps more important in multiple births.

[Clinical research on malaria: what for the future?]. / Quel avenir pour la recherche clinique sur le paludisme?

Malaria still remains one of the main public health problems in the world. In spite of early and numerous clinical trials, the situation seems to have been worsening in the last ten years. Malaria clinical research involves several levels: Several meta-analyses have been performed on this topic (in particular, the Cochrane Database Library has published studies on malaria prevention during pregnancy, management of clinical malaria attacks, vaccine trials or impregnated bed net trials). All these studies show the uneven quality of trials (only 10% to 50% can be kept in the analysis for methodological reasons), which seldom lead to similar conclusions. Besides, as resistances of both parasites and vectors to drugs or insecticides are regularly increasing, trials have to be repeated and new molecules have to be found and evaluated. Finally, practical application of such interventions may be difficult, due to the heterogeneity of epidemiological situations and the poverty of target populations. Various initiatives aiming to develop malaria clinical research have recently been launched. Donators are public or international (Global Fund, Roll Back Malaria Initiative, NIH, EDCTP programme), as well as private (Bill & Melinda Gates Foundation). These substantial funds should enhance the research of new antimalarial drugs and large-scale, adequately designed trials. However, to make sure these trials really benefit to populations exposed to the disease, ethical principles should be co-elaborated with developing countries, within collaborative networks between laboratories from industrialized and developing countries.

[Anopheles and malaria transmission in Ambohimena, a village in the Occidental fringe of Madagascar Highlands]. / Les anophèles et la transmission du paludisme à Ambohimena, village de la marge occidentale des Hautes-Terres malgaches.

The anopheline vectors and malaria transmission were investigated in the Middle West of Madagascar, in the village of Ambohimena (at the altitude of 940 meters) during two years (August 1996 to July 1998). This village is located outside the vector control area, where yearly DDT house spraying campaigns have been conducted between 1993 and 1998. Collection of mosquitoes was mainly based on all night man billing collections (650 man-nights), pyrethrum spray catches (224 bedrooms) and direct collections in outdoor resting places (140 toilets, 61 pigsties, 33 holes, 19 sheds, 79 sisal hedges, 70 cart shelters). Blood fed anophelines allowed analysis of the origin of blood with an ELISA method. Presence of circum-sporozoite protein was assessed with another ELISA method. The total number of collected anophelines was 14,280. Two malaria vectors were identified: Anopheles funestus Giles, 1900 and An. arabiensis Patton, 1902. An. funestus was the most abundant mosquito, especially during the hot rainy season. Two peaks of abundance were observed (in December and April). Endophagic rate (for mosquitoes aggressive for man) of 35.3%, an endophilic rate (for resting mosquitoes) of 78.0% and an anthropophilic rate (for indoor resting mosquitoes) of 64.0% were calculated. The average parity rate was relatively low (61.2%). The Plasmodium falciparum immunological sporozoite rate was 0.20%. An. funestus presented a higher vectorial capacity during the first round of rice cultivation (January) than during the second round (April-May). An. arabiensis was mostly abundant in December and January at the beginning of the rainy season. This species was exophagic (endophagic rate = 27.5%) and zoophilic (anthropophilic rate = 7.8%). The sporozoitic index was determined as zero (number of examined mosquitoes = 871). In this village, An. arabiensis presented only marginal importance for malaria transmission. Malaria transmission occurred from December to April. Annual entomological inoculation rate, only due to An. funestus, was 8.96 during the first year, and 3.17 during the second year. In this area where transmission is moderately stable, we suggest an extension of vector imagocidal control activities up to the western fringes of the Highlands.

[Limits and weaknesses of intermittent treatment in malaria prevention]. / Limites et faiblesses du traitement intermittent dans la prévention du paludisme.

WHO proposal of a new strategy for the control of malaria, intermittent treatment using sulfadoxine-pyrimethamine, encounters various conceptual and logistic problems. First, the treatment is dedicated only to a very small part of the population which is not representative of the population at risk. Secondly, it largely underestimates the risks of this type of drugs. At last, the difficulties of its management should lead to hamper this strategy. It would be preferable to study the real causes of the current strategy failure and to take it into account for a new strategy.

Malaria prevention strategies.

