Biomedical subjects

Jane A Alaii

Publications and source records attributed to Jane A Alaii.

12 recordsLinked to original sources

PubMed2006

Distribution, description, and local knowledge of larval habitats of Anopheles gambiae s.l. in a village in western Kenya.

A sampling census revealed 104 aquatic habitats of 6 types for Anopheles gambiae s.l. larvae in a village in western Kenya, namely burrow pits, drainage channels, livestock hoof prints, rain pools, tire tracks, and pools in streambeds. Most habitats were created by human activity and were highly clustered in dispersion pattern within the village landscape. Landscape analysis revealed that six of forty-seven 0.09 km(2) cells superimposed over the village harbored 65% of all habitats. Focus group discussions and in-depth interviews with villagers revealed the extent of knowledge of the village residents of larval habitats, mosquito sources in the local environment, and what might be done to prevent mosquito breeding. Participants did not associate specific habitats with anopheline larvae, expressed reluctance to eliminate habitats because they were sources of domestic water supply, but indicated willingness to participate in a source reduction program if support were available.

Animals↗

PubMed2004

Sustainability of reductions in malaria transmission and infant mortality in western Kenya with use of insecticide-treated bednets: 4 to 6 years of follow-up.

CONTEXT: Insecticide-treated bednets reduce malaria transmission and child morbidity and mortality in short-term trials, but this impact may not be sustainable. Previous investigators have suggested that bednet use might paradoxically increase mortality in older children through delayed acquisition of immunity to malaria. OBJECTIVES: To determine whether adherence to and public health benefits of insecticide-treated bednets can be sustained over time and whether bednet use during infancy increases all-cause mortality rates in older children in an area of intense perennial malaria transmission. DESIGN AND SETTING: A community randomized controlled trial in western Kenya (phase 1: January 1997 to February 2000) followed by continued surveillance of adherence, entomologic parameters, morbidity indicators, and all-cause mortality (phase 2: April 1999 to February 2002), and extended demographic monitoring (January to December 2002). PARTICIPANTS: A total of 130,000 residents of 221 villages in Asembo and Gem were randomized to receive insecticide-treated bednets at the start of phase 1 (111 villages) or phase 2 (110 villages). MAIN OUTCOME MEASURES: Proportion of children younger than 5 years using insecticide-treated bednets, mean number of Anopheles mosquitoes per house, and all-cause mortality rates. RESULTS: Adherence to bednet use in children younger than 5 years increased from 65.9% in phase 1 to 82.5% in phase 2 (P<.001). After 3 to 4 years of bednet use, the mean number of Anopheles mosquitoes per house in the study area was 77% lower than in a neighboring area without bednets (risk ratio, 0.23; 95% confidence interval [CI], 0.15-0.35). All-cause mortality rates in infants aged 1 to 11 months were significantly reduced in intervention villages during phase 1 (hazard ratio [HR], 0.78; 95% CI, 0.67-0.90); low rates were maintained during phase 2. Mortality rates did not differ during 2002 (after up to 6 years of bednet use) between children from former intervention and former control households born during phase 1 (HR, 1.01; 95% CI, 0.86-1.19). CONCLUSIONS: The public health benefits of insecticide-treated bednets were sustained for up to 6 years. There is no evidence that bednet use from birth increases all-cause mortality in older children in an area of intense perennial transmission of malaria.

Animals↗

PubMed2003

The efficacy of permethrin-treated bed nets on child mortality and morbidity in western Kenya I. Development of infrastructure and description of study site.

Randomized controlled trials in sub-Saharan Africa have shown that permethrin-treated bed nets and curtains reduce all-cause child mortality by 15-33% in areas with low or high but seasonal malaria transmission. This report describes the study site for a community-based, group-randomized, controlled trial in an area of high and year-round malaria transmission in western Kenya. We outline the development of the human and physical infrastructure required to conduct this trial and discuss some of the difficulties encountered and lessons learned in conducting it.

Bedding and Linens↗

PubMed2003

The efficacy of permethrin-treated bed nets on child mortality and morbidity in western Kenya II. Study design and methods.

This paper describes the study design and methods used in a large community-based, group-randomized, controlled trial of permethrin-treated bed nets (ITNs) in an area with intense, perennial malaria transmission in western Kenya conducted between 1996 and 1999. A multi-disciplinary framework was used to explore the efficacy of ITNs in the reduction of all-cause mortality in children less than five years old, the clinical, entomologic, immunologic, and economic impact of ITNs, the social and behavioral determinants of ITN use, and the use of a geographic information system to allow for spatial analyses of these outcomes. Methodologic difficulties encountered in such large-scale field trials are discussed.

Bedding and Linens↗

PubMed2003

Efficacy of permethrin-treated bed nets in the prevention of mortality in young children in an area of high perennial malaria transmission in western Kenya.

