Land use change alters malaria transmission parameters by modifying temperature in a highland area of Uganda

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73403/1/j.1365-3156.2000.00551.x.pd

Molecular epidemiology of drug-resistant malaria in western Kenya highlands

<p>Abstract</p> <p>Background</p> <p>Since the late 1980s a series of malaria epidemics has occurred in western Kenya highlands. Among the possible factors that may contribute to the highland malaria epidemics, parasite resistance to antimalarials has not been well investigated.</p> <p>Methods</p> <p>Using parasites from highland and lowland areas of western Kenya, we examined key mutations associated with <it>Plasmodium falciparum </it>resistance to sulfadoxine – pyrimethamine and chloroquine, including dihydrofolate reductase (<it>pfdhfr</it>) and dihydropteroate synthetase (<it>pfdhps</it>), chloroquine resistance transporter gene (<it>pfcrt</it>), and multi-drug resistance gene 1 (<it>pfmdr1</it>).</p> <p>Results</p> <p>We found that >70% of samples harbored 76T <it>pfcrt </it>mutations and over 80% of samples harbored quintuple mutations (51I/59R/108N <it>pfdhfr </it>and 437G/540E <it>pfdhps</it>) in both highland and lowland samples. Further, we did not detect significant difference in the frequencies of these mutations between symptomatic and asymptomatic malaria volunteers, and between highland and lowland samples.</p> <p>Conclusion</p> <p>These findings suggest that drug resistance of malaria parasites in the highlands could be contributed by the mutations and their high frequencies as found in the lowland. The results are discussed in terms of the role of drug resistance as a driving force for malaria outbreaks in the highlands.</p

Evaluating the community education programme of an insecticide-treated bed net trial on the Kenyan coast.

Increased interest in the potential contribution of insecticide-impregnated bed nets (ITBN) to malaria control has led to research efforts to determine the impact and sustainability of ITBN programmes in differing environments. There is a need to develop effective, feasible educational strategies that will both inform and motivate community members, and thus maximize the correct usage of ITBN. This is especially true in communities where indigenous usage of bed nets is low. This paper describes the educational component of a randomized controlled community intervention trial of ITBN, with childhood malaria morbidity as an outcome. The educational approach and messages for the ITBN trial were developed from anthropological survey data collected 4 years before the trial, and from community surveys conducted by project researchers. Low levels of understanding amongst mothers of the aetiological link between mosquitos and malaria led to the exclusion of the term 'malaria' from the initial educational messages promoting the use of ITBN. Appropriate individuals within the existing district health care structure were trained as community educators in the project. These educators conducted intensive teaching in the community through public meetings and group teaching in the first 6 months of the trial. The impact of these initial activities was assessed through interviews with a random sample of 100 mothers and 50 household heads. This allowed the identification of messages which had not been well understood and further educational methods were chosen to address the areas pinpointed. The community assessment also demonstrated that, in 1994, over 90% of mothers understood a protective role for bed nets against malaria and the ITBN education messages were changed to take account of this. The school programme was evaluated through determining outreach (the number of households accessed), changes in participant children's knowledge, post-teaching assessment of mothers' knowledge and discussions with parent-teacher associations. It was shown that 40% of intervention homes with children in the target group were accessed, participant children learned the educational messages well (scores increased from a pre-teaching mean of 59% to a post-teaching mean of 92%) and a high level of awareness of the ITBN trial was achieved in these homes (75%). However, specific messages of the education programmed were not well transferred to the home (30%). The discussion emphasises the need for allocation of adequate resources for education in programmes dependent on achieving a change in community practices. We also describe the value of ongoing communication between programme planners and a target population in maximizing the effectiveness of messages and methods used

Evidence for a mass community effect of insecticide-treated bednets on the incidence of malaria on the Kenyan coast.

The use of insecticide-treated bednets (ITBNs) has been shown to be effective in reducing mortality and morbidity from malaria. However, there is mixed evidence as to whether or not community-wide use of ITBNs engenders a 'mass effect', such that those not sleeping under bednets are offered protection from widespread ITBN use in the area in which they live. We have analysed data collected in Kilifi, Kenya, from a cohort of children followed from birth to investigate how the degree of net usage in the locality of a child affects the risk of developing malaria. This effect was explored using a Cox proportional hazards model. For those not using ITBNs, we found that an increasing level of ITBN usage within the area surrounding each child was associated with a decreasing risk of developing malaria, thus providing evidence in support of a mass community effect. The size and significance of this effect were found to decrease as non-overlapping areas of increasing distance away from a child's home were considered. The effect was significant for areas at distances of up to 1.5 km away from each child

The effect of delivery mechanisms on the uptake of bed net re-impregnation in Kilifi District, Kenya.

The results of recently completed trials in Africa of insecticide-treated bed nets (ITBN) offer new possibilities for malaria control. These experimental trials aimed for high ITBN coverage combined with high re-treatment rates. Whilst necessary to understand protective efficacy, the approaches used to deliver the intervention provide few indications of what coverage of net re-treatment would be under operational conditions. Varied delivery and financing strategies have been proposed for the sustainable delivery of ITBNs and re-treatment programmes. Following the completion of a randomized, controlled trial on the Kenyan coast, a series of suitable delivery strategies were used to continue net re-treatment in the area. The trial adopted a bi-annual, house-to-house re-treatment schedule free of charge using research project staff and resulted in over 95% coverage of nets issued to children. During the year following the trial, sentinel dipping stations were situated throughout the community and household members informed of their position and opening times. This free re-treatment service achieved between 61-67% coverage of nets used by children for three years. In 1997 a social marketing approach, that introduced cost-retrieval, was used to deliver the net re-treatment services. The immediate result of this transition was that significantly fewer of the mothers who had used the previous re-treatment services adopted this revised approach and coverage declined to 7%. The future of new delivery services and their financing are discussed in the context of their likely impact upon previously defined protective efficacy and cost-effectiveness estimates

Insecticide-treated bednets reduce mortality and severe morbidity from malaria among children on the Kenyan coast.

New tools to prevent malaria morbidity and mortality are needed to improve child survival in sub-Saharan Africa. Insecticide treated bednets (ITBN) have been shown, in one setting (The Gambia, West Africa), to reduce childhood mortality. To assess the impact of ITBN on child survival under different epidemiological and cultural conditions we conducted a community randomized, controlled trial of permethrin treated bednets (0.5 g/m2) among a rural population on the Kenyan Coast. Between 1991 and 1993 continuous community-based demographic surveillance linked to hospital-based in-patient surveillance identified all mortality and severe malaria morbidity events during a 2-year period among a population of over 11000 children under 5 years of age. In July 1993, 28 randomly selected communities were issued ITBN, instructed in their use and the nets re-impregnated every 6 months. The remaining 28 communities served as contemporaneous controls for the following 2 years, during which continuous demographic and hospital surveillance was maintained until the end of July 1995. The introduction of ITBN led to significant reductions in childhood mortality (PE 33%, CI 7-51%) and severe, life-threatening malaria among children aged 1-59 months (PE 44%, CI 19-62). These findings confirm the value of ITBN in improving child survival and provide the first evidence of their specific role in reducing severe morbidity from malaria