***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Summary Background Progress in malaria control is under threat by wide-scale insecticide resistance in malaria vectors . Two recent vector control products have been developed : a long-lasting insecticidal net that incorporates a synergist piperonyl butoxide ( PBO ) and a long-lasting indoor residual spraying formulation of the insecticide pirimiphos-methyl . We evaluated the effectiveness of PBO long-lasting insecticidal nets versus st and ard long-lasting insecticidal nets as single interventions and in combination with the indoor residual spraying of pirimiphos-methyl . Methods We did a four-group cluster r and omised controlled trial using a two-by-two factorial design of 48 clusters derived from 40 villages in Muleba ( Kagera , Tanzania ) . We r and omly assigned these clusters using restricted r and omisation to four groups : st and ard long-lasting insecticidal nets , PBO long-lasting insecticidal nets , st and ard long-lasting insecticidal nets plus indoor residual spraying , or PBO long-lasting insecticidal nets plus indoor residual spraying . Both st and ard and PBO nets were distributed in 2015 . Indoor residual spraying was applied only once in 2015 . We masked the inhabitants of each cluster to the type of nets received , as well as field staff who took blood sample s. Neither the investigators nor the participants were masked to indoor residual spraying . The primary outcome was the prevalence of malaria infection in children aged 6 months to 14 years  assessed by cross-sectional surveys at 4 , 9 , 16 , and 21 months after intervention . The endpoint for assessment of indoor residual spraying was 9 months and PBO long-lasting insecticidal nets was 21 months . This trial is registered with Clinical Trials.gov , number NCT02288637 . Findings 7184 ( 68·0 % ) of 10 560 households were selected for post-intervention survey , and 15 469 ( 89·0 % ) of 17 377 eligible children from the four surveys were included in the intention-to-treat analysis . Of the 878 households visited in the two indoor residual spraying groups , 827 ( 94 % ) had been sprayed . Reported use of long-lasting insecticidal nets , across all groups , was 15 341 ( 77·3 % ) of 19 852 residents after 1 year , decreasing to 12 503 ( 59·2 % ) of 21 105 in the second year . Malaria infection prevalence after 9 months was lower in the two groups that received PBO long-lasting insecticidal nets than in the two groups that received st and ard long-lasting insecticidal nets ( 531 [ 29 % ] of 1852 children vs 767 [ 42 % ] of 1809 ; odds ratio [ OR ] 0·37 , 95 % CI 0·21–0·65 ; p=0·0011 ) . At the same timepoint , malaria prevalence in the two groups that received indoor residual spraying was lower than in groups that did not receive indoor residual spraying ( 508 [ 28 % ] of 1846 children vs 790 [ 44 % ] of 1815 ; OR 0·33 , 95 % CI 0·19–0·55 ; p<0·0001 ) and there was evidence of an interaction between PBO long-lasting insecticidal nets and indoor residual spraying ( OR 2·43 , 95 % CI 1·19–4·97 ; p=0·0158 ) , indicating redundancy when combined . The PBO long-lasting insecticidal net effect was sustained after 21 months with a lower malaria prevalence than the st and ard long-lasting insecticidal net ( 865 [ 45 % ] of 1930 children vs 1255 [ 62 % ] of 2034 ; OR 0·40 , 0·20–0·81 ; p=0·0122 ) . Interpretation The PBO long-lasting insecticidal net and non-pyrethroid indoor residual spraying interventions showed improved control of malaria transmission compared with st and ard long-lasting insecticidal nets where pyrethroid resistance is prevalent and either intervention could be deployed to good effect . As a result , WHO has since recommended to increase coverage of PBO long-lasting insecticidal nets . Combining indoor residual spraying with pirimiphos-methyl and PBO long-lasting insecticidal nets provided no additional benefit compared with PBO long-lasting insecticidal nets alone or st and ard long-lasting insecticidal nets plus indoor residual spraying . Funding UK Department for International Development , Medical Research Council , and Wellcome Trust Summary Background Scale-up of insecticide-based interventions has averted more than 500 million malaria cases since 2000 . Increasing insecticide resistance could herald a rebound in disease and mortality . We aim ed to investigate whether insecticide resistance was associated with loss of effectiveness of long-lasting insecticidal nets and increased malaria disease burden . Methods This WHO-coordinated , prospect i ve , observational cohort study was done at 279 clusters ( villages or groups of villages in which phenotypic resistance was measurable ) in Benin , Cameroon , India , Kenya , and Sudan .  