A group-randomized controlled trial of insecticide (permethrin)-treated bed nets (ITNs) was conducted in an area of high perennial malaria transmission in western Kenya to test the effect of ITNs on all-cause mortality in children 1-59 months of age. Child deaths were monitored over a two-year period by biannual household census in Asembo (1997-1998) and in Gem (1998-1999). Overall, 1,722 deaths occurred in children 1-59 months followed for 35,932 child-years. Crude mortality rates/1,000 child-years were 51.9 versus 43.9 in control and ITN villages in children 1-59 months old. The protective efficacy (PE) (95% confidence interval) adjusted for age, study year, study site, and season was 16% (6-25%). Corresponding figures in 1-11- and 12-59-month-old children in control and ITN villages were 133.3 versus 102.3, PE = 23% (11-34%) and 31.1 versus 28.7, PE = 7% (-6-19%). The numbers of lives saved/1,000 child-years were 8, 31, and 2 for the groups 1-59, 1-11, and 12-59 months old, respectively. Stratified analysis by time to insecticide re-treatment showed that the PE of ITNs re-treated per study protocol (every six months) was 20% (10-29%), overall and 26% (12-37%) and 14% (-1-26%) in 1-11- and 12-59-month-old children, respectively. ITNs prevent approximately one in four infant deaths in areas of intense perennial malaria transmission, but their efficacy is compromised if re-treatment is delayed beyond six months.

Bedding and Linens↗

PubMed2003

Impact of permethrin-treated bed nets on the incidence of sick child visits to peripheral health facilities.

During a randomized controlled trial of insecticide (permethrin)-treated bed nets (ITNs) in an area with intense malaria transmission in western Kenya, we monitored 20,915 sick child visits (SCVs) by children less than five years of age visiting seven peripheral health facilities. The SCVs were monitored over a four-year period both before (1995-1996) and during the intervention (1997-1998). Results are used to estimate the effect of ITNs on the burden of malaria in this community and to evaluate the potential role of these facilities in assessment of the impact of large-scale public health interventions. Compared with baseline, a 27% greater reduction in the incidence of SCVs was seen in ITN villages than in control villages (37% versus 10%; P = 0.049). A similar reduction was observed in SCVs diagnosed as malaria (35% reduction in ITN villages versus 5% reduction in controls; P = 0.04). Two-hundred sixteen SCVs per 1,000 child-years were prevented; three-fourths of these were in children less than 24 months old. As a consequence of lack of laboratory facilities, severe anemia was rarely (< 2%) diagnosed, regardless of intervention status. No effect of ITNs on the incidence of respiratory tract infections, diarrhea, and other commonly diagnosed childhood illnesses was observed. The ITNs reduced the number of SCVs due to malaria, but had no effect on other illnesses. Routine statistics from these facilities provided useful information on trends in malaria incidence, but underestimated the burden of severe anemia.

Adolescent↗

PubMed2003

Permethrin-treated bed nets in the prevention of malaria and anemia in adolescent schoolgirls in western Kenya.

The impact of insecticide (permethrin)-treated bed nets (ITNs) on the health of adolescent schoolgirls was investigated during a community-based, randomized, controlled trial of ITNs in western Kenya. Two school-based cross-sectional surveys were conducted to determine the prevalence of malaria and anemia in 644 schoolgirls 12-18 years old in a rural area with intense perennial malaria transmission. In 12- and 13-year-old schoolgirls, ITNs were associated with a reduced prevalence of all cause anemia (hemoglobin level <12 g/dL, 16.9% versus 31.4%, adjusted odds ratio [OR] = 0.38, 95% confidence interval [CI] = 0.21, 0.69%) and a 0.34 g/dL (95% CI = 0.02, 0.66) increase in mean hemoglobin concentrations. No beneficial effect on all-cause anemia (adjusted OR = 0.79, 95% CI = 0.43, 1.45) or hemoglobin concentrations (difference in mean = 0.14 g/dL, 95% CI = -0.24, 0.53) was evident in older girls. In all age groups, no effect was found on malaria parasite prevalence or density, clinical malaria, all-cause morbidity, standard measures of nutritional status and growth, or the use of antimalarials and other medications. ITNs approximately halved the prevalence of mild anemia in young, school-attending, non-pregnant, adolescent girls, but had no impact in older girls or on other malaria-associated morbidity or nutritional status.

Adolescent↗

PubMed2003

Community reactions to the introduction of permethrin-treated bed nets for malaria control during a randomized controlled trial in western Kenya.

Prior to implementation of a randomized controlled trial of insecticide (permethrin)-treated bed nets (ITNs) in western Kenya, ethnographic studies were conducted to understand local perceptions of disease, sleeping patterns, and other factors that might affect use of ITNs. Educational activities took place prior to distribution, but immediately after distribution in Asembo only approximately half of the ITNs were in use. A qualitative study was then conducted to identify the community's perceptions about ITNs and the ITN project. While participants ranked malaria as important and recognized that malaria prevention could be beneficial, they believed ITNs would be only partly effective due to the perception that malaria has multiple causes. Concerns expressed included fear of the insecticide, thought by some to be a toxic family planning aid, the taking of blood during clinical studies, and the mixing up of family ITNs during net re-treatment, which would violate cultural taboos. Attempts were made to allay fears by improved communication on these subjects and modification of the study design.

