Enhancing Malaria Research, Surveillance, and Control in Endemic Areas of Kenya and Ethiopia.

Malaria control programs in Africa encounter daunting challenges that hinder progressive steps toward elimination of the disease. These challenges include widespread insecticide resistance in mosquito vectors, increasing outdoor malaria transmission, lack of vector surveillance and control tools suitable for outdoor biting vectors, weakness in malaria surveillance, and an inadequate number of skilled healthcare personnel. Ecological and epidemiological changes induced by environmental modifications resulting from water resource development projects pose additional barriers to malaria control. Cognizant of these challenges, our International Center of Excellence for Malaria Research (ICEMR) works in close collaboration with relevant government ministries and agencies to align its research efforts with the objectives and strategies of the national malaria control and elimination programs for the benefit of local communities. Our overall goal is to assess the impact of water resource development projects, shifting agricultural practices, and vector interventions on Plasmodium falciparum and P. vivax malaria in Kenya and Ethiopia. From 2017 to date, the ICEMR has advanced knowledge of malaria epidemiology, transmission, immunology, and pathogenesis, and developed tools to enhance vector surveillance and control, improved clinical malaria surveillance and diagnostic methods, and strengthened the capacity of local healthcare providers. Research findings from the ICEMR will inform health policy and strategic planning by ministries of health in their quest to sustain malaria control and achieve elimination goals.

Assessment of the role played by domestic animals in jigger infection in Kandara sub-county, Kenya (case control study).

INTRODUCTION: tungiasis is an ectoparasitosis caused by penetration of female sand flea, Tunga penetrans, into the skin of the susceptible animal and the consequent hypertrophy of the parasite. The objective of this study was to assess the association between domestic animals and jigger infection among the residents of Kandara sub-county in central Kenya. METHODS: this was a case-control study that involved 776 individuals. Half of this number entailed case group who were jigger infected while the other half was the control, composed of jigger free participants. Structured questionnaires were, administered among the heads of the households to which the participants belonged to gather information concerning the animals they kept. Univariate analysis was, applied. RESULTS: in this study, there were significant differences in age (P=0.008) between the two groups. Disparities in source of income (P<0.001) and level of education (P<0.001) came out as very significant factors in jigger infection. The case group was 10 times more likely to keep dogs than the control(9.6; 95% CI, 5.9-15.6). Case group was also 7 times more likely to rear chicken in comparison to the control (6.6; 95%, 4.2-10.4). The case group was 12 times more likely to let dogs loose in the compound in comparison to the control (12.1: 95%, 5.9-24.5). When compared to the control, this group was also 17 times more likely to keep chicken inside their houses (16.7: 95% CI, 6.8-35.9). Conclusion: there is a very high association between domestic animals and occurrence of tungiasis in Kandara sub-county.

Artisanal fishing supports breeding of malaria mosquitoes in Western Kenya.

BACKGROUND: Everyday hundreds of people, mainly men, set out to take part in a vibrant artisanal capture fishing (ACF) industry on Lake Victoria. It is not known whether actions of artisanal fishers, in their unrelenting quest for existence, surpass ecosystems' sustainability thresholds with potentially negative repercussions on human health with respect to malaria transmission potential. This article sought to fill this information gap. METHODS: This study used an ecosystem approach to find out how ACF processes facilitate the breeding of mosquitoes. The observational study adopted a cross-sectional design and was carried out on Mageta Island situated inside Lake Victoria in western Kenya. RESULTS: Of the 87 mosquito larval habitats identified 27 (31%) were created through ACF activities. The ACF-related habitats, hereafter collectively referred to as 'fishing habitats', included fishing boats (24), trenches (1) and fish bait mines (2). About half (48%) of Anopheles larvae were recovered from fishing habitats. The mean larval density in the fishing habitats (35.7 ± 1.15) was double that in non-fishing habitats (17.4 ± 0.539). Despite being the most common 'non-fishing habitat' type (N = 32), the mean number of Anopheles larvae present in rock pools (30.81 ± 10.54) was significantly less than those found inside fishing boats (N = 24; 40.08 ± 10.16). Overall, man-made habitats and those used to support livelihoods contained significantly more Anopheles larvae. CONCLUSIONS: These data show that artisanal capture fishing is a key driver of malaria epidemiology on Mageta Island. This suggests that larval source management strategies in the global south should pay attention to the heterogeneity in Anopheles breeding habitats created through livelihood activities.

