Combating malaria morbidity and mortality by reducing transmission

Jean-François Trape and Christophe Rogier present epidemiological data and an analysis of the relationship between transmission, morbidity from malaria which suggest that any intervention aiming to reduce transmission will not, on a long-term basis, reduce the burden of malaria in the majority of epidemiological contexts observed in tropical Africa. (Résumé d'auteur

Reducing the oral quinine-quinidine-cinchonin (Quinimax) treatment of uncomplicated malaria to three days does not increase the recurrence of attacks among children living in a highly endemic area of Senegal

A 3 d shortened course of the quinine-quinidine-cinchonin association Quinimax (trademark) was compared to the usual 7 d regimen for routinely treating 462 acute uncomplicated #Plasmodium falciparum$malaria attacks in 72 children under the age of 10 years in Dielmo, a holoendemic village in Senegal. 25 mg/kg Quinimax (trademark) salt daily, given in 3 equal doses, improved clinical status in 99.6$ and the partial acquired immunity of the children were probably responsible for the absence of any difference between the courses. Oral Quinimax (trademark) for 3 d is a possible alternative regimen to chloroquine and sulfadoxine-pyrimethamine for treating uncomplicated malaria in highly endemic areas of Africa where clinical resistance to these drugs exists. (Résumé d'auteur

A Multiscale Approach Using Patches of Finite Elements for Solving Wave Propagation Problems in Microwave Discharge Plasma

We consider the development of an efficient numerical method for the simulation of microwave discharge plasmas. The method uses the idea of finite element patch and can deal with very disparate length scales of the plasma. In this paper, the time-domain Maxwell's equations, which are coupled with the plasma transport equations via the time-varying electron current density, are solved with a two-level Schwarz type algorithm based on a variational formulation of the standard Yee scheme. The patch of finite elements is used to calculate in an iterative manner the solution in the plasma region where a better precision is required. This numerical approach provides the Yee scheme with an efficient local-grid refinement capacity while preserving its stability. A numerical analysis shows its accuracy and computational efficiency on nested Cartesian grids. Simulation of a microwave breakdown in air under atmospheric pressure is then performed and results are discussed. We believe that both the inherent versatility with regard to the variational formulation and the efficiency of the proposed method can make it particularly suitable in modeling of microwave discharge plasmas by providing more insights of their nature and behavior

Highly focused anopheline breeding sites and malaria transmission in Dakar

<p>Abstract</p> <p>Background</p> <p>Urbanization has a great impact on the composition of the vector system and malaria transmission dynamics. In Dakar, some malaria cases are autochthonous but parasite rates and incidences of clinical malaria attacks have been recorded at low levels. Ecological heterogeneity of malaria transmission was investigated in Dakar, in order to characterize the <it>Anopheles </it>breeding sites in the city and to study the dynamics of larval density and adult aggressiveness in ten characteristically different urban areas.</p> <p>Methods</p> <p>Ten study areas were sampled in Dakar and Pikine. Mosquitoes were collected by human landing collection during four nights in each area (120 person-nights). The <it>Plasmodium falciparum </it>circumsporozoite (CSP) index was measured by ELISA and the entomological inoculation rates (EIR) were calculated. Open water collections in the study areas were monitored weekly for physico-chemical characterization and the presence of anopheline larvae. Adult mosquitoes and hatched larvae were identified morphologically and by molecular methods.</p> <p>Results</p> <p>In September-October 2007, 19,451 adult mosquitoes were caught among which, 1,101 were <it>Anopheles gambiae s.l</it>. The Human Biting Rate ranged from 0.1 bites per person per night in Yoff Village to 43.7 in Almadies. Seven out of 1,101 <it>An. gambiae s.l</it>. were found to be positive for <it>P. falciparum </it>(CSP index = 0.64%). EIR ranged from 0 infected bites per person per year in Yoff Village to 16.8 in Almadies. The <it>An</it>. <it>gambiae </it>complex population was composed of <it>Anopheles arabiensis </it>(94.8%) and <it>Anopheles melas </it>(5.2%). None of the <it>An. melas </it>were infected with <it>P. falciparum</it>. Of the 54 water collection sites monitored, 33 (61.1%) served as anopheline breeding sites on at least one observation. No <it>An</it>. <it>melas </it>was identified among the larval samples. Some physico-chemical characteristics of water bodies were associated with the presence/absence of anopheline larvae and with larval density. A very close parallel between larval and adult densities was found in six of the ten study areas.</p> <p>Conclusion</p> <p>The results provide evidence of malaria transmission in downtown Dakar and its surrounding suburbs. Spatial heterogeneity of human biting rates was very marked and malaria transmission was highly focal. In Dakar, mean figures for transmission would not provide a comprehensive picture of the entomological situation; risk evaluation should therefore be undertaken on a small scale.</p