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1.
J Epidemiol Community Health ; 76(2): 158-167, 2022 02.
Article in English | MEDLINE | ID: mdl-34518330

ABSTRACT

BACKGROUND: Knowledge of one's HIV status is the gateway to treatment and prevention, but remains low among young people. We investigated the early impact (2016-2017) of Determined, Resilient, Empowered, AIDS-free, Mentored and Safe (DREAMS), a multisectoral HIV prevention package, on knowledge of HIV status among adolescent girls and young women (AGYW). METHODS: In 2017, randomly selected AGYW were enrolled into surveys, N=1081 aged 15-22 years in Nairobi slum settlements, and N=2174 aged 13-22 years in rural KwaZulu-Natal. We estimated the causal effect of being a DREAMS beneficiary on knowledge of HIV status (those who self-reported as HIV-positive or tested HIV-negative in the past year), accounting for an AGYW's propensity to be a DREAMS beneficiary. RESULTS: In Nairobi, knowledge of HIV status was higher among DREAMS beneficiaries compared with non-beneficiaries (92% vs 69%, adjusted OR=8.7; 95% CI 5.8 to 12.9), with DREAMS predicted to increase the outcome by 28%, from 65% if none were a DREAMS beneficiary to 93% if all were beneficiaries. The increase attributable to DREAMS was larger among younger participants: 32% and 23% among those aged 15-17 and 18-22 years, respectively. In KwaZulu-Natal, knowledge of status was higher among DREAMS beneficiaries aged 13-17 years (37% vs 26% among non-beneficiaries), with a 9% difference due to DREAMS (95% CI 4.8% to 14.4%), and no evidence of effect among 18-22 years (-2.8%; 95% CI -11.1% to 5.7%). CONCLUSION: DREAMS substantially increased knowledge of HIV status among AGYW in Nairobi, and among younger but not older AGYW in KwaZulu-Natal. Adolescent girls can be reached early (before age 18) with community-based HIV testing programmes in diverse high-prevalence settings, with a large impact on the proportion who know their HIV status.


Subject(s)
HIV Infections , Adolescent , Female , HIV Infections/epidemiology , HIV Infections/prevention & control , HIV Testing , Humans , Kenya/epidemiology , Rural Population , Sexual Behavior , South Africa , Young Adult
2.
PLoS One ; 16(10): e0258651, 2021.
Article in English | MEDLINE | ID: mdl-34653232

ABSTRACT

INTRODUCTION: To make valid comparisons across groups, a measurement instrument needs to be measurement invariant across those groups. The present study evaluates measurement invariance for experience of violence among adolescent girls and young women (AGYW) in two informal settlements in Nairobi, Kenya. METHODS: We used survey data collected from 1,081 AGYW aged 15-22 years from two Nairobi's informal settlements of Korogocho (n = 617) and Viwandani (n = 464) in 2017 through DREAMS (an initiative aimed at reducing HIV incidence among AGYW with a core package of evidence-based interventions) impact evaluation project. Experience of violence was measured using the 15-item WHO's violence against women instrument, and factorial (non)invariance assessed within exploratory structural equation modeling (ESEM) framework. Cross-group measurement invariance was assessed using Bayesian Multiple Indicator Multiple Causes (MIMIC) model across site, age groups, self-reported invitation to participate in DREAMS, marital status, currently in school, education level, religion, ethnic groups, ever had sex, slept hungry at night past 4 weeks, and wealth index. RESULTS: The mean and median ages of the AGYW were 17.9 years and 17 years, respectively. About 59% reported having had sex and 58% of AGYW were in school. The percentage reporting each act of violence varied from 1.6% ("attacked you with a weapon") to 26.5% ("insult you or make you feel bad about yourself"). About 44% (n = 474) of participants experienced ≥1 acts of violence, and 2.7% (n = 29) experienced at least half of the 15 acts. The structure underlying the 15 items was configurally similar to that proposed by WHO, with three factors reflecting either psychological, physical, or sexual violence. Noninvariance was detected for five items-spread across the three domains. Three of five items showed noninvariance only for sleeping hungry at night in the past 4 weeks. As the majority of items did not show evidence of noninvariance, differences in latent mean scores likely reflect actual differences and may not be attributable to measurement artifacts. CONCLUSIONS: Using state-of-the-art statistical techniques on a widely used instrument for measuring exposure to violence among women, this study provides support for the subscales of psychological, physical and sexual violence in a Kenyan AGYW population. The instrument supports comparisons across groups within this population. This is crucial when comparing violence against girls/women prevalence rates and to understand challenges and exchange strategies to reduce abuse or violence experienced by AGYW, or women in general.