Status of insecticide resistance in malaria vectors in Kwale County, Coastal Kenya.

BACKGROUND: The strategy for malaria vector control in the context of reducing malaria morbidity and mortality has been the scale-up of long-lasting insecticidal nets to universal coverage and indoor residual spraying. This has led to significant decline in malaria transmission. However, these vector control strategies rely on insecticides which are threatened by insecticide resistance. In this study the status of pyrethroid resistance in malaria vectors and it's implication in malaria transmission at the Kenyan Coast was investigated. RESULTS: Using World Health Organization diagnostic bioassay, levels of phenotypic resistance to permethrin and deltamethrin was determined. Anopheles arabiensis showed high resistance to pyrethroids while Anopheles gambiae sensu stricto (s.s.) and Anopheles funestus showed low resistance and susceptibility, respectively. Anopheles gambiae sensu lato (s.l.) mosquitoes were further genotyped for L1014S and L1014F kdr mutation by real time PCR. An allele frequency of 1.33% for L1014S with no L1014F was detected. To evaluate the implication of pyrethroid resistance on malaria transmission, Plasmodium falciparum infection rates in field collected adult mosquitoes was determined using enzyme linked immunosorbent assay and further, the behaviour of the vectors was assessed by comparing indoor and outdoor proportions of mosquitoes collected. Sporozoite infection rate was observed at 4.94 and 2.60% in An. funestus s.l. and An. gambiae s.l., respectively. A higher density of malaria vectors was collected outdoor and this also corresponded with high Plasmodium infection rates outdoor. CONCLUSIONS: This study showed phenotypic resistance to pyrethroids and low frequency of L1014S kdr mutation in An. gambiae s.l. The occurrence of phenotypic resistance with low levels of kdr frequencies highlights the need to investigate other mechanisms of resistance. Despite being susceptible to pyrethroids An. funestus s.l. could be driving malaria infections in the area.

Containment Studies of Transgenic Mosquitoes in Disease Endemic Countries: The Broad Concept of Facilities Readiness.

Genetic strategies for large scale pest or vector control using modified insects are not yet operational in Africa, and currently rely on import of the modified strains to begin preliminary, contained studies. Early involvement of research teams from participating countries is crucial to evaluate candidate field interventions. Following the recommended phased approach for novel strategies, evaluation should begin with studies in containment facilities. Experiences to prepare facilities and build international teams for research on transgenic mosquitoes revealed some important organizing themes underlying the concept of "facilities readiness," or the point at which studies in containment may proceed, in sub-Saharan African settings. First, "compliance" for research with novel or non-native living organisms was defined as the fulfillment of all legislative and regulatory requirements. This is not limited to regulations regarding use of transgenic organisms. Second, the concept of "colony utility" was related to the characteristics of laboratory colonies being produced so that results of studies may be validated across time, sites, and strains or technologies; so that the appropriate candidate strains are moved forward toward field studies. Third, the importance of achieving "defensible science" was recognized, including that study conclusions can be traced back to evidence, covering the concerns of various stakeholders over the long term. This, combined with good stewardship of resources and appropriate funding, covers a diverse set of criteria for declaring when "facilities readiness" has been attained. It is proposed that, despite the additional demands on time and resources, only with the balance of and rigorous achievement of each of these organizing themes can collaborative research into novel strategies in vector or pest control reliably progress past initial containment studies.

Quantifying the intensity of permethrin insecticide resistance in Anopheles mosquitoes in western Kenya.

