[Preliminary evaluation of the insecticide susceptibility in Anopheles gambiae and Culex quinquefasciatus from Lobito (Angola), using WHO standard assay]. / Premiers tests OMS d'évaluation de la sensibilité aux insecticides chez Anopheles gambiae et Culex quinquefasciatus à Lobito, Angola.

Field collections of the most common urban mosquito vectors Anopheles gambiae and Culex quinquefasciatus were carried out in June 2003, March 2004 and November 2005 to gather preliminary data on the insecticide susceptibility in mosquitoes from Lobito (Angola) using the WHO standard bioassays. Bioassays were performed on F0 adults emerging from the field larval collections and on unfed adults from landing catches on volunteers. Batches of mosquitoes from three selected locations (Alto Liro, San Jao and Bela Vista) were exposed for 1 hour to several insecticides such as DDT 4%, carbosulfan 0.4%, permethrin 1%, deltamethrin 0.05% and cyfluthrin 0.15%, in order to estimate the immediate knockdown times (kdT50 and kdT95) and the mortality rate after exposure. The results revealed that mosquito susceptibility to insecticides varied depending on the insecticide, the site and the period of collection. The main local malaria vector A. gambiae (both M and S forms) was basically resistant to DDT and susceptible to all pyrethoids, regardless of the period and the site of collections. The overall mortality rate due to DDT was 73% in Alto Liro, 89% in San Jao and varied depending on the period in Bela Vista between 95% in March 2004 and 100% in November 2005. The mortality due to pyrethoids was 100% at all locations, with the kdT50 and KdT95 times ranging between 9 and 16 minutes and between 18 and 29 minutes, respectively. Concerning the C. quinquefasciatus, populations from Yard and Caponte were resistant to all insecticides tested; the mortality rate was 40% with deltamethrin and 70% with permethrin, while no lethal effect was observed with DDT or carbosulfan. In conclusion, despite its probable high resistance to DDT, the main local malaria vector A. gambiae remained fully susceptible to pyrethroids. This could forecast a good biological efficacy of the scheduled vector control interventions in Angola, based on a large-scale distribution of long-lasting, insecticide-treated nets and on the implementation of indoor residual spraying. The local vector control programme must include well-adapted IEC campaigns and full participation of the community for better management of the insecticide resistance in targeted mosquitoes and for better control of malaria vector populations.

Surnotification du paludisme : l'exemple des consultations dans les centres de sante de Lobito; Angola

Dans la region holo et hyperendemiques du paludisme; une definition simple de l'acces palustre ne peut pas se fonder sur les donnees cliniques ni sur la densite parasitaire sanguine; quand on la connait ; D'autres variables doivent etre prises en compte; en fonction de l'epidemiologie de chaque region. Dans une region de transmission moyenne; hypo ou mesoendemique; la parasitologie reste importante pour confirmer un diagnostic. Les auteurs ont fait l'experience pendant cinq ans dans une surnotification du paludisme du fait d'un taux excessif d'examens paracliniques rendus positifs. Ils concluent que cet etat de fait n'est pas bon; ni pour la prise en charge de l'acces palustre simple ou d'autres pathologies infectieuses; ni pour les releves epidemiologiques. Le rapport 2008 sur le paludisme de l'OMS avait deja note ce fait en soulignant que de nombreuses statistiques du centre de sante en zone endemique se fondaient sur des donnees cliniques; ce qui entrainait une surestimation de la situation endemique. Beaucoup d'elements sont a prendre en consideration dans cette situation; qui pourrait etre corrigee par une revalorisation du diagnostic parasitologique surtout dans les zones isolees et la creation d'un reseau de diagnostic; capable de renforcer la prise en charge des cas au niveau individuel et le recueil epidemiologique au niveau global

Enquetes paludometriques en 2006 et 2007 dans la province de Benguela; Angola

Une bonne connaissance du facies epidemiologique est la prealable a toute activite de lutte antipaludique. La definition de ce facies epidemiologique doit reposer sur des donnees fiables; or les informations provenant des formations sanitaires sont parfois incorrectes et toujours parcellaires. Ainsi; les diagnostics parasitologiques errones entrainent souvent une mauvaise appreciation du degre d'epidemie palustre. La mise en place des sites sentinelles beneficiant d'un bon monitorage permet des evaluations epidemiologiques correctes. Dans ces travaux; les indices paludometriques obtenus a partir d'une serie enquetes trasversales a passage unique sont ressortis dans trois zones aux situations geographiques et ecologiques differentes et a differentes periodes de l'annee. Cette information est capitale avant la mise en place des methodes de lutte en perspective

[Impact of a new parasitologic laboratory for malaria diagnosis on diagnosis and cost of malaria in a company setting: experience from Angola]. / Impact de la création d'un laboratoire de diagnostic parasitologique du paludisme sur le diagnostic et le cout du paludisme dans une entreprise: une expérience Angolaise.