Subject(s)
Psychometrics/methods , Violence/statistics & numerical data , Adolescent , Bayes Theorem , Female , Humans , Incidence , Kenya/epidemiology , Models, Statistical , Violence/classification , Violence/psychology , World Health Organization , Young Adult
3.
BMC Public Health ; 21(1): 1107, 2021 06 10.
Article in English | MEDLINE | ID: mdl-34112119

ABSTRACT

BACKGROUND: The DREAMS Partnership promotes combination HIV prevention among adolescent girls and young women. We examined the extent to which DREAMS interventions reached early adolescent girls (EAG; aged 10-14 years) in two informal settlements in Nairobi, and the characteristics of those reached, after 3 years of implementation. METHODS: We utilized three data rounds from a randomly-sampled cohort of EAG established in 2017 in Korogocho and Viwandani informal settlements where DREAMS interventions were implemented. Interventions were classified as individual or contextual-level, with individual interventions further categorised as primary (prioritised for this age group), or secondary. We summarised self-reported invitation to participate in DREAMS, and uptake of eight interventions that were supported by DREAMS, during 2017-2019. Multivariable logistic regression analysis was used to identify individual and household characteristics associated with invitation to DREAMS and uptake of primary interventions. RESULTS: Data were available for 606, 516 (retention rate of 85%) and 494 (82%) EAG in 2017, 2018 and 2019, respectively. Proportions invited to DREAMS increased from 49% in 2017, to 77% by 2018, and to 88% by 2019. School-based HIV and violence prevention, and HIV testing and counselling were the most accessed interventions (both at 82%). Cumulative uptake of interventions was higher among those invited to participate in DREAMS compared to those never invited, particularly for new interventions such as social asset building and financial capability training. Contextual-level interventions were accessed infrequently. Most of those invited both in 2017 and 2018 accessed ≥3 interventions (96%), and 55% received all three primary interventions by 2019. CONCLUSIONS: Uptake of DREAMS interventions among a representative sample of EAG was high and quickly increased over the implementation period. The majority accessed multiple interventions, indicating that it is feasible to integrate and deliver a package of interventions to EAG in a challenging informal context.


Subject(s)
HIV Infections , Adolescent , Cohort Studies , Female , HIV Infections/prevention & control , Humans , Kenya , Schools
4.
Int J Public Health ; 65(9): 1805-1806, 2020 Dec.
Article in English | MEDLINE | ID: mdl-33145660

ABSTRACT

The authors would like to correct an error in the publication of the original article. The error is described below and correct details provided. What is presented in the lines 23, 29, 38 , and in table 4 is the corrected version.

5.
Int J Adolesc Youth ; 25(1): 836-848, 2020.
Article in English | MEDLINE | ID: mdl-32537261

ABSTRACT

Mental health issues are a predisposing factor for HIV acquisition. We examined the association between depressive symptoms and patterns of sexual experience among girls aged 10-14 years living in Korogocho and Viwandani slums in Nairobi, Kenya. We analysed data collected in 2017 from a random sample of 606 girls. Using Latent Class Analysis, we modelled patterns of sexual experiences and used multivariable regression analysis to determine the association between self-reported depressive symptoms and sexual experiences. Seven in ten girls reported at least one symptom of self-reported depression in the past 12 months. About 13% of girls had had a sexual experience, resulting in two patterns of sexual experience - naïve and experienced. Girls reporting depressive symptoms were more likely to be sexually experienced. Sexual and reproductive health programs targeting adolescent girls should consider including intervention packages that address mental health conditions such as depression.