BACKGROUND: The development and spread of resistance among local vectors to the major classes of insecticides used in Long-Lasting Insecticidal Nets (LLINs) and Indoor Residual Spraying (IRS) poses a major challenge to malaria vector control programs worldwide. The main methods of evaluating insecticide resistance in malaria vectors are the WHO tube bioassay and CDC bottle assays, with their weakness being determination of resistance at a fixed dose for variable populations. The CDC bottle assay using different insecticide dosages has proved applicable in ascertaining the intensity of resistance. METHODS: We determined the status and intensity of permethrin resistance and investigated the efficacy of commonly used LLINs (PermaNet® 2.0, PermaNet® 3.0 and Olyset®) against 3-5 day-old adult female Anopheles mosquitoes from four sub-counties; Teso, Bondo, Rachuonyo and Nyando in western Kenya. Knockdown was assessed to 4 doses of permethrin; 1× (21.5 µg/ml), 2× (43 µg/ml), 5× (107.5 µg/ml) and 10× (215 µg/ml) using CDC bottle assays. RESULTS: Mortality for 0.75% permethrin ranged from 23.5% to 96.1% in the WHO tube assay. Intensity of permethrin resistance was highest in Barkanyango Bondo, with 84% knockdown at the 30 min diagnostic time when exposed to the 10× dose. When exposed to the LLINs, mortality ranged between- 0-39% for Olyset®, 12-88% for PermaNet® 2.0 and 26-89% for PermaNet® 3.0. The efficacy of nets was reduced in Bondo and Teso. Results from this study show that there was confirmed resistance in all the sites; however, intensity assays were able to differentiate Bondo and Teso as the sites with the highest levels of resistance, which coincidentally were the two sub-counties with reduced net efficacy. CONCLUSIONS: There was a reduced efficacy of nets in areas with high resistance portraying that at certain intensities of resistance, vector control using LLINs may be compromised. It is necessary to incorporate intensity assays in order to determine the extent of threat that resistance poses to malaria control.

An Assessment of Participatory Integrated Vector Management for Malaria Control in Kenya.

BACKGROUND: The World Health Organization (WHO) recommends integrated vector management (IVM) as a strategy to improve and sustain malaria vector control. However, this approach has not been widely adopted. OBJECTIVES: We comprehensively assessed experiences and findings on IVM in Kenya with a view to sharing lessons that might promote its wider application. METHODS: The assessment used information from a qualitative external evaluation of two malaria IVM projects implemented between 2006 and 2011 and an analysis of their accumulated entomological and malaria case data. The project sites were Malindi and Nyabondo, located in coastal and western Kenya, respectively. The assessment focused on implementation of five key elements of IVM: integration of vector control methods, evidence-based decision making, intersectoral collaboration, advocacy and social mobilization, and capacity building. RESULTS: IVM was more successfully implemented in Malindi than in Nyabondo owing to greater community participation and multistakeholder engagement. There was a significant decline in the proportion of malaria cases among children admitted to Malindi Hospital, from 23.7% in 2006 to 10.47% in 2011 (p < 0.001). However, the projects' operational research methodology did not allow statistical attribution of the decline in malaria and malaria vectors to specific IVM interventions or other factors. CONCLUSIONS: Sustaining IVM is likely to require strong participation and support from multiple actors, including community-based groups, non-governmental organizations, international and national research institutes, and various government ministries. A cluster-randomized controlled trial would be essential to quantify the effectiveness and impact of specific IVM interventions, alone or in combination. CITATION: Mutero CM, Mbogo C, Mwangangi J, Imbahale S, Kibe L, Orindi B, Girma M, Njui A, Lwande W, Affognon H, Gichuki C, Mukabana WR. 2015. An assessment of participatory integrated vector management for malaria control in Kenya. Environ Health Perspect 123:1145-1151; http://dx.doi.org/10.1289/ehp.1408748.

Field evaluation of a push-pull system to reduce malaria transmission.

