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Biomedical subjects

U D'Alessandro

Publications and source records attributed to U D'Alessandro.

At least 19 recordsLinked to original sources
PubMed2006

A randomised trial to assess the safety and efficacy of artemether-lumefantrine (Coartem) for the treatment of uncomplicated Plasmodium falciparum malaria in Rwanda.

Coartem is a fixed-dose combination of artemether-lumefantrine that, given in six doses, provides effective treatment for children with uncomplicated Plasmodium falciparum infection in areas with highly endemic and multidrug-resistant malaria. In Rwanda since 2001, amodiaquine+sulfadoxine-pyrimethamine (AQ+SP) has been the first-line treatment, but resistance to this combination has rapidly emerged and spread. Coartem was considered as a possible alternative, and a randomised, open-label, clinical trial to test its safety, tolerability and efficacy was carried out in 2004-2005. Five hundred children aged 12-59 months with uncomplicated P. falciparum malaria were randomly allocated to AQ+SP or Coartem. Patients were followed up until day 28 after treatment. Adverse events and clinical and parasitological outcomes were recorded. Adequate clinical and parasitological response (ACPR) was significantly higher in children treated with Coartem than in those treated with AQ+SP: the PCR-adjusted 28-day ACPR was 96.68% for Coartem and 79.35% for AQ+SP. Both treatments rapidly cleared parasitaemia and fever, although parasite clearance was significantly faster in children treated with Coartem. Mean packed cell volume increased in all patients, with no significant differences between treatments. Coartem proved to be more efficacious than AQ+SP, with a good safety and tolerability profile.

Amodiaquine↗
PubMed2006

Accuracy of the health information system on malaria surveillance in Vietnam.

The health information system (HIS) is a key component of control programs and its accuracy is necessary for the assessment of disease risks, the formulation of priorities and the evaluation of the cost-effectiveness of different interventions. In order to assess the quality of the HIS in estimating malaria morbidity in Vietnam, we compared data obtained by a 2-year active (ACD) and passive case detection (PCD) study with those routinely collected at the local commune health centres (CHC) at three sites having different malaria epidemiology. The majority of malaria cases (80-95%) detected by ACD were missed by the HIS. Similarly, most malaria cases (50-90%) detected by PCD were also missed by the HIS, and this was proportional to the number of active private practitioners. Reasons for this low sensitivity are low CHC attendance, high attendance at private health facilities, widespread self-medication and attendance at central health facilities. In conclusion, although malaria has sharply decreased in Vietnam over the past 10 years, the current HIS greatly underestimates the malaria burden. Involvement of the private sector and the establishment of sentinel sites might improve the quality of data and the relevance of HIS in malaria control.

Adolescent↗
PubMed2006

[In vivo sensitivity of Plasmodium faciparum to chloroquine and sulfadoxine pyrimethamine in the Bobo Dioulasso region (1998-2001): risk factors associated with treatments failures to the two drugs].

The therapeutic efficacy of chloroquine (CQ) and sulfadoxine-pyrimethamine (SP) was determined over a 4 year period (1998-2001) in Bobo Dioulasso, Burkina Faso, with an analysis of the risk factors associated to treatment failures to the 2 drugs. In total, 2008 children (6 months-15 years old) attending in 4 health centres (1 urban and 3 rural) were included in the study. Children were alternatively allocated to either CQ or SP The WHO 14-days in vivo field test was carried out. PCV was measured at day 0 and 14. CQ treatment failure was 24.4% (229/940), most of them being late failures. Between 1998 and 2001 a significant increase in CQ treatment failure (p < 0.001) was observed. SP showed a good efficacy with a total treatment failure of 4.4% (33/749). However; a significant increase of resistance to this drug (p=0.001) was also observed between 1998 and 2001. Among children with anaemia at day 0.85% (23/27) were no more anaemic by day 14 in the SP group, while in the CQ group the proportion was lower; 69% (27/39). However the difference between the two drugs was not significant (p > 0.1). Univariate analysis showed that the site, the age of children, the time of recruitment and the parasitaemia were significantly associated with CQ treatment failure. In the multivariate analysis these 4 variables remain significantly and independently associated with the risk of CQ treatment failure. After adjusting for the effect of the 3 other factors, the risk of treatment failure was reduced by half in rural area compared to urban area as well as in children of 5-15 years of age compared to those under 5. The risk of treatment failure was significantly increased in 2000-2001 (OR = 1.66, p < 0.05) as compared to the 2 previous years (1998-1999). It was also twice higher in children with parasitaemia > or = 16,000/microl than in those having a lower parasitaemia. For SP we have not observed such connexions with the univariate and multivariate analysis.

