A theoretical approach to predicting the success of genetic manipulation of malaria mosquitoes in malaria control

BACKGROUND: Mosquitoes that have been genetically modified to better encapsulate the malaria parasite Plasmodium falciparum are being considered as a possible tool in the control of malaria. Hopes for this have been raised with the identification of genes involved in the encapsulation response and with advances in the tools required to transform mosquitoes. However, we have only very little understanding of the conditions that would allow such genes to spread in natural populations. METHODS: We present here a theoretical model that combines population genetical and epidemiological processes, thereby allowing one to predict not only these conditions (intensity of transmission, evolutionary cost of resistance, tools used to drive the genes) but also the impact of the spread of refractoriness on the prevalence of the disease. RESULTS: The main conclusions are 1) that efficient transposons will generally be able to drive genes that confer refractoriness through populations even if there is a substantial (evolutionary) cost of refractoriness, but 2) that this will decrease malaria prevalence in the human population substantially only if refractoriness is close to 100% effective. CONCLUSIONS: If refractoriness is less than 100% effective (because of, for example, environmentally induced variation in the effectiveness of the mosquito's immune response), control programmes based on genetic manipulation of mosquitoes will have very little impact on the epidemiology of malaria, at least in areas with intense transmission

Kanlı çınar

Taha Toros Arşivi, Dosya No: 117-Parklarİstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033

The impact of literacy-focused CPD on the self-perceptions of expertise in primary school teachers

This study examines the impact of extended professional development in early literacy acquisition on the self-perceptions and emotions of experienced teachers of 5 to 6 year old pupils. The story of the participants' learning journeys is told through a series of short thematic sections, reflections grounded in critical incident theory and an extended vignette. Teacher-participants expand their knowledge base and modify teaching practice consistent with the specific professional development, though this study is not principally concerned with measures of either of these. Of particular interest is the impact of CPD on the development of participants' self-perceptions in relation to expertise, on their emotional life, and the relationship between these in the drive to attain their learning goals. I hypothesise that positive affect is sufficient to sustain participants through the lowest emotional phases and that these low points can act as catalysts for further theoretical change. Each participating teacher was enrolled in year-long continuing professional development, either Local Authority led training in systematic, synthetic phonics or Reading Recovery Initial Professional Development (as part of the Every Child a Reader initiative) led by a teacher leader specialist. Adopting a social constructivist approach I used a range of qualitative research methods to garner data demonstrating the influence of the respective CPD throughout the focus period in 2008-9: a series of semi-structured interviews, lesson observations followed by jointly stimulated reflection and participants' reflective e-journals. I have taken a grounded theory type approach to data analysis

Public engagement and communication: who is in charge?

International audienceThe use of gene drive to control or eradicate pest and disease vector populations is a highly controversial topic. In order to maintain independence and public trust, scientists need know who is representing whom in this debate

Anopheles mosquitoes : not just flying malaria vectors ... especially in the field

The polymorphism of genes involved in the immunity of malaria vectors has been the subject of several recent studies with mosquitoes from natural populations. Most of the genes examined are known for their role against Plasmodium berghei and not necessarily for their role against Plasmodium falciparum. It seems, therefore, to be highly important not only to be cautious when linking natural selection with malaria epidemiology but also to consider the importance of other parasites and the environment on the mosquito genome

Outbreaks of arboviruses, biotechnological innovations and vector control : facing the unexpected

Outbreaks of arboviruses have occurred in the last decades in many places around the world and a variety of responses have been taken in order to control them. Responses ranged from vaccination campaigns to the use of conventional vector control methods. Innovative approaches relying on biotechnological novelties, often still under development, have been considered despite the lack of solid evidence of their efficacy. While discussing these different aspects of the fight against vector-borne diseases with a focus on the context of outbreaks, this chapter considers the social and ethical aspects related to both the rhetoric and the discussion about the implementation of new and innovative approaches

La lutte antivectorielle : comprendre où en est la recherche

Les pesticides biologiques (ou biopesticides) apparaissent aujourd'hui comme des outils prometteurs pour lutter contre les maladies transmises par les moustiques (ex. paludisme, dengue, chikungunya). Leur utilisation représente en effet une approche alternative aux insecticides de synthèse, puisqu'elle est plus respectueuse de l'environnement ni ne favorise la sélection de résistances chez les insectes ciblé

Les interactions entre les densovirus et leurs hôtes moustiques: Interactions moustiques/densovirus/environnement : des populations naturelles aux outils de lutte anti-vectorielle

National audienceLes pesticides biologiques (ou biopesticides) apparaissent aujourd’hui comme des outils prometteurs pour lutter contre les maladies transmises par les moustiques (ex. paludisme, dengue, chikungunya). Leur utilisation représente en effet une approche alternative aux insecticides de synthèse, puisqu’elle est plus respectueuse de l’environnement ni ne favorise la sélection de résistances chez les insectes ciblés. Parmi ces biopesticides potentiels, les densovirus (DV) sont aujourd’hui considérés avec intérêt. Si de nombreuses études se sont penchées sur l’influence des variations ou des conditions environnementales sur les parasites affectant l’Homme, moins nombreuses sont celles concernant des pathogènes affectant spécifiquement les moustiques, qu’ils soient présents naturellement dans l’environnement ou introduits comme biopesticides. Il est donc essentiel de comprendre les réponses écologiques et évolutives des moustiques et de leurs pathogènes aux modifications de l’environnement, afin de prévoir l’impact du changement climatique sur ces interactions