[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.

[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.

[Knowledge, attitudes and practice of populations faced with culicidae nuisances: results of 6 surveys taken in Cameroon in 1994]. / Connaissances, perceptions et pratiques des populations face aux nuisances culicidiennes: résultats de six enquêtes menées au Cameroun en 1994.

In 1994, six KAP studies were carried out in Cameroon to assess the importance of protective methods used by different population groups against culicine nuisance. The objective of these surveys was to evaluate the importance of the use of preventive measures by family against the parasite. The results show that in spite of a strongly resistant parasite in a hyperendemic malaria zone, the use of average protection remains very heterogeneous. Mosquito nets, identified as efficient protection, are used to varying degrees depending on the sites. In Douala, mosquito nets were found in 47% of households visited, with 65% of the inhabitants regularly using them. These figures rose to 75% and 82% respectively in a particularly exposed area of the city. In rural areas very few mosquito nets were identified with an average of one inhabitant per residence using them. The report of the study on the free distribution of mosquito nets and the reimpregnation of the nets six months later in Mbebe-Kikot village, showed that three years after the distribution of the nets, only 68% of the residences still had one mosquito net. In addition, only 9% of these nets were still in good condition. The results of these surveys showed that mosquito nets are more widely used in urban areas, with a higher number of inhabitants per household sleeping under them. They also showed that the free distribution of nets alone does not improve the protection of the population as they are not educated on the maintenance and care of the nets. So we can suggest to use different promotion and distribution strategies in urban area, where lot of people has got the experience of bed nets, and in rural area.

[Evaluation of malarial indices in the forest region of Djoum (southern Cameroon)]. / Evaluation des indices paludométriques dans la région forestière de Djoum (Sud Cameroun).

The authors report the results of a sample survey carried out in Djoum to evaluate the main malarial indexes among 0-15 years old children. These investigations suggest that malaria is hyperendemic in this forestry area, at the end of the dry season.

[Prevention and control of malaria in pregnant women in an urban setting (Yaoundé, Cameroun)]. / Prévention et lutte contre le paludisme chez les femmes enceintes en milieu urbain (Yaoundé, Cameroun).

The aim of this study was to evaluate the methods of preventing malaria (chemoprophylaxis, vector control) and of fever management (presumptive treatment of malaria) used for pregnant women in Yaounde, Cameroon and to identify the most important factors for assessing these practices. The 221 women studied were selected by cluster sampling. All had made extensive use of health services during pregnancy and 77% were using chemoprophylaxis. The number of febrile episodes in pregnant women who claimed to have used chemoprophylaxis was not significantly different to that in the women who did not use it. However, the mean birth weight of the babies of women who had used chemoprophylaxis was significantly higher. The women did not systematically use vector control measures; 21% used insect repellents (electric plaques, coil burners) and 20% used aerosol insecticides. Only 10% of the women slept under simple, untreated mosquito nets and none used mosquito nets impregnated with insecticide. Fifty per cent of the women had at least one episode of fever during pregnancy and 77% were treated for presumed malaria. However, the treatment was not standardized and was unsuitable in a third of cases. Possible changes in the chemoprophylaxis strategy are discussed.