Adolescent↗
PubMed2004

The sick placenta-the role of malaria.

The human placenta is an ideal site for the accumulation of Plasmodium falciparum malaria parasites, and as a consequence serious health problems arise for the mother and her baby. The pathogenesis of placental malaria is only partially understood, but it is clear that it leads to a distinct epidemiological pattern of malaria during pregnancy. The objectives of this review are: (1) To review recent data on the epidemiology of malaria in pregnancy, with emphasis on placental malaria; (2) to describe the pathological changes and immunological factors related to placental malaria; and (3) to discuss briefly the functional consequences of this infection for the mother and her baby. The review attempts to bring together local events at the maternal-fetal interface which encompass immunological and pathological processes which relate to the epidemiological pattern of malaria in pregnancy in areas of both high and low malaria transmission. An integrated understanding of the epidemiological, immunological and pathological processes must be achieved in order to understand how to control malaria in pregnancy. The yearly exposure of at least 50 million pregnancies to malaria infection makes it the commonest and most recurrent parasitic infection directly affecting the placenta. These statistics and our limited understanding of its pathogenesis suggest the research priorities on this subject.

Cytokines↗
PubMed2004

Malaria epidemiology in a rural area of the Mekong Delta: a prospective community-based study.

Over the past 10 years, the Mekong Delta region in Vietnam has experienced fast socio-economic development with subsequent changes in malaria vectors ecology. We conducted a 2-year prospective community-based study in a coastal rural area in the southern Mekong Delta to re-assess the malaria epidemiological situation and the dynamics of transmission. The incidence rate of clinical malaria, established on 558 individuals followed for 23 months by active case detection and biannual cross-sectional surveys, was 2.6/100 person-years. Over the 2-year study period, the parasite rate and malaria seroprevalence (Plasmodium falciparum and P. vivax) decreased significantly from 2.4% to almost 0%. Passive case detection (PCD) of clinical cases and serological follow-up of newborns carried out in a larger population confirmed the low and decreasing trend of malaria transmission. The majority of fever cases were seen in the private sector and most were unnecessarily treated with antimalarials. Training and involvement of the private sector in detection of malaria cases would greatly improve the quality of health care and health information system.

Adolescent↗
PubMed2003

The contribution of health-care services to a sound and sustainable malaria-control policy.

HIV and AIDS, tuberculosis, and malaria, besides presenting a large mortality and morbidity burden in developing countries, are also responsible for poor economic development. In the past international agencies devoted resources and efforts to control malaria and other diseases without taking into account health-system performance and sustainability. Even assuming that the Global Fund to Fight AIDS, Tuberculosis, and Malaria (GFATM)--a recent international initiative--would provide the necessary funds, a poorly performing health-care system will not be able to use these funds optimally. Moreover, even if all interventions are cost-effective, their impact on mortality and morbidity will only be marginal if access to proper care is not guaranteed. It is the responsibility of scientists and health managers to highlight to donor agencies the importance of an accessible and well functioning health-care system at all levels for the control of specific diseases.

Bedding and Linens↗
PubMed2002

Chloroquine and sulphadoxine-pyrimethamine efficacy for uncomplicated malaria treatment and haematological recovery in children in Bobo-Dioulasso, Burkina Faso during a 3-year period 1998-2000.

