The Anopheles coluzzii range extends into Kenya: detection, insecticide resistance profiles and population genetic structure in relation to conspecific populations in West and Central Africa

Background Anopheles coluzzii is a primary vector of malaria found in West and Central Africa, but its presence has hitherto never been documented in Kenya. A thorough understanding of vector bionomics is important as it enables the implementation of targeted and effective vector control interventions. Malaria vector surveillance efforts in the country have tended to focus on historically known primary vectors. The current study sought to determine the taxonomic status of samples collected from five different malaria epidemiological zones in Kenya as well as describe the population genetic structure and insecticide resistance profiles in relation to other An. coluzzii populations. Methods Mosquitoes were sampled as larvae from Busia, Kwale, Turkana, Kirinyaga and Kiambu counties, representing the range of malaria endemicities in Kenya, in 2019 and 2021 and emergent adults analysed using Whole Genome Sequencing (WGS) data processed in accordance with the Anopheles gambiae 1000 Genomes Project phase 3. Where available, historical samples from the same sites were included for WGS. Comparisons were made with An. coluzzii cohorts from West and Central Africa. Results This study reports the detection of An. coluzzii for the first time in Kenya. The species was detected in Turkana County across all three time points from which samples were analyzed and its presence confirmed through taxonomic analysis. Additionally, there was a lack of strong population genetic differentiation between An. coluzzii from Kenya and those from the more northerly regions of West and Central Africa, suggesting they represent a connected extension to the known species range. Mutations associated with target-site resistance to DDT and pyrethroids and metabolic resistance to DDT were found at high frequencies up to 64%. The profile and frequencies of the variants observed were similar to An. coluzzii from West and Central Africa but the ace-1 mutation linked to organophosphate and carbamate resistance present in An. coluzzii from coastal West Africa was absent in Kenya. Conclusions These findings emphasize the need for the incorporation of genomics in comprehensive and routine vector surveillance to inform on the range of malaria vector species, and their insecticide resistance status to inform the choice of effective vector control approaches

Layered Rare-Earth Hydroxide Unilameller Nanosheets: Synthesis, Characterization, and Adsorption

Unilameller nanosheets with a lateral dimension of one nanometer have been isolated from a colloidal solution of europium-containing layered rare-earth hydroxide (LRH) material by the flocculation method. The nanosheets were achieved by changing pH of the colloidal solution from 6.7 to 11.5. The resultant flocculated nanosheets show high efficiency in sorption of fluoride anions from aqueous media (40 mmol/g), providing a potentially useful sorbent material for water purification technology. The sorbent material is demonstrated to be reusable for at least ten times without a significant loss of adsorption efficiency. And the results fit the Langmuir adsorption curve, indicating the chemisorption nature of the nanosheets. Most importantly, the isolated nanosheets are expected to widen the applicability and flexibility in material synthesis using two-dimensional nanomaterials

Identification of hot spots of malaria transmission for targeted malaria control.

BACKGROUND: Variation in the risk of malaria within populations is a frequently described but poorly understood phenomenon. This heterogeneity creates opportunities for targeted interventions but only if hot spots of malaria transmission can be easily identified. METHODS: We determined spatial patterns in malaria transmission in a district in northeastern Tanzania, using malaria incidence data from a cohort study involving infants and household-level mosquito sampling data. The parasite prevalence rates and age-specific seroconversion rates (SCRs) of antibodies against Plasmodium falciparum antigens were determined in samples obtained from people attending health care facilities. RESULTS: Five clusters of higher malaria incidence were detected and interpreted as hot spots of transmission. These hot spots partially overlapped with clusters of higher mosquito exposure but could not be satisfactorily predicted by a probability model based on environmental factors. Small-scale local variation in malaria exposure was detected by parasite prevalence rates and SCR estimates for samples of health care facility attendees. SCR estimates were strongly associated with local malaria incidence rates and predicted hot spots of malaria transmission with 95% sensitivity and 85% specificity. CONCLUSIONS: Serological markers were able to detect spatial variation in malaria transmission at the microepidemiological level, and they have the potential to form an effective method for spatial targeting of malaria control efforts

The suitability of clay pots for indoor sampling of mosquitoes in an arid area in northern Tanzania.