Attitude to Health↗

PubMed2003

Factors affecting use of permethrin-treated bed nets during a randomized controlled trial in western Kenya.

Adherence with permethrin-treated bed net (ITN) use and their proper deployment was directly observed in 2,178 individuals (784 households) participating in a large-scale trial of ITNs on child mortality in western Kenya. The ITNs were distributed free of charge to ensure high coverage, resulting in a ratio of 1.46 persons per ITN. Approximately 30% of ITNs present were unused. The overall percentage adherence was 72.3%. The probability of adherence by individuals depended strongly on age (relative risk [RR] = 0.86, 95% confidence limit [CL] = 0.78-0.94), in which children less than five years of age were less likely to use ITNs than older individuals, and temperature, in which ITNs were more likely to be used in periods of cooler weather. A marginally significant diminution in adherence during the second year of the project was also observed (RR = 0.83, 95% CL = 0.68-1.01). Mosquito numbers, relative wealth, number of house occupants, and the educational level of the head of the household had no effect on adherence. In unstructured questioning of house residents, excessive heat was often cited as a reason for not deploying the child's ITN. The most important reason for non-adherence was disruption of sleeping arrangements, indicating that ITNs were not readily redeployed in the face of shifting sleeping patterns due to visitors, funerals, house construction, and other events. Challenges faced by health education programs to maximize adherence with ITN use are discussed.

Animals↗

PubMed2003

Perceptions of bed nets and malaria prevention before and after a randomized controlled trial of permethrin-treated bed nets in western Kenya.

A study of mothers' perceptions regarding bed nets and malaria was conducted before and after a randomized controlled trial of insecticide (permethrin)-treated bed nets (ITNs) in western Kenya. Awareness about the trial and the rationale for bed net use increased by the end of the trial. Knowledge that mosquitoes caused malaria also increased; however, a higher proportion of mothers from control, rather than intervention villages, cited this (44.4% versus 27.9%; P < 0.001). Mothers from intervention villages were more knowledgeable about the use and maintenance of bed nets and re-treatment with insecticide. Both groups specified advantages of ITNs. Mothers from intervention villages noted practical advantages such as protection against bedbugs and falling roof debris. Few (< 1%) mothers indicated that ITNs protected children against malaria. Intervention homes used significantly fewer mosquito coils, insect spray, medicines, and burned cow dung less often compared with those in control villages. Mothers were willing to pay approximately 4.5 U.S. dollars for a regular bed net, but only 10.5 U.S. cents (intervention) and 0.036 (control) for re-treating a bed net. This study suggests that, despite two years of experience of use, bed nets and insecticides would not be purchased as a household priority in this impoverished rural community.

Adult↗

PubMed2003

The household-level economics of using permethrin-treated bed nets to prevent malaria in children less than five years of age.

We measured the two-week household-level economic impact of insecticide (permethrin)-treated bed nets (ITNs) used to prevent malaria among children less than five years of age in Asembo, Kenya. The ITNs induced a two-week reduction of 15 Kenyan shillings (KSH) (0.25 U.S. dollars; P < 0.0001) in health care expenditures, but a statistically insignificant 0.5 day (P = 0.280) reduction in household time lost due to caring for sick children. The equivalent annual threshold cost was estimated at 6.50 U.S. dollars (95% confidence interval = 3.12-9.86). If the actual purchase price and maintenance costs of ITNs were greater than this threshold, then households would pay more than they would save (and vice-versa). Both seasonal effects and number of children per household had larger impacts than ITNs on health care expenditures and time lost from household activities. Health care expenditures by a household without ITNs and one child were only 32 KSH per two weeks (0.50 U.S. dollars; P = 0.002), leaving little opportunity for household-level, ITN-induced direct savings. The widespread adoption of the ITNs will therefore probably require a subsidy.

Antimalarials↗

PubMed2003

Implications of the western Kenya permethrin-treated bed net study for policy, program implementation, and future research.

The fifth, and probably last, large-scale, group-randomized, controlled trial of insecticide (permethrin)-treated bed nets (ITNs) showed that ITNs are efficacious in reducing all-cause post-neonatal mortality in an area of intense, perennial malaria transmission. The trial helped to define pregnant women and infants as target groups for this intervention in high transmission settings. High population coverage with ITNs in both target and non-target groups may be critical to enhance health and survival in pregnant women and infants. The proportion of households with ITNs (coverage), the proportion of individuals properly deploying ITNs each night (adherence), and the proportion of nets properly treated with insecticide (treatment) are the three key determinants of effectiveness of large-scale ITN programs. These three simple outcomes should serve as the basis for program objectives and monitoring and evaluation efforts. Coverage effects and economic analysis support the proposition that ITNs may be viewed as a public good, worthy of public support. Research should continue to improve the intervention tools (the net, the insecticide, and methods for durable treatment and re-treatment) and their deployment.

Animals↗