In malaria endemic areas treating every fever episode as a malaria onset would result in overdiagnosis with a margin of the error varying in function of epidemiological factors. When further compounded by overestimation related to errors in parasitologic diagnosis, clinical misdiagnosis leads to unwarranted hospitalization and inappropriate treatment. In a company setting this would mean unnecessary loss of employee work time. False positive diagnosis causes overestimation of chemoresistance, overconsumption of antimalarial drugs and underestimation of other infectious diseases. Judging from these high costs, it can be assumed that improving the reliability of parasitologic diagnosis would have a positive impact on the quality of clinical management, efficiency of antimalarial use and accuracy of epidemiological surveys. This assumption was confirmed by analysis of data following start-up of a parasitologic laboratory for malaria diagnosis in the health care clinic at Sonamet's fabrication yard in Lobito, Angola. Laboratory personnel receives expert training and audit findings demonstrate consistently reliable diagnosis. This experience underscores the need for reliable parasitologic diagnosis as a prerequisite for any large-scale malaria control program.

Impact de la creation d'un laboratoire de diagnostic parasitologique du paludisme sur le diagnostic et le cout du paludisme dans une entreprise : experience angolaise

En zone d'endemie palustre; il est abusif de considerer comme paludisme tout acces febrile; la marge d'erreur variant avec le facies geoclimatique. Quant a cette sur- estimation clinique s'ajoute une sureva l u ation par le diagnostic parasitologique; la gestion du paludisme peut s'alourdir d'inutiles hospitalisations et de traitements repetes; et; dans le cadre d'une entreprise industrielle;d'un nombre considerable de journees inutilement perdues. Les diagnostics positifs errones amenent l'evocation injustifiee de cas de chimioresistance en entrainant une surconsommation d'antipaludiques de derniere generation; tout en occultant les pathologies non palustres. L'absence de fiabilite de l'examen parasitologique se paye donc au prix fort; et seul son retablissement permet une prise en charge clinique de qualite; l'emploi au plus juste des antipaludiques; et des eva l u ations epidemiologiques correctes. C'est la lecon tiree de l'evolution des donnees observees apres implantation; dans le service medical d'une entreprise; d'un laboratoire de diagnostic parasitologique supervise et regulierement audite par des experts. Le constat amene a rappeler que la disponibilite d'un diagnostic parasitologique de qualite est un prealable a toute ambition de controle antipaludique probablement aussi a grande echelle

Data entry on a computer terminal: repetitive work strains on the oculomotor and central nervous systems.

Continuous telemetric recordings including E.K.G., E.O.G., and E.E.G. were carried out on two subjects during 4 working days: 1 day of "reference work" or classical clerical activities, 3 days of "data entry work". Although the time allowed for the task was not limited, the performance assessed from oculomotor patterns remained stable throughout the day, from one day to the next and from one subject to another. This stability was reflected on the stereotyped E.E.G. patterns recorded during the work period, the differences occurring between reading and typing were more acute in the left cortical hemisphere than in the right. As a result of these stable patterns, the ultradian oscillations of the behavioural and physiological parameters were less during data entry than during work reference. The only possible time adjustments were the interruptions or breaks between two document pages and their variations could be considered as indicators of work load.

Observations on a transient phase of focal swelling in degenerating unmyelinated nerve fibers.

This study describes the nature and time-course of a swelling phase during the degeneration of unmyelinated nerve fibers, as observed in highly organized cultures of rodent sensory ganglia. Observations were made on nerve fascicles after they were cut and during nutritional deprivation. About 12 hr after nerve transection, large, clear vacuoles appear throughout fascicles distal to the cut. These vacuoles are most numerous at 24 hr and then gradually subside; after 48 hr, only small granules mark the severed fascicles. Electron microscopy shows that the vacuoles are, in fact, massive focal dilations of unmyelinated axons. Similar focal dilations in unmyelinated axons are observed if cultures are not refed for 5-7 days; under these conditions glucose concentrations fall below 20 mg/100 ml and degenerative changes begin to appear in neuronal somas. If the gas-tight assembly is opened and the culture refed, there is rapid disappearance of axonal dilations (usually within 1 hr) and recovery of many of the damaged neurons. Cooling (4 degrees C) prevents this reversal, suggesting that an active process is involved. It is postulated that the swellings result from the failure of active axolemmal ion-pumping mechanisms prior to loss of selective permeability in the axon membrane. The reasons for the focal nature of the swellings is unknown. A literature review indicates that a phase of focal swelling has frequently been observed during the degeneration of unmyelinated nerve fibers in vivo.