Water storage clay pots have been recently explored as method for outdoor mosquito sampling and as novel device for administrating insect-pathogenic fungi to mosquitoes. Their suitability for indoor mosquito sampling in natural conditions is unknown. We tested clay pots as indoor resting sites alongside catches by CDC light trap in an area of low malaria endemicity in northern Tanzania. Mosquitoes were caught by clay pots although the rate of female Anopheles mosquito catches was 22.64 (95% CI 11.26-45.52) times greater for CDC light traps. The proportion of fed female Anophelines was significantly higher for clay pots compared to CDC light trap (p<0.001), indicating these methods sample different populations of mosquitoes. Although we were able to identify households with a consistently higher exposure to mosquitoes by CDC light trap, there was no apparent heterogeneity in mosquito catches by clay pots. We conclude that clay pots are not a reliable tool to sample mosquitoes in the dry season in an area of low transmission intensity with Anopheles arabiensis as principle vector

Data from: Submicroscopic Plasmodium falciparum gametocyte densities frequently result in mosquito infection

ABSTRACT: Submicroscopic Plasmodium falciparum gametocytemia (<5,000 gametocytes/mL) is common and may result in mosquito infection. We assessed the relation between gametocyte density and mosquito infection under experimental and field conditions using real-time quantitative nucleic acid sequence-based amplification (QT-NASBA) for gametocyte quantification. Serial dilutions of NF54 P. falciparum gametocytes showed a positive association between gametocyte density and the proportion of infected mosquitoes (beta=6.1; 95% confidence interval [CI], 2.7-9.6; P=0.001). Successful infection became unlikely below an estimated density of 250-300 gametocytes/mL. In the field, blood samples of 100 naturally infected children showed a positive association between gametocyte density and oocyst counts in mosquitoes (beta=0.38; 95% CI, 0.14-0.61; P=0.002). The relative contribution to malaria transmission was similar for carriers with submicroscopic and microscopic gametocytemia. Our results show that transmission occurs efficiently at submicroscopic gametocyte densities and that carriers harboring submicroscopic gametocytemia constitute a considerable proportion of the human infectious reservoir. USAGE NOTES: Characteristics of membrane feeding study blood donors and mosquito infections host = id of the host. readouts) from QT-NASBA into gametocyte density. ttp = time to positivity readout from QT-NASBA used to generate gametocyte density estimate. age = age of blood donor. asexual = asexual parasite density of blood donor (estimated using microscopy). no_dissected = number of mosquitoes dissected to determine mosquito infection. no_infected = number of mosquitoes dissected with observable oocysts Kenya_data.xls

Translating city development projects in informal settlements: reframing, anchoring and muddling through

Numerous programs have been launched to deal with the serious solid waste predicaments in informal settlements. However, in both policy and research, there is an increasing concern with the disparities that exist between solid waste policies and what they actually achieve in practice. Informed by the case of the city of Kisumu and its Kisumu Integrated Solid Waste Management Plan (KISWAMP), this paper examines how municipal waste management programs are translated into practice in informal settlements. It is based on action-research carried out by a multidisciplinary and transdiciplinary group of researchers, through focus groups, participatory workshops, collaborative action, in-depth interviews, document analysis and observations. City management literature and the concepts of reframing, anchoring and muddling through are used to understand the KISWAMP and its implementation. It starts by reconstructing the history of KISWAMP and how it became a project. Then, it examines what original aspects of KISWAMP were actually translated, i.e. which ones faded out and which ones became stabilized into and travel as best practices to other locations. The analysis shows how KISWAMP was translated into practice by reframing the meanings and status of waste as a profession, as a policy and as a critical service worthy to pay for among residents. KISWAMP also thrived to anchor the program into existing waste entrepreneurship practices . Municipal officers and politicians were also trained to connect the plan within the municipality, yet as many moved, KISWAMP remained weakly bounded to city budgets and decision-making processes. Trust also grew among residents being served by the new waste collection services. Yet in lower-income settlements with insufficient assets to anchor the project, distrust and resentment grew instead. Skips in the new waste transfer points soon disappeared and were not regularly evacuated. Still, the skip idea did not totally vanish as it was recovered by the new KUP program. A final aspect in the implementation of KISWAMP was the ability of waste entrepreneurs and officers to develop ways to muddle through arbitrary and loosely coupled partnership arrangements to evacuate transfer points; waste pickers’ coping strategies to compensate low paid labour;; or residents’ persistent illegal disposal of waste where the skip used to be