We determined the parasitological resistance and the clinical failure to chloroquine (CQ) and sulphadoxine-pyrimethamine (SP) by the WHO 14-day in vivo test over three consecutive years in 948 children aged 6-59 months with uncomplicated malaria attending four health centres in the province of Houet, Burkina Faso. Children were alternatively allocated to either CQ or SP. Packed cell volume (PCV) was measured at days 0 and 14. Parasitological resistance (RI, RII and RIII) to CQ was 18% (83 of 455) and to SP <1% (two of 308). Clinical failure with CQ was 12% (53 of 455) with no evidence of increase over time. Only one case of clinical failure was detected among the children treated with SP. The prevalence of anaemia (PCV <25%) was about 40% at day 0 and had decreased substantially by day 14 in both groups. However, in children treated with SP the prevalence of anaemia at day 14 was significantly lower than in those treated with CQ:RR = 3.15 (95% CI: 1.33-7.42, P = 0.008). CQ and SP are still efficacious for the treatment of uncomplicated malaria in children, at least in this area of Burkina Faso. However, the prevalences of CQ resistance reported from other areas of the country are worrying because of its potential spread. Regular surveillance of resistance to commonly used antimalarial drugs should continue.

Anemia↗
PubMed2001

History and importance of antimalarial drug resistance.

The emergence of Plasmodium falciparum resistance to widely used antimalarial drugs such as chloroquine (CQ) has made malaria control and treatment much more difficult. This is particularly dramatic for Africa, as few affordable alternatives are available. Drug pressure has been identified as one of the key factors for the emergence and spread of resistance. The contribution of the extensive use and misuse of antimalarial drugs to the selection of resistant parasites became particularly evident during the Global Malaria Eradication campaign, launched by World Health Organization (WHO) in 1955. The first reports confirming P. falciparum resistance to CQ came almost simultaneously in the early 1960s from South America and South-East Asia, where direct or indirect (through use of medicated cooking salt) mass drug administration (MDA) had been implemented. Similar approaches were very limited in Africa, where P. falciparum resistance to CQ was first reported from the eastern region in the late 1970s and spread progressively west. Most African countries still rely heavily on CQ as first-line treatment despite various levels of resistance, although some states have changed to sulphadoxine-pyrimethamine (SP) as the first-line drug. Unfortunately, the predicted SP useful therapeutic life might be very short, probably because of its prolonged half-life, causing a higher probability of selecting resistant strains and a consequent fast development of resistance. CQ resistance is not evenly distributed and important differences can be found within and between countries. It seems to have spread more rapidly in East than in West Africa. Considering the high level of CQ use in West Africa, other factors such as intensity of transmission, population immunity or population movements should be considered when explaining the different levels of resistance. Understanding such factors may help us in devising strategies to contain the spread of drug resistance.

Africa↗
PubMed2001

[Pleading for insecticide treated nets in malaria control programmes].

Insecticide Treated Nets (ITNs) represent for Malaria Control Programmes an important and efficacious tool for decreasing malaria incidence. In a large number of countries outside Africa, where in most cases malaria is unstable or the risk of epidemics is high, the long-term efficacy of ITNs is widely accepted. However, it is unclear whether this applies to situations where transmission is intermediate or intense. Comparisons of epidemiological data from areas with different transmission levels led to contradictory results in terms of the long-term impact of ITNs in Africa. Besides the methodological problems, these comparisons do not take into account the mortality indirectly linked to malaria and the time distribution of infective bites. This discussion helps in drawing attention to the possible risk of shifting mortality and morbidity to older age groups. Although an increased incidence of cerebral malaria cannot be ruled out in areas of intense transmission, the overall impact will probably be beneficial. These non-conclusive comparisons should not slow down the implementation of ITN programmes. The first report on the long-term effect of ITNs contradicts the more pessimistic predictions. Simply reducing the transmission peaks could substantially decrease malaria mortality and morbidity The improvement of the distribution and re-impregnation systems should make ITNs more operational.

Bedding and Linens↗
PubMed2000

Modelling a predictable disaster: the rise and spread of drug-resistantmalaria.