6.
PLoS One ; 15(4): e0231737, 2020.
Article in English | MEDLINE | ID: mdl-32320405

ABSTRACT

INTRODUCTION: We sought to estimate the prevalence, severity and identify predictors of violence among adolescent girls and young women (AGYW) in informal settlement areas of Nairobi, Kenya, selected for DREAMS (Determined Resilient Empowered AIDS-free, Mentored and Safe) investment. METHODS: Data were collected from 1687 AGYW aged 10-14 years (n = 606) and 15-22 years (n = 1081), randomly selected from a general population census in Korogocho and Viwandani in 2017, as part of an impact evaluation of the "DREAMS" Partnership. For 10-14 year-olds, we measured violence experienced either in the past 6 months or ever using a different set of questions from those used for 15-22 year-olds. Among 15-22 year-olds we measured prevalence of violence, experienced in the past 12 months, using World Health Organization (WHO) definitions for violence typologies. Predictors of violence were identified using multivariable logit models. RESULTS: Among 606 girls aged 10-14 years, about 54% and 7% ever experienced psychological and sexual violence, respectively. About 33%, 16% and 5% experienced psychological, physical and sexual violence in the past 6 months. The 10-14 year old girls who engaged in chores or activities for payment in the past 6 months, or whose family did not have enough food due to lack of money were at a greater risk for violence. Invitation to DREAMS and being a non-Christian were protective. Among 1081 AGYW aged 15-22 years, psychological violence was the most prevalent in the past year (33.1%), followed by physical violence (22.9%), and sexual violence (15.8%). About 7% experienced all three types of violence. Severe physical violence was more prevalent (13.8%) than moderate physical violence (9.2%). Among AGYW aged 15-22 years, being previously married/lived with partner, engaging in employment last month, food insecure were all risk factors for psychological violence. For physical violence, living in Viwandani and being a Muslim were protective; while being previously married or lived with a partner, or sleeping hungry at night during the past 4 weeks were risk factors. The odds of sexual violence were lower among AGYW aged 18-22 years and among Muslims. Engaging in sex and food insecurity increased chances for sexual violence. CONCLUSIONS: Prevalence of recent violence among AGYW is high in this population. This calls for increased effort geared towards addressing drivers of violence as an early entry point of HIV prevention effort in this vulnerable group.


Subject(s)
Food Supply/statistics & numerical data , HIV Infections/prevention & control , Physical Abuse/statistics & numerical data , Program Evaluation/statistics & numerical data , Sex Offenses/statistics & numerical data , Adolescent , Child , Cohort Studies , Female , HIV Infections/epidemiology , Humans , Kenya/epidemiology , Physical Abuse/prevention & control , Physical Abuse/psychology , Prevalence , Public-Private Sector Partnerships/organization & administration , Public-Private Sector Partnerships/statistics & numerical data , Risk Factors , Rural Population/statistics & numerical data , Sex Offenses/prevention & control , Sex Offenses/psychology , Socioeconomic Factors , Urban Population/statistics & numerical data , Young Adult
7.
Int J Public Health ; 65(4): 497-506, 2020 May.
Article in English | MEDLINE | ID: mdl-32270236

ABSTRACT

OBJECTIVES: To investigate the association between gender norms about romantic relationships and sexual experiences of very young male adolescents (VYMA) living in Korogocho slum in Nairobi, Kenya. METHODS: We used cross-sectional data from a sample of 426 VYMA living in Korogocho slum. We conducted an exploratory factor analysis and confirmatory factor analysis to, respectively, explore and validate the factor structure underlying gender norms scale items. We used structural equation modelling to assess the association between gender norms and sexual experiences of VYMA. RESULTS: We found high endorsement of heteronormative beliefs about romantic relationships and low endorsement of sexual double standards. Sexual experience was associated with low endorsement of heteronormative beliefs, being pre-pubertal, school absenteeism and being below recommended grade for age. Sharing a sleeping room with more than two people, been born outside Nairobi, and living in households headed by older persons lowered the likelihood of sexual experience. CONCLUSIONS: Our findings underscore the need for further research to understand how gender norms evolve as young boys transition through adolescence to adulthood and how these changes impact on sexual behaviors.