Pyrethroid long-lasting insecticidal nets were the principal form of malaria vector control in all study areas ; in Sudan this approach was supplemented by indoor residual spraying .  Cohorts of children from r and omly selected households in each cluster were recruited and followed up by community health workers to measure incidence of clinical malaria and prevalence of infection . Mosquitoes were assessed for susceptibility to pyrethroids using the st and ard WHO bioassay test . Country-specific results were combined using meta- analysis . Findings Between June 2 , 2012 , and Nov 4 , 2016 , 40 000 children were enrolled and assessed for clinical incidence during 1·4 million follow-up visits . 80 000 mosquitoes were assessed for insecticide resistance . Long-lasting insecticidal net users had lower infection prevalence ( adjusted odds ratio [ OR ] 0·63 , 95 % CI 0·51–0·78 ) and disease incidence ( adjusted rate ratio [ RR ] 0·62 , 0·41–0·94 ) than did non-users across a range of resistance levels . We found no evidence of an association between insecticide resistance and infection prevalence ( adjusted OR 0·86 , 0·70–1·06 ) or incidence ( adjusted RR 0·89 , 0·72–1·10 ) . Users of nets , although significantly better protected than non-users , were nevertheless subject to high malaria infection risk ( ranging from an average incidence in net users of 0·023 , [ 95 % CI 0·016–0·033 ] per person-year in India , to 0·80 [ 0·65–0·97 ] per person year in Kenya ; and an average infection prevalence in net users of 0·8 % [ 0·5–1·3 ] in India to an average infection prevalence of 50·8 % [ 43·4–58·2 ] in Benin ) . Interpretation Irrespective of resistance , population s in malaria endemic areas should continue to use long-lasting insecticidal nets to reduce their risk of infection . As nets provide only partial protection , the development of additional vector control tools should be prioritised to reduce the unacceptably high malaria burden . Funding Bill & Melinda Gates Foundation , UK Medical Research Council , and UK Department for International Development The effect of permethrin-treated bed nets ( ITNs ) on malaria vectors was studied as part of a large-scale , r and omized , controlled trial in western Kenya . Indoor resting densities of fed Anopheles gambiae s.l . and An . funestus in intervention houses were 58.5 % ( P = 0.010 ) and 94.5 % ( P = 0.001 ) lower , respectively , compared with control houses . The sporozoite infection rate in An . gambiae s.l . was 0.8 % in intervention areas compared with 3.4 % ( P = 0.026 ) in control areas , while the sporozoite infection rates in An . funestus were not significantly different between the two areas . We estimated the overall transmission of Plasmodium falciparum in intervention areas to be 90 % lower than in control areas . Permethrin resistance was not detected during the study period . As measured by densities of An . gambiae s.l . , the efficacy of bed nets decreased if one or more residents did not sleep under a net or if bed nets had not been re-treated within six months . These results indicate that ITNs are optimally effective if used every night and if permethrin is reapplied at least biannually Background The human population in the highl and s of Nyanza Province , western Kenya , is subject to sporadic epidemics of Plasmodium falciparum . Indoor residual spraying ( IRS ) and long-lasting insecticide treated nets ( LLINs ) are used widely in this area . These interventions are most effective when Anopheles rest and feed indoors and when biting occurs at times when individuals use LLINs . It is therefore important to test the current assumption of vector feeding preferences , and late night feeding times , in order to estimate the extent to which LLINs protect the inhabitants from vector bites . Methods Mosquito collection s were made for six consecutive nights each month between June 2011 and May 2012 . CDC light-traps were set next to occupied LLINs inside and outside r and omly selected houses and emptied hourly . The net usage of residents , their hours of house entry and exit and times of sleeping were recorded and the individual hourly exposure to