Acute and severe consequences of pregnancy-associated malaria (PAM), such as materno-fetal death or cerebral malaria, seem limited to unstable malaria areas. In areas of stable endemicity, the main consequences are maternal anaemia and low birth weight (LBW) babies, particularly in primigravidae. Placental malaria seems more frequent and its consequences more severe in HIV-infected women. Since 1964, several chemoprophylaxis controlled trials have been undertaken, mainly in Tropical Africa where malaria is stable. Most showed an increase in mean birth weight in the prophylaxis group, especially among primigravidae. Similar findings were made with anaemia. Prophylaxis seems less effective in the case of HIV-malaria co-infection, which may require an increase in the number of doses. At present, intermittent treatment with sulfadoxine-pyrimethamine given twice or thrice during pregnancy in antenatal clinics seems the best policy for preventing PAM. Such effective prophylaxis should be integrated with other antenatal clinic services. Recently identified molecular receptors involved in cytoadherence of parasitized erythrocytes to placenta could yield new therapeutic or vaccine approaches, specifically targeted to pregnant women.

[Malaria during pregnancy: consequences and interventional perspectives]. / Paludisme associé à la grossesse: conséquences et perspectives d'intervention.

The impact of malaria during pregnancy varies greatly according to the intensity of transmission. Severe acute complications including cerebral malaria or materno-fetal death seem to be confined to areas of unstable transmission where malaria is uncommon except during epidemics. In areas of stable endemicity, the main consequences are maternal anemia and intra-uterine growth retardation resulting in low birthweight (LBW) particularly after first pregnancies. Recent studies have demonstrated that frequency and severity of placental malaria are greater in pregnant women with concurrent HIV infection. Since 1964 several controlled trials have been conducted to evaluate chemoprophylaxis in pregnant women mainly in tropical Africa where malaria transmission is stable. Findings have usually demonstrated an increase in mean birthweight after prophylaxis especially among primigravidae. Prophylaxis also had beneficial effects on anemia. Another finding of these trials was that prevention is less effective for women with HIV co-infection and that higher doses may therefore be required in such cases. In our opinion prophylaxis should be actively promoted as a routine public health measure for pregnant women in endemic areas. Current recommendations call for the use of a sulfadoxine-pyrimethamine twice or three times during pregnancy in antenatal clinics. This combination is more effective as a result of strong resistance of parasites to chloroquine. High cost and possible adverse effects in pregnant women prohibit routine use of mefloquine in developing countries. Integration of malaria prophylaxis into antenatal care services with nutrition and immunization measures should enhance the overall efficacy of prevention in outlying clinical facilities. Recent identification of molecular receptors involved in the cytoadherence of parasitized red blood cells to the placenta may lead to the development of new therapeutic or vaccinal approaches for pregnant women.

[Joint clinical rounds in the ICU and satisfaction of the professionals]. / Sesiones clínicas conjuntas en UCI y satisfacción de los profesionales.

It is unknown if multidisciplinary clinical rounds provide a greater degree of satisfaction among the professionals than the traditional work methods.The objective was to compare the satisfaction of the physicians and nurses who evaluate the patients jointly with those of the professionals who do so separately and transmit the information «at bedside¼ (traditional method). An anonymous survey that examined eleven dimensions of expectations, motivation and satisfaction on the common work method was used. Greater global satisfaction was observed in regards to the joint work method both with the substitute nurses (8.3 ± 0.8 versus 3.1 ± 2.8; p < 0.001) as well as those of the staff (7.2 ± 1.3 versus 2.1 ± 1.3; p = 0.01). In the remaining dimensions examined, the scores of the professionals who participated in the joint clinical rounds were also significantly better. Among the physicians, there were no significant differences in the different dimensions or in the global satisfaction.As a conclusion, it can be stated that the joint and consensual work method for the assessment of the patients produces an improvement in all the dimensions of satisfaction, expectations, and professional performance in the nursing area that is not detected among the physicians.

Malaria prevention during pregnancy in unstable transmission areas: the highlands of Madagascar.