Subject(s)
Gender Identity , Sexual Behavior/psychology , Absenteeism , Academic Success , Adolescent , Cross-Sectional Studies , Factor Analysis, Statistical , Humans , Kenya , Male , Poverty Areas , Young Adult
8.
BMC Public Health ; 19(1): 1417, 2019 Oct 30.
Article in English | MEDLINE | ID: mdl-31666043

ABSTRACT

BACKGROUND: The DREAMS Partnership is an ambitious effort to deliver combinations of biomedical, behavioural and structural interventions to reduce HIV incidence among adolescent girls and young women (AGYW). To inform multi-sectoral programming at scale, across diverse settings in Kenya and South Africa, we identified who the programme is reaching, with which interventions and in what combinations. METHODS: Randomly-selected cohorts of 606 AGYW aged 10-14 years and 1081 aged 15-22 years in Nairobi and 2184 AGYW aged 13-22 years in uMkhanyakude, KwaZulu-Natal, were enrolled in 2017, after ~ 1 year of DREAMS implementation. In Gem, western Kenya, population-wide cross-sectional survey data were collected during roll-out in 2016 (n = 1365 AGYW 15-22 years). We summarised awareness and invitation to participate in DREAMS, uptake of interventions categorised by the DREAMS core package, and uptake of a subset of 'primary' interventions. We stratified by age-group and setting, and compared across AGYW characteristics. RESULTS: Awareness of DREAMS was higher among younger women (Nairobi: 89%v78%, aged 15-17v18-22 years; uMkhanyakude: 56%v31%, aged 13-17v18-22; and Gem: 28%v25%, aged 15-17v18-22, respectively). HIV testing was the most accessed intervention in Nairobi and Gem (77% and 85%, respectively), and school-based HIV prevention in uMkhanyakude (60%). Among those invited, participation in social asset building was > 50%; > 60% accessed ≥2 core package categories, but few accessed all primary interventions intended for their age-group. Parenting programmes and community mobilisation, including those intended for male partners, were accessed infrequently. In Nairobi and uMkhanyakude, AGYW were more likely to be invited to participate and accessed more categories if they were: aged < 18 years, in school and experienced socio-economic vulnerabilities. Those who had had sex, or a pregnancy, were less likely to be invited to participate but accessed more categories. CONCLUSIONS: In representative population-based samples, awareness and uptake of DREAMS were high after 1 year of implementation. Evidence of 'layering' (receiving multiple interventions from the DREAMS core package), particularly among more socio-economically vulnerable AGYW, indicate that intervention packages can be implemented at scale, for intended recipients, in real-world contexts. Challenges remain for higher coverage and greater 'layering', including among older, out-of-school AGYW, and community-based programmes for families and men.


Subject(s)
Awareness , HIV Infections/prevention & control , Health Behavior , Health Promotion/methods , Patient Acceptance of Health Care , Primary Prevention/methods , Program Evaluation , Adolescent , Adult , Child , Cross-Sectional Studies , Female , Health Knowledge, Attitudes, Practice , Humans , Incidence , Kenya , Male , Pregnancy , Sexual Behavior , Sexual Partners , South Africa , Surveys and Questionnaires , Young Adult
9.
Med Care ; 57(11): e65-e72, 2019 11.
Article in English | MEDLINE | ID: mdl-30807453

ABSTRACT

BACKGROUND: Given the increased international interest in improvement strategies for patient experiences with care, it is important to understand whether the same specific care experiences affect global ratings across countries. Moreover, reporting of these global ratings currently substantially varies in both research and public reporting. OBJECTIVES: The objectives of this study were to examine the differential magnitude of associations between Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) specific care experiences and global ratings, and to explore implications for reporting these global ratings. METHODS: HCAHPS data were collected from 11,289 patients across 7 European countries. We studied the association between 11 experience items and 2 global ratings (0-10 hospital rating, hospital recommendation) using multilevel ordered logistic regression analysis. Using interaction terms, we examined consistency of these associations across countries. Assuming homogeneous use and interpretations of response categories of these specific experiences across patients within and between countries, we investigated what the associations between specific experiences and global ratings imply for reporting global ratings across countries. RESULTS: All specific experiences were associated with both global ratings. "Being talked to about care after leaving the hospital" showed the strongest association. There were relatively little differential effects across countries. A reporting strategy with different cutpoints across countries might provide a more equitable comparison of global ratings. CONCLUSIONS: Our findings highlight a differential contribution of HCAHPS specific experiences to overall ratings across countries. Research and public reporting may consider examining in more detail within and across populations global rating cutpoints that represent the same true level of positive patient experiences.


