Residual Malaria Transmission: magnitude and drivers of persistent Plasmodium infections despite high coverage of control interventions in Burkina Faso, West Africa

This study collected baseline data on malaria vectors to characterize the drivers and the factors of persistent malaria transmission in two villages in the western part of Burkina Faso. Mosquitoes were collected in each village using the Human landing catch and pyrethrum spray catch and identified using the morphological keys. Molecular analyses were performed for the identification of An. gambiae complex species, the detection of Plasmodium infection and kdr-995F mutation. Anopheles mosquito larvae were also collected in the same villages, reared to adult's stage for the WHO tube and cone tests performing. The physical integrity of the LLINs already used by people in each village was assessed using the proportional hole index (pHI). An. gambiae s.l. was the main malaria vector accounting for 79.82% (5560/6965) of all collected mosquitoes. The biting pattern of An. gambiae s.l. was almost constant during the survey with an early aggressiveness before 8 p.m. and later biting activity after 6 a.m. The EIR varied from 0.13 to 2.55 infected bites per human per night (average: 1.03 infected bites per human per night). An. gambiae s.l. populations were full susceptible to Chlorpyrifos-methyl (0.4%) and Malathion (5%) with high kdr-995F mutation frequencies (>0.8). The physical integrity assessment showed high proportion of good nets in Santidougou compared to those collected in Kimidougou. This study highlighted a persistence of malaria transmission despite the intense use of vector control tools as LLINs and IRS by correlating mosquito biting time and human behavior. It provided a baseline guide for the monitoring of the residual malaria transmission in sub-Saharan Africa and encouraging the development of new alternative strategies to support the current malaria control tools.

[Main characteristics of the street food sector in Bobo-Dioulasso, Burkina Faso]

To investigate the sector of food sold in the streets of Bobo-Dioulasso and identify relevant information for action, a survey on knowledge and practices of street food vendors and consumers was conducted in June 2005. Data have been collected in 928 street food selling posts. Structured questionnaires were used to collect data from 874 street vendors and 2474 consumers. Street food sites are concentrated in places where administration and trade activities are usually running. The street food seller is a married and illiterate woman of 32 years old. Cereals (48.5%), meat (33.9%), milk (9.6%) and fruits (4.4%) are the basic consumables. The street food consumer is a non married man, 27 years old working in profit-making activity. Consumers use many criteria to choose the place to eat, at times or permanently. The street food sector represents a source of income and induces change in household eating habits. Street food in Bobo-Dioulasso needs to be better organised, by using an holistic approach that involves all the actors.

[Influence of social perceptions and practices on the use of bednets in the malaria control programme in Ivory Coast (West Africa)]

The National Malaria Programme in Ivory Coast has encountered difficulty in winning public acceptance of insecticide-treated bednets. We speculate that resistance to the use of bednets could be rooted in social perceptions, beliefs and practices in the communities. The purpose of this study was to identify sociocultural and environmental factors that could be used to support promotion strategies and acceptance of impregnated bednets in Ivory Coast. Survey findings confirmed that bednets were not in widespread use among the population (25%). The most widely used methods were burning mosquito coils (50%) and indoor spraying (31%). Use of impregnated bednets was low (6%). Most survey respondents (73%) indicated initial appreciation for the effectiveness of bednets in protecting against mosquitoes as a nuisance. However only 9% of respondents thought that impregnated bednets provided protection against malaria although they did not necessarily use them. Design was a determinant factor for the use, and even acceptance, of bednets. The population want rectangular, permanently impregnated bednets large enough to accommodate at least 2 persons. Cost was a major obstacle to wider use by the population. According to our data the best price for the population would be between 2000 and 2500 FCFA as compared to the current price of 3500 FCFA in Ivory Coast.