C F Curtis

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..By showing an impact on the vector population in the community these results provide a strong argument for organized free provision of net treatment, rather than relying on marketing...

..There is much emphasis on social marketing as a means of scaling up coverage with insecticide-treated nets and the question has arisen whether nets provided free-of-charge will be looked after by householders...

..No significant impact of washing or heating was detected and an Olyset net was as good as new after four years use, but did not cause as much mosquito mortality as bifenthrin treated nets...

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..After five washes, the Permanet, which is sold as a long-lasting insecticidal product, performed no better than the other nets in our experimental conditions...

..It is suggested that 'urban island' populations of An. arabiensis and of An. gambiae s.s. M-form in the rainforest belt of West Africa might be appropriate targets for elimination of these malaria vectors by the sterile insect technique...

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..gambiae complex in this situation and the need to decide whether carbosulfan-treated curtains are acceptably safe for use to reduce risks of malaria transmission...

..Thus any scheme, for malaria transmission control by replacement of vectors by genetically-manipulated non-vectors, would have to be able to replace more than one species...

..Where Cx. quinquefasciatus breeding in pits form a major component of the vector population, use of polystyrene-bead layers could assist considerably in the process of eliminating lymphatic filariasis by mass drug administration...

..Meanwhile pyrethroids should continue to be used for public health interventions that contribute substantially to morbidity and mortality reduction, such as ITNs for malaria control...

..In Tanzania, pyrethroid resistance has not been detected in malaria vectors, but it has emerged in bedbugs after seven years use of treated nets...

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..falciparum populations. Moreover, the data have major implications for the design and interpretation of population genetic studies of selection on P. falciparum genes...

..The importance of high population coverage is emphasized, and the advantages of providing treatment free of charge, rather than charging individuals, are pointed out...

..Chris Curtis presents an opposing viewpoint, that low-tech control approaches are the practical ones under current conditions...

..Moreover, analyses of specimens collected in the Bamako area in 1987 show that the kdr allele was already present in the Savanna population at that time, and that the frequency of this allele has gradually increased since then...

..Culex bioassay mortality was lower (alphacypermethrin 56-74%; cyfluthrin 63-65%; deltamethrin 50-81 %) and results with the three pyrethroid insecticides at their recommended doses did not differ significantly...

..Resistance management for ITNs will need to use mechanisms other than negative cross-resistance to be effective...

..The conclusion is made that pyriproxyfen can be a very effective means of malaria control if all possible vector breeding places in the area can be located...

..Due to migration of malaria patients, there is a likelihood the disease could be spread to other parts of the island. Therefore, action should be taken to eliminate these pits as breeding sites...

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..These findings emphasize the need to radio-sterilize males as adults in order to minimize the fitness cost. Such males may be intended for sterile insect technique population suppression or for trial releases of transgenic anophelines...

..Observation of the time for knockdown gave clearer discrimination between resistant and susceptible strains than did observation of percentage mortality after a standard exposure time...

..A high frequency of the kdr resistance gene has not prevented pyrethroid-treated nets from functioning, but it is important to develop alternative fabric treatments in case stronger forms of resistance emerge...

..A low percentage of human blood meals at some sites suggested that zooprophylaxis could be effective in reducing challenge from Plasmodium falciparum...

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..Bedbugs have not returned to a village where nearly all the beds have been provided with pyrethroid-treated bednets for 14 years...

..However, comparative tests with a susceptible and a permethrin-resistant strain of A. stephensi showed that exposure for 1 hour was at least as sensitive in detecting resistance as was the short exposure method...

..However, the reduced required frequency for visiting every pit made the pyriproxyfen method the one of choice. The same low concentration of pyriproxyfen also effectively inhibited emergence of adults from river-bed pools...

..Such compensation has been suggested with West African An. gambiae where treated nets continue to work well against a highly resistant wild population. However, this does not seem to apply to our resistant An. stephensi...

..With the rising incidence of SP-resistant P. falciparum infection, PG-DS could provide an effective, affordable and already available therapeutic alternative for malaria in East Africa at least until chlorproguanil-dapsone is registered...

..These results confirm the olfactometer findings and demonstrate anthropophagic behaviour not previously recorded in this species. This finding has implications for prospective manipulation of host preference for genetic control purposes...

..Releases on level 12 of a 21-storey apartment block, with ovitraps on each storey, showed similar easy and rapid dispersal to the top and bottom of the block...

..gambiae s.s., whilst host specific cues such as human skin residues play a major role and very effectively demonstrated anthropophilic behaviour in the laboratory...