Malaria continues to place a disease burden on millions of people throughout the tropics, especially in sub-Saharan Africa. Although efforts to control mosquito populations and reduce human-vector contact, such as long-lasting insecticidal nets and indoor residual spraying, have led to significant decreases in malaria incidence, further progress is now threatened by the widespread development of physiological and behavioural insecticide-resistance as well as changes in the composition of vector populations. A mosquito-directed push-pull system based on the simultaneous use of attractive and repellent volatiles offers a complementary tool to existing vector-control methods. In this study, the combination of a trap baited with a five-compound attractant and a strip of net-fabric impregnated with micro-encapsulated repellent and placed in the eaves of houses, was tested in a malaria-endemic village in western Kenya. Using the repellent delta-undecalactone, mosquito house entry was reduced by more than 50%, while the traps caught high numbers of outdoor flying mosquitoes. Model simulations predict that, assuming area-wide coverage, the addition of such a push-pull system to existing prevention efforts will result in up to 20-fold reductions in the entomological inoculation rate. Reductions of such magnitude are also predicted when mosquitoes exhibit a high resistance against insecticides. We conclude that a push-pull system based on non-toxic volatiles provides an important addition to existing strategies for malaria prevention.

Tracking the mutual shaping of the technical and social dimensions of solar-powered mosquito trapping systems (SMoTS) for malaria control on Rusinga Island, western Kenya.

BACKGROUND: There has been increasing effort in recent years to incorporate user needs in technology design and re-design. This project employed a bottom-up approach that engaged end users from the outset. Bottom-up approaches have the potential to bolster novel interventions and move them towards adaptive and evidence-based strategies. The present study concerns an innovative use of solar-powered mosquito trapping systems (SMoTS) to control malaria in western Kenya. Our paper highlights the co-dependence of research associated with the development of the SMoTS technology on one hand and research for enhancing the sustainable uptake of that very same intervention within the community on the other. METHODS: During the pre-intervention year, we examined the design, re-design and piloting of a novel technology to generate lessons for malaria elimination on Rusinga Island. Initial ideas about many technological necessities were evaluated and re-designed following feedback from various sources, including technical and social research as well as broader interactions with the social environment. We documented the interlocking of the multiple processes and activities that took place through process observation and document reviews. We analysed the data within the conceptual framework of system innovation by identifying mutual shaping between technical and social factors. RESULTS: Our findings illustrate how various project stakeholders including project staff, collaborators, donor, and community members simultaneously pursued interdependent technological transformations and social interests. In the ongoing process, we observed how partial outcomes in the technological domain influenced social events at a later phase and vice versa. CONCLUSIONS: Looking at malaria intervention projects employing novel technologies as niches that may evolve towards system innovation, helps to reveal interrelations between the various technical and social aspects. Revealing these interrelations requires a different role for research and different perspective on innovation where innovation is more than the technical aspects. This approach therefore requires that research is designed in a way that enables obtaining feedback from both aspects.

Repellent Activities of Essential Oils of Some Plants Used Traditionally to Control the Brown Ear Tick, Rhipicephalus appendiculatus.

Essential oils of eight plants, selected after an ethnobotanical survey conducted in Bukusu community in Bungoma County, western Kenya (Tagetes minuta, Tithonia diversifolia, Juniperus procera, Solanecio mannii, Senna didymobotrya, Lantana camara, Securidaca longepedunculata, and Hoslundia opposita), were initially screened (at two doses) for their repellence against brown ear tick, Rhipicephalus appendiculatus, using a dual-choice climbing assay. The oils of T. minuta and T. diversifolia were then selected for more detailed study. Dose-response evaluations of these oils showed that T. minuta oil was more repellent (RD50 = 0.0021 mg) than that of T. diversifolia (RD50 = 0.263 mg). Gas chromatography-linked mass spectrometric (GC-MS) analyses showed different compositions of the two oils. T. minuta oil is comprised mainly of cis-ocimene (43.78%), dihydrotagetone (16.71%), piperitenone (10.15%), trans-tagetone (8.67%), 3,9-epoxy-p-mentha-1,8(10)diene (6.47%), ß -ocimene (3.25%), and cis-tagetone (1.95%), whereas T. diversifolia oil is comprised mainly of α -pinene (63.64%), ß -pinene (15.00%), isocaryophyllene (7.62%), nerolidol (3.70%), 1-tridecanol (1.75%), limonene (1.52%), and sabinene (1.00%). The results provide scientific rationale for traditional use of raw products of these plants in controlling livestock ticks by the Bukusu community and lay down some groundwork for exploiting partially refined products such as essential oils of these plants in protecting cattle against infestations with R. appendiculatus.