vectors indoors and outdoors was calculated . Using these data , the true protective efficacy of nets ( P * ) , for this population was estimated , and compared between genders , age groups and from month to month . Results Primary vector species ( Anopheles funestus s.l . and Anopheles arabiensis ) were more likely to feed indoors but the secondary vector Anopheles coustani demonstrated exophagic behaviour ( p < 0.05 ) . A rise in vector biting activity was recorded at 19:30 outdoors and 18:30 indoors . Individuals using LLINs experienced a moderate reduction in their overall exposure to malaria vectors from 1.3 to 0.47 bites per night . The P * for the population over the study period was calculated as 51 % and varied significantly with age and season ( p < 0.01 ) . Conclusions In the present study , LLINs offered the local population partial protection against malaria vector bites . It is likely that P * would be estimated to be greater if the overall suppression of the local vector population due to widespread community net use could be taken into account . However , the overlap of early biting habit of vectors and human activity in this region indicates that additional methods of vector control are required to limit transmission . Regular surveillance of both vector behaviour and domestic human-behaviour patterns would assist the planning of future control interventions in this region Summary Domestic and personal protection measures against malaria exposure either divert host-seeking vectors to other hosts or kill those attempting to feed . Here , we explicitly model mosquito host-seeking processes in the context of local host availability and eluci date the impacts and mechanisms of pyrethroid-treated bed nets in Africa . It has been suggested that excitorepellent insecticides could increase exposure of unprotected humans by concentrating mosquito biting activity on this vulnerable group . This worst-case scenario is confirmed as a possibility where vector population s lack alternative hosts , but an approximate ‘ break-even ’ scenario , with users experiencing little overall change in exposure , is more likely because of increased mosquito mortality while foraging for re sources . Insecticidal nets are predicted to have epidemiologically significant impacts on transmission experienced by users and non-users at levels of coverage that can be achieved by sustainable net distribution systems , regardless of excitorepellency or the ecological setting . The results are consistent with the outcome of several r and omised controlled trials , predicting enormous reductions in transmission at individual and community levels . As financial support , technology and distribution systems for insecticide-treated nets improve , massive reductions in malaria transmission could be realised Background : The widespread insecticide resistance in malaria vector population s is a serious threat to the efficacy of vector control tools . As a result , the World Health Organization ( WHO ) supports the development of alternative tools that combine several insecticides with the aim of improving vector control and the management of insecticide resistance . In the present study , a long-lasting insecticidal net treated with a mixture of chlorfenapyr and alphacypermethrin was evaluated against wild pyrethroid-resistant Anopheles gambiae s.s in M’bé , Côte d’Ivoire . Centers for Disease Control and Prevention ( CDC ) bottle tests were carried out with resistant An . gambiae s.s . of M’bé and the susceptible strain , to assess the resistance level to chlorfenapyr and alphacypermethrin . Results : CDC bottle bioassays revealed a high level of resistance of An . gambiae s.s . population from M’bé to alphacypermethrin , whereas they revealed low resistance to chlorfenapyr . In experimental huts , Interceptor ® G2 that was unwashed or washed 20 times killed 87 % and 82 % of An . gambiae s.s . , respectively , whereas Interceptor ® 
    Output:
    
Higher outdoor biting diminishes the cases of malaria averted by vector control .
This reduction in LLIN effectiveness appears to be exacerbated in areas where mosquito population s are resistant to insecticides used in bed nets , but no association was found between physiological resistance and outdoor biting .
Substantial spatial heterogeneity in mosquito biting behavior between communities could contribute to differences in effectiveness of malaria control across Africa