Translating city development projects in informal settlements: reframing, anchoring and muddling through

Numerous programs have been launched to deal with the serious solid waste predicaments in informal settlements. However, in both policy and research, there is an increasing concern with the disparities that exist between solid waste policies and what they actually achieve in practice. Informed by the case of the city of Kisumu and its Kisumu Integrated Solid Waste Management Plan (KISWAMP), this paper examines how municipal waste management programs are translated into practice in informal settlements. It is based on action-research carried out by a multidisciplinary and transdiciplinary group of researchers, through focus groups, participatory workshops, collaborative action, in-depth interviews, document analysis and observations. City management literature and the concepts of reframing, anchoring and muddling through are used to understand the KISWAMP and its implementation. It starts by reconstructing the history of KISWAMP and how it became a project. Then, it examines what original aspects of KISWAMP were actually translated, i.e. which ones faded out and which ones became stabilized into and travel as best practices to other locations. The analysis shows how KISWAMP was translated into practice by reframing the meanings and status of waste as a profession, as a policy and as a critical service worthy to pay for among residents. KISWAMP also thrived to anchor the program into existing waste entrepreneurship practices . Municipal officers and politicians were also trained to connect the plan within the municipality, yet as many moved, KISWAMP remained weakly bounded to city budgets and decision-making processes. Trust also grew among residents being served by the new waste collection services. Yet in lower-income settlements with insufficient assets to anchor the project, distrust and resentment grew instead. Skips in the new waste transfer points soon disappeared and were not regularly evacuated. Still, the skip idea did not totally vanish as it was recovered by the new KUP program. A final aspect in the implementation of KISWAMP was the ability of waste entrepreneurs and officers to develop ways to muddle through arbitrary and loosely coupled partnership arrangements to evacuate transfer points; waste pickers’ coping strategies to compensate low paid labour;; or residents’ persistent illegal disposal of waste where the skip used to be

Socio-environmental entrepreneurship and the provision of critical services in informal settlements

This paper contributes to the understanding of processes by which small-scale entrepreneurs who provide household waste collection in informal settlements succeed in formalized co-production of such services. The paper draws on the social and solidarity economy and social and environmental entrepreneurship theoretical frameworks, which offer complementary understandings of diverse strategies to tackle everyday challenges. Two questions are addressed: How do informal waste collection initiatives get established, succeed and grow? What are the implications of this transition for the entrepreneurs themselves, the communities, the environmental governance system and the scholarship? A case study is presented, based on three waste picker entrepreneurs in Kisumu, Kenya, who have consolidated and expanded their operations in informal settlements but also extended social and environmental activities into formal settlements. The paper demonstrates how initiatives, born as community-based organizations, become successful social micro-enterprises, driven by a desire to address socioenvironmental challenges in their neighbourhoods

Characteristics of membrane feeding study blood donors and mosquito infections

host = id of the host. readouts) from QT-NASBA into gametocyte density. ttp = time to positivity readout from QT-NASBA used to generate gametocyte density estimate. age = age of blood donor. asexual = asexual parasite density of blood donor (estimated using microscopy). no_dissected = number of mosquitoes dissected to determine mosquito infection. no_infected = number of mosquitoes dissected with observable oocyst