Subject(s)
Delivery of Health Care/standards , Health Personnel/standards , Hospitals/standards , Patient Satisfaction/statistics & numerical data , Quality Indicators, Health Care , Adult , Aged , Cross-Sectional Studies , Europe , Female , Global Health/standards , Health Care Surveys , Humans , Logistic Models , Male , Middle Aged , Multilevel Analysis
10.
Med Care ; 55(12): e150-e157, 2017 12.
Article in English | MEDLINE | ID: mdl-29135779

ABSTRACT

BACKGROUND: Hospital-level findings on patient experiences with care are increasingly reported publicly. A critical aspect left unexamined is the commonality of composite measures of patient experiences across different groups of patients, nursing units, hospitals, and countries. Absence of commonality is termed measurement noninvariance and is hypothesized to have a strong impact on performance assessment. AIM: The aim of this study is to examine measurement invariance across groups and levels under study (patients, nursing units, hospitals, and countries) and illustrate the degree to which this method of analysis impacts hospital rankings. RESEARCH DESIGN: Data were collected from 11,289 patients in 7 European countries, 186 hospitals, and 824 nursing units. Multilevel factor analytic models were applied to evaluate measurement invariance across the hierarchical levels of the study and across groups at specific levels (self-perceived health at patient level; unit speciality at nursing unit level). Hospital rankings for the final multilevel model were compared with those from a single-level factor model that is unsuspecting of measurement invariance. RESULTS: Cross-group invariance was shown for levels of self-perceived health and to a large degree also for nursing unit speciality. Patient experience composite measures were, however, not invariant across patient, unit, and hospital levels. Hospital rankings were largely impacted when accounted for this cross-level invariance. The percentage of hospitals with discordant ranks by >10 percentile points varied from 26.7% in Spain to 70% in Poland. CONCLUSIONS: Leaving unexamined possible noninvariance across groups and hierarchical levels may have far reaching consequences for how the public perceives hospitals' position relative to other hospitals.


Subject(s)
Hospitals/standards , Length of Stay/statistics & numerical data , Patient Participation/statistics & numerical data , Patient Satisfaction/statistics & numerical data , Professional-Patient Relations , Diagnosis-Related Groups/standards , Europe , Female , Humans , Male , Qualitative Research , Quality of Health Care
11.
PLoS Negl Trop Dis ; 11(10): e0005977, 2017 Oct.
Article in English | MEDLINE | ID: mdl-29040267

ABSTRACT

BACKGROUND: For the first time, differential attraction of pathogen vectors to vertebrate animals is investigated for novel repellents which when applied to preferred host animals turn them into non-hosts thereby providing a new paradigm for innovative vector control. For effectively controlling tsetse flies (Glossina spp.), vectors of African trypanosomosis, causing nagana, repellents more powerful than plant derived, from a non-host animal the waterbuck, Kobus ellipsiprymnus defassa, have recently been identified. Here we investigate these repellents in the field to protect cattle from nagana by making cattle as unattractive as the buck. METHODOLOGY/PRINCIPAL FINDINGS: To dispense the waterbuck repellents comprising guaiacol, geranylacetone, pentanoic acid and δ-octalactone, (patent application) we developed an innovative collar-mounted release system for individual cattle. We tested protecting cattle, under natural tsetse challenge, from tsetse transmitted nagana in a large field trial comprising 1,100 cattle with repellent collars in Kenya for 24 months. The collars provided substantial protection to livestock from trypanosome infection by reducing disease levels >80%. Protected cattle were healthier, showed significantly reduced disease levels, higher packed cell volume and significantly increased weight. Collars >60% reduced trypanocide use, 72.7% increase in ownership of oxen per household and enhanced traction power (protected animals ploughed 66% more land than unprotected). Land under cultivation increased by 73.4%. Increase in traction power of protected animals reduced by 69.1% acres tilled by hand per household per ploughing season. Improved food security and household income from very high acceptance of collars (99%) motivated the farmers to form a registered community based organization promoting collars for integrated tsetse control and their commercialization. CONCLUSION/SIGNIFICANCE: Clear demonstration that repellents from un-preferred hosts prevent contact between host and vector, thereby preventing disease transmission: a new paradigm for vector control. Evidence that deploying water buck repellents converts cattle into non-hosts for tsetse flies-'cows in waterbuck clothing'.