Malaria transmission in Madagascar is highly variable from one region to the next, and the consequences of the disease on pregnant women and their foetuses are not fully documented. In midwestern Madagascar, the high-transmission lowlands in the west of the country meet the central plateaux, where malaria is unstable because of the high altitude and annual indoor spraying of DDT since 1993. We studied five of the region's main maternity clinics. We began by interviewing sample groups of women of childbearing age living within the vicinity of each clinic. This enabled us to determine the extent to which they had accessed and made use of available maternal health services during pregnancy and delivery, and, hence, to estimate the feasibility of boosting the prophylaxis. We then spent a whole year (from June 1996 to May 1997) observing deliveries at the five clinics in order to gauge the prevalence of placental infection and its consequences on birthweight in various transmission situations. Although only between 2 and 15% of the women said that they had taken prophylaxis during their previous pregnancy, the vast majority had benefited from preventive care: 97% had attended an antenatal visit on at least one occasion and 84% had had the assistance of medical or paramedical staff during delivery, even when their homes were situated relatively far away from the clinic (76%). In total, we observed 1637 deliveries with a mean placental malaria prevalence rate of 8.1%. Individual prevalence rates, however, were found to differ significantly between the maternity clinics situated in the east (minimum 2.1%) and west (maximum 26.2%) of the region. There were also marked variations in line with the seasonal fluctuations in entomological transmission. On the whole, a greater percentage of low birthweights (LBWs) was recorded at the lowland clinics than at the highland ones (17.1% vs. 9.7%), possibly because of the higher malaria infection rate in low altitude areas. On the other hand, the relative risk of LBW linked to placental infection was far greater in the highlands [4.9 (3.3-7.3)] than in the lowlands [1.9 (1.2-3.0)]. Although the rate of placental malaria among women inhabiting the country's central plateaux may be low, it means that transmission--and, hence, the risk of LBW because of placental infection--still persists in spite of the indoor DDT spraying programme. For maximum efficacy, we recommend a combination of vector control (extended to lower altitude areas outside the current OPID zone) and preventive care--i.e. individual chemoprophylaxis--for all highland women during pregnancy.

Sesiones clínicas conjuntas en UCI y satisfacción de los profesionales / Joint clinical rounds in the ICU and satisfaction of the professionals

Se desconoce si las sesiones clínicas multidisciplinarias (clinical rounds) comportan mayor grado de satisfacción, entre los profesionales que los métodos tradicionales de trabajo. El objetivo fue comparar la satisfacción de médicos y enfermeras que valoran los pacientes conjuntamente con la de aquellos profesionales que lo realizan por separado y transmiten la información «a pie de cama» (método tradicional). Se empleó una encuesta anónima donde se exploraron once dimensiones de expectativas, motivación y satisfacción sobre el método de trabajo habitual. Se observó una mayor satisfacción global respecto al método de trabajo conjunto tanto en las enfermeras suplentes (8,3 ± 0,8 versus 3,1 ± 2,8; p < 0,001) como en las de plantilla (7,2 ± 1,3 versus 2,1 ± 1,3; p = 0,01). En el resto de dimensiones exploradas también fueron significativamente mejores las puntuaciones de las profesionales que participaban en sesiones conjuntas. Entre los médicos no existieron diferencias significativas en las diferentes dimensiones ni en la satisfacción global. Como conclusión puede afirmarse que el método de trabajo conjunto y consensuado para la valoración de los enfermos produce, en enfermería, una mejora en todas las dimensiones de satisfacción, expectativas y desempeño profesional que no se detecta entre los médicos (AU)

It is unknown if multidisciplinary clinical rounds provide a greater degree of satisfaction among the professionals than the traditional work methods. The objective was to compare the satisfaction of the physicians and nurses who evaluate the patients jointly with those of the professionals who do so separately and transmit the information «at bedside» (traditional method). An anonymous survey that examined eleven dimensions of expectations, motivation and satisfaction on the common work method was used. Greater global satisfaction was observed in regards to the joint work method both with the substitute nurses (8.3± 0.8 versus 3.1 ± 2.8; p < 0.001) as well as those of the staff (7.2 ± 1.3 versus 2.1 ± 1.3; p = 0.01). In the remaining dimensions examined, the scores of the professionals who participated in the joint clinical rounds were also significantly better. Among the physicians, there were no significant differences in the different dimensions or in the global satisfaction. As a conclusion, it can be stated that the joint and consensual work method for the assessment of the patients produces an improvement in all the dimensions of satisfaction, expectations, and professional performance in the nursing area that is not detected among the physicians (AU)