The evolution of drug-resistant malaria is one of the most important factors thwarting the development of effective malaria disease control. Several mathematical models have been developed to try and understand the dynamics of this process and how it can be slowed or even avoided. Much of the mathematics describing the evolution of drug resistance in malaria focuses on the derivation and mechanics of the calculations, which can make it inaccessible to experimentalists and field workers. In this article, Ian Hastings and Umberto D'Alessandro describe general model results without recourse to mathematical details, identify the factors that should be considered in the design of drug control programmes, and discuss the crucial parameters that remain unknown and need to be measured in the field or laboratory.

Animals↗
PubMed2000

Child malaria treatment practices among mothers in the district of Yanfolila, Sikasso region, Mali.

We studied child malaria treatment practices among mothers living in the District of Yanfolila in southern Mali. For sampling, we first chose five of 13 health areas with probability proportional to size. Then villages, compounds and mothers with at least one child aged 1-5 years were randomly chosen. We assessed the spleen size of one 1-5 year-old child of each mother, collected a thick blood film and recorded the body temperature of every child whose mother thought he/she was sick. 399 mothers in 28 villages were interviewed with a structured questionnaire divided into two parts. If the child had had soumaya (a term previously associated with uncomplicated malaria) during the past rainy season, we asked about signs and symptoms, health-seeking behaviour (who the mother consulted first) and treatment. If not, information about knowledge of the disease and treatment to be given was collected. 86% of the mothers interviewed stated that their child had been sick and almost half of them had had soumaya. All mothers named at least one sign by which they recognized the disease. Vomiting, fever and dark urine/yellow eyes/jaundice were the three most common signs mentioned. 75.8% managed their child's disease at home and used both traditional and modern treatment. The most common anti-malarial drug was chloroquine, often given at inappropriate dosage. The sensitivity and specificity of the mothers' diagnosis was poor, although this might be explained by the large percentage of children who had already been treated at the time of the interview. The results of our survey call for prompt educational action for the correct treatment of uncomplicated malaria/soumaya, particularly for mothers and possibly for shopkeepers. The high spleen rate (58.1%) among randomly selected children confirms that malaria is a common disease in this area. Improved case-management at home could only be beneficial.

Adult↗
PubMed1999

Reduction in the mean number of Plasmodium falciparum genotypes in Gambian children immunized with the malaria vaccine SPf66.

SPf66, a synthetic peptide Plasmodium falciparum vaccine, did not protect young Gambian children against clinical attacks of malaria. Nevertheless, Gambian children who had been vaccinated with SPf66 and who were parasitaemic at the end of the first malaria transmission season after vaccination had significantly fewer detectable P. falciparum genotypes than control children, as determined by polymerase chain reaction analysis of 3 polymorphic loci--the msp1 block 2 repeat region, the msp2 repeat region, and the R11 region of the glutamate-rich protein gene (glurp). Geometric mean numbers of genotypes were 1.66 vs. 1.87, 1.95 vs. 2.43, and 1.21 vs. 1.50 for msp1, msp2 and glurp, respectively (P = 0.31, P = 0.04 and P < 0.01). Differences between groups became a little more marked for msp1 and msp2 when children with symptomatic malaria were excluded. No significant difference was found between parasites obtained from SPf66-vaccinated or control children in the prevalences of amino acid alleles at positions 44 and 47 in the 11 amino acid sequence of the merozoite surface protein 1 molecule, which is present in SPf66. The reduction in the number of genotypes observed could not be explained by a difference in parasite densities between SPf66-vaccinated and control children, as geometric mean parasite densities were almost identical in the 2 groups. These observations suggest that SPf66 vaccine may have induced an immune response which reduced the incidence of new infections in immunized children or accelerated the rate of clearance of parasites of individual genotypes. However, no reduction in the prevalence or density of parasitaemia was recorded in SPf66-vaccinated children, suggesting the existence of some kind of density-dependent mechanism for controlling low levels of malaria parasitaemia.

Animals↗