Subject(s)
Cattle Diseases/prevention & control , Insect Repellents , Insect Vectors/physiology , Odorants , Trypanosomiasis, African/veterinary , Tsetse Flies/physiology , Animal Husbandry , Animals , Antelopes , Cattle , Cattle Diseases/epidemiology , Cattle Diseases/parasitology , Kenya/epidemiology , Trypanosomiasis, African/prevention & control , Trypanosomiasis, African/transmission
12.
PLoS One ; 8(8): e71812, 2013.
Article in English | MEDLINE | ID: mdl-23940789

ABSTRACT

Lentic freshwater systems including those inhabited by aquatic stages of mosquitoes derive most of their carbon inputs from terrestrial organic matter mainly leaf litter. The leaf litter is colonized by microbial communities that provide the resource base for mosquito larvae. While the microbial biomass associated with different leaf species in container aquatic habitats is well documented, the taxonomic composition of these microbes and their response to common environmental stressors is poorly understood. We used indoor aquatic microcosms to determine the abundances of major taxonomic groups of bacteria in leaf litters from seven plant species and their responses to low concentrations of four pesticides with different modes of action on the target organisms; permethrin, malathion, atrazine and glyphosate. We tested the hypotheses that leaf species support different quantities of major taxonomic groups of bacteria and that exposure to pesticides at environmentally relevant concentrations alters bacterial abundance and community structure in mosquito larval habitats. We found support for both hypotheses suggesting that leaf litter identity and chemical contamination may alter the quality and quantity of mosquito food base (microbial communities) in larval habitats. The effect of pesticides on microbial communities varied significantly among leaf types, suggesting that the impact of pesticides on natural microbial communities may be highly complex and difficult to predict. Collectively, these findings demonstrate the potential for detritus composition within mosquito larval habitats and exposure to pesticides to influence the quality of mosquito larval habitats.


Subject(s)
Bacteria/classification , Bacteria/drug effects , Culicidae/microbiology , Larva/microbiology , Pesticides/toxicity , Plant Leaves , Animals , Bacterial Load , Culicidae/drug effects , Culicidae/growth & development , Ecosystem , Environmental Exposure , Larva/drug effects , Microbiota/drug effects , Plant Leaves/classification , Plant Leaves/drug effects
13.
Malar J ; 12: 13, 2013 Jan 08.
Article in English | MEDLINE | ID: mdl-23297732

ABSTRACT

BACKGROUND: Over the past 20 years, numerous studies have investigated the ecology and behaviour of malaria vectors and Plasmodium falciparum malaria transmission on the coast of Kenya. Substantial progress has been made to control vector populations and reduce high malaria prevalence and severe disease. The goal of this paper was to examine trends over the past 20 years in Anopheles species composition, density, blood-feeding behaviour, and P. falciparum sporozoite transmission along the coast of Kenya. METHODS: Using data collected from 1990 to 2010, vector density, species composition, blood-feeding patterns, and malaria transmission intensity was examined along the Kenyan coast. Mosquitoes were identified to species, based on morphological characteristics and DNA extracted from Anopheles gambiae for amplification. Using negative binomial generalized estimating equations, mosquito abundance over the period were modelled while adjusting for season. A multiple logistic regression model was used to analyse the sporozoite rates. RESULTS: Results show that in some areas along the Kenyan coast, Anopheles arabiensis and Anopheles merus have replaced An. gambiae sensu stricto (s.s.) and Anopheles funestus as the major mosquito species. Further, there has been a shift from human to animal feeding for both An. gambiae sensu lato (s.l.) (99% to 16%) and An. funestus (100% to 3%), and P. falciparum sporozoite rates have significantly declined over the last 20 years, with the lowest sporozoite rates being observed in 2007 (0.19%) and 2008 (0.34%). There has been, on average, a significant reduction in the abundance of An. gambiae s.l. over the years (IRR = 0.94, 95% CI 0.90-0.98), with the density standing at low levels of an average 0.006 mosquitoes/house in the year 2010. CONCLUSION: Reductions in the densities of the major malaria vectors and a shift from human to animal feeding have contributed to the decreased burden of malaria along the Kenyan coast. Vector species composition remains heterogeneous but in many areas An. arabiensis has replaced An. gambiae as the major malaria vector. This has important implications for malaria epidemiology and control given that this vector predominately rests and feeds on humans outdoors. Strategies for vector control need to continue focusing on tools for protecting residents inside houses but additionally employ outdoor control tools because these are essential for further reducing the levels of malaria transmission.


Subject(s)
Anopheles/classification , Anopheles/growth & development , Disease Vectors , Malaria, Falciparum/epidemiology , Malaria, Falciparum/transmission , Animals , Anopheles/parasitology , Anopheles/physiology , Feeding Behavior , Female , Humans , Kenya/epidemiology , Plasmodium falciparum/isolation & purification , Population Density
14.
Parasit Vectors ; 5: 202, 2012 Sep 19.
Article in English | MEDLINE | ID: mdl-22992518

ABSTRACT

BACKGROUND: Synthetic odour baits present an unexploited potential for sampling, surveillance and control of malaria and other mosquito vectors. However, application of such baits is impeded by the unavailability of robust odour delivery devices that perform reliably under field conditions. In the present study the suitability of low density polyethylene (LDPE) and nylon strips for dispensing synthetic attractants of host-seeking Anopheles gambiae mosquitoes was evaluated. METHODS: Baseline experiments assessed the numbers of An. gambiae mosquitoes caught in response to low density polyethylene (LDPE) sachets filled with attractants, attractant-treated nylon strips, control LDPE sachets, and control nylon strips placed in separate MM-X traps. Residual attraction of An. gambiae to attractant-treated nylon strips was determined subsequently. The effects of sheet thickness and surface area on numbers of mosquitoes caught in MM-X traps containing the synthetic kairomone blend dispensed from LDPE sachets and nylon strips were also evaluated. Various treatments were tested through randomized 4 × 4 Latin Square experimental designs under semi-field conditions in western Kenya. RESULTS: Attractant-treated nylon strips collected 5.6 times more An. gambiae mosquitoes than LDPE sachets filled with the same attractants. The attractant-impregnated nylon strips were consistently more attractive (76.95%; n = 9,120) than sachets containing the same attractants (18.59%; n = 2,203), control nylon strips (2.17%; n = 257) and control LDPE sachets (2.29%; n = 271) up to 40 days post-treatment (P < 0.001). The higher catches of mosquitoes achieved with nylon strips were unrelated to differences in surface area between nylon strips and LDPE sachets. The proportion of mosquitoes trapped when individual components of the attractant were dispensed in LDPE sachets of optimized sheet thicknesses was significantly higher than when 0.03 mm-sachets were used (P < 0.001). CONCLUSION: Nylon strips continuously dispense synthetic mosquito attractants several weeks post treatment. This, added to the superior performance of nylon strips relative to LDPE material in dispensing synthetic mosquito attractants, opens up the opportunity for showcasing the effectiveness of odour-baited devices for sampling, surveillance and control of disease vectors.


Subject(s)
Anopheles/drug effects , Chemotactic Factors/administration & dosage , Mosquito Control/instrumentation , Nylons/chemistry , Polyethylene/chemistry , Animals , Kenya , Time Factors
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